"Varadarajan, Charulatha" <charu@xxxxxx> writes: >> -----Original Message----- >> From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >> Sent: Wednesday, September 29, 2010 6:36 AM >> To: Varadarajan, Charulatha >> Cc: tony@xxxxxxxxxxx; wim@xxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; linux- >> watchdog@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; >> paul@xxxxxxxxx; Cousson, Benoit; Nayak, Rajendra; Basak, Partha >> Subject: Re: [PATCH v8 0/6] OMAP: WDT: Implement WDT in hwmod way >> >> Hi Charu, >> >> "Varadarajan, Charulatha" <charu@xxxxxx> writes: >> >> > Series of patches to port watchdog module to use hwmod APIs >> > for OMAP2PLUS chips and use runtime APIs for all OMAP chips. >> > For this hwmod database for OMAP2PLUS watchdog instances are >> > populated and implements watchdog module to use PM runtime APIs. >> > >> > This patch series is generated on "origin/pm-core" which >> > has Kevin's pm-next series, the runtime PM core patch series, >> > and a collection of hwmod fixes that Paul/Benoit have lined up >> > for 2.6.37. >> > >> > Tested on OMAP2430, OMAP4430 (ES1.0 & ES2.0), OMAP3430 SDP boards >> > and zoom3 board. Also verified that this patch series does not >> > break the OMAP1 build. >> >> I found a little snag with this series. Try testing with >> omap2plus_defconfig and changing CONFIG_OMAP_WATCHDOG=n. >> >> If CONFIG_OMAP_WATCHDOG is not enabled in the kernel config, the system >> will reboot soon after bootup. > > Thanks for finding this issue. > > After watchdog module reset, the WDTs are enabled. The default time > for a system reset after a watchdog module reset is ~10s as per the > default value of the WDT registers. Hence the above problem is observed. > > If CONFIG_OMAP_WATCHDOG is defined, wdt's probe is called within this > 10s time and watchdog_disable is called during probe. Hence we are not > finding this issue if CONFIG_OMAP_WATCHDOG is defined. > > Ideally, because of the above, watchdog should be with > HWMOD_INIT_NO_RESET flag. > > If agreed, I would send the below patch (extended to other OMAPs) > on top of my watchdog timer hwmod series with proper change log. Using HWMOD_INIT_NO_RESET makes us still dependent on the bootloader settings. Instead, I would rather have a small piece of code in omap_init_wdt() which disarms the watchdog so we don't have any assumptions about bootloader behavior. The question remains whether this disarm should be #ifndef CONFIG_OMAP_WATCHDOG or if it should happen all the time. In case the watchdog is a module, it's probe may not happen within the timeout period and they system may reboot also, so I lean towards disarming the watchdog unconditionally. Kevin > diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach- > omap2/omap_hwmod_3xxx_data.c > index 5bfe9c9..c567b24 100644 > --- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c > +++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c > @@ -260,6 +260,7 @@ static struct omap_hwmod omap3xxx_wd_timer2_hwmod = { > .slaves = omap3xxx_wd_timer2_slaves, > .slaves_cnt = ARRAY_SIZE(omap3xxx_wd_timer2_slaves), > .omap_chip = OMAP_CHIP_INIT(CHIP_IS_OMAP3430), > + .flags = HWMOD_INIT_NO_RESET, > }; > > -V Charulatha > > <<snip>> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
