On Tue, Feb 24, 2026 at 12:39:04AM +0530, Ekansh Gupta wrote: > Introduce DMA-backed GEM buffer objects for the QDA accelerator > driver and integrate them with the existing memory manager and IOMMU > device abstraction. > > A new qda_gem_obj structure wraps drm_gem_object and tracks the > kernel virtual address, DMA address, size and owning qda_iommu_device. > qda_gem_create_object() allocates a GEM object, aligns the requested > size, and uses qda_memory_manager_alloc() to obtain DMA-coherent > memory from a per-process IOMMU device. The GEM object implements > a .mmap callback that validates the VMA offset and calls into > qda_dma_mmap(), which maps the DMA memory into userspace and sets > appropriate VMA flags. > > The DMA backend is implemented in qda_memory_dma.c, which allocates > and frees coherent memory via dma_alloc_coherent() and > dma_free_coherent(), while storing a SID-prefixed DMA address in > the GEM object for later use by DSP firmware. The memory manager > is extended to maintain a mapping from processes to IOMMU devices > using qda_file_priv and a process_assignment_lock, and provides > qda_memory_manager_alloc() and qda_memory_manager_free() helpers > for GEM allocations.
Why are you not using drm_gem_dma_helper? > > This patch lays the groundwork for GEM allocation and mmap IOCTLs > as well as future PRIME and job submission support for QDA buffers. Documentation/process/submitting-patches.rst, "This patch" > > Signed-off-by: Ekansh Gupta <[email protected]> > --- > drivers/accel/qda/Makefile | 2 + > drivers/accel/qda/qda_drv.c | 23 +++- > drivers/accel/qda/qda_drv.h | 7 ++ > drivers/accel/qda/qda_gem.c | 187 +++++++++++++++++++++++++++++++ > drivers/accel/qda/qda_gem.h | 63 +++++++++++ > drivers/accel/qda/qda_memory_dma.c | 91 ++++++++++++++++ > drivers/accel/qda/qda_memory_dma.h | 46 ++++++++ > drivers/accel/qda/qda_memory_manager.c | 194 > +++++++++++++++++++++++++++++++++ > drivers/accel/qda/qda_memory_manager.h | 33 ++++++ > 9 files changed, 645 insertions(+), 1 deletion(-) > > diff --git a/drivers/accel/qda/Makefile b/drivers/accel/qda/Makefile > index f547398e1a72..88c324fa382c 100644 > --- a/drivers/accel/qda/Makefile > +++ b/drivers/accel/qda/Makefile > @@ -11,5 +11,7 @@ qda-y := \ > qda_cb.o \ > qda_memory_manager.o \ > qda_ioctl.o \ > + qda_gem.o \ > + qda_memory_dma.o \ > > obj-$(CONFIG_DRM_ACCEL_QDA_COMPUTE_BUS) += qda_compute_bus.o > diff --git a/drivers/accel/qda/qda_drv.c b/drivers/accel/qda/qda_drv.c > index 86758a9cd982..19798359b14e 100644 > --- a/drivers/accel/qda/qda_drv.c > +++ b/drivers/accel/qda/qda_drv.c > @@ -15,7 +15,7 @@ > #include "qda_ioctl.h" > #include "qda_rpmsg.h" > > -static struct qda_drm_priv *get_drm_priv_from_device(struct drm_device *dev) > +struct qda_drm_priv *get_drm_priv_from_device(struct drm_device *dev) And this is a namespace leak. Please name all your functions in a selected style (qda_foo()). > { > if (!dev) > return NULL; > @@ -88,6 +88,7 @@ static int qda_open(struct drm_device *dev, struct drm_file > *file) > return -ENOMEM; > > qda_file_priv->pid = current->pid; > + qda_file_priv->assigned_iommu_dev = NULL; /* Will be assigned on first > allocation */ Why? Also, isn't qda_file_priv zero-filled? > > qda_user = alloc_qda_user(qdev); > if (!qda_user) { > @@ -118,6 +119,26 @@ static void qda_postclose(struct drm_device *dev, struct > drm_file *file) > > qda_file_priv = (struct