* Adrian Hunter <adrian.hunter@xxxxxxxxx> [2010-12-01 22:16:44 +0200]: > On 01/12/10 20:47, ext G, Manjunath Kondaiah wrote: > >Certain errata in OMAP2+ processors will require forcing > >master standby to "no standby" mode before completing on going > >operation. Without this, the results will be unpredictable. > > > >Since current implementation of PM run time framework does not support > >changing sysconfig settings during middle of the on going operation, > >these API's will support the same. One API will force the device's > >sysconfig mstandby mode settings to "no standby" and other API will > >release "no standby" mode and sets it to "smart standby" or "no > >standby? depending on HWMOD_SWSUP_MSTANDBY value. > > > >These API's should be used by device drivers only incase of > >erratum applicable to their modules if there is no other methods > >to resolve. > > > >These API's are required for multiple DMA errata which require > >putting DMA controller in no mstandby mode before stopping dma. > > > >The applicable errata: > >1. Erratum ID: i557(Applicable for omap36xx all ES versions) > >The channel hangs when the Pause bit (DMA4_CDPi [7] ) is cleared > >through config port while in Standby. > > > >2. Erratum ID: i541 > >sDMA FIFO draining does not finish. Applicable to all omap2+ except > >omap4. > > > >3. Erratum ID:i88 > >The sDMA to be put in no mstandby mode before disabling the channel > >after completing the data transfer operation. > >Applicable only for OMAP3430 ES1.0 > > > >Also fixes typo HWMOD_SWSUP_MSTDBY to HWMOD_SWSUP_MSTANDBY in > >omap_hwmod.h > > > >Signed-off-by: G, Manjunath Kondaiah<manjugk@xxxxxx> > >Cc: Kevin Hilman<khilman@xxxxxxxxxxxxxxxxxxx> > >Cc: Paul Walmsley<paul@xxxxxxxxx> > >Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > > >--- > >Change summary: > >v3: Review comments incorporated for: > >https://patchwork.kernel.org/patch/282212/ > >v4: added mutex changes > >v5: typo fixes for errata and erratum > >v6: fixed oh increment bug and also mutex(missing in v5) > > > > arch/arm/mach-omap2/omap_hwmod.c | 47 +++++++++++++++++++- > > 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 | 60 +++++++++++++++++++++++++ > > 4 files changed, 111 insertions(+), 2 deletions(-) > > > > Does not seem to handle overlapping requests to set/clear > midle mode. We can have use count so that we can avoid register access during middle of operation if mstandby mode is already changed to "no standby" mode. > > Also, there is a mutex but don't these functions get called > sometimes in interrupt context? I feel we should leave this to caller of these API's. The caller should make sure that, he disables interrupts if it is used in interrupt context. -Manjunath -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
