diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2010-04-30 16:35:37 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-20 16:21:40 -0400 |
commit | 85bcb5ee889e0ebb9154718939e049de265fcdfb (patch) | |
tree | daeec28274c8b68fea502c41af84d45d2681ebc5 /Documentation/usb/dma.txt | |
parent | 842f16905dfc6743c1dd80c3d29b49ba3ab7f7c8 (diff) |
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/dma.txt')
-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. | |||
16 | manage dma mappings for existing dma-ready buffers (see below). | 16 | manage dma mappings for existing dma-ready buffers (see below). |
17 | 17 | ||
18 | - URBs have an additional "transfer_dma" field, as well as a transfer_flags | 18 | - URBs have an additional "transfer_dma" field, as well as a transfer_flags |
19 | bit saying if it's valid. (Control requests also have "setup_dma" and a | 19 | bit saying if it's valid. (Control requests also have "setup_dma", but |
20 | corresponding transfer_flags bit.) | 20 | drivers must not use it.) |
21 | 21 | ||
22 | - "usbcore" will map those DMA addresses, if a DMA-aware driver didn't do | 22 | - "usbcore" will map this DMA address, if a DMA-aware driver didn't do |
23 | it first and set URB_NO_TRANSFER_DMA_MAP or URB_NO_SETUP_DMA_MAP. HCDs | 23 | it first and set URB_NO_TRANSFER_DMA_MAP. HCDs |
24 | don't manage dma mappings for URBs. | 24 | don't manage dma mappings for URBs. |
25 | 25 | ||
26 | - There's a new "generic DMA API", parts of which are usable by USB device | 26 | - 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. | |||
53 | to use this type of memory ("dma-coherent"), and memory returned from | 53 | to use this type of memory ("dma-coherent"), and memory returned from |
54 | kmalloc() will work just fine. | 54 | kmalloc() will work just fine. |
55 | 55 | ||
56 | For control transfers you can use the buffer primitives or not for each | ||
57 | of the transfer buffer and setup buffer independently. Set the flag bits | ||
58 | URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP to indicate which | ||
59 | buffers you have prepared. For non-control transfers URB_NO_SETUP_DMA_MAP | ||
60 | is ignored. | ||
61 | |||
62 | The memory buffer returned is "dma-coherent"; sometimes you might need to | 56 | The memory buffer returned is "dma-coherent"; sometimes you might need to |
63 | force a consistent memory access ordering by using memory barriers. It's | 57 | force a consistent memory access ordering by using memory barriers. It's |
64 | not using a streaming DMA mapping, so it's good for small transfers on | 58 | 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?") | |||
130 | void usb_buffer_unmap (struct urb *urb); | 124 | void usb_buffer_unmap (struct urb *urb); |
131 | 125 | ||
132 | The calls manage urb->transfer_dma for you, and set URB_NO_TRANSFER_DMA_MAP | 126 | The calls manage urb->transfer_dma for you, and set URB_NO_TRANSFER_DMA_MAP |
133 | so that usbcore won't map or unmap the buffer. The same goes for | 127 | so that usbcore won't map or unmap the buffer. They cannot be used for |
134 | urb->setup_dma and URB_NO_SETUP_DMA_MAP for control requests. | 128 | setup_packet buffers in control requests. |
135 | 129 | ||
136 | Note that several of those interfaces are currently commented out, since | 130 | Note that several of those interfaces are currently commented out, since |
137 | they don't have current users. See the source code. Other than the dmasync | 131 | they don't have current users. See the source code. Other than the dmasync |