Add the datapath component that manages BOs and submits them to running
workloads on the qaic device via the dma_bridge hardware.

Change-Id: I7a94cfb2741491f5fc044ae537f53d6cc0d97fee
Signed-off-by: Jeffrey Hugo <quic_jh...@quicinc.com>
---
 drivers/gpu/drm/qaic/qaic_data.c | 2152 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 2152 insertions(+)
 create mode 100644 drivers/gpu/drm/qaic/qaic_data.c

diff --git a/drivers/gpu/drm/qaic/qaic_data.c b/drivers/gpu/drm/qaic/qaic_data.c
new file mode 100644
index 0000000..12d8b39
--- /dev/null
+++ b/drivers/gpu/drm/qaic/qaic_data.c
@@ -0,0 +1,2152 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/* Copyright (c) 2019-2021, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All rights 
reserved. */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/moduleparam.h>
+#include <linux/scatterlist.h>
+#include <linux/spinlock.h>
+#include <linux/srcu.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <drm/drm_file.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_print.h>
+#include <uapi/drm/qaic_drm.h>
+
+#include "qaic.h"
+#include "qaic_trace.h"
+
+#define SEM_VAL_MASK   GENMASK_ULL(11, 0)
+#define SEM_INDEX_MASK GENMASK_ULL(4, 0)
+#define BULK_XFER      BIT(3)
+#define GEN_COMPLETION BIT(4)
+#define INBOUND_XFER   1
+#define OUTBOUND_XFER  2
+#define REQHP_OFF      0x0 /* we read this */
+#define REQTP_OFF      0x4 /* we write this */
+#define RSPHP_OFF      0x8 /* we write this */
+#define RSPTP_OFF      0xc /* we read this */
+
+#define ENCODE_SEM(val, index, sync, cmd, flags)                       \
+                       ((val) |                                        \
+                       (index) << 16 |                                 \
+                       (sync) << 22 |                                  \
+                       (cmd) << 24 |                                   \
+                       ((cmd) ? BIT(31) : 0) |                         \
+                       (((flags) & SEM_INSYNCFENCE) ? BIT(30) : 0) |   \
+                       (((flags) & SEM_OUTSYNCFENCE) ? BIT(29) : 0))
+#define NUM_EVENTS     128
+#define NUM_DELAYS     10
+
+static unsigned int wait_exec_default_timeout = 5000; /* 5 sec default */
+module_param(wait_exec_default_timeout, uint, 0600);
+
+static unsigned int datapath_poll_interval_us = 100; /* 100 usec default */
+module_param(datapath_poll_interval_us, uint, 0600);
+
+struct dbc_req { /* everything must be little endian encoded */
+       /*
+        * A request ID is assigned to each memory handle going in DMA queue.
+        * As a single memory handle can enqueue multiple elements in DMA queue
+        * all of them will have the same request ID.
+        */
+       __le16  req_id;
+       /* Future use */
+       __u8    seq_id;
+       /*
+        * Special encoded variable
+        * 7    0 - Do not force to generate MSI after DMA is completed
+        *      1 - Force to generate MSI after DMA is completed
+        * 6:5  Reserved
+        * 4    1 - Generate completion element in the response queue
+        *      0 - No Completion Code
+        * 3    0 - DMA request is a Link list transfer
+        *      1 - DMA request is a Bulk transfer
+        * 2    Reserved
+        * 1:0  00 - No DMA transfer involved
+        *      01 - DMA transfer is part of inbound transfer
+        *      10 - DMA transfer has outbound transfer
+        *      11 - NA
+        */
+       __u8    cmd;
+       __le32  resv;
+       /* Source address for the transfer */
+       __le64  src_addr;
+       /* Destination address for the transfer */
+       __le64  dest_addr;
+       /* Length of transfer request */
+       __le32  len;
+       __le32  resv2;
+       /* Doorbell address */
+       __le64  db_addr;
+       /*
+        * Special encoded variable
+        * 7    1 - Doorbell(db) write
+        *      0 - No doorbell write
+        * 6:2  Reserved
+        * 1:0  00 - 32 bit access, db address must be aligned to 32bit-boundary
+        *      01 - 16 bit access, db address must be aligned to 16bit-boundary
+        *      10 - 8 bit access, db address must be aligned to 8bit-boundary
+        *      11 - Reserved
+        */
+       __u8    db_len;
+       __u8    resv3;
+       __le16  resv4;
+       /* 32 bit data written to doorbeel address */
+       __le32  db_data;
+       /*
+        * Special encoded variable
+        * All the fields of sem_cmdX are passed from user and all are ORed
+        * together to form sem_cmd.
+        * 0:11         Semaphore value
+        * 15:12        Reserved
+        * 20:16        Semaphore index
+        * 21           Reserved
+        * 22           Semaphore Sync
+        * 23           Reserved
+        * 26:24        Semaphore command
+        * 28:27        Reserved
+        * 29           Semaphore DMA out bound sync fence
+        * 30           Semaphore DMA in bound sync fence
+        * 31           Enable semaphore command
+        */
+       __le32  sem_cmd0;
+       __le32  sem_cmd1;
+       __le32  sem_cmd2;
+       __le32  sem_cmd3;
+} __packed;
+
+struct dbc_rsp { /* everything must be little endian encoded */
+       /* Request ID of the memory handle whose DMA transaction is completed */
+       __le16  req_id;
+       /* Status of the DMA transaction. 0 : Success otherwise failure */
+       __le16  status;
+} __packed;
+
+inline int get_dbc_req_elem_size(void)
+{
+       return sizeof(struct dbc_req);
+}
+
+inline int get_dbc_rsp_elem_size(void)
+{
+       return sizeof(struct dbc_rsp);
+}
+
+static int reserve_pages(unsigned long start_pfn, unsigned long nr_pages,
+                        bool reserve)
+{
+       unsigned long pfn;
+       unsigned long end_pfn = start_pfn + nr_pages;
+       struct page *page;
+
+       for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+               if (!pfn_valid(pfn))
+                       return -EINVAL;
+               page =  pfn_to_page(pfn);
+               if (reserve)
+                       SetPageReserved(page);
+               else
+                       ClearPageReserved(page);
+       }
+       return 0;
+}
+
+static void free_slice(struct kref *kref)
+{
+       struct bo_slice *slice = container_of(kref, struct bo_slice, ref_count);
+
+       list_del(&slice->slice);
+       drm_gem_object_put(&slice->bo->base);
+       sg_free_table(slice->sgt);
+       kfree(slice->sgt);
+       kfree(slice->reqs);
+       kfree(slice);
+}
+
+static int copy_sgt(struct qaic_device *qdev, struct sg_table **sgt_out,
+                   struct sg_table *sgt_in, u64 size, u64 offset)
+{
+       int total_len, len, nents, offf = 0, offl = 0;
+       struct scatterlist *sg, *sgn, *sgf, *sgl;
+       struct sg_table *sgt;
+       int ret, j;
+
+       /* find out number of relevant nents needed for this mem */
+       total_len = 0;
+       sgf = NULL;
+       sgl = NULL;
+       nents = 0;
+
+       size = size ? size : PAGE_SIZE;
+       for (sg = sgt_in->sgl; sg; sg = sg_next(sg)) {
+               len = sg_dma_len(sg);
+
+               if (!len)
+                       continue;
+               if (offset >= total_len && offset < total_len + len) {
+                       sgf = sg;
+                       offf = offset - total_len;
+               }
+               if (sgf)
+                       nents++;
+               if (offset + size >= total_len &&
+                   offset + size <= total_len + len) {
+                       sgl = sg;
+                       offl = offset + size - total_len;
+                       break;
+               }
+               total_len += len;
+       }
+
+       if (!sgf || !sgl) {
+               trace_qaic_mem_err(qdev, "Failed to find SG first and/or SG 
last", ret);
+               ret = -EINVAL;
+               goto out;
+       }
+
+       sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+       if (!sgt) {
+               trace_qaic_mem_err(qdev, "Failed to allocate SG table 
structure", ret);
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       ret = sg_alloc_table(sgt, nents, GFP_KERNEL);
+       if (ret) {
+               trace_qaic_mem_err_1(qdev, "Failed to allocate SG table",
+                                    "SG table entries", ret, nents);
+               goto free_sgt;
+       }
+
+       /* copy relevant sg node and fix page and length */
+       sgn = sgf;
+       for_each_sgtable_sg(sgt, sg, j) {
+               memcpy(sg, sgn, sizeof(*sg));
+               if (sgn == sgf) {
+                       sg_dma_address(sg) += offf;
+                       sg_dma_len(sg) -= offf;
+                       sg_set_page(sg, sg_page(sgn),
+                                   sg_dma_len(sg), offf);
+               } else {
+                       offf = 0;
+               }
+               if (sgn == sgl) {
+                       sg_dma_len(sg) = offl - offf;
+                       sg_set_page(sg, sg_page(sgn),
+                                   offl - offf, offf);
+                       sg_mark_end(sg);
+                       break;
+               }
+               sgn = sg_next(sgn);
+       }
+
+       *sgt_out = sgt;
+       return ret;
+
+free_sgt:
+       kfree(sgt);
+out:
+       *sgt_out = NULL;
+       return ret;
+}
+
+static int encode_reqs(struct qaic_device *qdev, struct bo_slice *slice,
+                      struct qaic_attach_slice_entry *req)
+{
+       __u8 cmd = BULK_XFER;
+       __le64 db_addr = cpu_to_le64(req->db_addr);
+       __u8 db_len;
+       __le32 db_data = cpu_to_le32(req->db_data);
+       struct scatterlist *sg;
+       u64 dev_addr;
+       int presync_sem;
+       int i;
+
+       if (!slice->no_xfer)
+               cmd |= (slice->dir == DMA_TO_DEVICE ? INBOUND_XFER :
+                                                               OUTBOUND_XFER);
+
+       if (req->db_len && !IS_ALIGNED(req->db_addr, req->db_len / 8)) {
+               trace_qaic_mem_err_2(qdev, "Invalid Doorbell values",
+                                    "Doorbell length", "Doorbell address",
+                                    -EINVAL, req->db_len, req->db_addr);
+               return -EINVAL;
+       }
+
+       presync_sem = req->sem0.presync + req->sem1.presync +
+                     req->sem2.presync + req->sem3.presync;
+       if (presync_sem > 1) {
+               trace_qaic_mem_err_2(qdev, "Invalid presync values",
+                                    "sem0.presync", "sem1.presync",
+                                    -EINVAL, req->sem0.presync,
+                                    req->sem1.presync);
+               trace_qaic_mem_err_2(qdev, "", "sem2.presync", "sem3.presync",
+                                    -EINVAL, req->sem2.presync,
+                                    req->sem3.presync);
+               return -EINVAL;
+       }
+
+       presync_sem = req->sem0.presync << 0 | req->sem1.presync << 1 |
+                     req->sem2.presync << 2 | req->sem3.presync << 3;
+
+       switch (req->db_len) {
+       case 32:
+               db_len = BIT(7);
+               break;
+       case 16:
+               db_len = BIT(7) | 1;
+               break;
+       case 8:
+               db_len = BIT(7) | 2;
+               break;
+       case 0:
+               db_len = 0; /* doorbell is not active for this command */
+               break;
+       default:
+               trace_qaic_mem_err_1(qdev, "Invalid Doorbell length", "Doorbell 
length",
+                                    -EINVAL, req->db_len);
+               return -EINVAL; /* should never hit this */
+       }
+
+       /*
+        * When we end up splitting up a single request (ie a buf slice) into
+        * multiple DMA requests, we have to manage the sync data carefully.
