From mboxrd@z Thu Jan 1 00:00:00 1970 From: "G, Manjunath Kondaiah" Subject: Re: [PATCH v7] OMAP2+: PM: omap device: API's for handling mstandby mode Date: Fri, 3 Dec 2010 15:17:47 +0530 Message-ID: <20101203092514.GA10048@GLPP-machine> References: <1291298392-28729-1-git-send-email-manjugk@ti.com> <4CF8AC8B.9040800@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from na3sys009aog104.obsmtp.com ([74.125.149.73]:42005 "EHLO na3sys009aog104.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932303Ab0LCJrW (ORCPT ); Fri, 3 Dec 2010 04:47:22 -0500 Received: by gyd12 with SMTP id 12so4938156gyd.34 for ; Fri, 03 Dec 2010 01:47:20 -0800 (PST) Content-Disposition: inline In-Reply-To: <4CF8AC8B.9040800@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Cousson, Benoit" Cc: Paul Walmsley , "linux-omap@vger.kernel.org" , Kevin Hilman , "linux-arm-kernel@lists.infradead.org" * Cousson, Benoit [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 > >Cc: Kevin Hilman > >Cc: Paul Walmsley > >Cc: linux-arm-kernel@lists.infradead.org > > 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: manjugk@ti.com (G, Manjunath Kondaiah) Date: Fri, 3 Dec 2010 15:17:47 +0530 Subject: [PATCH v7] OMAP2+: PM: omap device: API's for handling mstandby mode In-Reply-To: <4CF8AC8B.9040800@ti.com> References: <1291298392-28729-1-git-send-email-manjugk@ti.com> <4CF8AC8B.9040800@ti.com> Message-ID: <20101203092514.GA10048@GLPP-machine> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Cousson, Benoit [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 > >Cc: Kevin Hilman > >Cc: Paul Walmsley > >Cc: linux-arm-kernel at lists.infradead.org > > 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