Re: [PATCH] watchdog: at91rm9200: allow building when using device tree

[Alexandre Belloni <alexandre.belloni@free-electrons.com>]

On 30/10/2014 at 16:43:09 +0100, Arnd Bergmann wrote :
> On Thursday 30 October 2014 16:17:19 Alexandre Belloni wrote:
> > 
> > On 30/10/2014 at 15:43:43 +0100, Arnd Bergmann wrote :
> > > On Thursday 30 October 2014 15:36:24 Boris Brezillon wrote:
> > > > On Thu, 30 Oct 2014 15:15:34 +0100
> > > > Alexandre Belloni <alexandre.belloni@free-electrons.com> wrote:
> > > > 
> > > > > When building with device tree, ARCH_AT91RM9200 may not be selected. Allow
> > > > > building that driver by also depending on ARCH_AT91.
> > > > > 
> > > > > Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> > > > 
> > > > Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > > > 
> > > 
> > > Doesn't this reintroduce the bug fixed by commit 09549cd0172 ("watchdog:
> > > Revert the AT91RM9200_WATCHDOG dependency")?
> > > 
> > > At least in 3.18-rc2, the driver still uses at91_st_write/at91_st_read.
> > > 
> > 
> > Hum, right, then we have no better way to express that than depends on
> > SOC_AT91RM9200, would that be acceptable ?
> > 
> 
> Sounds fine to me, but why can't we just fix the dependency?

My plan was to create a driver for the system time in
drivers/clocksource from at91rm9200_time.c, export a syscon from there
that could be used by the watchdog driver.

But meanwhile, we can go with your patch.

> 
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
> index 74f1eaf97801..7f51e406b240 100644
> --- a/arch/arm/mach-at91/at91rm9200_devices.c
> +++ b/arch/arm/mach-at91/at91rm9200_devices.c
> @@ -719,10 +719,19 @@ static void __init at91_add_device_rtc(void) {}
>   * -------------------------------------------------------------------- */
>  
>  #if defined(CONFIG_AT91RM9200_WATCHDOG) || defined(CONFIG_AT91RM9200_WATCHDOG_MODULE)
> +static struct resource wdt_resources[] = {
> +	[0] = {
> +		.start	= AT91RM9200_BASE_ST,
> +		.end	= AT91RM9200_BASE_ST + SZ_256 - 1,
> +		.flags	= IORESOURCE_MEM,
> +	};
> +};
> +
>  static struct platform_device at91rm9200_wdt_device = {
> -	.name		= "at91_wdt",
> +	.name		= "at91rm9200_wdt",
>  	.id		= -1,
> -	.num_resources	= 0,
> +	.resource	= wdt_resources,
> +	.num_resources	= 1,
>  };
>  
>  static void __init at91_add_device_watchdog(void)
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index d0107d424ee4..0592db68f3a8 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -154,14 +154,14 @@ config ARM_SP805_WATCHDOG
>  
>  config AT91RM9200_WATCHDOG
>  	tristate "AT91RM9200 watchdog"
> -	depends on ARCH_AT91RM9200
> +	depends on ARCH_AT91 || COMPILE_TEST
>  	help
>  	  Watchdog timer embedded into AT91RM9200 chips. This will reboot your
>  	  system when the timeout is reached.
>  
>  config AT91SAM9X_WATCHDOG
>  	tristate "AT91SAM9X / AT91CAP9 watchdog"
> -	depends on ARCH_AT91 && !ARCH_AT91RM9200
> +	depends on ARCH_AT91
>  	select WATCHDOG_CORE
>  	help
>  	  Watchdog timer embedded into AT91SAM9X and AT91CAP9 chips. This will
> diff --git a/drivers/watchdog/at91rm9200_wdt.c b/drivers/watchdog/at91rm9200_wdt.c
> index dee6cc21d270..6b846e009268 100644
> --- a/drivers/watchdog/at91rm9200_wdt.c
> +++ b/drivers/watchdog/at91rm9200_wdt.c
> @@ -26,11 +26,27 @@
>  #include <linux/uaccess.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> -#include <mach/at91_st.h>
>  
>  #define WDT_DEFAULT_TIME	5	/* seconds */
>  #define WDT_MAX_TIME		256	/* seconds */
>  
> +static void __iomem *at91_st_base;
> +
> +#define at91_st_read(field) \
> +	readl(at91_st_base + field)
> +
> +#define at91_st_write(field, value) \
> +	writel(value, at91_st_base + field)
> +
> +#define	AT91_ST_CR		0x00			/* Control Register */
> +#define 	AT91_ST_WDRST		(1 << 0)		/* Watchdog Timer Restart */
> +
> +#define	AT91_ST_WDMR		0x08			/* Watchdog Mode Register */
> +#define		AT91_ST_WDV		(0xffff <<  0)		/* Watchdog Counter Value */
> +#define		AT91_ST_RSTEN		(1	<< 16)		/* Reset Enable */
> +#define		AT91_ST_EXTEN		(1	<< 17)		/* External Signal Assertion Enable */
> +
> +
>  static int wdt_time = WDT_DEFAULT_TIME;
>  static bool nowayout = WATCHDOG_NOWAYOUT;
>  
> @@ -203,12 +222,17 @@ static struct miscdevice at91wdt_miscdev = {
>  
>  static int at91wdt_probe(struct platform_device *pdev)
>  {
> +	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	int res;
>  
>  	if (at91wdt_miscdev.parent)
>  		return -EBUSY;
>  	at91wdt_miscdev.parent = &pdev->dev;
>  
> +	at91_st_base = devm_ioremap_resource(&pdev->dev, regs);
> +	if (!at91_st_base)
> +		return -ENXIO;
> +
>  	res = misc_register(&at91wdt_miscdev);
>  	if (res)
>  		return res;
> @@ -255,6 +279,7 @@ static int at91wdt_resume(struct platform_device *pdev)
>  #endif
>  
>  static const struct of_device_id at91_wdt_dt_ids[] = {
> +	{ .compatible = "atmel,at91rm9200-st" },
>  	{ .compatible = "atmel,at91rm9200-wdt" },
>  	{ /* sentinel */ }
>  };
> @@ -267,7 +292,7 @@ static struct platform_driver at91wdt_driver = {
>  	.suspend	= at91wdt_suspend,
>  	.resume		= at91wdt_resume,
>  	.driver		= {
> -		.name	= "at91_wdt",
> +		.name	= "at91rm9200_wdt",
>  		.owner	= THIS_MODULE,
>  		.of_match_table = at91_wdt_dt_ids,
>  	},
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com