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linux-next/sound/arm/pxa2xx-ac97-lib.c
Mike Dunn 3b4bc7bccc ALSA: pxa27x: fix ac97 warm reset 
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>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org
2013-01-08 11:27:35 +00:00

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/*
* Based on sound/arm/pxa2xx-ac97.c and sound/soc/pxa/pxa2xx-ac97.c
* which contain:
*
* Author: Nicolas Pitre
* Created: Dec 02, 2004
* Copyright: MontaVista Software Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#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>
#include <mach/irqs.h>
#include <mach/regs-ac97.h>
#include <mach/audio.h>
static DEFINE_MUTEX(car_mutex);
static DECLARE_WAIT_QUEUE_HEAD(gsr_wq);
static volatile long gsr_bits;
static struct clk *ac97_clk;
static struct clk *ac97conf_clk;
static int reset_gpio;
extern void pxa27x_assert_ac97reset(int reset_gpio, int on);
/*
* Beware PXA27x bugs:
*
* o Slot 12 read from modem space will hang controller.
* o CDONE, SDONE interrupt fails after any slot 12 IO.
*
* We therefore have an hybrid approach for waiting on SDONE (interrupt or
* 1 jiffy timeout if interrupt never comes).
*/
unsigned short pxa2xx_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
{
unsigned short val = -1;
volatile u32 *reg_addr;
mutex_lock(&car_mutex);
/* set up primary or secondary codec space */
if (cpu_is_pxa25x() && reg == AC97_GPIO_STATUS)
reg_addr = ac97->num ? &SMC_REG_BASE : &PMC_REG_BASE;
else
reg_addr = ac97->num ? &SAC_REG_BASE : &PAC_REG_BASE;
reg_addr += (reg >> 1);
/* start read access across the ac97 link */
GSR = GSR_CDONE | GSR_SDONE;
gsr_bits = 0;
val = *reg_addr;
if (reg == AC97_GPIO_STATUS)
goto out;
if (wait_event_timeout(gsr_wq, (GSR | gsr_bits) & GSR_SDONE, 1) <= 0 &&
!((GSR | gsr_bits) & GSR_SDONE)) {
printk(KERN_ERR "%s: read error (ac97_reg=%d GSR=%#lx)\n",
__func__, reg, GSR | gsr_bits);
val = -1;
goto out;
}
/* valid data now */
GSR = GSR_CDONE | GSR_SDONE;
gsr_bits = 0;
val = *reg_addr;
/* but we've just started another cycle... */
wait_event_timeout(gsr_wq, (GSR | gsr_bits) & GSR_SDONE, 1);
out: mutex_unlock(&car_mutex);
return val;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_read);
void pxa2xx_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
unsigned short val)
{
volatile u32 *reg_addr;
mutex_lock(&car_mutex);
/* set up primary or secondary codec space */
if (cpu_is_pxa25x() && reg == AC97_GPIO_STATUS)
reg_addr = ac97->num ? &SMC_REG_BASE : &PMC_REG_BASE;
else
reg_addr = ac97->num ? &SAC_REG_BASE : &PAC_REG_BASE;
reg_addr += (reg >> 1);
GSR = GSR_CDONE | GSR_SDONE;
gsr_bits = 0;
*reg_addr = val;
if (wait_event_timeout(gsr_wq, (GSR | gsr_bits) & GSR_CDONE, 1) <= 0 &&
!((GSR | gsr_bits) & GSR_CDONE))
printk(KERN_ERR "%s: write error (ac97_reg=%d GSR=%#lx)\n",
__func__, reg, GSR | gsr_bits);
mutex_unlock(&car_mutex);
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_write);
#ifdef CONFIG_PXA25x
static inline void pxa_ac97_warm_pxa25x(void)
{
gsr_bits = 0;
GCR |= GCR_WARM_RST | GCR_PRIRDY_IEN | GCR_SECRDY_IEN;
wait_event_timeout(gsr_wq, gsr_bits & (GSR_PCR | GSR_SCR), 1);
}
static inline void pxa_ac97_cold_pxa25x(void)
{
GCR &= GCR_COLD_RST; /* clear everything but nCRST */
GCR &= ~GCR_COLD_RST; /* then assert nCRST */
gsr_bits = 0;
GCR = GCR_COLD_RST;
GCR |= GCR_CDONE_IE|GCR_SDONE_IE;
wait_event_timeout(gsr_wq, gsr_bits & (GSR_PCR | GSR_SCR), 1);
}
#endif
#ifdef CONFIG_PXA27x
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);
udelay(10);
GCR |= GCR_WARM_RST;
pxa27x_assert_ac97reset(reset_gpio, 0);
udelay(500);
}
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 */
gsr_bits = 0;
/* PXA27x Developers Manual section 13.5.2.2.1 */
clk_enable(ac97conf_clk);
udelay(5);
clk_disable(ac97conf_clk);
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
#ifdef CONFIG_PXA3xx
static inline void pxa_ac97_warm_pxa3xx(void)
{
