Patchwork [RFC] rtc: rtc-s3c: use clk_prepare_enable and clk_disable_unprepare

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Submitter Vivek Gautam
Date April 9, 2013, 9:45 a.m.
Message ID <1365500744-14839-1-git-send-email-gautam.vivek@samsung.com>
Download mbox | patch
Permalink /patch/235021/
State New
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Vivek Gautam - April 9, 2013, 9:45 a.m.
Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
calls as required by common clock framework, to get rid of
WARN_ON on prepare_count.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
---

This fixes the warnings in the boot log coming out of enabling
the common clock framework in exynos platform.

However, on doing system suspend/resume using rtc wake mechanism
we still get following warning dump for the first time we suspend
using commands:
    echo +10 > /sys/class/rtc/rtc0/wakealarm
    echo mem > /sys/power/state

[   12.530000] ------------[ cut here ]------------
[   12.530000] WARNING: at kernel/mutex.c:199 __mutex_lock_slowpath+0x2c0/0x340()
[   12.530000] Modules linked in:
[   12.530000] [<80014c60>] (unwind_backtrace+0x0/0xf8) from [<8001ebd0>] (warn_slowpath_common+0x54/0x68)
[   12.530000] [<8001ebd0>] (warn_slowpath_common+0x54/0x68) from [<8001ec00>] (warn_slowpath_null+0x1c/0x24)
[   12.530000] [<8001ec00>] (warn_slowpath_null+0x1c/0x24) from [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340)
[   12.530000] [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) from [<8033f5d4>] (mutex_lock+0xc/0x24)
[   12.530000] [<8033f5d4>] (mutex_lock+0xc/0x24) from [<80299e18>] (clk_prepare+0x18/0x34)
[   12.530000] [<80299e18>] (clk_prepare+0x18/0x34) from [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98)
[   12.530000] [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) from [<8006ad78>] (handle_irq_event_percpu+0x54/0x194)
[   12.530000] [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) from [<8006aef4>] (handle_irq_event+0x3c/0x5c)
[   12.530000] [<8006aef4>] (handle_irq_event+0x3c/0x5c) from [<8006db00>] (handle_fasteoi_irq+0xa4/0x134)
[   12.530000] [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) from [<8006a594>] (generic_handle_irq+0x30/0x40)
[   12.530000] [<8006a594>] (generic_handle_irq+0x30/0x40) from [<8000f4fc>] (handle_IRQ+0x40/0x90)
[   12.530000] [<8000f4fc>] (handle_IRQ+0x40/0x90) from [<80008544>] (gic_handle_irq+0x38/0x68)
[   12.530000] [<80008544>] (gic_handle_irq+0x38/0x68) from [<8000e200>] (__irq_svc+0x40/0x70)
[   12.530000] Exception stack(0x8182be60 to 0x8182bea8)
[   12.530000] be60: 00000000 00000000 0000000c ffffffff 60000013 8049fc50 00000000 80479a10
[   12.530000] be80: 60000013 ee97de98 804799c0 00000001 0000000d 8182bea8 803412dc 803412e0
[   12.530000] bea0: 60000013 ffffffff
[   12.530000] [<8000e200>] (__irq_svc+0x40/0x70) from [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38)
[   12.530000] [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) from [<80070bc4>] (resume_irqs+0x9c/0xb8)
[   12.530000] [<80070bc4>] (resume_irqs+0x9c/0xb8) from [<8021d528>] (dpm_resume_start+0xc/0x18)
[   12.530000] [<8021d528>] (dpm_resume_start+0xc/0x18) from [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4)
[   12.530000] [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) from [<80054814>] (pm_suspend+0x19c/0x214)
[   12.530000] [<80054814>] (pm_suspend+0x19c/0x214) from [<80053a58>] (state_store+0x120/0x12c)
[   12.530000] [<80053a58>] (state_store+0x120/0x12c) from [<801ae9d8>] (kobj_attr_store+0x14/0x20)
[   12.530000] [<801ae9d8>] (kobj_attr_store+0x14/0x20) from [<801092c8>] (sysfs_write_file+0xfc/0x17c)
[   12.530000] [<801092c8>] (sysfs_write_file+0xfc/0x17c) from [<800b0d84>] (vfs_write+0xa8/0x138)
[   12.530000] [<800b0d84>] (vfs_write+0xa8/0x138) from [<800b10e4>] (sys_write+0x40/0x68)
[   12.530000] [<800b10e4>] (sys_write+0x40/0x68) from [<8000e600>] (ret_fast_syscall+0x0/0x30)
[   12.530000] ---[ end trace 8643216fba2e8cb5 ]---

 drivers/rtc/rtc-s3c.c |   58 ++++++++++++++++++++++++------------------------
 1 files changed, 29 insertions(+), 29 deletions(-)
Sylwester Nawrocki - April 9, 2013, 10:09 a.m.
On 04/09/2013 11:45 AM, Vivek Gautam wrote:
> Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
> calls as required by common clock framework, to get rid of
> WARN_ON on prepare_count.

