Re: [PATCH 1/1] Watchdog: OMAP3: fix wrong boot status from wdt reboot

["zumeng.chen" <zchen@windriver.com>]

On 2012年07月05日 21:05, Bedia, Vaibhav wrote:
> Hello,
>
> On Wed, Jul 04, 2012 at 21:24:01, Zumeng Chen wrote:
>> Does the following fix make sense?
>>
>> WDIOC_GETBOOTSTATUS always return 0 even if the machine
>> comes from omap-wdt reboot. Because WKUP_MOD is not right
>> for OMAP3, so give the right addr 0xA00 of PRM_RSTST for
>> get_reset_sources, which inputs the signal from omap-wdt
>> reboot, and return 1 when coming from omap-wdt reboot for
>> WDIOC_GETBOOTSTATUS.
>>
>> Signed-off-by: Zumeng Chen<zumeng.chen@windriver.com>
>> ---
>>   arch/arm/mach-omap2/prcm.c  |    4 +++-
>>   drivers/watchdog/omap_wdt.c |    3 +++
>>   drivers/watchdog/omap_wdt.h |    3 +++
>>   3 files changed, 9 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/prcm.c b/arch/arm/mach-omap2/prcm.c
>> index 480f40a..43f3feb 100644
>> --- a/arch/arm/mach-omap2/prcm.c
>> +++ b/arch/arm/mach-omap2/prcm.c
>> @@ -49,8 +49,10 @@ void __iomem *prcm_mpu_base;
>>   u32 omap_prcm_get_reset_sources(void)
>>   {
>>   	/* XXX This presumably needs modification for 34XX */
>> -	if (cpu_is_omap24xx() || cpu_is_omap34xx())
>> +	if (cpu_is_omap24xx())
>>   		return omap2_prm_read_mod_reg(WKUP_MOD, OMAP2_RM_RSTST)&  0x7f;
>> +	if (cpu_is_omap34xx())
>> +		return omap2_prm_read_mod_reg(0xA00, OMAP2_RM_RSTST)&  0x7f;
>>   	if (cpu_is_omap44xx())
>>   		return omap2_prm_read_mod_reg(WKUP_MOD, OMAP4_RM_RSTST)&  0x7f;
> Instead of adding more cpu_is_* checks maybe you could switch to a
> function pointers based approach here?
I don't see any more checks VS before like ( cpu_is_omap24xx() || 
cpu_is_omap34xx())

Actually what we want is just to read a register with different offset
responding to the different SOC.
>>
>> diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
>> index 8285d65..ea57078 100644
>> --- a/drivers/watchdog/omap_wdt.c
>> +++ b/drivers/watchdog/omap_wdt.c
>> @@ -234,6 +234,9 @@ static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
>>   		if (cpu_is_omap24xx())
>>   			return put_user(omap_prcm_get_reset_sources(),
>>   					(int __user *)arg);
>> +		if (cpu_is_omap34xx())
>> +			return put_user(omap_prcm_get_reset_sources()&  0x10>>
>> +				OMAP3_PRM_RSTST_BIT, (int __user *)arg);
>>   		return put_user(0, (int __user *)arg);
> Usage of PRCM bit masks in the driver looks wrong. Why not
Maybe the not proper definition causes "looks wrong".
It should be MPU_WD_RST_BIT, so you see, it is about
watchdog bit.

Anyway, I'll try to send V2 patch with Hubhrajyoti's and your
comments

Regards,
Zumeng
> introduce an API like omap_prcm_check_reset_reason() which
> returns true or false based on the reset reason being checked?
>
> In case of WDT, the driver can then pass the right flag to
> userspace.
>
> Regards,
> Vaibhav B.
>
>>   	case WDIOC_KEEPALIVE:
>>   		pm_runtime_get_sync(wdev->dev);
>> diff --git a/drivers/watchdog/omap_wdt.h b/drivers/watchdog/omap_wdt.h
>> index 09b774c..d8d5daa 100644
>> --- a/drivers/watchdog/omap_wdt.h
>> +++ b/drivers/watchdog/omap_wdt.h
>> @@ -40,6 +40,9 @@
>>   #define OMAP_WATCHDOG_WPS		(0x34)
>>   #define OMAP_WATCHDOG_SPR		(0x48)
>>
>> +/* PRM_RSTST MPU_WD_RST bit */
>> +#define OMAP3_PRM_RSTST_BIT		4
>> +
>>   /* Using the prescaler, the OMAP watchdog could go for many
>>    * months before firing.  These limits work without scaling,
>>    * with the 60 second default assumed by most tools and docs.
>> -- 
>> 1.7.5.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>

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