On 01/07/13 23:55, 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 mikedunn@newsguy.com

Acked-by: Igor Grinberg grinberg@compulab.co.il

---

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);
  

} #endif

On 01/07/13 23:55, Mike Dunn wrote:

This patch fixes some code that implements a work-around to a hardware bug in the ac97 controller on the pxa27x. A bug in the controller's warm reset functionality requires that the mfp used by the controller as the AC97_nRESET line be temporarily reconfigured as a generic output gpio (AF0) and manually held high for the duration of the warm reset cycle. This is what was done in the original code, but it was broken long ago by commit fb1bf8cd ([ARM] pxa: introduce processor specific pxa27x_assert_ac97reset()) which changed the mfp to a GPIO input instead of a high output.

The fix requires the ac97 controller to obtain the gpio via gpio_request_one(), with arguments that configure the gpio as an output initially driven high.

Tested on a palm treo 680 machine. Reportedly, this broken code only prevents a warm reset on hardware that lacks a pull-up on the line, which appears to be the case for me.

Signed-off-by: Mike Dunn mikedunn@newsguy.com

Since I've participated in the patch development, please, add:

Signed-off-by: Igor Grinberg grinberg@compulab.co.il

Thanks!

---

arch/arm/mach-pxa/include/mach/mfp-pxa27x.h | 3 +++ arch/arm/mach-pxa/pxa27x.c | 4 ++-- sound/arm/pxa2xx-ac97-lib.c | 18 +++++++++++++++++- 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h b/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h index a611ad3..b6132aa 100644 --- a/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h +++ b/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h @@ -463,6 +463,9 @@ GPIO76_LCD_PCLK, \ GPIO77_LCD_BIAS

+/* these enable a work-around for a hw bug in pxa27x during ac97 warm reset */ +#define GPIO113_AC97_nRESET_GPIO_HIGH MFP_CFG_OUT(GPIO113, AF0, DEFAULT) +#define GPIO95_AC97_nRESET_GPIO_HIGH MFP_CFG_OUT(GPIO95, AF0, DEFAULT)

extern int keypad_set_wake(unsigned int on); #endif /* __ASM_ARCH_MFP_PXA27X_H */ diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c index 8047ee0..616cb87 100644 --- a/arch/arm/mach-pxa/pxa27x.c +++ b/arch/arm/mach-pxa/pxa27x.c @@ -47,9 +47,9 @@ void pxa27x_clear_otgph(void) EXPORT_SYMBOL(pxa27x_clear_otgph);

static unsigned long ac97_reset_config[] = {

• GPIO113_GPIO,

• GPIO113_AC97_nRESET_GPIO_HIGH, GPIO113_AC97_nRESET,

• GPIO95_GPIO,

• GPIO95_AC97_nRESET_GPIO_HIGH, GPIO95_AC97_nRESET,

};

diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c index 1ecd0a66..fff7753 100644 --- a/sound/arm/pxa2xx-ac97-lib.c +++ b/sound/arm/pxa2xx-ac97-lib.c @@ -18,6 +18,7 @@ #include <linux/delay.h> #include <linux/module.h> #include <linux/io.h> +#include <linux/gpio.h>

#include <sound/ac97_codec.h> #include <sound/pxa2xx-lib.h> @@ -344,8 +345,21 @@ int pxa2xx_ac97_hw_probe(struct platform_device *dev) }

if (cpu_is_pxa27x()) {

• /* Use GPIO 113 as AC97 Reset on Bulverde */
  

• /*
  

•  * This gpio is needed for a work-around to a bug in the ac97
  

•  * controller during warm reset.  The direction and level is set
  

•  * here so that it is an output driven high when switching from
  

•  * AC97_nRESET alt function to generic gpio.
  