+        * There can only be one presync sem.  That needs to be on every xfer
+        * so that the DMA engine doesn't transfer data before the receiver is
+        * ready.  We only do the doorbell and postsync sems after the xfer.
+        * To guarantee previous xfers for the request are complete, we use a
+        * fence.
+        */
+       dev_addr = req->dev_addr;
+       for_each_sgtable_sg(slice->sgt, sg, i) {
+               slice->reqs[i].cmd = cmd;
+               slice->reqs[i].src_addr =
+                       cpu_to_le64(slice->dir == DMA_TO_DEVICE ?
+                                       sg_dma_address(sg) : dev_addr);
+               slice->reqs[i].dest_addr =
+                       cpu_to_le64(slice->dir == DMA_TO_DEVICE ?
+                                       dev_addr : sg_dma_address(sg));
+               /*
+                * sg_dma_len(sg) returns size of a DMA segment, maximum DMA
+                * segment size is set to UINT_MAX by qaic and hence return
+                * values of sg_dma_len(sg) can never exceed u32 range. So,
+                * by down sizing we are not corrupting the value.
+                */
+               slice->reqs[i].len = cpu_to_le32((u32)sg_dma_len(sg));
+               switch (presync_sem) {
+               case BIT(0):
+                       slice->reqs[i].sem_cmd0 = 
cpu_to_le32(ENCODE_SEM(req->sem0.val,
+                                                                        
req->sem0.index,
+                                                                        
req->sem0.presync,
+                                                                        
req->sem0.cmd,
+                                                                        
req->sem0.flags));
+                       break;
+               case BIT(1):
+                       slice->reqs[i].sem_cmd1 = 
cpu_to_le32(ENCODE_SEM(req->sem1.val,
+                                                                        
req->sem1.index,
+                                                                        
req->sem1.presync,
+                                                                        
req->sem1.cmd,
+                                                                        
req->sem1.flags));
+                       break;
+               case BIT(2):
+                       slice->reqs[i].sem_cmd2 = 
cpu_to_le32(ENCODE_SEM(req->sem2.val,
+                                                                        
req->sem2.index,
+                                                                        
req->sem2.presync,
+                                                                        
req->sem2.cmd,
+                                                                        
req->sem2.flags));
+                       break;
+               case BIT(3):
+                       slice->reqs[i].sem_cmd3 = 
cpu_to_le32(ENCODE_SEM(req->sem3.val,
+                                                                        
req->sem3.index,
+                                                                        
req->sem3.presync,
+                                                                        
req->sem3.cmd,
+                                                                        
req->sem3.flags));
+                       break;
+               }
+               dev_addr += sg_dma_len(sg);
+       }
+       /* add post transfer stuff to last segment */
+       i--;
+       slice->reqs[i].cmd |= GEN_COMPLETION;
+       slice->reqs[i].db_addr = db_addr;
+       slice->reqs[i].db_len = db_len;
+       slice->reqs[i].db_data = db_data;
+       /*
+        * Add a fence if we have more than one request going to the hardware
+        * representing the entirety of the user request, and the user request
+        * has no presync condition.
+        * Fences are expensive, so we try to avoid them.  We rely on the
+        * hardware behavior to avoid needing one when there is a presync
+        * condition.  When a presync exists, all requests for that same
+        * presync will be queued into a fifo.  Thus, since we queue the
+        * post xfer activity only on the last request we queue, the hardware
+        * will ensure that the last queued request is processed last, thus
+        * making sure the post xfer activity happens at the right time without
+        * a fence.
+        */
+       if (i && !presync_sem)
+               req->sem0.flags |= (slice->dir == DMA_TO_DEVICE ?
+                                   SEM_INSYNCFENCE : SEM_OUTSYNCFENCE);
+       slice->reqs[i].sem_cmd0 = cpu_to_le32(ENCODE_SEM(req->sem0.val,
+                                                      req->sem0.index,
+                                                      req->sem0.presync,
+                                                      req->sem0.cmd,
+                                                      req->sem0.flags));
+       slice->reqs[i].sem_cmd1 = cpu_to_le32(ENCODE_SEM(req->sem1.val,
+                                                      req->sem1.index,
+                                                      req->sem1.presync,
+                                                      req->sem1.cmd,
+                                                      req->sem1.flags));
+       slice->reqs[i].sem_cmd2 = cpu_to_le32(ENCODE_SEM(req->sem2.val,
+                                                      req->sem2.index,
+                                                      req->sem2.presync,
+                                                      req->sem2.cmd,
+                                                      req->sem2.flags));
+       slice->reqs[i].sem_cmd3 = cpu_to_le32(ENCODE_SEM(req->sem3.val,
+                                                      req->sem3.index,
+                                                      req->sem3.presync,
+                                                      req->sem3.cmd,
+                                                      req->sem3.flags));
+
+       return 0;
+}
+
+static int qaic_map_one_slice(struct qaic_device *qdev, struct qaic_bo *bo,
+                             struct qaic_attach_slice_entry *slice_ent)
+{
+       struct sg_table *sgt = NULL;
+       struct bo_slice *slice;
+       int ret;
+
+       ret = copy_sgt(qdev, &sgt, bo->sgt, slice_ent->size, slice_ent->offset);
+       if (ret) {
+               trace_qaic_mem_err(qdev, "Failed to copy sgt", ret);
+               goto out;
+       }
+
+       slice = kmalloc(sizeof(*slice), GFP_KERNEL);
+       if (!slice) {
+               ret = -ENOMEM;
+               trace_qaic_mem_err(qdev, "Failed to allocate memory for slice 
handle", ret);
+               goto free_sgt;
+       }
+
+       slice->reqs = kcalloc(sgt->nents, sizeof(*slice->reqs), GFP_KERNEL);
+       if (!slice->reqs) {
+               ret = -ENOMEM;
+               trace_qaic_mem_err(qdev, "Failed to allocate memory for 
requests", ret);
+               goto free_slice;
+       }
+
+       slice->no_xfer = !slice_ent->size;
+       slice->sgt = sgt;
+       slice->nents = sgt->nents;
+       slice->dir = bo->dir;
+       slice->bo = bo;
+       slice->size = slice_ent->size;
+       slice->offset = slice_ent->offset;
+
+       ret = encode_reqs(qdev, slice, slice_ent);
+       if (ret) {
+               trace_qaic_mem_err(qdev, "Failed to encode requests", ret);
+               goto free_req;
+       }
+
+       bo->total_slice_nents += sgt->nents;
+       kref_init(&slice->ref_count);
+       drm_gem_object_get(&bo->base);
+       list_add_tail(&slice->slice, &bo->slices);
+
+       return 0;
+
+free_req:
+       kfree(slice->reqs);
+free_slice:
+       kfree(slice);
+free_sgt:
+       sg_free_table(sgt);
+       kfree(sgt);
+out:
+       return ret;
+}
+
+static int create_sgt(struct qaic_device *qdev, struct sg_table **sgt_out,
+                     u64 size)
+{
+       struct scatterlist *sg;
+       struct sg_table *sgt;
+       struct page **pages;
+       int *pages_order;
+       int buf_extra;
+       int max_order;
+       int nr_pages;
+       int ret = 0;
+       int i, j, k;
+       int order;
+
+       if (size) {
+               nr_pages = DIV_ROUND_UP(size, PAGE_SIZE);
+               /*
+                * calculate how much extra we are going to allocate, to remove
+                * later
+                */
+               buf_extra = (PAGE_SIZE - size % PAGE_SIZE) % PAGE_SIZE;
+               max_order = min(MAX_ORDER - 1, get_order(size));
+       } else {
+               /* allocate a single page for book keeping */
+               nr_pages = 1;
+               buf_extra = 0;
+               max_order = 0;
+       }
+
+       pages = kvmalloc_array(nr_pages, sizeof(*pages) + sizeof(*pages_order), 
GFP_KERNEL);
+       if (!pages) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       pages_order = (void *)pages + sizeof(*pages) * nr_pages;
+
+       /*
+        * Allocate requested memory, using alloc_pages. It is possible to 
allocate
+        * the requested memory in multiple chunks by calling alloc_pages
+        * multiple times. Use SG table to handle multiple allocated pages.
