From: Rob Clark rob@ti.com
Add some helpers to iterate through all attachers and get the most restrictive segment size/count/boundary.
Signed-off-by: Rob Clark rob@ti.com --- drivers/base/dma-buf.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 19 ++++++++++++++ 2 files changed, 82 insertions(+)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 24e88fe..757ee20 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -192,6 +192,69 @@ void dma_buf_put(struct dma_buf *dmabuf) EXPORT_SYMBOL_GPL(dma_buf_put);
/** + * dma_buf_max_seg_size - helper for exporters to get the minimum of + * all attached device's max segment size + */ +unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf) +{ + struct dma_buf_attachment *attach; + unsigned int max = (unsigned int)-1; + + if (WARN_ON(!dmabuf)) + return 0; + + mutex_lock(&dmabuf->lock); + list_for_each_entry(attach, &dmabuf->attachments, node) + max = min(max, dma_get_max_seg_size(attach->dev)); + mutex_unlock(&dmabuf->lock); + + return max; +} +EXPORT_SYMBOL_GPL(dma_buf_max_seg_size); + +/** + * dma_buf_max_seg_count - helper for exporters to get the minimum of + * all attached device's max segment count + */ +unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf) +{ + struct dma_buf_attachment *attach; + unsigned int max = (unsigned int)-1; + + if (WARN_ON(!dmabuf)) + return 0; + + mutex_lock(&dmabuf->lock); + list_for_each_entry(attach, &dmabuf->attachments, node) + max = min(max, dma_get_max_seg_count(attach->dev)); + mutex_unlock(&dmabuf->lock); + + return max; +} +EXPORT_SYMBOL_GPL(dma_buf_max_seg_count); + +/** + * dma_buf_get_seg_boundary - helper for exporters to get the most + * restrictive segment alignment of all the attached devices + */ +unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf) +{ + struct dma_buf_attachment *attach; + unsigned int mask = (unsigned int)-1; + + if (WARN_ON(!dmabuf)) + return 0; + + mutex_lock(&dmabuf->lock); + list_for_each_entry(attach, &dmabuf->attachments, node) + mask &= dma_get_seg_boundary(attach->dev); + mutex_unlock(&dmabuf->lock); + + return mask; +} +EXPORT_SYMBOL_GPL(dma_buf_get_seg_boundary); + +/** * dma_buf_attach - Add the device to dma_buf's attachments list; optionally, * calls attach() of dma_buf_ops to allow device-specific attach functionality * @dmabuf: [in] buffer to attach device to. diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index eb48f38..9533b9b 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -167,6 +167,10 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags); struct dma_buf *dma_buf_get(int fd); void dma_buf_put(struct dma_buf *dmabuf);
+unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf); +unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf); +unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf); + struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, enum dma_data_direction); void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, @@ -220,6 +224,21 @@ static inline void dma_buf_put(struct dma_buf *dmabuf) return; }
+static inline unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf) +{ + return 0; +} + +static inline unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf) +{ + return 0; +} + +static inline unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf) +{ + return 0; +} + static inline struct sg_table *dma_buf_map_attachment( struct dma_buf_attachment *attach, enum dma_data_direction write) {