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-rw-r--r--include/linux/dmaengine.h28
1 files changed, 16 insertions, 12 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 2910e7dadc7f..f838764993eb 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -404,14 +404,16 @@ enum dma_residue_granularity {
DMA_RESIDUE_GRANULARITY_BURST = 2,
};
-/* struct dma_slave_caps - expose capabilities of a slave channel only
- *
- * @src_addr_widths: bit mask of src addr widths the channel supports
- * @dst_addr_widths: bit mask of dstn addr widths the channel supports
- * @directions: bit mask of slave direction the channel supported
- * since the enum dma_transfer_direction is not defined as bits for each
- * type of direction, the dma controller should fill (1 << <TYPE>) and same
- * should be checked by controller as well
+/**
+ * struct dma_slave_caps - expose capabilities of a slave channel only
+ * @src_addr_widths: bit mask of src addr widths the channel supports.
+ * Width is specified in bytes, e.g. for a channel supporting
+ * a width of 4 the mask should have BIT(4) set.
+ * @dst_addr_widths: bit mask of dst addr widths the channel supports
+ * @directions: bit mask of slave directions the channel supports.
+ * Since the enum dma_transfer_direction is not defined as bit flag for
+ * each type, the dma controller should set BIT(<TYPE>) and same
+ * should be checked by controller as well
* @max_burst: max burst capability per-transfer
* @cmd_pause: true, if pause and thereby resume is supported
* @cmd_terminate: true, if terminate cmd is supported
@@ -678,11 +680,13 @@ struct dma_filter {
* @dev_id: unique device ID
* @dev: struct device reference for dma mapping api
* @src_addr_widths: bit mask of src addr widths the device supports
+ * Width is specified in bytes, e.g. for a device supporting
+ * a width of 4 the mask should have BIT(4) set.
* @dst_addr_widths: bit mask of dst addr widths the device supports
- * @directions: bit mask of slave direction the device supports since
- * the enum dma_transfer_direction is not defined as bits for
- * each type of direction, the dma controller should fill (1 <<
- * <TYPE>) and same should be checked by controller as well
+ * @directions: bit mask of slave directions the device supports.
+ * Since the enum dma_transfer_direction is not defined as bit flag for
+ * each type, the dma controller should set BIT(<TYPE>) and same
+ * should be checked by controller as well
* @max_burst: max burst capability per-transfer
* @residue_granularity: granularity of the transfer residue reported
* by tx_status