qda_file_priv *)file->driver_priv; > if (qda_file_priv) { Cant it be NULL? When? > + if (qda_file_priv->assigned_iommu_dev) { > + struct qda_iommu_device *iommu_dev = > qda_file_priv->assigned_iommu_dev; > + unsigned long flags; > + > + /* Decrement reference count - if it reaches 0, reset > PID assignment */ > + if (refcount_dec_and_test(&iommu_dev->refcount)) { > + /* Last reference released - reset PID > assignment */ > + spin_lock_irqsave(&iommu_dev->lock, flags); > + iommu_dev->assigned_pid = 0; This is the part that needs to be discussed in the commit message instead of a generic description of the patch. What is assigned_pid / assigned_iommu_dev? Why do they need to be assigned? > + iommu_dev->assigned_file_priv = NULL; > + spin_unlock_irqrestore(&iommu_dev->lock, flags); > + > + qda_dbg(qdev, "Reset PID assignment for IOMMU > device %u (process %d exited)\n", > + iommu_dev->id, qda_file_priv->pid); > + } else { > + qda_dbg(qdev, "Decremented reference for IOMMU > device %u from process %d\n", > + iommu_dev->id, qda_file_priv->pid); > + } > + } > + > qda_user = qda_file_priv->qda_user; > if (qda_user) > free_qda_user(qda_user); > diff --git a/drivers/accel/qda/qda_drv.h b/drivers/accel/qda/qda_drv.h > index e0ba37702a86..8a2cd474958b 100644 > --- a/drivers/accel/qda/qda_drv.h > +++ b/drivers/accel/qda/qda_drv.h > @@ -33,6 +33,8 @@ struct qda_file_priv { > pid_t pid; > /* Pointer to qda_user structure for backward compatibility */ > struct qda_user *qda_user; > + /* IOMMU device assigned to this process */ > + struct qda_iommu_device *assigned_iommu_dev; > }; > > /** > @@ -153,4 +155,9 @@ void qda_deinit_device(struct qda_dev *qdev); > int qda_register_device(struct qda_dev *qdev); > void qda_unregister_device(struct qda_dev *qdev); > > +/* > + * Utility function to get DRM private data from DRM device > + */ > +struct qda_drm_priv *get_drm_priv_from_device(struct drm_device *dev); > + > #endif /* __QDA_DRV_H__ */ > diff --git a/drivers/accel/qda/qda_gem.c b/drivers/accel/qda/qda_gem.c > new file mode 100644 > index 000000000000..bbd54e2502d3 > --- /dev/null > +++ b/drivers/accel/qda/qda_gem.c > @@ -0,0 +1,187 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. > +#include <drm/drm_gem.h> > +#include <drm/drm_prime.h> > +#include <linux/slab.h> > +#include <linux/dma-mapping.h> > +#include "qda_drv.h" > +#include "qda_gem.h" > +#include "qda_memory_manager.h" > +#include "qda_memory_dma.h" > + > +static int validate_gem_obj_for_mmap(struct qda_gem_obj *qda_gem_obj) > +{ > + if (qda_gem_obj->size == 0) { > + qda_err(NULL, "Invalid GEM object size\n"); > + return -EINVAL; > + } > + if (!qda_gem_obj->iommu_dev || !qda_gem_obj->iommu_dev->dev) { > + qda_err(NULL, "Allocated buffer missing IOMMU device\n"); > + return -EINVAL; > + } > + if (!qda_gem_obj->iommu_dev->dev) { > + qda_err(NULL, "Allocated buffer missing IOMMU device\n"); > + return -EINVAL; > + } > + if (!qda_gem_obj->virt) { > + qda_err(NULL, "Allocated buffer missing virtual address\n"); > + return -EINVAL; > + } > + if (qda_gem_obj->dma_addr == 0) { > + qda_err(NULL, "Allocated buffer missing DMA address\n"); > + return -EINVAL; > + } Is any of these conditions real? > + > + return 0; > +} > + > +static int validate_vma_offset(struct drm_gem_object *drm_obj, struct > vm_area_struct *vma) > +{ > + u64 expected_offset = drm_vma_node_offset_addr(&drm_obj->vma_node); > + u64 