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author | Alan Stern <stern@rowland.harvard.edu> | 2010-04-30 16:35:37 -0400 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-20 13:21:40 -0700 |
commit | 85bcb5ee889e0ebb9154718939e049de265fcdfb (patch) | |
tree | daeec28274c8b68fea502c41af84d45d2681ebc5 /Documentation/usb | |
parent | 842f16905dfc6743c1dd80c3d29b49ba3ab7f7c8 (diff) | |
download | linux-85bcb5ee889e0ebb9154718939e049de265fcdfb.tar.gz linux-85bcb5ee889e0ebb9154718939e049de265fcdfb.tar.bz2 linux-85bcb5ee889e0ebb9154718939e049de265fcdfb.zip |
USB: remove URB_NO_SETUP_DMA_MAP
Now that URB_NO_SETUP_DMA_MAP is no longer in use, this patch (as1376)
removes all references to it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/usb')
-rw-r--r-- | Documentation/usb/dma.txt | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt index a37e59cf2786..84ef865237db 100644 --- a/Documentation/usb/dma.txt +++ b/Documentation/usb/dma.txt @@ -16,11 +16,11 @@ OR: they can now be DMA-aware. manage dma mappings for existing dma-ready buffers (see below). - URBs have an additional "transfer_dma" field, as well as a transfer_flags - bit saying if it's valid. (Control requests also have "setup_dma" and a - corresponding transfer_flags bit.) + bit saying if it's valid. (Control requests also have "setup_dma", but + drivers must not use it.) -- "usbcore" will map those DMA addresses, if a DMA-aware driver didn't do - it first and set URB_NO_TRANSFER_DMA_MAP or URB_NO_SETUP_DMA_MAP. HCDs +- "usbcore" will map this DMA address, if a DMA-aware driver didn't do + it first and set URB_NO_TRANSFER_DMA_MAP. HCDs don't manage dma mappings for URBs. - There's a new "generic DMA API", parts of which are usable by USB device @@ -53,12 +53,6 @@ and effects like cache-trashing can impose subtle penalties. to use this type of memory ("dma-coherent"), and memory returned from kmalloc() will work just fine. - For control transfers you can use the buffer primitives or not for each - of the transfer buffer and setup buffer independently. Set the flag bits - URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP to indicate which - buffers you have prepared. For non-control transfers URB_NO_SETUP_DMA_MAP - is ignored. - The memory buffer returned is "dma-coherent"; sometimes you might need to force a consistent memory access ordering by using memory barriers. It's not using a streaming DMA mapping, so it's good for small transfers on @@ -130,8 +124,8 @@ of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?") void usb_buffer_unmap (struct urb *urb); The calls manage urb->transfer_dma for you, and set URB_NO_TRANSFER_DMA_MAP - so that usbcore won't map or unmap the buffer. The same goes for - urb->setup_dma and URB_NO_SETUP_DMA_MAP for control requests. + so that usbcore won't map or unmap the buffer. They cannot be used for + setup_packet buffers in control requests. Note that several of those interfaces are currently commented out, since they don't have current users. See the source code. Other than the dmasync |