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Diffstat (limited to 'Documentation/DMA-mapping.txt')
| -rw-r--r-- | Documentation/DMA-mapping.txt | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/Documentation/DMA-mapping.txt b/Documentation/DMA-mapping.txt index f4ac37f..6845574 100644 --- a/Documentation/DMA-mapping.txt +++ b/Documentation/DMA-mapping.txt @@ -443,15 +443,9 @@ Only streaming mappings specify a direction, consistent mappings implicitly have a direction attribute setting of PCI_DMA_BIDIRECTIONAL. -The SCSI subsystem provides mechanisms for you to easily obtain -the direction to use, in the SCSI command: - - scsi_to_pci_dma_dir(SCSI_DIRECTION) - -Where SCSI_DIRECTION is obtained from the 'sc_data_direction' -member of the SCSI command your driver is working on. The -mentioned interface above returns a value suitable for passing -into the streaming DMA mapping interfaces below. +The SCSI subsystem tells you the direction to use in the +'sc_data_direction' member of the SCSI command your driver is +working on. For Networking drivers, it's a rather simple affair. For transmit packets, map/unmap them with the PCI_DMA_TODEVICE direction |