actual_offset = vma->vm_pgoff << PAGE_SHIFT; > + > + if (actual_offset != expected_offset) { What?? > + qda_err(NULL, "VMA offset mismatch: expected=0x%llx, > actual=0x%llx\n", > + expected_offset, actual_offset); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static void setup_vma_flags(struct vm_area_struct *vma) > +{ > + vm_flags_set(vma, VM_DONTEXPAND); > + vm_flags_set(vma, VM_DONTDUMP); > +} > + > +void qda_gem_free_object(struct drm_gem_object *gem_obj) > +{ > + struct qda_gem_obj *qda_gem_obj = to_qda_gem_obj(gem_obj); > + struct qda_drm_priv *drm_priv = get_drm_priv_from_device(gem_obj->dev); > + > + if (qda_gem_obj->virt) { > + if (drm_priv && drm_priv->iommu_mgr) > + qda_memory_manager_free(drm_priv->iommu_mgr, > qda_gem_obj); > + } > + > + drm_gem_object_release(gem_obj); > + kfree(qda_gem_obj); > +} > + > +int qda_gem_mmap_obj(struct drm_gem_object *drm_obj, struct vm_area_struct > *vma) > +{ > + struct qda_gem_obj *qda_gem_obj = to_qda_gem_obj(drm_obj); > + int ret; > + > + ret = validate_gem_obj_for_mmap(qda_gem_obj); > + if (ret) { > + qda_err(NULL, "GEM object validation failed: %d\n", ret); > + return ret; > + } > + > + ret = validate_vma_offset(drm_obj, vma); > + if (ret) { > + qda_err(NULL, "VMA offset validation failed: %d\n", ret); > + return ret; > + } > + > + /* Reset vm_pgoff for DMA mmap */ > + vma->vm_pgoff = 0; > + > + ret = qda_dma_mmap(qda_gem_obj, vma); > + > + if (ret == 0) { > + setup_vma_flags(vma); > + qda_dbg(NULL, "GEM object mapped successfully\n"); > + } else { > + qda_err(NULL, "GEM object mmap failed: %d\n", ret); > + } > + > + return ret; > +} > + > +static const struct drm_gem_object_funcs qda_gem_object_funcs = { > + .free = qda_gem_free_object, > + .mmap = qda_gem_mmap_obj, > +}; > + > +struct qda_gem_obj *qda_gem_alloc_object(struct drm_device *drm_dev, size_t > aligned_size) > +{ > + struct qda_gem_obj *qda_gem_obj; > + int ret; > + > + qda_gem_obj = kzalloc_obj(*qda_gem_obj, GFP_KERNEL); > + if (!qda_gem_obj) > + return ERR_PTR(-ENOMEM); > + > + ret = drm_gem_object_init(drm_dev, &qda_gem_obj->base, aligned_size); > + if (ret) { > + qda_err(NULL, "Failed to initialize GEM object: %d\n", ret); > + kfree(qda_gem_obj); > + return ERR_PTR(ret); > + } > + > + qda_gem_obj->base.funcs = &qda_gem_object_funcs; > + qda_gem_obj->size = aligned_size; > + > + qda_dbg(NULL, "Allocated GEM object size=%zu\n", aligned_size); > + return qda_gem_obj; > +} > + > +void qda_gem_cleanup_object(struct qda_gem_obj *qda_gem_obj) > +{ > + drm_gem_object_release(&qda_gem_obj->base); > + kfree(qda_gem_obj); > +} > + > +struct drm_gem_object *qda_gem_lookup_object(struct drm_file *file_priv, u32 > handle) > +{ > + struct drm_gem_object *gem_obj; > + > + gem_obj = drm_gem_object_lookup(file_priv, handle); > + if (!gem_obj) > + return ERR_PTR(-ENOENT); > + > + return gem_obj; > +} > + > +int qda_gem_create_handle(struct drm_file *file_priv, struct drm_gem_object > *gem_obj, u32 *handle) > +{ > + int ret; > + > + ret = drm_gem_handle_create(file_priv, gem_obj, handle); > + drm_gem_object_put(gem_obj); > + > + return ret; > +} > + > +struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev, > + struct qda_memory_manager > *iommu_mgr, size_t size, > + struct drm_file *file_priv) > +{ > + struct qda_gem_obj *qda_gem_obj; > + size_t aligned_size; > + int ret; > + > + if (size == 0) { > + qda_err(NULL, "Invalid size for GEM object