Merge tag 'iommu-fixes-v5.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / kernel / dma / mapping.c

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 2b06a80..7ee5284 100644 (file)
--- 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)