+        */
+       i = 0;
+       while (nr_pages > 0) {
+               order = min(get_order(nr_pages * PAGE_SIZE), max_order);
+               while (1) {
+                       pages[i] = alloc_pages(GFP_KERNEL | GFP_HIGHUSER |
+                                              __GFP_NOWARN | __GFP_ZERO |
+                                              (order ? __GFP_NORETRY : 
__GFP_RETRY_MAYFAIL),
+                                              order);
+                       if (pages[i])
+                               break;
+                       if (!order--) {
+                               ret = -ENOMEM;
+                               trace_qaic_mem_err_1(qdev, "Kernel ran out of 
free pages",
+                                                    "Memory requested in byte",
+                                                    ret, nr_pages);
+                               goto free_partial_alloc;
+                       }
+               }
+
+               max_order = order;
+               pages_order[i] = order;
+
+               nr_pages -= 1 << order;
+               if (nr_pages <= 0)
+                       /* account for over allocation */
+                       buf_extra += abs(nr_pages) * PAGE_SIZE;
+               i++;
+       }
+
+       sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
+       if (!sgt) {
+               ret = -ENOMEM;
+               goto free_partial_alloc;
+       }
+
+       if (sg_alloc_table(sgt, i, GFP_KERNEL)) {
+               ret = -ENOMEM;
+               goto free_sgt;
+       }
+
+       /* Populate the SG table with the allocate memory pages */
+       sg = sgt->sgl;
+       for (k = 0; k < i; k++, sg = sg_next(sg)) {
+               /* Last entry requires special handling */
+               if (k < i - 1) {
+                       sg_set_page(sg, pages[k], PAGE_SIZE << pages_order[k], 
0);
+               } else {
+                       sg_set_page(sg, pages[k],
+                                   (PAGE_SIZE << pages_order[k]) - buf_extra, 
0);
+                       sg_mark_end(sg);
+               }
+
+               ret = reserve_pages(page_to_pfn(pages[k]), 
DIV_ROUND_UP(sg->length, PAGE_SIZE),
+                                   true);
+               if (ret)
+                       goto clear_pages;
+       }
+
+       kvfree(pages);
+       *sgt_out = sgt;
+       return ret;
+
+clear_pages:
+       for (j = 0; j < k; j++)
+               ret = reserve_pages(page_to_pfn(pages[j]), 1 << pages_order[j],
+                                   false);
+       sg_free_table(sgt);
+free_sgt:
+       kfree(sgt);
+free_partial_alloc:
+       for (j = 0; j < i; j++)
+               __free_pages(pages[j], pages_order[j]);
+       kvfree(pages);
+out:
+       *sgt_out = NULL;
+       return ret;
+}
+
+static bool invalid_sem(struct qaic_sem *sem)
+{
+       if (sem->val & ~SEM_VAL_MASK || sem->index & ~SEM_INDEX_MASK ||
+           !(sem->presync == 0 || sem->presync == 1) || sem->pad ||
+           sem->flags & ~(SEM_INSYNCFENCE | SEM_OUTSYNCFENCE) ||
+           sem->cmd > SEM_WAIT_GT_0)
+               return true;
+       return false;
+}
+
+static int qaic_validate_req(struct qaic_device *qdev,
+                            struct qaic_attach_slice_entry *slice_ent,
+                            u32 count, u64 total_size)
+{
+       int i;
+
+       for (i = 0; i < count; i++) {
+               if (!(slice_ent[i].db_len == 32 || slice_ent[i].db_len == 16 ||
+                     slice_ent[i].db_len == 8 || slice_ent[i].db_len == 0) ||
+                     invalid_sem(&slice_ent[i].sem0) ||
+                     invalid_sem(&slice_ent[i].sem1) ||
+                     invalid_sem(&slice_ent[i].sem2) ||
+                     invalid_sem(&slice_ent[i].sem3)) {
+                       trace_qaic_mem_err(qdev, "Invalid semaphore or doorbell 
len", -EINVAL);
+                       return -EINVAL;
+               }
+               if (slice_ent[i].offset + slice_ent[i].size > total_size) {
+                       trace_qaic_mem_err_1(qdev, "Invalid size of buffer 
slice", "Slice size",
+                                            -EINVAL, slice_ent[i].size);
+                       trace_qaic_mem_err_2(qdev, "", "offset", "buffer slice 
size",
+                                            -EINVAL, slice_ent[i].offset, 
total_size);
+                       return -EINVAL;
+               }
+       }
+
+       return 0;
+}
+
+static void qaic_free_sgt(struct sg_table *sgt)
+{
+       struct scatterlist *sg;
+
+       for (sg = sgt->sgl; sg; sg = sg_next(sg))
+               if (sg_page(sg)) {
+                       reserve_pages(page_to_pfn(sg_page(sg)),
+                                     DIV_ROUND_UP(sg->length, PAGE_SIZE), 
false);
+                       __free_pages(sg_page(sg), get_order(sg->length));
+               }
+       sg_free_table(sgt);
+       kfree(sgt);
+}
+
+static void qaic_gem_print_info(struct drm_printer *p, unsigned int indent,
+                               const struct drm_gem_object *obj)
+{
+       struct qaic_bo *bo = to_qaic_bo(obj);
+
+       drm_printf_indent(p, indent, "user requested size=%llu\n", bo->size);
+}
+
+static const struct vm_operations_struct drm_vm_ops = {
+       .open = drm_gem_vm_open,
+       .close = drm_gem_vm_close,
+};
+
+static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct 
vm_area_struct *vma)
+{
+       struct qaic_bo *bo = to_qaic_bo(obj);
+       unsigned long offset = 0;
+       struct scatterlist *sg;
+       int ret;
+
+       if (obj->import_attach) {
+               trace_qaic_mmap_err(bo->dbc->qdev, "mmap is not supported for 
import/PRIME buffers", ret);
+               return -EINVAL;
+       }
+
+       for (sg = bo->sgt->sgl; sg; sg = sg_next(sg)) {
+               if (sg_page(sg)) {
+                       ret = remap_pfn_range(vma, vma->vm_start + offset,
+                                             page_to_pfn(sg_page(sg)),
+                                             sg->length, vma->vm_page_prot);
+                       if (ret)
+                               goto out;
+                       offset += sg->length;
+               }
+       }
+
+out:
+       return ret;
+}
+
+static void qaic_free_object(struct drm_gem_object *obj)
+{
+       struct qaic_bo *bo = to_qaic_bo(obj);
+
+       if (obj->import_attach) {
+               /* DMABUF/PRIME Path */
+               dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach);
+               dma_buf_put(obj->import_attach->dmabuf);
+       } else {
+               /* Private buffer allocation path */
+               qaic_free_sgt(bo->sgt);
+       }
+
+       drm_gem_object_release(obj);
+       kfree(bo);
+}
+
+static const struct drm_gem_object_funcs qaic_gem_funcs = {
+       .free = qaic_free_object,
+       .print_info = qaic_gem_print_info,
+       .mmap = qaic_gem_object_mmap,
+       .vm_ops = &drm_vm_ops,
+};
+
+static struct qaic_bo *qaic_alloc_init_bo(void)
+{
+       struct qaic_bo *bo;
+
+       bo = kzalloc(sizeof(*bo), GFP_KERNEL);
+       if (!bo) {
+               trace_qaic_mem_err(bo->dbc->qdev, "Failed to allocate qaic BO", 
-ENOMEM);
+               return ERR_PTR(-ENOMEM);
+       }
+
+       INIT_LIST_HEAD(&bo->slices);
+       init_completion(&bo->xfer_done);
+       complete_all(&bo->xfer_done);
+
+       return bo;
+}
+
+int qaic_create_bo_ioctl(struct drm_device *dev, void *data,
+                        struct drm_file *file_priv)
+{
+       struct qaic_create_bo *args = data;
+       int usr_rcu_id, qdev_rcu_id;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       struct qaic_user *usr;
+       struct qaic_bo *bo;
+       size_t size;
+       int ret;
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_mem_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_mem_err(qdev, "Failed to acquire device RCU lock", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       size = PAGE_ALIGN(args->size);
+       if (size == 0) {
+               ret = -EINVAL;
+               trace_qaic_mem_err_1(qdev, "Failed to PAGE_ALIGN for given 
buffer size",
+                                    "buffer size(B)", ret, args->size);
+               goto unlock_dev_srcu;
+       }
+