creation\n"); > + return ERR_PTR(-EINVAL); > + } > + > + aligned_size = PAGE_ALIGN(size); > + > + qda_gem_obj = qda_gem_alloc_object(drm_dev, aligned_size); > + if (IS_ERR(qda_gem_obj)) > + return (struct drm_gem_object *)qda_gem_obj; > + > + ret = qda_memory_manager_alloc(iommu_mgr, qda_gem_obj, file_priv); > + if (ret) { > + qda_err(NULL, "Memory manager allocation failed: %d\n", ret); > + qda_gem_cleanup_object(qda_gem_obj); > + return ERR_PTR(ret); > + } > + > + qda_dbg(NULL, "GEM object created successfully size=%zu\n", > aligned_size); > + return &qda_gem_obj->base; > +} > diff --git a/drivers/accel/qda/qda_gem.h b/drivers/accel/qda/qda_gem.h > new file mode 100644 > index 000000000000..caae9cda5363 > --- /dev/null > +++ b/drivers/accel/qda/qda_gem.h > @@ -0,0 +1,63 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. > + */ > +#ifndef _QDA_GEM_H > +#define _QDA_GEM_H > + > +#include <linux/xarray.h> > +#include <drm/drm_device.h> > +#include <drm/drm_gem.h> > +#include <linux/dma-mapping.h> > + > +/* Forward declarations */ > +struct qda_memory_manager; > +struct qda_iommu_device; > + > +/** > + * struct qda_gem_obj - QDA GEM buffer object > + * > + * This structure represents a GEM buffer object that can be either > + * allocated by the driver or imported from another driver via dma-buf. > + */ > +struct qda_gem_obj { > + /* DRM GEM object base structure */ > + struct drm_gem_object base; > + /* Kernel virtual address of allocated memory */ > + void *virt; > + /* DMA address for allocated buffers */ > + dma_addr_t dma_addr; > + /* Size of the buffer in bytes */ > + size_t size; > + /* IOMMU device that performed the allocation */ > + struct qda_iommu_device *iommu_dev; > +}; > + > +/* > + * Helper macro to cast a drm_gem_object to qda_gem_obj > + */ > +#define to_qda_gem_obj(gem_obj) container_of(gem_obj, struct qda_gem_obj, > base) > + > +/* > + * GEM object lifecycle management > + */ > +struct drm_gem_object *qda_gem_create_object(struct drm_device *drm_dev, > + struct qda_memory_manager > *iommu_mgr, > + size_t size, struct drm_file > *file_priv); > +void qda_gem_free_object(struct drm_gem_object *gem_obj); > +int qda_gem_mmap_obj(struct drm_gem_object *gem_obj, struct vm_area_struct > *vma); > + > +/* > + * Helper functions for GEM object allocation and cleanup > + * These are used internally and by the PRIME import code > + */ > +struct qda_gem_obj *qda_gem_alloc_object(struct drm_device *drm_dev, size_t > aligned_size); > +void qda_gem_cleanup_object(struct qda_gem_obj *qda_gem_obj); > + > +/* > + * Utility functions for GEM operations > + */ > +struct drm_gem_object *qda_gem_lookup_object(struct drm_file *file_priv, u32 > handle); > +int qda_gem_create_handle(struct drm_file *file_priv, struct drm_gem_object > *gem_obj, u32 *handle); > + > +#endif /* _QDA_GEM_H */ > diff --git a/drivers/accel/qda/qda_memory_dma.c > b/drivers/accel/qda/qda_memory_dma.c > new file mode 100644 > index 000000000000..ffdd5423c88c > --- /dev/null > +++ b/drivers/accel/qda/qda_memory_dma.c > @@ -0,0 +1,91 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. > +#include <linux/slab.h> > +#include <linux/dma-mapping.h> > +#include "qda_drv.h" > +#include "qda_memory_dma.h" > + > +static dma_addr_t get_actual_dma_addr(struct qda_gem_obj *gem_obj) > +{ > + return gem_obj->dma_addr - ((u64)gem_obj->iommu_dev->sid << 32); > +} > + > +static void