diff mbox

ARM: OMAP2+: hwmod: fix _idle() hwmod state sanity check sequence

Message ID 1459812638-38789-1-git-send-email-s-anna@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Suman Anna April 4, 2016, 11:30 p.m. UTC
The omap_hwmod _enable() function can return success without setting
the hwmod state to _HWMOD_STATE_ENABLED for IPs with reset lines when
all of the reset lines are asserted. The omap_hwmod _idle() function
also performs a similar check, but after checking for the hwmod state
first. This triggers the WARN when pm_runtime_get and pm_runtime_put
are invoked on IPs with all reset lines asserted. Reverse the checks
for hwmod state and reset lines status to fix this.

Issue found during a unbind operation on a device with reset lines
still asserted, example backtrace below

 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 879 at arch/arm/mach-omap2/omap_hwmod.c:2207 _idle+0x1e4/0x240()
 omap_hwmod: mmu_dsp: idle state can only be entered from enabled state
 Modules linked in:
 CPU: 1 PID: 879 Comm: sh Not tainted 4.4.0-00008-ga989d951331a #3
 Hardware name: Generic OMAP5 (Flattened Device Tree)
 [<c0018e60>] (unwind_backtrace) from [<c0014dc4>] (show_stack+0x10/0x14)
 [<c0014dc4>] (show_stack) from [<c037ac28>] (dump_stack+0x90/0xc0)
 [<c037ac28>] (dump_stack) from [<c003f420>] (warn_slowpath_common+0x78/0xb4)
 [<c003f420>] (warn_slowpath_common) from [<c003f48c>] (warn_slowpath_fmt+0x30/0x40)
 [<c003f48c>] (warn_slowpath_fmt) from [<c0028c20>] (_idle+0x1e4/0x240)
 [<c0028c20>] (_idle) from [<c0029080>] (omap_hwmod_idle+0x28/0x48)
 [<c0029080>] (omap_hwmod_idle) from [<c002a5a4>] (omap_device_idle+0x3c/0x90)
 [<c002a5a4>] (omap_device_idle) from [<c0427a90>] (__rpm_callback+0x2c/0x60)
 [<c0427a90>] (__rpm_callback) from [<c0427ae4>] (rpm_callback+0x20/0x80)
 [<c0427ae4>] (rpm_callback) from [<c0427f84>] (rpm_suspend+0x138/0x74c)
 [<c0427f84>] (rpm_suspend) from [<c0428b78>] (__pm_runtime_idle+0x78/0xa8)
 [<c0428b78>] (__pm_runtime_idle) from [<c041f514>] (__device_release_driver+0x64/0x100)
 [<c041f514>] (__device_release_driver) from [<c041f5d0>] (device_release_driver+0x20/0x2c)
 [<c041f5d0>] (device_release_driver) from [<c041d85c>] (unbind_store+0x78/0xf8)
 [<c041d85c>] (unbind_store) from [<c0206df8>] (kernfs_fop_write+0xc0/0x1c4)
 [<c0206df8>] (kernfs_fop_write) from [<c018a120>] (__vfs_write+0x20/0xdc)
 [<c018a120>] (__vfs_write) from [<c018a9cc>] (vfs_write+0x90/0x164)
 [<c018a9cc>] (vfs_write) from [<c018b1f0>] (SyS_write+0x44/0x9c)
 [<c018b1f0>] (SyS_write) from [<c0010420>] (ret_fast_syscall+0x0/0x1c)
 ---[ end trace a4182013c75a9f50 ]---

While at this, fix the sequence in _shutdown() as well, though there
is no easy reproducible scenario.