+       bo = qaic_alloc_init_bo();
+       if (IS_ERR(bo)) {
+               ret = PTR_ERR(bo);
+               trace_qaic_mem_err(qdev, "Failed to Allocate/Init BO", ret);
+               goto unlock_dev_srcu;
+       }
+       obj = &bo->base;
+
+       drm_gem_private_object_init(dev, obj, size);
+
+       obj->funcs = &qaic_gem_funcs;
+       ret = create_sgt(qdev, &bo->sgt, size);
+       if (ret) {
+               trace_qaic_mem_err(qdev, "Failed to Create SGT", ret);
+               goto free_bo;
+       }
+
+       bo->size = args->size;
+
+       ret = drm_gem_handle_create(file_priv, obj, &args->handle);
+       if (ret) {
+               trace_qaic_mem_err(qdev, "Failed to Create SGT", ret);
+               goto free_sgt;
+       }
+
+       bo->handle = args->handle;
+       drm_gem_object_put(obj);
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+
+       return 0;
+
+free_sgt:
+       qaic_free_sgt(bo->sgt);
+free_bo:
+       kfree(bo);
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+int qaic_mmap_bo_ioctl(struct drm_device *dev, void *data,
+                      struct drm_file *file_priv)
+{
+       struct qaic_mmap_bo *args = data;
+       int usr_rcu_id, qdev_rcu_id;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       struct qaic_user *usr;
+       int ret;
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_mmap_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_mmap_err(qdev, "Failed to acquire device RCU lock", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       obj = drm_gem_object_lookup(file_priv, args->handle);
+       if (!obj) {
+               ret = -ENOENT;
+               trace_qaic_mmap_err_1(qdev, "Invalid BO handle passed", "BO 
handle",
+                                     ret, args->handle);
+               goto unlock_dev_srcu;
+       }
+
+       ret = drm_gem_create_mmap_offset(obj);
+       if (ret == 0)
+               args->offset = drm_vma_node_offset_addr(&obj->vma_node);
+
+       drm_gem_object_put(obj);
+
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+struct drm_gem_object *qaic_gem_prime_import(struct drm_device *dev,
+                                            struct dma_buf *dma_buf)
+{
+       struct dma_buf_attachment *attach;
+       struct drm_gem_object *obj;
+       struct qaic_bo *bo;
+       size_t size;
+       int ret;
+
+       bo = qaic_alloc_init_bo();
+       if (IS_ERR(bo)) {
+               ret = PTR_ERR(bo);
+               trace_qaic_mem_err(bo->dbc->qdev, "Failed to Allocate/Init BO", 
ret);
+               goto out;
+       }
+
+       obj = &bo->base;
+       get_dma_buf(dma_buf);
+
+       attach = dma_buf_attach(dma_buf, dev->dev);
+       if (IS_ERR(attach)) {
+               ret = PTR_ERR(attach);
+               trace_qaic_mem_err(bo->dbc->qdev, "Failed to attach dma_buf", 
ret);
+               goto attach_fail;
+       }
+
+       size = PAGE_ALIGN(attach->dmabuf->size);
+       if (size == 0) {
+               ret = -EINVAL;
+               trace_qaic_mem_err(bo->dbc->qdev, "Invalid dma_buf size 0", 
ret);
+               goto size_align_fail;
+       }
+
+       drm_gem_private_object_init(dev, obj, size);
+       /*
+        * I have skipped dma_buf_map_attachment() as we do not know the 
direction just yet.
+        * Once the direction is know in the subsequent IOCTL to attach slicing 
we can do it then.
+        */
+
+       obj->funcs = &qaic_gem_funcs;
+       obj->import_attach = attach;
+       obj->resv = dma_buf->resv;
+
+       return obj;
+
+size_align_fail:
+       dma_buf_detach(dma_buf, attach);
+attach_fail:
+       dma_buf_put(dma_buf);
+       kfree(bo);
+out:
+       return ERR_PTR(ret);
+}
+
+static int qaic_prepare_import_bo(struct qaic_bo *bo,
+                                 struct qaic_attach_slice_hdr *hdr)
+{
+       struct drm_gem_object *obj = &bo->base;
+       struct sg_table *sgt;
+       int ret;
+
+       if (obj->import_attach->dmabuf->size < hdr->size) {
+               trace_qaic_attach_err_2(bo->dbc->qdev, "Invalid import/PRIME 
buffer size",
+                                       "DMABUF size", "Requested buffer size",
+                                       ret, obj->import_attach->dmabuf->size,
+                                       hdr->size);
+               return -EINVAL;
+       }
+
+       sgt = dma_buf_map_attachment(obj->import_attach, hdr->dir);
+       if (IS_ERR(sgt)) {
+               ret = PTR_ERR(sgt);
+               trace_qaic_attach_err(bo->dbc->qdev, "DMABUF map attachment 
failed", ret);
+               return ret;
+       }
+
+       bo->sgt = sgt;
+       bo->size = hdr->size;
+
+       return 0;
+}
+
+static int qaic_prepare_export_bo(struct qaic_device *qdev, struct qaic_bo *bo,
+                                 struct qaic_attach_slice_hdr *hdr)
+{
+       int ret;
+
+       if (bo->size != hdr->size) {
+               trace_qaic_attach_err_2(qdev, "Invalid export buffer size",
+                                       "DMABUF size", "Requested buffer size",
+                                       -EINVAL, bo->size, hdr->size);
+               return -EINVAL;
+       }
+
+       ret = dma_map_sgtable(&qdev->pdev->dev, bo->sgt, hdr->dir, 0);
+       if (ret) {
+               trace_qaic_attach_err(qdev, "DMA map sgtable failed", ret);
+               return -EFAULT;
+       }
+
+       return 0;
+}
+
+static int qaic_prepare_bo(struct qaic_device *qdev, struct qaic_bo *bo,
+                          struct qaic_attach_slice_hdr *hdr)
+{
+       int ret;
+
+       if (bo->base.import_attach)
+               ret = qaic_prepare_import_bo(bo, hdr);
+       else
+               ret = qaic_prepare_export_bo(qdev, bo, hdr);
+
+       if (ret == 0)
+               bo->dir = hdr->dir;
+
+       return ret;
+}
+
+static void qaic_unprepare_import_bo(struct qaic_bo *bo)
+{
+       dma_buf_unmap_attachment(bo->base.import_attach, bo->sgt, bo->dir);
+       bo->sgt = NULL;
+       bo->size = 0;
+}
+
+static void qaic_unprepare_export_bo(struct qaic_device *qdev, struct qaic_bo 
*bo)
+{
+       dma_unmap_sgtable(&qdev->pdev->dev, bo->sgt, bo->dir, 0);
+}
+
+static void qaic_unprepare_bo(struct qaic_device *qdev, struct qaic_bo *bo)
+{
+       if (bo->base.import_attach)
+               qaic_unprepare_import_bo(bo);
+       else
+               qaic_unprepare_export_bo(qdev, bo);
+
+       bo->dir = 0;
+}
+
+static void qaic_free_slices_bo(struct qaic_bo *bo)
+{
+       struct bo_slice *slice, *temp;
+
+       list_for_each_entry_safe(slice, temp, &bo->slices, slice) {
+               kref_put(&slice->ref_count, free_slice);
+       }
+}
+
+static int qaic_attach_slicing_bo(struct qaic_device *qdev,
+                                 struct qaic_bo *bo,
+                                 struct qaic_attach_slice_hdr *hdr,
+                                 struct qaic_attach_slice_entry *slice_ent)
+{
+       int ret, i;
+
+       for (i = 0; i < hdr->count; i++) {
+               ret = qaic_map_one_slice(qdev, bo, &slice_ent[i]);
+               if (ret) {
+                       qaic_free_slices_bo(bo);
+                       return ret;
+               }
+       }
+
+       if (bo->total_slice_nents > qdev->dbc[hdr->dbc_id].nelem) {
+               trace_qaic_attach_err(qdev, "DMA map sg failed", ret);
+               qaic_free_slices_bo(bo);
+               return -ENOSPC;
+       }
+
+       bo->sliced = true;
+       bo->nr_slice = hdr->count;
+       list_add_tail(&bo->bo_list, &qdev->dbc[hdr->dbc_id].bo_lists);
+
+       return 0;
+}
+
+int qaic_attach_slice_bo_ioctl(struct drm_device *dev, void *data,
+                              struct drm_file *file_priv)
+{
+       struct qaic_attach_slice_entry *slice_ent;
+       struct qaic_attach_slice *args = data;
+       struct dma_bridge_chan  *dbc;
+       int usr_rcu_id, qdev_rcu_id;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       unsigned long arg_size;
+       struct qaic_user *usr;
+       u8 __user *user_data;
+       struct qaic_bo *bo;
+       int ret;
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_attach_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_attach_err(qdev, "Failed to acquire device RCU 
lock", ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->hdr.count == 0) {