setup_gem_object(struct qda_gem_obj *gem_obj, void *virt, > + dma_addr_t dma_addr, struct qda_iommu_device > *iommu_dev) > +{ > + gem_obj->virt = virt; > + gem_obj->dma_addr = dma_addr; > + gem_obj->iommu_dev = iommu_dev; > +} > + > +static void cleanup_gem_object_fields(struct qda_gem_obj *gem_obj) > +{ > + gem_obj->virt = NULL; > + gem_obj->dma_addr = 0; > + gem_obj->iommu_dev = NULL; > +} > + > +int qda_dma_alloc(struct qda_iommu_device *iommu_dev, > + struct qda_gem_obj *gem_obj, size_t size) > +{ > + void *virt; > + dma_addr_t dma_addr; > + > + if (!iommu_dev || !iommu_dev->dev) { > + qda_err(NULL, "Invalid iommu_dev or device for DMA > allocation\n"); > + return -EINVAL; > + } > + > + virt = dma_alloc_coherent(iommu_dev->dev, size, &dma_addr, GFP_KERNEL); > + if (!virt) > + return -ENOMEM; > + > + dma_addr += ((u64)iommu_dev->sid << 32); > + > + qda_dbg(NULL, "DMA address with SID prefix: 0x%llx (sid=%u)\n", > + (u64)dma_addr, iommu_dev->sid); > + > + setup_gem_object(gem_obj, virt, dma_addr, iommu_dev); > + > + return 0; > +} > + > +void qda_dma_free(struct qda_gem_obj *gem_obj) > +{ > + if (!gem_obj || !gem_obj->iommu_dev) { > + qda_dbg(NULL, "Invalid gem_obj or iommu_dev for DMA free\n"); > + return; > + } > + > + qda_dbg(NULL, "DMA freeing: size=%zu, device_id=%u, dma_addr=0x%llx\n", > + gem_obj->size, gem_obj->iommu_dev->id, gem_obj->dma_addr); > + > + dma_free_coherent(gem_obj->iommu_dev->dev, gem_obj->size, > + gem_obj->virt, get_actual_dma_addr(gem_obj)); > + > + cleanup_gem_object_fields(gem_obj); > +} > + > +int qda_dma_mmap(struct qda_gem_obj *gem_obj, struct vm_area_struct *vma) > +{ > + struct qda_iommu_device *iommu_dev; > + int ret; > + > + if (!gem_obj || !gem_obj->virt || !gem_obj->iommu_dev || > !gem_obj->iommu_dev->dev) { > + qda_err(NULL, "Invalid parameters for DMA mmap\n"); > + return -EINVAL; > + } > + > + iommu_dev = gem_obj->iommu_dev; > + > + ret = dma_mmap_coherent(iommu_dev->dev, vma, gem_obj->virt, > + get_actual_dma_addr(gem_obj), gem_obj->size); > + > + if (ret) > + qda_err(NULL, "DMA mmap failed: size=%zu, device_id=%u, > ret=%d\n", > + gem_obj->size, iommu_dev->id, ret); if (ret) { qda_err(); return ret; // or goto err_foo; } return 0; > + else > + qda_dbg(NULL, "DMA mmap successful: size=%zu\n", gem_obj->size); It feels like the driver is over-verbose if debugging is enabled. > + > + return ret; > +} > diff --git a/drivers/accel/qda/qda_memory_dma.h > b/drivers/accel/qda/qda_memory_dma.h > new file mode 100644 > index 000000000000..79b3c4053a82 > --- /dev/null > +++ b/drivers/accel/qda/qda_memory_dma.h > @@ -0,0 +1,46 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. > + */ > + > +#ifndef _QDA_MEMORY_DMA_H > +#define _QDA_MEMORY_DMA_H > + > +#include <linux/dma-mapping.h> > +#include "qda_memory_manager.h" > + > +/** > + * qda_dma_alloc() - Allocate DMA coherent memory for a GEM object > + * @iommu_dev: Pointer to the QDA IOMMU device structure > + * @gem_obj: Pointer to GEM object to allocate memory for > + * @size: Size of memory to allocate in bytes > + * > + * Allocates DMA-coherent memory and sets up the GEM object with the > + * allocated memory details including virtual and DMA addresses. > + * > + * Return: 0 on success, negative error code on failure > + */ Move the kerneldoc from the headers to the driver code, otherwise they are mostly ignored by the automatic validators. > +int qda_dma_alloc(struct