Fixes: 747834ab8347 ("ARM: OMAP2+: hwmod: revise hardreset behavior")
Signed-off-by: Suman Anna <s-anna@ti.com>
---
Hi Paul,

There are couple of pr_debug statements that only print once the code
flow passes through certain conditions. Not sure if you wanted them
to be printed first thing when entering the functions or only if the
function is really doing something. But it is still not consistent
between _enable(), _idle() and _shutdown().

regards
Suman

 arch/arm/mach-omap2/omap_hwmod.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Paul Walmsley April 10, 2016, 6:42 p.m. UTC | #1
Hi Suman

On Mon, 4 Apr 2016, Suman Anna wrote:

> The omap_hwmod _enable() function can return success without setting
> the hwmod state to _HWMOD_STATE_ENABLED for IPs with reset lines when
> all of the reset lines are asserted. The omap_hwmod _idle() function
> also performs a similar check, but after checking for the hwmod state
> first. This triggers the WARN when pm_runtime_get and pm_runtime_put
> are invoked on IPs with all reset lines asserted. Reverse the checks
> for hwmod state and reset lines status to fix this.
> 
> Issue found during a unbind operation on a device with reset lines
> still asserted, example backtrace below
> 
>  ------------[ cut here ]------------
>  WARNING: CPU: 1 PID: 879 at arch/arm/mach-omap2/omap_hwmod.c:2207 _idle+0x1e4/0x240()
>  omap_hwmod: mmu_dsp: idle state can only be entered from enabled state
>  Modules linked in:
>  CPU: 1 PID: 879 Comm: sh Not tainted 4.4.0-00008-ga989d951331a #3
>  Hardware name: Generic OMAP5 (Flattened Device Tree)
>  [<c0018e60>] (unwind_backtrace) from [<c0014dc4>] (show_stack+0x10/0x14)
>  [<c0014dc4>] (show_stack) from [<c037ac28>] (dump_stack+0x90/0xc0)
>  [<c037ac28>] (dump_stack) from [<c003f420>] (warn_slowpath_common+0x78/0xb4)
>  [<c003f420>] (warn_slowpath_common) from [<c003f48c>] (warn_slowpath_fmt+0x30/0x40)
>  [<c003f48c>] (warn_slowpath_fmt) from [<c0028c20>] (_idle+0x1e4/0x240)
>  [<c0028c20>] (_idle) from [<c0029080>] (omap_hwmod_idle+0x28/0x48)
>  [<c0029080>] (omap_hwmod_idle) from [<c002a5a4>] (omap_device_idle+0x3c/0x90)
>  [<c002a5a4>] (omap_device_idle) from [<c0427a90>] (__rpm_callback+0x2c/0x60)
>  [<c0427a90>] (__rpm_callback) from [<c0427ae4>] (rpm_callback+0x20/0x80)
>  [<c0427ae4>] (rpm_callback) from [<c0427f84>] (rpm_suspend+0x138/0x74c)
>  [<c0427f84>] (rpm_suspend) from [<c0428b78>] (__pm_runtime_idle+0x78/0xa8)
>  [<c0428b78>] (__pm_runtime_idle) from [<c041f514>] (__device_release_driver+0x64/0x100)
>  [<c041f514>] (__device_release_driver) from [<c041f5d0>] (device_release_driver+0x20/0x2c)
>  [<c041f5d0>] (device_release_driver) from [<c041d85c>] (unbind_store+0x78/0xf8)
>  [<c041d85c>] (unbind_store) from [<c0206df8>] (kernfs_fop_write+0xc0/0x1c4)
>  [<c0206df8>] (kernfs_fop_write) from [<c018a120>] (__vfs_write+0x20/0xdc)
>  [<c018a120>] (__vfs_write) from [<c018a9cc>] (vfs_write+0x90/0x164)
>  [<c018a9cc>] (vfs_write) from [<c018b1f0>] (SyS_write+0x44/0x9c)
>  [<c018b1f0>] (SyS_write) from [<c0010420>] (ret_fast_syscall+0x0/0x1c)
>  ---[ end trace a4182013c75a9f50 ]---
> 
> While at this, fix the sequence in _shutdown() as well, though there
> is no easy reproducible scenario.
> 
> Fixes: 747834ab8347 ("ARM: OMAP2+: hwmod: revise hardreset behavior")
> Signed-off-by: Suman Anna <s-anna@ti.com>

Thanks, I'm going to queue this for v4.7, mostly to get in more testing 
and integration time.  Let me know if you think it's important enough to 
go into v4.6-rc.


