diff options
Diffstat (limited to 'kernel/dma/mapping.c')
| -rw-r--r-- | kernel/dma/mapping.c | 80 |
1 files changed, 72 insertions, 8 deletions
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 2b06a809d0b9..7ee5284bff58 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -177,12 +177,8 @@ void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size, } EXPORT_SYMBOL(dma_unmap_page_attrs); -/* - * dma_maps_sg_attrs returns 0 on error and > 0 on success. - * It should never return a value < 0. - */ -int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, - enum dma_data_direction dir, unsigned long attrs) +static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); int ents; @@ -197,13 +193,81 @@ int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, ents = dma_direct_map_sg(dev, sg, nents, dir, attrs); else ents = ops->map_sg(dev, sg, nents, dir, attrs); - BUG_ON(ents < 0); - debug_dma_map_sg(dev, sg, nents, ents, dir); + + if (ents > 0) + debug_dma_map_sg(dev, sg, nents, ents, dir); + else if (WARN_ON_ONCE(ents != -EINVAL && ents != -ENOMEM && + ents != -EIO)) + return -EIO; return ents; } + +/** + * dma_map_sg_attrs - Map the given buffer for DMA + * @dev: The device for which to perform the DMA operation + * @sg: The sg_table object describing the buffer + * @dir: DMA direction + * @attrs: Optional DMA attributes for the map operation + * + * Maps a buffer described by a scatterlist passed in the sg argument with + * nents segments for the @dir DMA operation by the @dev device. + * + * Returns the number of mapped entries (which can be less than nents) + * on success. Zero is returned for any error. + * + * dma_unmap_sg_attrs() should be used to unmap the buffer with the + * original sg and original nents (not the value returned by this funciton). + */ +unsigned int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs) +{ + int ret; + + ret = __dma_map_sg_attrs(dev, sg, nents, dir, attrs); + if (ret < 0) + return 0; + return ret; +} EXPORT_SYMBOL(dma_map_sg_attrs); +/** + * dma_map_sgtable - Map the given buffer for DMA + * @dev: The device for which to perform the DMA operation + * @sgt: The sg_table object describing the buffer + * @dir: DMA direction + * @attrs: Optional DMA attributes for the map operation + * + * Maps a buffer described by a scatterlist stored in the given sg_table + * object for the @dir DMA operation by the @dev device. After success, the + * ownership for the buffer is transferred to the DMA domain. One has to + * call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the + * ownership of the buffer back to the CPU domain before touching the + * buffer by the CPU. + * + * Returns 0 on success or a negative error code on error. The following + * error codes are supported with the given meaning: + * + * -EINVAL - An invalid argument, unaligned access or other error + * in usage. Will not succeed if retried. + * -ENOMEM - Insufficient resources (like memory or IOVA space) to + * complete the mapping. Should succeed if retried later. + * -EIO - Legacy error code with an unknown meaning. eg. this is + * returned if a lower level call returned DMA_MAPPING_ERROR. + */ +int dma_map_sgtable(struct device *dev, struct sg_table *sgt, + enum dma_data_direction dir, unsigned long attrs) +{ + int nents; + + nents = __dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs); + if (nents < 0) + return nents; + sgt->nents = nents; + return 0; +} +EXPORT_SYMBOL_GPL(dma_map_sgtable); + void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs) |