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Subject: Re: [PATCH 1/6] ARM: ks8695: watchdog: stop using mach/*.h
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Linus Walleij <linus.walleij@linaro.org>, arm@kernel.org,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-watchdog@vger.kernel.org
References: <20190415202501.941196-1-arnd@arndb.de>
From:   Greg Ungerer <gerg@uclinux.org>
Message-ID: <2424c672-e3fb-4c32-4c24-fafc59d03a96@uclinux.org>
Date:   Fri, 3 May 2019 17:02:23 +1000
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Hi Arnd,

On 16/4/19 6:24 am, Arnd Bergmann wrote:
> drivers should not rely on machine specific headers but
> get their information from the platform device.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

I dug out some old ks8695 based hardware to try this out.
I had a lot of trouble getting anything modern working on it.
In the end I still don't have a reliable test bed to test this properly.

Your patch series works as well as the kernel before the changes,
so I am happy enough to ack them as they are.

Acked-by: Greg Ungerer <gerg@kernel.org>

Ultimately though I am left wondering if the ks8695 support in the
kernel is useful to anyone the way it is at the moment. With a minimal
kernel configuration I can boot up to a shell - but the system is
really unreliable if you try to interactively use it. I don't think
it is the hardware - it seems to run reliably with the old code
it has running from flash on it. I am only testing the new kernel,
running with the existing user space root filesystem on it (which
dates from 2004 :-)

Regards
Greg


>   arch/arm/mach-ks8695/devices.c | 13 ++++++++++++-
>   drivers/watchdog/Kconfig       |  2 +-
>   drivers/watchdog/ks8695_wdt.c  | 30 +++++++++++++++++-------------
>   3 files changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/mach-ks8695/devices.c b/arch/arm/mach-ks8695/devices.c
> index 61cf20beb45f..57766817d86f 100644
> --- a/arch/arm/mach-ks8695/devices.c
> +++ b/arch/arm/mach-ks8695/devices.c
> @@ -169,11 +169,22 @@ void __init ks8696_add_device_hpna(void)
>   /* --------------------------------------------------------------------
>    *  Watchdog
>    * -------------------------------------------------------------------- */
> +#define KS8695_TMR_OFFSET      (0xF0000 + 0xE400)
> +#define KS8695_TMR_PA          (KS8695_IO_PA + KS8695_TMR_OFFSET)
> +static struct resource ks8695_wdt_resources[] = {
> +	[0] = {
> +		.name	= "tmr",
> +		.start	= KS8695_TMR_PA,
> +		.end	= KS8695_TMR_PA + 0xf,
> +		.flags	= IORESOURCE_MEM,
> +	},
> +};
>   
>   static struct platform_device ks8695_wdt_device = {
>   	.name		= "ks8695_wdt",
>   	.id		= -1,
> -	.num_resources	= 0,
> +	.resource	= ks8695_wdt_resources,
> +	.num_resources	= ARRAY_SIZE(ks8695_wdt_resources),
>   };
>   
>   static void __init ks8695_add_device_watchdog(void)
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 242eea859637..046e01daef57 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -397,7 +397,7 @@ config IXP4XX_WATCHDOG
>   
>   config KS8695_WATCHDOG
>   	tristate "KS8695 watchdog"
> -	depends on ARCH_KS8695
> +	depends on ARCH_KS8695 || COMPILE_TEST
>   	help
>   	  Watchdog timer embedded into KS8695 processor. This will reboot your
>   	  system when the timeout is reached.
> diff --git a/drivers/watchdog/ks8695_wdt.c b/drivers/watchdog/ks8695_wdt.c
> index 1e41818a44bc..87c542c2f912 100644
> --- a/drivers/watchdog/ks8695_wdt.c
> +++ b/drivers/watchdog/ks8695_wdt.c
> @@ -23,10 +23,8 @@
>   #include <linux/watchdog.h>
>   #include <linux/io.h>
>   #include <linux/uaccess.h>
> -#include <mach/hardware.h>
>   
> -#define KS8695_TMR_OFFSET	(0xF0000 + 0xE400)
> -#define KS8695_TMR_VA		(KS8695_IO_VA + KS8695_TMR_OFFSET)
> +#define KS8695_CLOCK_RATE  25000000
>   
>   /*
>    * Timer registers
> @@ -57,6 +55,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
>   
>   static unsigned long ks8695wdt_busy;
>   static DEFINE_SPINLOCK(ks8695_lock);
> +static void __iomem *tmr_reg;
>   
>   /* ......................................................................... */
>   
> @@ -69,8 +68,8 @@ static inline void ks8695_wdt_stop(void)
>   
>   	spin_lock(&ks8695_lock);
>   	/* disable timer0 */
> -	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
> -	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
> +	tmcon = __raw_readl(tmr_reg + KS8695_TMCON);
> +	__raw_writel(tmcon & ~TMCON_T0EN, tmr_reg + KS8695_TMCON);
>   	spin_unlock(&ks8695_lock);
>   }
>   
> @@ -84,15 +83,15 @@ static inline void ks8695_wdt_start(void)
>   
>   	spin_lock(&ks8695_lock);
>   	/* disable timer0 */
> -	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
> -	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
> +	tmcon = __raw_readl(tmr_reg + KS8695_TMCON);
> +	__raw_writel(tmcon & ~TMCON_T0EN, tmr_reg + KS8695_TMCON);
>   
>   	/* program timer0 */
> -	__raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
> +	__raw_writel(tval | T0TC_WATCHDOG, tmr_reg + KS8695_T0TC);
>   
>   	/* re-enable timer0 */
> -	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
> -	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
> +	tmcon = __raw_readl(tmr_reg + KS8695_TMCON);
> +	__raw_writel(tmcon | TMCON_T0EN, tmr_reg + KS8695_TMCON);
>   	spin_unlock(&ks8695_lock);
>   }
>   
> @@ -105,9 +104,9 @@ static inline void ks8695_wdt_reload(void)
>   
>   	spin_lock(&ks8695_lock);
>   	/* disable, then re-enable timer0 */
> -	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
> -	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
> -	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
> +	tmcon = __raw_readl(tmr_reg + KS8695_TMCON);
> +	__raw_writel(tmcon & ~TMCON_T0EN, tmr_reg + KS8695_TMCON);
> +	__raw_writel(tmcon | TMCON_T0EN, tmr_reg + KS8695_TMCON);
>   	spin_unlock(&ks8695_lock);
>   }
>   
> @@ -238,6 +237,11 @@ static struct miscdevice ks8695wdt_miscdev = {
>   static int ks8695wdt_probe(struct platform_device *pdev)
>   {
>   	int res;
> +	struct resource *resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +	tmr_reg = devm_ioremap_resource(&pdev->dev, resource);
> +	if (!tmr_reg)
> +		return -ENXIO;
>   
>   	if (ks8695wdt_miscdev.parent)
>   		return -EBUSY;
>