diff options
author | Dmitry Torokhov <dtor@insightbb.com> | 2007-05-01 00:24:54 -0400 |
---|---|---|
committer | Dmitry Torokhov <dtor@insightbb.com> | 2007-05-01 00:24:54 -0400 |
commit | bc95f3669f5e6f63cf0b84fe4922c3c6dd4aa775 (patch) | |
tree | 427fcf2a7287c16d4b5aa6cbf494d59579a6a8b1 /Documentation/arm/Samsung-S3C24XX/DMA.txt | |
parent | 3d29cdff999c37b3876082278a8134a0642a02cd (diff) | |
parent | dc87c3985e9b442c60994308a96f887579addc39 (diff) |
Merge master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
drivers/usb/input/Makefile
drivers/usb/input/gtco.c
Diffstat (limited to 'Documentation/arm/Samsung-S3C24XX/DMA.txt')
-rw-r--r-- | Documentation/arm/Samsung-S3C24XX/DMA.txt | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/Documentation/arm/Samsung-S3C24XX/DMA.txt b/Documentation/arm/Samsung-S3C24XX/DMA.txt new file mode 100644 index 00000000000..37f4edcc5d8 --- /dev/null +++ b/Documentation/arm/Samsung-S3C24XX/DMA.txt @@ -0,0 +1,46 @@ + S3C2410 DMA + =========== + +Introduction +------------ + + The kernel provides an interface to manage DMA transfers + using the DMA channels in the cpu, so that the central + duty of managing channel mappings, and programming the + channel generators is in one place. + + +DMA Channel Ordering +-------------------- + + Many of the range do not have connections for the DMA + channels to all sources, which means that some devices + have a restricted number of channels that can be used. + + To allow flexibilty for each cpu type and board, the + dma code can be given an dma ordering structure which + allows the order of channel search to be specified, as + well as allowing the prohibition of certain claims. + + struct s3c24xx_dma_order has a list of channels, and + each channel within has a slot for a list of dma + channel numbers. The slots are searched in order, for + the presence of a dma channel number with DMA_CH_VALID + orred in. + + If the order has the flag DMA_CH_NEVER set, then after + checking the channel list, the system will return no + found channel, thus denying the request. + + A board support file can call s3c24xx_dma_order_set() + to register an complete ordering set. The routine will + copy the data, so the original can be discared with + __initdata. + + +Authour +------- + +Ben Dooks, +Copyright (c) 2007 Ben Dooks, Simtec Electronics +Licensed under the GPL v2 |