> There are couple of pr_debug statements that only print once the code
> flow passes through certain conditions. Not sure if you wanted them
> to be printed first thing when entering the functions or only if the
> function is really doing something. But it is still not consistent
> between _enable(), _idle() and _shutdown().

Yeah those need to be cleaned up.  Seems like the best thing to do 
is to move them all to the beginning of their respective functions.


- Paul
Suman Anna April 10, 2016, 9:13 p.m. UTC | #2
Hi Paul,

On 04/10/2016 01:42 PM, Paul Walmsley wrote:
> Hi Suman
> 
> On Mon, 4 Apr 2016, Suman Anna wrote:
> 
>> The omap_hwmod _enable() function can return success without setting
>> the hwmod state to _HWMOD_STATE_ENABLED for IPs with reset lines when
>> all of the reset lines are asserted. The omap_hwmod _idle() function
>> also performs a similar check, but after checking for the hwmod state
>> first. This triggers the WARN when pm_runtime_get and pm_runtime_put
>> are invoked on IPs with all reset lines asserted. Reverse the checks
>> for hwmod state and reset lines status to fix this.
>>
>> Issue found during a unbind operation on a device with reset lines
>> still asserted, example backtrace below
>>
>>  ------------[ cut here ]------------
>>  WARNING: CPU: 1 PID: 879 at arch/arm/mach-omap2/omap_hwmod.c:2207 _idle+0x1e4/0x240()
>>  omap_hwmod: mmu_dsp: idle state can only be entered from enabled state
>>  Modules linked in:
>>  CPU: 1 PID: 879 Comm: sh Not tainted 4.4.0-00008-ga989d951331a #3
>>  Hardware name: Generic OMAP5 (Flattened Device Tree)
>>  [<c0018e60>] (unwind_backtrace) from [<c0014dc4>] (show_stack+0x10/0x14)
>>  [<c0014dc4>] (show_stack) from [<c037ac28>] (dump_stack+0x90/0xc0)
>>  [<c037ac28>] (dump_stack) from [<c003f420>] (warn_slowpath_common+0x78/0xb4)
>>  [<c003f420>] (warn_slowpath_common) from [<c003f48c>] (warn_slowpath_fmt+0x30/0x40)
>>  [<c003f48c>] (warn_slowpath_fmt) from [<c0028c20>] (_idle+0x1e4/0x240)
>>  [<c0028c20>] (_idle) from [<c0029080>] (omap_hwmod_idle+0x28/0x48)
>>  [<c0029080>] (omap_hwmod_idle) from [<c002a5a4>] (omap_device_idle+0x3c/0x90)
>>  [<c002a5a4>] (omap_device_idle) from [<c0427a90>] (__rpm_callback+0x2c/0x60)
>>  [<c0427a90>] (__rpm_callback) from [<c0427ae4>] (rpm_callback+0x20/0x80)
>>  [<c0427ae4>] (rpm_callback) from [<c0427f84>] (rpm_suspend+0x138/0x74c)
>>  [<c0427f84>] (rpm_suspend) from [<c0428b78>] (__pm_runtime_idle+0x78/0xa8)
>>  [<c0428b78>] (__pm_runtime_idle) from [<c041f514>] (__device_release_driver+0x64/0x100)
>>  [<c041f514>] (__device_release_driver) from [<c041f5d0>] (device_release_driver+0x20/0x2c)
>>  [<c041f5d0>] (device_release_driver) from [<c041d85c>] (unbind_store+0x78/0xf8)
>>  [<c041d85c>] (unbind_store) from [<c0206df8>] (kernfs_fop_write+0xc0/0x1c4)
>>  [<c0206df8>] (kernfs_fop_write) from [<c018a120>] (__vfs_write+0x20/0xdc)
>>  [<c018a120>] (__vfs_write) from [<c018a9cc>] (vfs_write+0x90/0x164)
>>  [<c018a9cc>] (vfs_write) from [<c018b1f0>] (SyS_write+0x44/0x9c)
>>  [<c018b1f0>] (SyS_write) from [<c0010420>] (ret_fast_syscall+0x0/0x1c)
>>  ---[ end trace a4182013c75a9f50 ]---
>>
>> While at this, fix the sequence in _shutdown() as well, though there
>> is no easy reproducible scenario.
>>
>> Fixes: 747834ab8347 ("ARM: OMAP2+: hwmod: revise hardreset behavior")
>> Signed-off-by: Suman Anna <s-anna@ti.com>
> 
> Thanks, I'm going to queue this for v4.7, mostly to get in more testing 
> and integration time.  Let me know if you think it's important enough to 
> go into v4.6-rc.

