Create a new mtk_svp_cma heap from the CMA reserved buffer.

When the first allocating buffer, use cma_alloc to prepare whole the
CMA range, then send its range to TEE to protect and manage.
For the later allocating, we just adds the cma_used_size.

When SVP done, cma_release will release the buffer, then kernel may
reuse it.

Signed-off-by: Yong Wu <yong...@mediatek.com>
---
 drivers/dma-buf/heaps/Kconfig           |   2 +-
 drivers/dma-buf/heaps/mtk_secure_heap.c | 121 +++++++++++++++++++++++-
 2 files changed, 119 insertions(+), 4 deletions(-)

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 729c0cf3eb7c..e101f788ecbf 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -15,7 +15,7 @@ config DMABUF_HEAPS_CMA
 
 config DMABUF_HEAPS_MTK_SECURE
        bool "DMA-BUF MediaTek Secure Heap"
-       depends on DMABUF_HEAPS && TEE
+       depends on DMABUF_HEAPS && TEE && CMA
        help
          Choose this option to enable dma-buf MediaTek secure heap for Secure
          Video Path. This heap is backed by TEE client interfaces. If in
diff --git a/drivers/dma-buf/heaps/mtk_secure_heap.c 
b/drivers/dma-buf/heaps/mtk_secure_heap.c
index daf6cf2121a1..3f568fe6b569 100644
--- a/drivers/dma-buf/heaps/mtk_secure_heap.c
+++ b/drivers/dma-buf/heaps/mtk_secure_heap.c
@@ -4,11 +4,12 @@
  *
  * Copyright (C) 2023 MediaTek Inc.
  */
-
+#include <linux/cma.h>
 #include <linux/dma-buf.h>
 #include <linux/dma-heap.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/tee_drv.h>
@@ -25,9 +26,11 @@
  * MediaTek secure (chunk) memory type
  *
  * @KREE_MEM_SEC_CM_TZ: static chunk memory carved out for trustzone.
+ * @KREE_MEM_SEC_CM_CMA: dynamic chunk memory carved out from CMA.
  */
 enum kree_mem_type {
        KREE_MEM_SEC_CM_TZ = 1,
+       KREE_MEM_SEC_CM_CMA,
 };
 
 struct mtk_secure_heap_buffer {
@@ -42,6 +45,13 @@ struct mtk_secure_heap {
        const enum kree_mem_type mem_type;
        u32                      mem_session;
        struct tee_context      *tee_ctx;
+
+       struct cma              *cma;
+       struct page             *cma_page;
+       unsigned long           cma_paddr;
+       unsigned long           cma_size;
+       unsigned long           cma_used_size;
+       struct mutex            lock; /* lock for cma_used_size */
 };
 
 struct mtk_secure_heap_attachment {
@@ -90,6 +100,42 @@ static int mtk_kree_secure_session_init(struct 
mtk_secure_heap *sec_heap)
        return ret;
 }
 
+static int mtk_sec_mem_cma_allocate(struct mtk_secure_heap *sec_heap, size_t 
size)
+{
+       /*
+        * Allocate CMA only when allocating buffer for the first time, and just
+        * increase cma_used_size at the other times.
+        */
+       mutex_lock(&sec_heap->lock);
+       if (sec_heap->cma_used_size)
+               goto add_size;
+
+       mutex_unlock(&sec_heap->lock);
+       sec_heap->cma_page = cma_alloc(sec_heap->cma, sec_heap->cma_size >> 
PAGE_SHIFT,
+                                      get_order(PAGE_SIZE), false);
+       if (!sec_heap->cma_page)
+               return -ENOMEM;
+
+       mutex_lock(&sec_heap->lock);
+add_size:
+       sec_heap->cma_used_size += size;
+       mutex_unlock(&sec_heap->lock);
+       return sec_heap->cma_used_size;
+}
+
+static void mtk_sec_mem_cma_free(struct mtk_secure_heap *sec_heap, size_t size)
+{
+       bool cma_is_empty;
+
+       mutex_lock(&sec_heap->lock);
+       sec_heap->cma_used_size -= size;
+       cma_is_empty = !sec_heap->cma_used_size;
+       mutex_unlock(&sec_heap->lock);
+
+       if (cma_is_empty)
+               cma_release(sec_heap->cma, sec_heap->cma_page, 
sec_heap->cma_size >> PAGE_SHIFT);
+}
+
 static int
 mtk_sec_mem_tee_service_call(struct tee_context *tee_ctx, u32 session,
                             unsigned int command, struct tee_param *params)
@@ -114,23 +160,47 @@ static int mtk_sec_mem_allocate(struct mtk_secure_heap 
*sec_heap,
 {
        struct tee_param params[MTK_TEE_PARAM_NUM] = {0};
        u32 mem_session = sec_heap->mem_session;
+       bool cma_frst_alloc = false;
        int ret;
 
