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OMAP: DMA: mstandby mode and runtime pm support

Kevin Hilman linux-arm-kernel linux-omap 1 version New

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Cover letter [PATCH 0/3] OMAP: DMA: mstandby mode and runtime pm support
Quoted 2 lines · Manjunath Kondaiah

This patch series is remaining part of dma hwmod to support pm runtime and for handling mstandby mode for all applicable DMA mstandby mode errata.

This is still not runtime-suspending when I use my DMA test in linking mode.

If I put a large enough period between transfers, it should autosuspend during transfers. It seems to do auto-suspend and resume once, but then it never suspends again.

I tested with my dmatest module[1], and loaded with:

  # insmod ./dmatest.ko linking=1 forever=1 forever_period=1024

Not only does it not auto-suspend between transfers (which I expected), it also doesn't suspend after removing the module which stops all active channels.

Kevin

[1] git://gitorious.org/omap-test/dmatest.git

Quoted 65 lines

The alignment for pm runtime API's usage is at:
http://thread.gmane.org/gmane.linux.ports.arm.omap/51588/focus=52493
http://thread.gmane.org/gmane.linux.ports.arm.omap/50762/focus=50840

The alignment for handling mstandby mode errata handling is at:
http://thread.gmane.org/gmane.linux.ports.arm.omap/47398/focus=47426
http://thread.gmane.org/gmane.linux.ports.arm.omap/47479/focus=47537

Testing:
Compile tested for
- omap1_defconfig
- omap2plus_defconfig

Boot test on:
- OMAP1710-H3
- OMAP2420-H4
- OMAP3430-LDP
- OMAP3630-Zoom3
- OMAP4430-Blaze

DMA memory to memory test cases(including chaining) are executed for all the above boards and for each test case, /sys/devices/platform/omap/omap_dma_system.0/power/runtime_status was verified and after completion of the tests, runtime_status will be always suspended.

Apart from that, offmode testing is done for OMAP3430-LDP using the procedure:
echo 1 > /debug/pm_debug/sleep_while_idle
echo 1 > /debug/pm_debug/enable_off_mode
echo 5 > /sys/devices/platform/omap/omap_uart.0/sleep_timeout echo 5 > /sys/devices/platform/omap/omap_uart.1/sleep_timeout echo 5 > /sys/devices/platform/omap/omap_uart.2/sleep_timeout

With the above steps, core off mode count gets increasing if the the board is idle for more than 5 seconds.

Baseline:
Applies cleanly on top of mainline 2.6.38-rc6:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
commit f5412be599602124d2bdd49947b231dd77c0bf99

Author: Linus Torvalds <[email protected]>
Date:   Mon Feb 21 17:25:52 2011 -0800
    Linux 2.6.38-rc6

Note: OMAP1 is tested on top of 2.6.38-rc5 since rc6 is broken for omap1 build

Patch Summary:
==============
G, Manjunath Kondaiah (2):
OMAP2+: PM: omap device: API's for handling mstandby mode OMAP2+: DMA: prevent races while setting M idle mode to nostandby

Manjunath G Kondaiah (1):
OMAP: PM: DMA: Enable runtime pm

 arch/arm/mach-omap1/dma.c                     |    1 +
 arch/arm/mach-omap2/dma.c                     |   16 ++
 arch/arm/mach-omap2/omap_hwmod.c              |   42 ++++++
 arch/arm/plat-omap/dma.c                      |  190 +++++++++++++++++++++----
 arch/arm/plat-omap/include/plat/dma.h         |    1 +
 arch/arm/plat-omap/include/plat/omap_device.h |    2 +
 arch/arm/plat-omap/include/plat/omap_hwmod.h  |    4 +-
 arch/arm/plat-omap/omap_device.c              |   64 +++++++++
 8 files changed, 293 insertions(+), 27 deletions(-)

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