int timeout = 100;
gsr_bits = 0;
/* Can't use interrupts */
GCR |= GCR_WARM_RST;
while (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)) && timeout--)
mdelay(1);
}
static inline void pxa_ac97_cold_pxa3xx(void)
{
int timeout = 1000;
/* Hold CLKBPB for 100us */
GCR = 0;
GCR = GCR_CLKBPB;
udelay(100);
GCR = 0;
GCR &= GCR_COLD_RST; /* clear everything but nCRST */
GCR &= ~GCR_COLD_RST; /* then assert nCRST */
gsr_bits = 0;
/* Can't use interrupts on PXA3xx */
GCR &= ~(GCR_PRIRDY_IEN|GCR_SECRDY_IEN);
GCR = GCR_WARM_RST | GCR_COLD_RST;
while (!(GSR & (GSR_PCR | GSR_SCR)) && timeout--)
mdelay(10);
}
#endif
bool pxa2xx_ac97_try_warm_reset(struct snd_ac97 *ac97)
{
unsigned long gsr;
#ifdef CONFIG_PXA25x
if (cpu_is_pxa25x())
pxa_ac97_warm_pxa25x();
else
#endif
#ifdef CONFIG_PXA27x
if (cpu_is_pxa27x())
pxa_ac97_warm_pxa27x();
else
#endif
#ifdef CONFIG_PXA3xx
if (cpu_is_pxa3xx())
pxa_ac97_warm_pxa3xx();
else
#endif
BUG();
gsr = GSR | gsr_bits;
if (!(gsr & (GSR_PCR | GSR_SCR))) {
printk(KERN_INFO "%s: warm reset timeout (GSR=%#lx)\n",
__func__, gsr);
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_try_warm_reset);
bool pxa2xx_ac97_try_cold_reset(struct snd_ac97 *ac97)
{
unsigned long gsr;
#ifdef CONFIG_PXA25x
if (cpu_is_pxa25x())
pxa_ac97_cold_pxa25x();
else
#endif
#ifdef CONFIG_PXA27x
if (cpu_is_pxa27x())
pxa_ac97_cold_pxa27x();
else
#endif
#ifdef CONFIG_PXA3xx
if (cpu_is_pxa3xx())
pxa_ac97_cold_pxa3xx();
else
#endif
BUG();
gsr = GSR | gsr_bits;
if (!(gsr & (GSR_PCR | GSR_SCR))) {
printk(KERN_INFO "%s: cold reset timeout (GSR=%#lx)\n",
__func__, gsr);
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_try_cold_reset);
void pxa2xx_ac97_finish_reset(struct snd_ac97 *ac97)
{
GCR &= ~(GCR_PRIRDY_IEN|GCR_SECRDY_IEN);
GCR |= GCR_SDONE_IE|GCR_CDONE_IE;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_finish_reset);
static irqreturn_t pxa2xx_ac97_irq(int irq, void *dev_id)
{
long status;
status = GSR;
if (status) {
GSR = status;
gsr_bits |= status;
wake_up(&gsr_wq);
/* Although we don't use those we still need to clear them
since they tend to spuriously trigger when MMC is used
(hardware bug? go figure)... */
if (cpu_is_pxa27x()) {
MISR = MISR_EOC;
PISR = PISR_EOC;
MCSR = MCSR_EOC;
}
return IRQ_HANDLED;
}
return IRQ_NONE;
}
#ifdef CONFIG_PM
int pxa2xx_ac97_hw_suspend(void)
{
GCR |= GCR_ACLINK_OFF;
clk_disable(ac97_clk);
return 0;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_hw_suspend);
int pxa2xx_ac97_hw_resume(void)
{
clk_enable(ac97_clk);
return 0;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_hw_resume);
#endif
int pxa2xx_ac97_hw_probe(struct platform_device *dev)
{
int ret;
pxa2xx_audio_ops_t *pdata = dev->dev.platform_data;
if (pdata) {
switch (pdata->reset_gpio) {
case 95:
case 113:
reset_gpio = pdata->reset_gpio;
break;
case 0:
reset_gpio = 113;
break;
case -1:
break;
default:
dev_err(&dev->dev, "Invalid reset GPIO %d\n",
pdata->reset_gpio);
}
} else {
if (cpu_is_pxa27x())
reset_gpio = 113;
}
if (cpu_is_pxa27x()) {
/*
* 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);
ac97conf_clk = NULL;
goto err_conf;
}
}
ac97_clk = clk_get(&dev->dev, "AC97CLK");
if (IS_ERR(ac97_clk)) {
ret = PTR_ERR(ac97_clk);
ac97_clk = NULL;
goto err_clk;
}
ret = clk_enable(ac97_clk);
if (ret)
goto err_clk2;
ret = request_irq(IRQ_AC97, pxa2xx_ac97_irq, 0, "AC97", NULL);
if (ret < 0)
goto err_irq;
return 0;
err_irq:
GCR |= GCR_ACLINK_OFF;
err_clk2:
clk_put(ac97_clk);
ac97_clk = NULL;
err_clk:
if (ac97conf_clk) {
clk_put(ac97conf_clk);
ac97conf_clk = NULL;
}
err_conf:
return ret;
}
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) {
clk_put(ac97conf_clk);
ac97conf_clk = NULL;
}
clk_disable(ac97_clk);
clk_put(ac97_clk);
ac97_clk = NULL;
}
EXPORT_SYMBOL_GPL(pxa2xx_ac97_hw_remove);
MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("Intel/Marvell PXA sound library");
MODULE_LICENSE("GPL");
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