* Cousson, Benoit <b-cousson@xxxxxx> [2010-12-03 09:38:35 +0100]: > On 12/2/2010 2:59 PM, 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. > > > >The hwmod API "omap_hwmod_set_master_standbymode" will use > >no_stdby_cnt(introduced in omap_hwmod structure) for controlling > >access to sysconfig register settings in case of overlapping > >request/release API's are called. It also disables interrupts during > >syconfig register access. > > > >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 > > You have to CC lakml during send-email, but it should not be in the > changelog. > > On the other hand, it is a good practice to add all the authors of > the file you change in CC. > > >--- > >v3: Review comments incorporated for: > >https://patchwork.kernel.org/patch/282212/ > > > >v4: added mutex changes > >https://patchwork.kernel.org/patch/338611/ > > > >v5: typo fixes for errata and erratum > >https://patchwork.kernel.org/patch/352481/ > > > >v6: fixed oh increment bug and also mutex(missing in v5) > >https://patchwork.kernel.org/patch/372231/ > > > >v7: replaced mutex lock with spin lock. Added use count for controlling > >access to sysconfig registers in case if overlapping request/release API's > >are used. > > I'm not sure it should be done here. I'd rather keep that code in > the DMA, since this is the only user of that feature. Are you referring to spin lock or usage count? -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
