4 files changed, 72 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
index 3b5ca298..0b6b5913 100644
--- a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
@@ -514,6 +514,13 @@ static int gk20a_ctrl_vsm_mapping(struct gk20a *g,
         return err;
 }
 
+static int gk20a_ctrl_get_buffer_info(
+        struct gk20a *g, struct nvgpu_gpu_get_buffer_info_args *args)
+{
+        return gk20a_mm_get_buffer_info(dev_from_gk20a(g), args->in.dmabuf_fd,
+                                        &args->out.id, &args->out.length);
+}
+
 long gk20a_ctrl_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
         struct platform_device *dev = filp->private_data;
@@ -729,6 +736,10 @@ long gk20a_ctrl_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg
                         (struct nvgpu_gpu_vsms_mapping *)buf);
                 break;
 
+        case NVGPU_GPU_IOCTL_GET_BUFFER_INFO:
+                err = gk20a_ctrl_get_buffer_info(g,
+                        (struct nvgpu_gpu_get_buffer_info_args *)buf);
+                break;
 
         default:
                 dev_dbg(dev_from_gk20a(g), "unrecognized gpu ioctl cmd: 0x%x", cmd);
diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index 1bc35597..141a37af 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -120,6 +120,8 @@ struct gk20a_dmabuf_priv {
         int pin_count;
 
         struct list_head states;
+
+        u64 buffer_id;
 };
 
 static void gk20a_vm_remove_support_nofree(struct vm_gk20a *vm);
@@ -3044,6 +3046,7 @@ int gk20a_dmabuf_alloc_drvdata(struct dma_buf *dmabuf, struct device *dev)
 {
         struct gk20a_dmabuf_priv *priv;
         static DEFINE_MUTEX(priv_lock);
+        static u64 priv_count = 0;
 
         priv = dma_buf_get_drvdata(dmabuf, dev);
         if (likely(priv))
@@ -3060,6 +3063,7 @@ int gk20a_dmabuf_alloc_drvdata(struct dma_buf *dmabuf, struct device *dev)
         }
         mutex_init(&priv->lock);
         INIT_LIST_HEAD(&priv->states);
+        priv->buffer_id = ++priv_count;
         dma_buf_set_drvdata(dmabuf, dev, priv, gk20a_mm_delete_priv);
 priv_exist_or_err:
         mutex_unlock(&priv_lock);
@@ -3145,8 +3149,11 @@ int gk20a_vm_map_buffer(struct vm_gk20a *vm,
 
         /* get ref to the mem handle (released on unmap_locked) */
         dmabuf = dma_buf_get(dmabuf_fd);
-        if (IS_ERR(dmabuf))
+        if (IS_ERR(dmabuf)) {
+                dev_warn(dev_from_vm(vm), "%s: fd %d is not a dmabuf",
+                         __func__, dmabuf_fd);
                 return PTR_ERR(dmabuf);
+        }
 
         err = gk20a_dmabuf_alloc_drvdata(dmabuf, dev_from_vm(vm));
         if (err) {
@@ -3653,6 +3660,37 @@ const struct gk20a_mmu_level *gk20a_mm_get_mmu_levels(struct gk20a *g,
                  gk20a_mm_levels_64k : gk20a_mm_levels_128k;
 }
 
+int gk20a_mm_get_buffer_info(struct device *dev, int dmabuf_fd,
+                             u64 *buffer_id, u64 *buffer_len)
+{
+        struct dma_buf *dmabuf;
+        struct gk20a_dmabuf_priv *priv;
+        int err = 0;
+
+        dmabuf = dma_buf_get(dmabuf_fd);
+        if (IS_ERR(dmabuf)) {
+                dev_warn(dev, "%s: fd %d is not a dmabuf", __func__, dmabuf_fd);
+                return PTR_ERR(dmabuf);
+        }
+
+        err = gk20a_dmabuf_alloc_drvdata(dmabuf, dev);
+        if (err) {
+                dev_warn(dev, "Failed to allocate dmabuf drvdata (err = %d)",
+                         err);
+                goto clean_up;
+        }
+
+        priv = dma_buf_get_drvdata(dmabuf, dev);
+        if (likely(priv)) {
+                *buffer_id = priv->buffer_id;
+                *buffer_len = dmabuf->size;
+        }
+
+clean_up:
+        dma_buf_put(dmabuf);
+        return err;
+}
+
 void gk20a_init_mm(struct gpu_ops *gops)
 {
         gops->mm.is_debug_mode_enabled = gk20a_mm_mmu_debug_mode_enabled;
diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
index 7bbaf283..7be4383b 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
@@ -688,4 +688,7 @@ static inline void nvgpu_free(void *p)
                 vfree(p);
 }
 
+int gk20a_mm_get_buffer_info(struct device *dev, int dmabuf_fd,
+                             u64 *buffer_id, u64 *buffer_len);
+
 #endif /* MM_GK20A_H */
diff --git a/include/uapi/linux/nvgpu.h b/include/uapi/linux/nvgpu.h
index 6024edee..6a8e44c5 100644
--- a/include/uapi/linux/nvgpu.h
+++ b/include/uapi/linux/nvgpu.h
@@ -314,6 +314,22 @@ struct nvgpu_gpu_vsms_mapping {
         __u64 vsms_map_buf_addr;
 };
 
+struct nvgpu_gpu_get_buffer_info_args {
+        union {
+                struct {
+                        __u32 dmabuf_fd;   /* dma-buf fd */
+                } in;
+                struct {
+                        __u64 id;          /* Unique within live
+                                            * buffers */
+                        __u64 length;      /* Allocated length of the
+                                            * buffer */
+                        __u64 reserved0;
+                        __u64 reserved1;
+                } out;
+        };
+};
+
 #define NVGPU_GPU_IOCTL_ZCULL_GET_CTX_SIZE \
         _IOR(NVGPU_GPU_IOCTL_MAGIC, 1, struct nvgpu_gpu_zcull_get_ctx_size_args)
 #define NVGPU_GPU_IOCTL_ZCULL_GET_INFO \
@@ -352,9 +368,11 @@ struct nvgpu_gpu_vsms_mapping {
         _IOWR(NVGPU_GPU_IOCTL_MAGIC, 18, struct nvgpu_gpu_num_vsms)
 #define NVGPU_GPU_IOCTL_VSMS_MAPPING \
         _IOWR(NVGPU_GPU_IOCTL_MAGIC, 19, struct nvgpu_gpu_vsms_mapping)
+#define NVGPU_GPU_IOCTL_GET_BUFFER_INFO \
+        _IOWR(NVGPU_GPU_IOCTL_MAGIC, 20, struct nvgpu_gpu_get_buffer_info_args)
 
 #define NVGPU_GPU_IOCTL_LAST            \
-        _IOC_NR(NVGPU_GPU_IOCTL_VSMS_MAPPING)
+        _IOC_NR(NVGPU_GPU_IOCTL_GET_BUFFER_INFO)
 #define NVGPU_GPU_IOCTL_MAX_ARG_SIZE    \
         sizeof(struct nvgpu_gpu_prepare_compressible_read_args)