+               ret = -EINVAL;
+               trace_qaic_attach_err(qdev, "Invalid slice count 0", ret);
+               goto unlock_dev_srcu;
+       }
+
+       arg_size = args->hdr.count * sizeof(*slice_ent);
+       if (arg_size / args->hdr.count != sizeof(*slice_ent)) {
+               ret = -EINVAL;
+               trace_qaic_attach_err_1(qdev, "Invalid slice count",
+                                       "Slice count", ret, args->hdr.count);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->hdr.dbc_id >= qdev->num_dbc) {
+               ret = -EINVAL;
+               trace_qaic_attach_err_1(qdev, "Invalid DBC ID", "DBC ID", ret,
+                                       args->hdr.dbc_id);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->hdr.size == 0) {
+               ret = -EINVAL;
+               trace_qaic_attach_err(qdev, "Invalid BO size 0", ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (!(args->hdr.dir == DMA_TO_DEVICE  ||
+             args->hdr.dir == DMA_FROM_DEVICE)) {
+               ret = -EINVAL;
+               trace_qaic_attach_err_1(qdev, "Invalid DMA direction",
+                                       "DMA directions", ret, args->hdr.dir);
+               goto unlock_dev_srcu;
+       }
+
+       dbc = &qdev->dbc[args->hdr.dbc_id];
+       if (dbc->usr != usr) {
+               ret = -EINVAL;
+               trace_qaic_attach_err_1(qdev, "User handle mismatch", "DBC ID",
+                                       ret, args->hdr.dbc_id);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->data == 0) {
+               ret = -EINVAL;
+               trace_qaic_attach_err(qdev, "Invalid data pointer (NULL).", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       user_data = u64_to_user_ptr(args->data);
+
+       slice_ent = kzalloc(arg_size, GFP_KERNEL);
+       if (!slice_ent) {
+               ret = -EINVAL;
+               trace_qaic_attach_err_1(qdev, "Failed to allocate memory for 
slice entries",
+                                       "Number of slice", ret, 
args->hdr.count);
+               goto unlock_dev_srcu;
+       }
+
+       ret = copy_from_user(slice_ent, user_data, arg_size);
+       if (ret) {
+               ret = -EFAULT;
+               trace_qaic_attach_err(qdev, "Failed to copy data from user to 
kernel", ret);
+               goto free_slice_ent;
+       }
+
+       ret = qaic_validate_req(qdev, slice_ent, args->hdr.count, 
args->hdr.size);
+       if (ret)
+               goto free_slice_ent;
+
+       obj = drm_gem_object_lookup(file_priv, args->hdr.handle);
+       if (!obj) {
+               trace_qaic_attach_err_1(qdev, "Invalid BO handle", "BO handle",
+                                       ret, args->hdr.handle);
+               ret = -ENOENT;
+               goto free_slice_ent;
+       }
+
+       bo = to_qaic_bo(obj);
+
+       ret = qaic_prepare_bo(qdev, bo, &args->hdr);
+       if (ret)
+               goto put_bo;
+
+       ret = qaic_attach_slicing_bo(qdev, bo, &args->hdr, slice_ent);
+       if (ret)
+               goto unprepare_bo;
+
+       if (args->hdr.dir == DMA_TO_DEVICE)
+               dma_sync_sgtable_for_cpu(&qdev->pdev->dev, bo->sgt, 
args->hdr.dir);
+
+       bo->dbc = dbc;
+       drm_gem_object_put(obj);
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+
+       return 0;
+
+unprepare_bo:
+       qaic_unprepare_bo(qdev, bo);
+put_bo:
+       drm_gem_object_put(obj);
+free_slice_ent:
+       kfree(slice_ent);
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+static inline int copy_exec_reqs(struct qaic_device *qdev,
+                                struct bo_slice *slice, u32 dbc_id, u32 head,
+                                u32 *ptail)
+{
+       struct dma_bridge_chan *dbc = &qdev->dbc[dbc_id];
+       struct dbc_req *reqs = slice->reqs;
+       u32 tail = *ptail;
+       u32 avail;
+
+       avail = head - tail;
+       if (head <= tail)
+               avail += dbc->nelem;
+
+       --avail;
+
+       if (avail < slice->nents) {
+               trace_qaic_exec_err_2(qdev, "No enough resources to execute 
this BO slice",
+                                     "resource available", "resource needed",
+                                     -EAGAIN, avail, slice->nents);
+               return -EAGAIN;
+       }
+
+       if (tail + slice->nents > dbc->nelem) {
+               avail = dbc->nelem - tail;
+               avail = min_t(u32, avail, slice->nents);
+               memcpy(dbc->req_q_base + tail * get_dbc_req_elem_size(),
+                      reqs, sizeof(*reqs) * avail);
+               reqs += avail;
+               avail = slice->nents - avail;
+               if (avail)
+                       memcpy(dbc->req_q_base, reqs, sizeof(*reqs) * avail);
+       } else {
+               memcpy(dbc->req_q_base + tail * get_dbc_req_elem_size(),
+                      reqs, sizeof(*reqs) * slice->nents);
+       }
+
+       *ptail = (tail + slice->nents) % dbc->nelem;
+
+       return 0;
+}
+
+/*
+ * Based on the value of resize we may only need to transmit first_n
+ * entries and the last entry, with last_bytes to send from the last entry.
+ * Note that first_n could be 0.
+ */
+static inline int copy_partial_exec_reqs(struct qaic_device *qdev,
+                                        struct bo_slice *slice,
+                                        u64 resize, u32 dbc_id,
+                                        u32 head, u32 *ptail)
+{
+       struct dma_bridge_chan *dbc = &qdev->dbc[dbc_id];
+       struct dbc_req *reqs = slice->reqs;
+       struct dbc_req *last_req;
+       u32 tail = *ptail;
+       u64 total_bytes;
+       u64 last_bytes;
+       u32 first_n;
+       u32 avail;
+       int ret;
+       int i;
+
+       avail = head - tail;
+       if (head <= tail)
+               avail += dbc->nelem;
+
+       --avail;
+
+       total_bytes = 0;
+       for (i = 0; i < slice->nents; i++) {
+               total_bytes += le32_to_cpu(reqs[i].len);
+               if (total_bytes >= resize)
+                       break;
+       }
+
+       if (total_bytes < resize) {
+               /* User space should have used the full buffer path. */
+               ret = -EINVAL;
+               trace_qaic_exec_err_2(qdev, "Resize too big for partial buffer",
+                                     "partial/full size of BO slice",
+                                     "slice resize", ret, total_bytes, resize);
+               return ret;
+       }
+
+       first_n = i;
+       last_bytes = i ? resize + le32_to_cpu(reqs[i].len) - total_bytes : 
resize;
+
+       if (avail < (first_n + 1)) {
+               trace_qaic_exec_err_2(qdev, "Not enough resources to execute 
this BO slice",
+                                     "resource available", "resource needed",
+                                     -EAGAIN, avail, first_n + 1);
+               return -EAGAIN;
+       }
+
+       if (first_n) {
+               if (tail + first_n > dbc->nelem) {
+                       avail = dbc->nelem - tail;
+                       avail = min_t(u32, avail, first_n);
+                       memcpy(dbc->req_q_base + tail * get_dbc_req_elem_size(),
+                              reqs, sizeof(*reqs) * avail);
+                       last_req = reqs + avail;
+                       avail = first_n - avail;
+                       if (avail)
+                               memcpy(dbc->req_q_base, last_req,
+                                      sizeof(*reqs) * avail);
+               } else {
+                       memcpy(dbc->req_q_base + tail * get_dbc_req_elem_size(),
+                              reqs, sizeof(*reqs) * first_n);
+               }
+       }
+
+       /* Copy over the last entry. Here we need to adjust len to the left over
+        * size, and set src and dst to the entry it is copied to.
+        */
+       last_req =  dbc->req_q_base +
+                   (tail + first_n) % dbc->nelem * get_dbc_req_elem_size();
+       memcpy(last_req, reqs + slice->nents - 1, sizeof(*reqs));
+
+       /*
+        * last_bytes holds size of a DMA segment, maximum DMA segment size is
+        * set to UINT_MAX by qaic and hence last_bytes can never exceed u32
+        * range. So, by down sizing we are not corrupting the value.
