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From: Heiko =?utf-8?q?St=C3=BCbner?= <heiko <at> sntech.de>
Subject: [PATCH v2 0/4] ARM: S3C24XX: add dmaengine based dma-driver
Newsgroups: gmane.linux.kernel
Date: Wednesday 14th August 2013 11:59:13 UTC (over 3 years ago)
This series tries to provide a basic dmaengine driver for the s3c24xx
SoCs to subsequently retire the old one with custom API.

Since v1 three big changes happened (appart from fixing received comments):

For one the limitation of sg-lists to 1 element is gone.Secondly the
specifics of the virtual channels (target bus, handshake, etc) are not
encoded with channel ids but in the platformdata - making a later dt
binding easier, as these informations can there be gathered by the xlate
function. And lastly I also added a preliminary mechanism to handle the
specific needs for the earlier variants of the driver.

While s3c2443 and later can use any channel for any peripheral with just
marking the target-peripheral-id in a register, earlier SoCs can only use
specific channels and the target-ids also vary depending on the channel.

Therefore on newer SoCs the chansel element only needs to contain the
requested target-id, while on the older variants use it to encode both
the valid channels and the channel-specific peripheral-id.

On affected SoCs the target-id is always 3 bit wide, so we use these and
an additional 4th bit to hold the valid state. As the older SoCs all have
4 dma channels this can live happily in an u16 element.

The s3c24xx series will most likely not see any new offspring, but even
if it happens any new model will probably use the newer more flexible
variant of the dma controller, so this should not restrict anything
in the future.

SDI is valid on channels 0, 2 and 3 - with varying hw request sources.
For it the chansel field would look like

 ((BIT(3) | 1) << 3 * 4) | // channel 3, with request source 1
 ((BIT(3) | 2) << 2 * 4) | // channel 2, with request source 2
 ((BIT(3) | 2) << 0 * 4)   // channel 0, with request source 2

Heiko Stuebner (4):
  ARM: S3C24XX: number the dma clocks
  dmaengine: add driver for Samsung s3c24xx SoCs
  ARM: S3C24XX: add platform-devices for new dma driver for s3c2412 and
  ARM: SAMSUNG: set s3c24xx_dma_filter for s3c64xx-spi0 device

 arch/arm/mach-s3c24xx/clock-s3c2412.c     |    8 +-
 arch/arm/mach-s3c24xx/common-s3c2443.c    |   12 +-
 arch/arm/mach-s3c24xx/common.c            |  106 +++
 arch/arm/mach-s3c24xx/common.h            |    3 +
 arch/arm/mach-s3c24xx/mach-jive.c         |    1 +
 arch/arm/mach-s3c24xx/mach-smdk2413.c     |    1 +
 arch/arm/mach-s3c24xx/mach-smdk2416.c     |    1 +
 arch/arm/mach-s3c24xx/mach-smdk2443.c     |    1 +
 arch/arm/mach-s3c24xx/mach-vstms.c        |    1 +
 arch/arm/plat-samsung/devs.c              |    5 +-
 drivers/dma/Kconfig                       |   12 +
 drivers/dma/Makefile                      |    1 +
 drivers/dma/s3c24xx-dma.c                 | 1255
 include/linux/platform_data/dma-s3c24xx.h |   43 +
 14 files changed, 1439 insertions(+), 11 deletions(-)
 create mode 100644 drivers/dma/s3c24xx-dma.c
 create mode 100644 include/linux/platform_data/dma-s3c24xx.h

CD: 3ms