•  */
  

• ret = gpio_request_one(reset_gpio, GPIOF_OUT_INIT_HIGH,
  

• 		       "pxa27x ac97 reset");
  

• if (ret < 0) {
  

• 	pr_err("%s: gpio_request_one() failed: %d\n",
  

• 	       __func__, ret);
  

• 	goto err_conf;
  

• }
  

  pxa27x_assert_ac97reset(reset_gpio, 0);
• ac97conf_clk = clk_get(&dev->dev, "AC97CONFCLK"); if (IS_ERR(ac97conf_clk)) { ret = PTR_ERR(ac97conf_clk);

@@ -388,6 +402,8 @@ EXPORT_SYMBOL_GPL(pxa2xx_ac97_hw_probe);

void pxa2xx_ac97_hw_remove(struct platform_device *dev) {

• if (cpu_is_pxa27x())

• gpio_free(reset_gpio);
  

  GCR |= GCR_ACLINK_OFF; free_irq(IRQ_AC97, NULL); if (ac97conf_clk) {

On 01/07/13 23:55, Mike Dunn wrote:

This patch does nothing functionally, it just gives the function a new name and modifies the prototype slightly in order to clarify what the function is doing (which is not necessarily asserting the reset). Some commentary also added.

Tested on a palm treo 680 machine.

Signed-off-by: Mike Dunn mikedunn@newsguy.com

Acked-by: Igor Grinberg grinberg@compulab.co.il

---

arch/arm/mach-pxa/pxa27x.c | 20 ++++++++++++++------ sound/arm/pxa2xx-ac97-lib.c | 8 ++++---- 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c index 616cb87..69985b06 100644 --- a/arch/arm/mach-pxa/pxa27x.c +++ b/arch/arm/mach-pxa/pxa27x.c @@ -53,17 +53,25 @@ static unsigned long ac97_reset_config[] = { GPIO95_AC97_nRESET, };

-void pxa27x_assert_ac97reset(int reset_gpio, int on) +void pxa27x_configure_ac97reset(int reset_gpio, bool to_gpio) {

• /*

• * This helper function is used to work around a bug in the pxa27x's
  

• * ac97 controller during a warm reset.  The configuration of the
  

• * reset_gpio is changed as follows:
  

• * to_gpio == true: configured to generic output gpio and driven high
  

• * to_gpio == false: configured to ac97 controller alt fn AC97_nRESET
  

• */
  

• if (reset_gpio == 113)

• pxa2xx_mfp_config(on ? &ac97_reset_config[0] :
  

• 		       &ac97_reset_config[1], 1);
  

• pxa2xx_mfp_config(to_gpio ? &ac97_reset_config[0] :
  

• 		  &ac97_reset_config[1], 1);
  
  

  if (reset_gpio == 95)

• pxa2xx_mfp_config(on ? &ac97_reset_config[2] :
  

• 		       &ac97_reset_config[3], 1);
  

• pxa2xx_mfp_config(to_gpio ? &ac97_reset_config[2] :
  

• 		  &ac97_reset_config[3], 1);
  

} -EXPORT_SYMBOL_GPL(pxa27x_assert_ac97reset); +EXPORT_SYMBOL_GPL(pxa27x_configure_ac97reset);

/* Crystal clock: 13MHz */ #define BASE_CLK 13000000 diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c index fff7753..e6f4633 100644 --- a/sound/arm/pxa2xx-ac97-lib.c +++ b/sound/arm/pxa2xx-ac97-lib.c @@ -34,7 +34,7 @@ static struct clk *ac97_clk; static struct clk *ac97conf_clk; static int reset_gpio;

-extern void pxa27x_assert_ac97reset(int reset_gpio, int on); +extern void pxa27x_configure_ac97reset(int reset_gpio, bool to_gpio);

/*

• Beware PXA27x bugs:

@@ -140,10 +140,10 @@ static inline void pxa_ac97_warm_pxa27x(void) gsr_bits = 0;

/* warm reset broken on Bulverde, so manually keep AC97 reset high */

• pxa27x_assert_ac97reset(reset_gpio, 1);

• pxa27x_configure_ac97reset(reset_gpio, true); udelay(10); GCR |= GCR_WARM_RST;

• pxa27x_assert_ac97reset(reset_gpio, 0);

• pxa27x_configure_ac97reset(reset_gpio, false); udelay(500);

}

@@ -358,7 +358,7 @@ int pxa2xx_ac97_hw_probe(struct platform_device *dev) __func__, ret); goto err_conf; }

• pxa27x_assert_ac97reset(reset_gpio, 0);
  

• pxa27x_configure_ac97reset(reset_gpio, false);
  
  

  ac97conf_clk = clk_get(&dev->dev, "AC97CONFCLK"); if (IS_ERR(ac97conf_clk)) {