Nope, not essential for the -rc cycle. I am fine with it getting queued
for v4.7.

> 
> 
>> There are couple of pr_debug statements that only print once the code
>> flow passes through certain conditions. Not sure if you wanted them
>> to be printed first thing when entering the functions or only if the
>> function is really doing something. But it is still not consistent
>> between _enable(), _idle() and _shutdown().
> 
> Yeah those need to be cleaned up.  Seems like the best thing to do 
> is to move them all to the beginning of their respective functions.

You want that fixed in this patch or a separate patch?

regards
Suman
Paul Walmsley April 10, 2016, 11:02 p.m. UTC | #3
Hi Suman

On Sun, 10 Apr 2016, Suman Anna wrote:

> >> There are couple of pr_debug statements that only print once the code
> >> flow passes through certain conditions. Not sure if you wanted them
> >> to be printed first thing when entering the functions or only if the
> >> function is really doing something. But it is still not consistent
> >> between _enable(), _idle() and _shutdown().
> > 
> > Yeah those need to be cleaned up.  Seems like the best thing to do 
> > is to move them all to the beginning of their respective functions.
> 
> You want that fixed in this patch or a separate patch?

A separate one would be great.  No rush



- Paul
diff mbox

Patch

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index b6d62e4cdfdd..027371c29fb9 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -2207,15 +2207,15 @@  static int _idle(struct omap_hwmod *oh)
 
 	pr_debug("omap_hwmod: %s: idling\n", oh->name);
 
+	if (_are_all_hardreset_lines_asserted(oh))
+		return 0;
+
 	if (oh->_state != _HWMOD_STATE_ENABLED) {
 		WARN(1, "omap_hwmod: %s: idle state can only be entered from enabled state\n",
 			oh->name);
 		return -EINVAL;
 	}
 
-	if (_are_all_hardreset_lines_asserted(oh))
-		return 0;
-
 	if (oh->class->sysc)
 		_idle_sysc(oh);
 	_del_initiator_dep(oh, mpu_oh);
@@ -2262,6 +2262,9 @@  static int _shutdown(struct omap_hwmod *oh)
 	int ret, i;
 	u8 prev_state;
 
+	if (_are_all_hardreset_lines_asserted(oh))
+		return 0;
+
 	if (oh->_state != _HWMOD_STATE_IDLE &&
 	    oh->_state != _HWMOD_STATE_ENABLED) {
 		WARN(1, "omap_hwmod: %s: disabled state can only be entered from idle, or enabled state\n",
@@ -2269,9 +2272,6 @@  static int _shutdown(struct omap_hwmod *oh)
 		return -EINVAL;
 	}
 
-	if (_are_all_hardreset_lines_asserted(oh))
-		return 0;
-
 	pr_debug("omap_hwmod: %s: disabling\n", oh->name);
 
 	if (oh->class->pre_shutdown) {