[PATCH] omap: wd_timer: Fix crash frm wdt_probe when !CONFIG_RUNTIME_PM

-----Original Message-----
From: Kevin Hilman [mailto:khilman at ti.com]
Sent: Wednesday, January 05, 2011 11:23 PM
To: Santosh Shilimkar
Cc: Paul Walmsley; linux-arm-kernel at lists.infradead.org; linux-
omap at vger.kernel.org
Subject: Re: [PATCH] omap: wd_timer: Fix crash frm wdt_probe when
!CONFIG_RUNTIME_PM

Santosh Shilimkar [off-list ref] writes:

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Commit ff2516fb 'wd_timer: disable on boot via hwmod postsetup

mechanism'

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introduced watchdog timer state state management using

postsetup_state.

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This was done to allow some board files to support watchdog

coverage

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throughout kernel initialization and it work as intended when

RUNTIME_PM

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is enabled.

With !CONFIG_RUNTIME_PM and no board is specifically requests

watchdog

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to remain enabled the omap_wdt_probe crashesh. This is because

hwmod

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in absense of runtime PM unable to turn watchdog clocks because

it's

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state is set to be disabled. For rest of the device, the state is
set as enabled in absense of RUNTIME_PM

[    1.372558] Unhandled fault: imprecise external abort (0x1406)

at

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0xad733eeb
[    1.379913] Internal error: : 1406 [#1] SMP
[    1.384277] last sysfs file:
[    1.387359] Modules linked in:
[    1.390563] CPU: 0    Tainted: G        W
(2.6.37-rc7-00265-g4298a4c-dirty #23)
[    1.398468] PC is at omap_wdt_disable+0x2c/0x3c
[    1.403198] LR is at omap_wdt_probe+0x124/0x1e0
[    1.407928] pc : [<c02f5bf4>]    lr : [<c03be10c>]    psr:

60000013

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[    1.407958] sp : df833f00  ip : 00000000  fp : 00000000
[    1.419921] r10: c0ac57ac  r9 : df959e00  r8 : 00000000
[    1.425384] r7 : df959e08  r6 : df8000c0  r5 : df95bebc  r4 :

df87dde0

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[    1.432189] r3 : fc314000  r2 : 00005555  r1 : fc314034  r0 :

df87dde0

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This patch make the default watchdog state to be enabled in case

of

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!CONFIG_RUNTIME_PM. This fixes the crash

Signed-off-by: Santosh Shilimkar <redacted>
Cc: Paul Walmsley <paul@pwsan.com>
---
Paul, I am not too sure if it breaks your _shutdown idea of

watchdog

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timer.  Patch generated against 'omap-for-linus' branch and boot
tested on OMAP4 with and without CONFIG_OMAP_WATCHDOG.

 arch/arm/mach-omap2/io.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
index e66687b..b879a16 100644
--- a/arch/arm/mach-omap2/io.c
+++ b/arch/arm/mach-omap2/io.c

@@ -378,7 +378,11 @@ void __init

omap2_init_common_infrastructure(void)

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 	 * XXX ideally we could detect whether the MPU WDT was

currently

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 	 * enabled here and make this conditional
 	 */
+#ifdef CONFIG_PM_RUNTIME
 	postsetup_state = _HWMOD_STATE_DISABLED;
+#else
+	postsetup_state = _HWMOD_STATE_ENABLED;
+#endif

You shouldn't need the 'else' part of this since the default a few
lines
above this code is already setting that for the !CONFIG_PM_RUNTIME
case.

Yep. Just 'CONFIG_PM_RUNTIME' wrapping is enough.