qda_iommu_device *iommu_dev, > + struct qda_gem_obj *gem_obj, size_t size); > + > +/** > + * qda_dma_free() - Free DMA coherent memory for a GEM object > + * @gem_obj: Pointer to GEM object to free memory for > + * > + * Frees DMA-coherent memory previously allocated for the GEM object > + * and cleans up the GEM object fields. > + */ > +void qda_dma_free(struct qda_gem_obj *gem_obj); > + > +/** > + * qda_dma_mmap() - Map DMA memory into userspace > + * @gem_obj: Pointer to GEM object containing DMA memory > + * @vma: Virtual memory area to map into > + * > + * Maps DMA-coherent memory into userspace virtual address space. > + * > + * Return: 0 on success, negative error code on failure > + */ > +int qda_dma_mmap(struct qda_gem_obj *gem_obj, struct vm_area_struct *vma); > + > +#endif /* _QDA_MEMORY_DMA_H */ > diff --git a/drivers/accel/qda/qda_memory_manager.c > b/drivers/accel/qda/qda_memory_manager.c > index b4c7047a89d4..e225667557ee 100644 > --- a/drivers/accel/qda/qda_memory_manager.c > +++ b/drivers/accel/qda/qda_memory_manager.c > @@ -6,8 +6,11 @@ > #include <linux/spinlock.h> > #include <linux/workqueue.h> > #include <linux/xarray.h> > +#include <drm/drm_file.h> > #include "qda_drv.h" > +#include "qda_gem.h" > #include "qda_memory_manager.h" > +#include "qda_memory_dma.h" > > static void cleanup_all_memory_devices(struct qda_memory_manager *mem_mgr) > { > @@ -55,6 +58,8 @@ static void init_iommu_device_fields(struct > qda_iommu_device *iommu_dev, > spin_lock_init(&iommu_dev->lock); > refcount_set(&iommu_dev->refcount, 0); > INIT_WORK(&iommu_dev->remove_work, qda_memory_manager_remove_work); > + iommu_dev->assigned_pid = 0; > + iommu_dev->assigned_file_priv = NULL; > } > > static int allocate_device_id(struct qda_memory_manager *mem_mgr, > @@ -78,6 +83,194 @@ static int allocate_device_id(struct qda_memory_manager > *mem_mgr, > return ret; > } > > +static struct qda_iommu_device *find_device_for_pid(struct > qda_memory_manager *mem_mgr, > + pid_t pid) > +{ > + unsigned long index; > + void *entry; > + struct qda_iommu_device *found_dev = NULL; > + unsigned long flags; > + > + xa_lock(&mem_mgr->device_xa); > + xa_for_each(&mem_mgr->device_xa, index, entry) { > + struct qda_iommu_device *iommu_dev = entry; > + > + spin_lock_irqsave(&iommu_dev->lock, flags); > + if (iommu_dev->assigned_pid == pid) { > + found_dev = iommu_dev; > + refcount_inc(&found_dev->refcount); > + qda_dbg(NULL, "Reusing device id=%u for PID=%d > (refcount=%u)\n", > + found_dev->id, pid, > refcount_read(&found_dev->refcount)); And what if there are two different FastRPC sessions within the same PID? > + spin_unlock_irqrestore(&iommu_dev->lock, flags); > + break; > + } > + spin_unlock_irqrestore(&iommu_dev->lock, flags); > + } > + xa_unlock(&mem_mgr->device_xa); > + > + return found_dev; > +} > + > +static struct qda_iommu_device *assign_available_device_to_pid(struct > qda_memory_manager *mem_mgr, > + pid_t pid, > + struct drm_file > *file_priv) > +{ > + unsigned long index; > + void *entry; > + struct qda_iommu_device *selected_dev = NULL; > + unsigned long flags; > + > + xa_lock(&mem_mgr->device_xa); > + xa_for_each(&mem_mgr->device_xa, index, entry) { > + struct qda_iommu_device *iommu_dev = entry; > + > + spin_lock_irqsave(&iommu_dev->lock, flags); > + if (iommu_dev->assigned_pid == 0) { > + iommu_dev->assigned_pid = pid; > + iommu_dev->assigned_file_priv = file_priv; > + selected_dev = iommu_dev; > + refcount_set(&selected_dev->refcount, 1); > + qda_dbg(NULL, "Assigned device id=%u to PID=%d\n", > + selected_dev->id, pid); > + spin_unlock_irqrestore(&iommu_dev->lock, flags); > + break; > + } > + spin_unlock_irqrestore(&iommu_dev->lock, flags); > + } > + xa_unlock(&mem_mgr->device_xa); > + > + return selected_dev; > +} > + > +static struct qda_iommu_device *get_process_iommu_device(struct > qda_memory_manager *mem_mgr, > + struct drm_file > *file_priv) > +{ > + struct qda_file_priv *qda_priv; > + > + if (!file_priv || !file_priv->driver_priv) > + return NULL; > + > + qda_priv = (struct qda_file_priv *)file_priv->driver_priv; > + return qda_priv->assigned_iommu_dev; > +} > + > +static int qda_memory_manager_assign_device(struct qda_memory_manager > *mem_mgr, > + struct drm_file *file_priv) > +{ > + struct qda_file_priv *qda_priv; > + struct qda_iommu_device *selected_dev = NULL; > + int ret = 0; > + pid_t current_pid; > + > + if (!file_priv || !file_priv->driver_priv) { > + qda_err(NULL, "Invalid file_priv or driver_priv\n"); > + return -EINVAL; > + } > + > + qda_priv = (struct qda_file_priv *)file_priv->driver_priv; > + current_pid = qda_priv->pid; > + > + mutex_lock(&mem_mgr->process_assignment_lock); > + > + if (qda_priv->assigned_iommu_dev) { > + qda_dbg(NULL, "PID=%d already has device id=%u assigned\n", > + current_pid, qda_priv->assigned_iommu_dev->id); > + ret = 0; > + goto unlock_and_return; > + } > + > + selected_dev = find_device_for_pid(mem_mgr, current_pid); > + > + if (selected_dev) { > + qda_priv->assigned_iommu_dev = selected_dev; > + goto unlock_and_return; > + } > + > + selected_dev = assign_available_device_to_pid(mem_mgr, current_pid, > file_priv); > + > + if (!selected_dev) { > + qda_err(NULL, "No available device for PID=%d\n", current_pid); > + ret = -ENOMEM; > + goto unlock_and_return; > + } > + > + qda_priv->assigned_iommu_dev = selected_dev; > + > +unlock_and_return: > + mutex_unlock(&mem_mgr->process_assignment_lock); > + return ret; > +} > + > +static struct qda_iommu_device *get_or_assign_iommu_device(struct > qda_memory_manager *mem_mgr, > + struct drm_file > *file_priv, > + size_t size) > +{ > + struct qda_iommu_device *iommu_dev; > + int ret; > + > + iommu_dev = get_process_iommu_device(mem_mgr, file_priv); > + if (iommu_dev) > + return iommu_dev; > + > + ret = qda_memory_manager_assign_device(mem_mgr, file_priv); > + if (ret) > + return NULL; > + > + iommu_dev = get_process_iommu_device(mem_mgr, file_priv); > + if (iommu_dev) > + return iommu_dev; > + > + return NULL; > +} > + > +int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, struct > qda_gem_obj *gem_obj, > + struct drm_file *file_priv) > +{ > + struct qda_iommu_device *selected_dev; > + size_t size; > + int ret; > + > + if (!mem_mgr || !gem_obj || !file_priv) { > + qda_err(NULL, "Invalid parameters for memory allocation\n"); > + return -EINVAL; > + } > + > + size = gem_obj->size; > + if (size == 0) { > + qda_err(NULL, "Invalid allocation size: 0\n"); > + return -EINVAL; > + } > + > + selected_dev = get_or_assign_iommu_device(mem_mgr, file_priv, size); > + > + if (!selected_dev) { > + qda_err(NULL, "Failed to get/assign device for allocation > (size=%zu)\n", size); > + return -ENOMEM; > + } > + > + ret = qda_dma_alloc(selected_dev, gem_obj, size); > + > + if (ret) { > + qda_err(NULL, "Allocation failed: size=%zu, device_id=%u, > ret=%d\n", > + size, selected_dev->id, ret); > + return ret; > + } > + > + qda_dbg(NULL, "Successfully allocated: size=%zu, device_id=%u, > dma_addr=0x%llx\n", > + size, selected_dev->id, gem_obj->dma_addr); > + return 0; > +} > + > +void qda_memory_manager_free(struct qda_memory_manager *mem_mgr, struct > qda_gem_obj *gem_obj) > +{ > + if (!gem_obj || !gem_obj->iommu_dev) { > + qda_dbg(NULL, "Invalid gem_obj or iommu_dev for free\n"); > + return; > + } > + > + qda_dma_free(gem_obj); > +} > + > int qda_memory_manager_register_device(struct qda_memory_manager *mem_mgr, > struct qda_iommu_device *iommu_dev) > { > @@ -134,6 +327,7 @@ int qda_memory_manager_init(struct qda_memory_manager > *mem_mgr) > > xa_init_flags(&mem_mgr->device_xa, XA_FLAGS_ALLOC); > atomic_set(&mem_mgr->next_id, 0); > + mutex_init(&mem_mgr->process_assignment_lock); > mem_mgr->wq = create_workqueue("memory_manager_wq"); > if (!mem_mgr->wq) { > qda_err(NULL, "Failed to create memory manager workqueue\n"); > diff --git a/drivers/accel/qda/qda_memory_manager.h > b/drivers/accel/qda/qda_memory_manager.h > index 3bf4cd529909..bac44284ef98 100644 > --- a/drivers/accel/qda/qda_memory_manager.h > +++ b/drivers/accel/qda/qda_memory_manager.h > @@ -11,6 +11,8 @@ > #include <linux/spinlock.h> > #include <linux/workqueue.h> > #include <linux/xarray.h> > +#include <drm/drm_file.h> > +#include "qda_gem.h" > > /** > * struct qda_iommu_device - IOMMU device instance for memory management > @@ -35,6 +37,10 @@ struct qda_iommu_device { > u32 sid; > /* Pointer to parent memory manager */ > struct qda_memory_manager *manager; > + /* Process ID of the process assigned to this device */ > + pid_t assigned_pid; > + /* DRM file private data for the assigned process */ > + struct drm_file *assigned_file_priv; > }; > > /** > @@ -51,6 +57,8 @@ struct qda_memory_manager { > atomic_t next_id; > /* Workqueue for asynchronous device operations */ > struct workqueue_struct *wq; > + /* Mutex protecting process-to-device assignments */ > + struct mutex process_assignment_lock; > }; > > /** > @@ -98,4 +106,29 @@ int qda_memory_manager_register_device(struct > qda_memory_manager *mem_mgr, > void qda_memory_manager_unregister_device(struct qda_memory_manager *mem_mgr, > struct qda_iommu_device *iommu_dev); > > +/** > + * qda_memory_manager_alloc() - Allocate memory for a GEM object > + * @mem_mgr: Pointer to memory manager > + * @gem_obj: Pointer to GEM object to allocate memory for > + * @file_priv: DRM file private data for process association > + * > + * Allocates memory for the specified GEM object using an appropriate IOMMU > + * device. The allocation is associated with the calling process via > + * file_priv. > + * > + * Return: 0 on success, negative error code on failure > + */ > +int qda_memory_manager_alloc(struct qda_memory_manager *mem_mgr, struct > qda_gem_obj *gem_obj, > + struct drm_file *file_priv); > + > +/** > + * qda_memory_manager_free() - Free memory for a GEM object > + * @mem_mgr: Pointer to memory manager > + * @gem_obj: Pointer to GEM object to free memory for > + * > + * Releases memory previously allocated for the specified GEM object and > + * removes any associated IOMMU mappings. > + */ > +void qda_memory_manager_free(struct qda_memory_manager *mem_mgr, struct > qda_gem_obj *gem_obj); > + > #endif /* _QDA_MEMORY_MANAGER_H */ > > -- > 2.34.1 > -- With best wishes Dmitry