+        */
+       last_req->len = cpu_to_le32((u32)last_bytes);
+       last_req->src_addr = reqs[first_n].src_addr;
+       last_req->dest_addr = reqs[first_n].dest_addr;
+
+       *ptail = (tail + first_n + 1) % dbc->nelem;
+
+       return 0;
+}
+
+static int __qaic_execute_bo_ioctl(struct drm_device *dev, void *data,
+                                  struct drm_file *file_priv, bool is_partial)
+{
+       struct qaic_partial_execute_entry *pexec;
+       struct qaic_execute *args = data;
+       struct qaic_execute_entry *exec;
+       struct dma_bridge_chan *dbc;
+       int usr_rcu_id, qdev_rcu_id;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       struct bo_slice *slice;
+       struct qaic_user *usr;
+       u8 __user *user_data;
+       unsigned long flags;
+       u64 received_ts = 0;
+       u32 queue_level = 0;
+       struct qaic_bo *bo;
+       u64 submit_ts = 0;
+       unsigned long n;
+       bool queued;
+       int ret = 0;
+       int dbc_id;
+       int rcu_id;
+       u32 head;
+       u32 tail;
+       u64 size;
+       int i, j;
+
+       received_ts = ktime_get_ns();
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_exec_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_exec_err(qdev, "Failed to acquire device RCU lock", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->hdr.dbc_id >= qdev->num_dbc) {
+               ret = -EINVAL;
+               trace_qaic_exec_err_1(qdev, "Invalid DBC ID", "DBC ID", ret, 
args->hdr.dbc_id);
+               goto unlock_dev_srcu;
+       }
+
+       dbc_id = args->hdr.dbc_id;
+       dbc = &qdev->dbc[dbc_id];
+
+       size = is_partial ? sizeof(*pexec) : sizeof(*exec);
+
+       n = (unsigned long)size * args->hdr.count;
+       if (args->hdr.count == 0 || n / args->hdr.count != size) {
+               ret = -EINVAL;
+               trace_qaic_exec_err_1(qdev, "Invalid number of execute 
requests",
+                                     "execute count", ret, args->hdr.count);
+               goto unlock_dev_srcu;
+       }
+
+       user_data = u64_to_user_ptr(args->data);
+
+       exec = kcalloc(args->hdr.count, size, GFP_KERNEL);
+       pexec = (struct qaic_partial_execute_entry *)exec;
+       if (!exec) {
+               ret = -ENOMEM;
+               trace_qaic_exec_err_1(qdev, "Failed to allocate execute entry 
structure",
+                                     "execute count", ret, args->hdr.count);
+               goto unlock_dev_srcu;
+       }
+
+       if (copy_from_user(exec, user_data, n)) {
+               ret = -EFAULT;
+               trace_qaic_exec_err(qdev, "Failed to copy data from user to 
kernel", ret);
+               goto free_exec;
+       }
+
+       rcu_id = srcu_read_lock(&dbc->ch_lock);
+       if (!dbc->usr || dbc->usr->handle != usr->handle) {
+               ret = -EPERM;
+               trace_qaic_exec_err_1(qdev, "User handle mismatch", "DBC ID", 
ret, dbc_id);
+               goto release_ch_rcu;
+       }
+
+       if (dbc->in_ssr) {
+               ret = -EPIPE;
+               trace_qaic_exec_err(qdev, "In SSR", ret);
+               goto release_ch_rcu;
+       }
+
+       head = readl(dbc->dbc_base + REQHP_OFF);
+       tail = readl(dbc->dbc_base + REQTP_OFF);
+
+       if (head == U32_MAX || tail == U32_MAX) {
+               /* PCI link error */
+               ret = -ENODEV;
+               trace_qaic_exec_err(qdev, "Failed to read HW head pointer and 
tail pointer", ret);
+               goto release_ch_rcu;
+       }
+
+       queue_level = head <= tail ? tail - head : dbc->nelem - (head - tail);
+
+       for (i = 0; i < args->hdr.count; i++) {
+               /*
+                * ref count will be decemented when the transfer of this
+                * buffer is complete. It is inside dbc_irq_threaded_fn().
+                */
+               obj = drm_gem_object_lookup(file_priv,
+                                           is_partial ? pexec[i].handle : 
exec[i].handle);
+               if (!obj) {
+                       ret = -ENOENT;
+                       trace_qaic_exec_err_2(qdev, "Invalid BO handle 
provided",
+                                             "BO handle", "execute index",
+                                             ret, is_partial ? pexec[i].handle 
:
+                                             exec[i].handle, i);
+                       goto sync_to_cpu;
+               }
+
+               bo = to_qaic_bo(obj);
+
+               if (!bo->sliced) {
+                       ret = -EINVAL;
+                       trace_qaic_exec_err_1(qdev, "Slicing information is not 
attached to BO",
+                                             "BO Handle", ret, bo->handle);
+                       goto sync_to_cpu;
+               }
+
+               if (is_partial && pexec[i].resize > bo->size) {
+                       ret = -EINVAL;
+                       trace_qaic_exec_err_2(qdev, "Resize value too large for 
partial execute IOCTL",
+                                             "BO size", "Resize",
+                                             ret, bo->size, pexec[i].resize);
+                       goto sync_to_cpu;
+               }
+
+               spin_lock_irqsave(&dbc->xfer_lock, flags);
+               queued = bo->queued;
+               bo->queued = true;
+               if (queued) {
+                       spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+                       ret = -EINVAL;
+                       trace_qaic_exec_err_1(qdev, "BO is already queued",
+                                             "BO handle", ret, bo->handle);
+                       goto sync_to_cpu;
+               }
+
+               bo->req_id = dbc->next_req_id++;
+
+               list_for_each_entry(slice, &bo->slices, slice) {
+                       /*
+                        * If this slice does not falls under the given
+                        * resize then skip this slice and continue the loop
+                        */
+                       if (is_partial && pexec[i].resize &&
+                           pexec[i].resize <= slice->offset)
+                               continue;
+
+                       for (j = 0; j < slice->nents; j++)
+                               slice->reqs[j].req_id = cpu_to_le16(bo->req_id);
+
+                       /*
+                        * If it is a partial execute ioctl call then check if
+                        * resize has cut this slice short then do a partial 
copy
+                        * else do complete copy
+                        */
+                       if (is_partial && pexec[i].resize &&
+                           pexec[i].resize < slice->offset + slice->size)
+                               ret = copy_partial_exec_reqs(qdev, slice,
+                                                            pexec[i].resize - 
slice->offset,
+                                                            dbc_id, head, 
&tail);
+                       else
+                               ret = copy_exec_reqs(qdev, slice, dbc_id, head, 
&tail);
+                       if (ret) {
+                               bo->queued = false;
+                               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+                               goto sync_to_cpu;
+                       }
+               }
+               reinit_completion(&bo->xfer_done);
+               list_add_tail(&bo->xfer_list, &dbc->xfer_list);
+               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+               dma_sync_sgtable_for_device(&qdev->pdev->dev, bo->sgt, bo->dir);
+       }
+
+       submit_ts = ktime_get_ns();
+       writel(tail, dbc->dbc_base + REQTP_OFF);
+
+       /* Collect kernel Profiling data */
+       for (i = 0; i < args->hdr.count; i++) {
+               /*
+                * Since we already committed the BO to hardware, the only way
+                * this should fail is a pending signal.  We can't cancel the
+                * submit to hardware, so we have to just skip the profiling
+                * data.  In case the signal is not fatal to the process, we
+                * return success so that the user doesn't try to resubmit.
+                */
+               obj = drm_gem_object_lookup(file_priv,
+                                           is_partial ? pexec[i].handle : 
exec[i].handle);
+               if (!obj) {
+                       trace_qaic_exec_err_2(qdev, "Invalid BO handle 
provided",
+                                             "BO handle", "execute index",
+                                             ret, is_partial ? pexec[i].handle 
:
+                                             exec[i].handle, i);
+                       break;
+               }
+               bo = to_qaic_bo(obj);
+               bo->perf_stats.req_received_ts = received_ts;
+               bo->perf_stats.req_submit_ts = submit_ts;
+               bo->perf_stats.queue_level_before = queue_level;
+               queue_level += bo->total_slice_nents;
+               drm_gem_object_put(obj);
+       }
+
+       if (poll_datapath)
+               schedule_work(&dbc->poll_work);
+
+       goto release_ch_rcu;
+
+sync_to_cpu:
+       if (likely(obj))
+               drm_gem_object_put(obj);
+       for (j = 0; j < i; j++) {
+               spin_lock_irqsave(&dbc->xfer_lock, flags);
+               bo = list_last_entry(&dbc->xfer_list, struct qaic_bo,
+                                    xfer_list);
+               obj = &bo->base;
+               bo->queued = false;
+               list_del(&bo->xfer_list);
+               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+               dma_sync_sgtable_for_cpu(&qdev->pdev->dev, bo->sgt, bo->dir);
+               /* Release ref to BO */
+               drm_gem_object_put(obj);
+       }
+release_ch_rcu:
+       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+free_exec:
+       kfree(exec);
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+int qaic_execute_bo_ioctl(struct drm_device *dev, void *data,
+                         struct drm_file *file_priv)
+{
+       return __qaic_execute_bo_ioctl(dev, data, file_priv, false);
+}
+
+int qaic_partial_execute_bo_ioctl(struct drm_device *dev, void *data,
+                                 struct drm_file *file_priv)
+{
+       return __qaic_execute_bo_ioctl(dev, data, file_priv, true);
+}
+
+/*
+ * Our interrupt handling is a bit more complicated than a simple ideal, but
+ * sadly necessary.
+ *
+ * Each dbc has a completion queue.  Entries in the queue correspond to DMA
+ * requests which the device has processed.  The hardware already has a built
+ * in irq mitigation.  When the device puts an entry into the queue, it will
+ * only trigger an interrupt if the queue was empty.  Therefore, when adding
+ * the Nth event to a non-empty queue, the hardware doesn't trigger an
+ * interrupt.  This means the host doesn't get additional interrupts signaling
+ * the same thing - the queue has something to process.
+ * This behavior can be overridden in the DMA request.
+ * This means that when the host receives an interrupt, it is required to
+ * drain the queue.
+ *
+ * This behavior is what NAPI attempts to accomplish, although we can't use
+ * NAPI as we don't have a netdev.  We use threaded irqs instead.
+ *
+ * However, there is a situation where the host drains the queue fast enough
+ * that every event causes an interrupt.  Typically this is not a problem as
+ * the rate of events would be low.  However, that is not the case with
+ * lprnet for example.  On an Intel Xeon D-2191 where we run 8 instances of
+ * lprnet, the host receives roughly 80k interrupts per second from the device
+ * (per /proc/interrupts).  While NAPI documentation indicates the host should
+ * just chug along, sadly that behavior causes instability in some hosts.
+ *
+ * Therefore, we implement an interrupt disable scheme similar to NAPI.  The
+ * key difference is that we will delay after draining the queue for a small
+ * time to allow additional events to come in via polling.  Using the above
+ * lprnet workload, this reduces the number of interrupts processed from
+ * ~80k/sec to about 64 in 5 minutes and appears to solve the system
+ * instability.