+       if (sec_heap->cma) {
+               ret = mtk_sec_mem_cma_allocate(sec_heap, sec_buf->size);
+               if (ret < 0)
+                       return ret;
+               /*
+                * When CMA allocates for the first time, pass the CMA range to 
TEE
+                * to protect it. It's the first allocating if the 
cma_used_size is equal
+                * to this required buffer size.
+                */
+               cma_frst_alloc = (ret == sec_buf->size);
+       }
+
        params[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
        params[0].u.value.a = SZ_4K;                    /* alignment */
        params[0].u.value.b = sec_heap->mem_type;       /* memory type */
        params[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
        params[1].u.value.a = sec_buf->size;
        params[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT;
+       if (sec_heap->cma && cma_frst_alloc) {
+               params[2].u.value.a = sec_heap->cma_paddr;
+               params[2].u.value.b = sec_heap->cma_size;
+       }
 
        /* Always request zeroed buffer */
        ret = mtk_sec_mem_tee_service_call(sec_heap->tee_ctx, mem_session,
                                           TZCMD_MEM_SECURECM_ZALLOC, params);
-       if (ret)
-               return -ENOMEM;
+       if (ret) {
+               ret = -ENOMEM;
+               goto free_cma;
+       }
 
        sec_buf->sec_handle = params[2].u.value.a;
        return 0;
+
+free_cma:
+       if (sec_heap->cma)
+               mtk_sec_mem_cma_free(sec_heap, sec_buf->size);
+       return ret;
 }
 
 static void mtk_sec_mem_release(struct mtk_secure_heap *sec_heap,
@@ -145,6 +215,9 @@ static void mtk_sec_mem_release(struct mtk_secure_heap 
*sec_heap,
 
        mtk_sec_mem_tee_service_call(sec_heap->tee_ctx, mem_session,
                                     TZCMD_MEM_SECURECM_UNREF, params);
+
+       if (sec_heap->cma)
+               mtk_sec_mem_cma_free(sec_heap, sec_buf->size);
 }
 
 static int mtk_sec_heap_attach(struct dma_buf *dmabuf, struct 
dma_buf_attachment *attachment)
@@ -317,8 +390,41 @@ static struct mtk_secure_heap mtk_sec_heap[] = {
                .name           = "mtk_svp",
                .mem_type       = KREE_MEM_SEC_CM_TZ,
        },
+       {
+               .name           = "mtk_svp_cma",
+               .mem_type       = KREE_MEM_SEC_CM_CMA,
+       },
 };
 
+static int __init mtk_secure_cma_init(struct reserved_mem *rmem)
+{
+       struct mtk_secure_heap *sec_heap = NULL;
+       int ret, i;
+
+       for (i = 0; i < ARRAY_SIZE(mtk_sec_heap); i++) {
+               if (mtk_sec_heap[i].mem_type != KREE_MEM_SEC_CM_CMA)
+                       continue;
+               sec_heap = &mtk_sec_heap[i];
+               break;
+       }
+       if (!sec_heap)
+               return -ENOENT;
+
+       ret = cma_init_reserved_mem(rmem->base, rmem->size, 0, sec_heap->name,
+                                   &sec_heap->cma);
+       if (ret) {
+               pr_err("%s: %s set up CMA fail\n", __func__, rmem->name);
+               return ret;
+       }
+       sec_heap->cma_paddr = rmem->base;
+       sec_heap->cma_size = rmem->size;
+
+       return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(mtk_secure_cma, "mediatek,secure_cma_chunkmem",
+                      mtk_secure_cma_init);
+
 static int mtk_sec_heap_init(void)
 {
        struct mtk_secure_heap *sec_heap = mtk_sec_heap;
@@ -331,6 +437,15 @@ static int mtk_sec_heap_init(void)
                exp_info.ops = &mtk_sec_heap_ops;
                exp_info.priv = (void *)sec_heap;
 
+               if (sec_heap->mem_type == KREE_MEM_SEC_CM_CMA) {
+                       if (!sec_heap->cma) {
+                               pr_err("CMA is not ready for %s.\n", 
sec_heap->name);
+                               continue;
+                       } else {
+                               mutex_init(&sec_heap->lock);
+                       }
+               }
+
                heap = dma_heap_add(&exp_info);
                if (IS_ERR(heap))
                        return PTR_ERR(heap);
-- 
2.25.1

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