From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Grinberg Subject: Re: [PATCH 1/4] ALSA: pxa2xx: fix ac97 cold reset Date: Mon, 07 Jan 2013 11:16:55 +0200 Message-ID: <50EA9287.5030304@compulab.co.il> References: <1357499640-13871-1-git-send-email-mikedunn@newsguy.com> <1357499640-13871-2-git-send-email-mikedunn@newsguy.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1357499640-13871-2-git-send-email-mikedunn@newsguy.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Mike Dunn Cc: Marek Vasut , alsa-devel@alsa-project.org, Eric Miao , Mark Brown , Robert Jarzmik , linux-arm-kernel@lists.infradead.org List-Id: alsa-devel@alsa-project.org On 01/06/13 21:13, Mike Dunn wrote: > Cold reset on the pxa27x currently fails and > > pxa2xx_ac97_try_cold_reset: cold reset timeout (GSR=0x44) > > appears in the kernel log. Through trial-and-error (the pxa270 developer's > manual is mostly incoherent on the topic of ac97 reset), I got cold reset to > complete by setting the WARM_RST bit in the GCR register (and later noticed that > pxa3xx does this for cold reset as well). Also, a timeout loop is needed to > wait for the reset to complete. > > Tested on a palm treo 680 machine. > > Signed-off-by: Mike Dunn > --- > sound/arm/pxa2xx-ac97-lib.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c > index 6fc0ae9..1ecd0a66 100644 > --- a/sound/arm/pxa2xx-ac97-lib.c > +++ b/sound/arm/pxa2xx-ac97-lib.c > @@ -148,6 +148,8 @@ static inline void pxa_ac97_warm_pxa27x(void) > > static inline void pxa_ac97_cold_pxa27x(void) > { > + unsigned int timeout; > + > GCR &= GCR_COLD_RST; /* clear everything but nCRST */ > GCR &= ~GCR_COLD_RST; /* then assert nCRST */ > > @@ -157,8 +159,10 @@ static inline void pxa_ac97_cold_pxa27x(void) > clk_enable(ac97conf_clk); > udelay(5); > clk_disable(ac97conf_clk); > - GCR = GCR_COLD_RST; > - udelay(50); > + GCR = GCR_COLD_RST | GCR_WARM_RST; > + timeout = 100; /* wait for the codec-ready bit to be set */ > + while (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)) && timeout--) > + mdelay(1); Can we use msleep() instead? May be this will require to change the granularity to 10... > } > #endif > -- Regards, Igor. From mboxrd@z Thu Jan 1 00:00:00 1970 From: grinberg@compulab.co.il (Igor Grinberg) Date: Mon, 07 Jan 2013 11:16:55 +0200 Subject: [PATCH 1/4] ALSA: pxa2xx: fix ac97 cold reset In-Reply-To: <1357499640-13871-2-git-send-email-mikedunn@newsguy.com> References: <1357499640-13871-1-git-send-email-mikedunn@newsguy.com> <1357499640-13871-2-git-send-email-mikedunn@newsguy.com> Message-ID: <50EA9287.5030304@compulab.co.il> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/06/13 21:13, Mike Dunn wrote: > Cold reset on the pxa27x currently fails and > > pxa2xx_ac97_try_cold_reset: cold reset timeout (GSR=0x44) > > appears in the kernel log. Through trial-and-error (the pxa270 developer's > manual is mostly incoherent on the topic of ac97 reset), I got cold reset to > complete by setting the WARM_RST bit in the GCR register (and later noticed that > pxa3xx does this for cold reset as well). Also, a timeout loop is needed to > wait for the reset to complete. > > Tested on a palm treo 680 machine. > > Signed-off-by: Mike Dunn > --- > sound/arm/pxa2xx-ac97-lib.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c > index 6fc0ae9..1ecd0a66 100644 > --- a/sound/arm/pxa2xx-ac97-lib.c > +++ b/sound/arm/pxa2xx-ac97-lib.c > @@ -148,6 +148,8 @@ static inline void pxa_ac97_warm_pxa27x(void) > > static inline void pxa_ac97_cold_pxa27x(void) > { > + unsigned int timeout; > + > GCR &= GCR_COLD_RST; /* clear everything but nCRST */ > GCR &= ~GCR_COLD_RST; /* then assert nCRST */ > > @@ -157,8 +159,10 @@ static inline void pxa_ac97_cold_pxa27x(void) > clk_enable(ac97conf_clk); > udelay(5); > clk_disable(ac97conf_clk); > - GCR = GCR_COLD_RST; > - udelay(50); > + GCR = GCR_COLD_RST | GCR_WARM_RST; > + timeout = 100; /* wait for the codec-ready bit to be set */ > + while (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)) && timeout--) > + mdelay(1); Can we use msleep() instead? May be this will require to change the granularity to 10... > } > #endif > -- Regards, Igor.