+ */
+irqreturn_t dbc_irq_handler(int irq, void *data)
+{
+       struct dma_bridge_chan *dbc = data;
+       int rcu_id;
+       u32 head;
+       u32 tail;
+
+       rcu_id = srcu_read_lock(&dbc->ch_lock);
+
+       if (!dbc->usr) {
+               srcu_read_unlock(&dbc->ch_lock, rcu_id);
+               return IRQ_HANDLED;
+       }
+
+       head = readl(dbc->dbc_base + RSPHP_OFF);
+       if (head == U32_MAX) { /* PCI link error */
+               srcu_read_unlock(&dbc->ch_lock, rcu_id);
+               return IRQ_NONE;
+       }
+
+       tail = readl(dbc->dbc_base + RSPTP_OFF);
+       if (tail == U32_MAX) { /* PCI link error */
+               srcu_read_unlock(&dbc->ch_lock, rcu_id);
+               return IRQ_NONE;
+       }
+
+       if (head == tail) { /* queue empty */
+               srcu_read_unlock(&dbc->ch_lock, rcu_id);
+               return IRQ_NONE;
+       }
+
+       disable_irq_nosync(irq);
+       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+       return IRQ_WAKE_THREAD;
+}
+
+void irq_polling_work(struct work_struct *work)
+{
+       struct dma_bridge_chan *dbc = container_of(work,
+                                                  struct dma_bridge_chan,
+                                                  poll_work);
+       unsigned long flags;
+       int rcu_id;
+       u32 head;
+       u32 tail;
+
+       rcu_id = srcu_read_lock(&dbc->ch_lock);
+
+       while (1) {
+               if (dbc->qdev->in_reset) {
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+               if (!dbc->usr) {
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+               spin_lock_irqsave(&dbc->xfer_lock, flags);
+               if (list_empty(&dbc->xfer_list)) {
+                       spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+
+               head = readl(dbc->dbc_base + RSPHP_OFF);
+               if (head == U32_MAX) { /* PCI link error */
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+
+               tail = readl(dbc->dbc_base + RSPTP_OFF);
+               if (tail == U32_MAX) { /* PCI link error */
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+
+               if (head != tail) {
+                       irq_wake_thread(dbc->irq, dbc);
+                       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+                       return;
+               }
+
+               cond_resched();
+               usleep_range(datapath_poll_interval_us,
+                            2 * datapath_poll_interval_us);
+       }
+}
+
+irqreturn_t dbc_irq_threaded_fn(int irq, void *data)
+{
+       struct dma_bridge_chan *dbc = data;
+       int event_count = NUM_EVENTS;
+       int delay_count = NUM_DELAYS;
+       struct qaic_device *qdev;
+       struct qaic_bo *bo, *i;
+       struct dbc_rsp *rsp;
+       unsigned long flags;
+       int rcu_id;
+       u16 status;
+       u16 req_id;
+       u32 head;
+       u32 tail;
+
+       rcu_id = srcu_read_lock(&dbc->ch_lock);
+
+       head = readl(dbc->dbc_base + RSPHP_OFF);
+       if (head == U32_MAX) /* PCI link error */
+               goto error_out;
+
+       qdev = dbc->qdev;
+read_fifo:
+
+       if (!event_count) {
+               event_count = NUM_EVENTS;
+               cond_resched();
+       }
+
+       /*
+        * if this channel isn't assigned or gets unassigned during processing
+        * we have nothing further to do
+        */
+       if (!dbc->usr)
+               goto error_out;
+
+       tail = readl(dbc->dbc_base + RSPTP_OFF);
+       if (tail == U32_MAX) /* PCI link error */
+               goto error_out;
+
+       if (head == tail) { /* queue empty */
+               if (delay_count) {
+                       --delay_count;
+                       usleep_range(100, 200);
+                       goto read_fifo; /* check for a new event */
+               }
+               goto normal_out;
+       }
+
+       delay_count = NUM_DELAYS;
+       while (head != tail) {
+               if (!event_count)
+                       break;
+               --event_count;
+               rsp = dbc->rsp_q_base + head * sizeof(*rsp);
+               req_id = le16_to_cpu(rsp->req_id);
+               status = le16_to_cpu(rsp->status);
+               if (status)
+                       pci_dbg(qdev->pdev, "req_id %d failed with status %d\n",
+                               req_id, status);
+               spin_lock_irqsave(&dbc->xfer_lock, flags);
+               /*
+                * A BO can receive multiple interrupts, since a BO can be
+                * divided into multiple slices and a buffer receives as many
+                * interrupts as slices. So until it receives interrupts for
+                * all the slices we cannot mark that buffer complete.
+                */
+               list_for_each_entry_safe(bo, i, &dbc->xfer_list, xfer_list) {
+                       if (bo->req_id == req_id)
+                               bo->nr_slice_xfer_done++;
+                       else
+                               continue;
+
+                       if (bo->nr_slice_xfer_done < bo->nr_slice)
+                               break;
+
+                       /*
+                        * At this point we have received all the interrupts for
+                        * BO, which means BO execution is complete.
+                        */
+                       dma_sync_sgtable_for_cpu(&qdev->pdev->dev, bo->sgt, 
bo->dir);
+                       bo->nr_slice_xfer_done = 0;
+                       bo->queued = false;
+                       list_del(&bo->xfer_list);
+                       bo->perf_stats.req_processed_ts = ktime_get_ns();
+                       complete_all(&bo->xfer_done);
+                       drm_gem_object_put(&bo->base);
+                       break;
+               }
+               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+               head = (head + 1) % dbc->nelem;
+       }
+
+       /*
+        * Update the head pointer of response queue and let the device know
+        * that we have consumed elements from the queue.
+        */
+       writel(head, dbc->dbc_base + RSPHP_OFF);
+
+       /* elements might have been put in the queue while we were processing */
+       goto read_fifo;
+
+normal_out:
+       if (likely(!poll_datapath))
+               enable_irq(irq);
+       else
+               schedule_work(&dbc->poll_work);
+       /* checking the fifo and enabling irqs is a race, missed event check */
+       tail = readl(dbc->dbc_base + RSPTP_OFF);
+       if (tail != U32_MAX && head != tail) {
+               if (likely(!poll_datapath))
+                       disable_irq_nosync(irq);
+               goto read_fifo;
+       }
+       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+       return IRQ_HANDLED;
+
+error_out:
+       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+       if (likely(!poll_datapath))
+               enable_irq(irq);
+       else
+               schedule_work(&dbc->poll_work);
+
+       return IRQ_HANDLED;
+}
+
+int qaic_wait_bo_ioctl(struct drm_device *dev, void *data,
+                      struct drm_file *file_priv)
+{
+       struct qaic_wait *args = data;
+       int usr_rcu_id, qdev_rcu_id;
+       struct dma_bridge_chan *dbc;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       unsigned long timeout;
+       struct qaic_user *usr;
+       struct qaic_bo *bo;
+       int rcu_id;
+       int ret;
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_wait_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_wait_err(qdev, "Failed to acquire device RCU lock", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->pad != 0) {
+               ret = -EINVAL;
+               trace_qaic_wait_err(qdev, "Pad value is non-zero", ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->dbc_id >= qdev->num_dbc) {
+               ret = -EINVAL;
+               trace_qaic_wait_err_1(qdev, "Invalid DBC ID", "DBC ID", ret, 
args->dbc_id);
+               goto unlock_dev_srcu;
+       }
+
+       dbc = &qdev->dbc[args->dbc_id];
+
+       rcu_id = srcu_read_lock(&dbc->ch_lock);
+       if (dbc->usr != usr) {
+               ret = -EPERM;
+               trace_qaic_wait_err_1(qdev, "Mismatch user handle", "DBC ID", 
ret, args->dbc_id);
+               goto unlock_ch_srcu;
+       }
+
+       if (dbc->in_ssr) {
+               ret = -EPIPE;
+               trace_qaic_wait_err(qdev, "In SSR", ret);
+               goto unlock_ch_srcu;
+       }
+
+       obj = drm_gem_object_lookup(file_priv, args->handle);
+       if (!obj) {
+               ret = -ENOENT;
+               trace_qaic_wait_err_1(qdev, "Invalid BO handle", "handle", ret, 
args->handle);
+               goto unlock_ch_srcu;
+       }
+
+       bo = to_qaic_bo(obj);
+       timeout = args->timeout ? args->timeout : wait_exec_default_timeout;
+       timeout = msecs_to_jiffies(timeout);
+       ret = wait_for_completion_interruptible_timeout(&bo->xfer_done, 
timeout);
+       if (!ret) {
+               ret = -ETIMEDOUT;
+               trace_qaic_wait_err_1(qdev, "Wait timeout", "timeout", ret,
+                                     jiffies_to_msecs(timeout));
+               goto put_obj;
+       }
+       if (ret > 0)
+               ret = 0;
+
+       if (!dbc->usr) {
+               ret = -EPERM;
+               trace_qaic_wait_err(qdev, "User disappeared", ret);
+       } else if (dbc->in_ssr) {
+               /*
+                * While waiting for this buffer transaction, it is possible
+                * that SSR was triggered on this DBC.  Thus we flushed all
+                * buffers on this DBC in transfer queue and marked them as
+                * complete.  Therefore, return an error as this buffer
+                * transaction failed.
+                */
+               ret = -EPIPE;
+               trace_qaic_wait_err(qdev, "In SSR", ret);
+       }
+
+put_obj:
+       drm_gem_object_put(obj);
+unlock_ch_srcu:
+       srcu_read_unlock(&dbc->ch_lock, rcu_id);
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+int qaic_perf_stats_bo_ioctl(struct drm_device *dev, void *data,
+                            struct drm_file *file_priv)
+{
+       struct qaic_perf_stats_entry *ent = NULL;
+       struct qaic_perf_stats *args = data;
+       int usr_rcu_id, qdev_rcu_id;
+       struct drm_gem_object *obj;
+       struct qaic_device *qdev;
+       struct qaic_user *usr;
+       struct qaic_bo *bo;
+       int ret, i;
+
+       usr = file_priv->driver_priv;
+       usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+       if (!usr->qddev) {
+               ret = -ENODEV;
+               trace_qaic_stats_err(qdev, "Failed to acquire user RCU lock", 
ret);
+               goto unlock_usr_srcu;
+       }
+
+       qdev = usr->qddev->qdev;
+       qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+       if (qdev->in_reset) {
+               ret = -ENODEV;
+               trace_qaic_stats_err(qdev, "Failed to acquire device RCU lock", 
ret);
+               goto unlock_dev_srcu;
+       }
+
+       if (args->hdr.dbc_id >= qdev->num_dbc) {
+               ret = -EINVAL;
+               trace_qaic_stats_err_1(qdev, "Invalid DBC ID", "DBC ID", ret, 
args->hdr.dbc_id);
+               goto unlock_dev_srcu;
+       }
+
+       ent = kcalloc(args->hdr.count, sizeof(*ent), GFP_KERNEL);
+       if (!ent) {
+               ret = -EINVAL;
+               trace_qaic_stats_err_1(qdev, "Failed to allocate memory for 
perf stats structure",
+                                      "query count", ret, args->hdr.count);
+               goto unlock_dev_srcu;
+       }
+
+       ret = copy_from_user(ent, u64_to_user_ptr(args->data),
+                            args->hdr.count * sizeof(*ent));
+       if (ret) {
+               ret = -EFAULT;
+               trace_qaic_stats_err(qdev, "Failed to copy data from user to 
kernel", ret);
+               goto free_ent;
+       }
+
+       for (i = 0; i < args->hdr.count; i++) {
+               obj = drm_gem_object_lookup(file_priv, ent[i].handle);
+               if (!obj) {
+                       ret = -ENOENT;
+                       trace_qaic_stats_err_1(qdev, "Invalid BO handle",
+                                              "BO handle", ret, ent[i].handle);
+                       goto free_ent;
+               }
+               bo = to_qaic_bo(obj);
+               /*
+                * perf stats ioctl is called before wait ioctl is complete then
+                * the latency information is invalid.
+                */
+               if (bo->perf_stats.req_processed_ts < 
bo->perf_stats.req_submit_ts) {
+                       ent[i].device_latency_us = 0;
+               } else {
+                       ent[i].device_latency_us = 
(bo->perf_stats.req_processed_ts -
+                                                   
bo->perf_stats.req_submit_ts) / 1000;
+               }
+               ent[i].submit_latency_us = (bo->perf_stats.req_submit_ts -
+                                          bo->perf_stats.req_received_ts) / 
1000;
+               ent[i].queue_level_before = bo->perf_stats.queue_level_before;
+               ent[i].num_queue_element = bo->total_slice_nents;
+               drm_gem_object_put(obj);
+       }
+
+       if (copy_to_user(u64_to_user_ptr(args->data), ent,
+                        args->hdr.count * sizeof(*ent))) {
+               ret = -EFAULT;
+               trace_qaic_stats_err(qdev, "Failed to copy data to user from 
kernel", ret);
+       }
+
+free_ent:
+       kfree(ent);
+unlock_dev_srcu:
+       srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+       srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+       return ret;
+}
+
+static void empty_xfer_list(struct qaic_device *qdev, struct dma_bridge_chan 
*dbc)
+{
+       unsigned long flags;
+       struct qaic_bo *bo;
+
+       spin_lock_irqsave(&dbc->xfer_lock, flags);
+       while (!list_empty(&dbc->xfer_list)) {
+               bo = list_first_entry(&dbc->xfer_list, typeof(*bo), xfer_list);
+               bo->queued = false;
+               list_del(&bo->xfer_list);
+               spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+               dma_sync_sgtable_for_cpu(&qdev->pdev->dev, bo->sgt, bo->dir);
+               complete_all(&bo->xfer_done);
+               drm_gem_object_put(&bo->base);
+               spin_lock_irqsave(&dbc->xfer_lock, flags);
+       }
+       spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+}
+
+int disable_dbc(struct qaic_device *qdev, u32 dbc_id, struct qaic_user *usr)
+{
+       if (!qdev->dbc[dbc_id].usr ||
+           qdev->dbc[dbc_id].usr->handle != usr->handle)
+               return -EPERM;
+
+       qdev->dbc[dbc_id].usr = NULL;
+       synchronize_srcu(&qdev->dbc[dbc_id].ch_lock);
+       return 0;
+}
+
+/**
+ * enable_dbc - Enable the DBC. DBCs are disabled by removing the context of
+ * user. Add user context back to DBC to enable it. This fucntions trusts the
+ * DBC ID passed and expects the DBC to be disabled.
+ * @qdev: Qranium device handle
+ * @dbc_id: ID of the DBC
+ * @usr: User context
+ */
+void enable_dbc(struct qaic_device *qdev, u32 dbc_id, struct qaic_user *usr)
+{
+       qdev->dbc[dbc_id].usr = usr;
+}
+
+void wakeup_dbc(struct qaic_device *qdev, u32 dbc_id)
+{
+       struct dma_bridge_chan *dbc = &qdev->dbc[dbc_id];
+
+       dbc->usr = NULL;
+       empty_xfer_list(qdev, dbc);
+       synchronize_srcu(&dbc->ch_lock);
+}
+
+void release_dbc(struct qaic_device *qdev, u32 dbc_id, bool set_state)
+{
+       struct bo_slice *slice, *slice_temp;
+       struct qaic_bo *bo, *bo_temp;
+       struct dma_bridge_chan *dbc;
+
+       dbc = &qdev->dbc[dbc_id];
+       if (!dbc->in_use)
+               return;
+
+       wakeup_dbc(qdev, dbc_id);
+
+       dma_free_coherent(&qdev->pdev->dev, dbc->total_size, dbc->req_q_base,
+                         dbc->dma_addr);
+       dbc->total_size = 0;
+       dbc->req_q_base = NULL;
+       dbc->dma_addr = 0;
+       dbc->nelem = 0;
+       dbc->usr = NULL;
+       if (set_state)
+               set_dbc_state(qdev, dbc_id, DBC_STATE_IDLE);
+
+       list_for_each_entry_safe(bo, bo_temp, &dbc->bo_lists, bo_list) {
+               list_for_each_entry_safe(slice, slice_temp, &bo->slices, slice)
+                       kref_put(&slice->ref_count, free_slice);
+               bo->sliced = false;
+               INIT_LIST_HEAD(&bo->slices);
+               bo->total_slice_nents = 0;
+               bo->dir = 0;
+               bo->dbc = NULL;
+               bo->nr_slice = 0;
+               bo->nr_slice_xfer_done = 0;
+               bo->queued = false;
+               bo->req_id = 0;
+               init_completion(&bo->xfer_done);
+               complete_all(&bo->xfer_done);
+               list_del(&bo->bo_list);
+               bo->perf_stats.req_received_ts = 0;
+               bo->perf_stats.req_submit_ts = 0;
+               bo->perf_stats.req_processed_ts = 0;
+               bo->perf_stats.queue_level_before = 0;
+       }
+
+       dbc->in_use = false;
+       wake_up(&dbc->dbc_release);
+}
+
+void qaic_data_get_fifo_info(struct dma_bridge_chan *dbc, u32 *head, u32 *tail)
+{
+       if (!dbc || !head || !tail)
+               return;
+
+       *head = readl(dbc->dbc_base + REQHP_OFF);
+       *tail = readl(dbc->dbc_base + REQTP_OFF);
+}
+
+/**
+ * dbc_enter_ssr - Prepare to enter in sub system reset(SSR) for given DBC ID
+ * During SSR we cannot support execute ioctl and wait ioctl for the given DBC.
+ * We control this behaviour using in_ssr flag in DBC.
+ * @qdev: Qranium device handle
+ * @dbc_id: ID of the DBC which will enter SSR
+ */
+void dbc_enter_ssr(struct qaic_device *qdev, u32 dbc_id)
+{
+       struct dma_bridge_chan *dbc = &qdev->dbc[dbc_id];
+
+       dbc->in_ssr = true;
+       empty_xfer_list(qdev, dbc);
+       synchronize_srcu(&dbc->ch_lock);
+}
+
+/**
+ * dbc_exit_ssr - Prepare to exit from sub system reset(SSR) for given DBC ID
+ * After SSR we exit SSR we can resume our supporting execute ioctl and
+ * wait ioctl. We control this behaviour using in_ssr flag in DBC.
+ * @qdev: Qranium device handle
+ * @dbc_id: ID of the DBC which will exit SSR
+ */
+void dbc_exit_ssr(struct qaic_device *qdev, u32 dbc_id)
+{
+       qdev->dbc[dbc_id].in_ssr = false;
+}
-- 
2.7.4

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