Hmm, do you think warnings like below are any better that WARN_ON() on wrong
clock's prepare_count value ? :)

> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> ---
> 
> This fixes the warnings in the boot log coming out of enabling
> the common clock framework in exynos platform.
> 
> However, on doing system suspend/resume using rtc wake mechanism
> we still get following warning dump for the first time we suspend
> using commands:
>     echo +10 > /sys/class/rtc/rtc0/wakealarm
>     echo mem > /sys/power/state
> 
> [   12.530000] ------------[ cut here ]------------
> [   12.530000] WARNING: at kernel/mutex.c:199 __mutex_lock_slowpath+0x2c0/0x340()
> [   12.530000] Modules linked in:
> [   12.530000] [<80014c60>] (unwind_backtrace+0x0/0xf8) from [<8001ebd0>] (warn_slowpath_common+0x54/0x68)
> [   12.530000] [<8001ebd0>] (warn_slowpath_common+0x54/0x68) from [<8001ec00>] (warn_slowpath_null+0x1c/0x24)
> [   12.530000] [<8001ec00>] (warn_slowpath_null+0x1c/0x24) from [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340)
> [   12.530000] [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) from [<8033f5d4>] (mutex_lock+0xc/0x24)
> [   12.530000] [<8033f5d4>] (mutex_lock+0xc/0x24) from [<80299e18>] (clk_prepare+0x18/0x34)
> [   12.530000] [<80299e18>] (clk_prepare+0x18/0x34) from [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98)
> [   12.530000] [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) from [<8006ad78>] (handle_irq_event_percpu+0x54/0x194)
> [   12.530000] [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) from [<8006aef4>] (handle_irq_event+0x3c/0x5c)
> [   12.530000] [<8006aef4>] (handle_irq_event+0x3c/0x5c) from [<8006db00>] (handle_fasteoi_irq+0xa4/0x134)
> [   12.530000] [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) from [<8006a594>] (generic_handle_irq+0x30/0x40)
> [   12.530000] [<8006a594>] (generic_handle_irq+0x30/0x40) from [<8000f4fc>] (handle_IRQ+0x40/0x90)
> [   12.530000] [<8000f4fc>] (handle_IRQ+0x40/0x90) from [<80008544>] (gic_handle_irq+0x38/0x68)
> [   12.530000] [<80008544>] (gic_handle_irq+0x38/0x68) from [<8000e200>] (__irq_svc+0x40/0x70)
> [   12.530000] Exception stack(0x8182be60 to 0x8182bea8)
> [   12.530000] be60: 00000000 00000000 0000000c ffffffff 60000013 8049fc50 00000000 80479a10
> [   12.530000] be80: 60000013 ee97de98 804799c0 00000001 0000000d 8182bea8 803412dc 803412e0
> [   12.530000] bea0: 60000013 ffffffff
> [   12.530000] [<8000e200>] (__irq_svc+0x40/0x70) from [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38)
> [   12.530000] [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) from [<80070bc4>] (resume_irqs+0x9c/0xb8)
> [   12.530000] [<80070bc4>] (resume_irqs+0x9c/0xb8) from [<8021d528>] (dpm_resume_start+0xc/0x18)
> [   12.530000] [<8021d528>] (dpm_resume_start+0xc/0x18) from [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4)
> [   12.530000] [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) from [<80054814>] (pm_suspend+0x19c/0x214)
> [   12.530000] [<80054814>] (pm_suspend+0x19c/0x214) from [<80053a58>] (state_store+0x120/0x12c)
> [   12.530000] [<80053a58>] (state_store+0x120/0x12c) from [<801ae9d8>] (kobj_attr_store+0x14/0x20)
> [   12.530000] [<801ae9d8>] (kobj_attr_store+0x14/0x20) from [<801092c8>] (sysfs_write_file+0xfc/0x17c)
> [   12.530000] [<801092c8>] (sysfs_write_file+0xfc/0x17c) from [<800b0d84>] (vfs_write+0xa8/0x138)
> [   12.530000] [<800b0d84>] (vfs_write+0xa8/0x138) from [<800b10e4>] (sys_write+0x40/0x68)
> [   12.530000] [<800b10e4>] (sys_write+0x40/0x68) from [<8000e600>] (ret_fast_syscall+0x0/0x30)
> [   12.530000] ---[ end trace 8643216fba2e8cb5 ]---
> 
>  drivers/rtc/rtc-s3c.c |   58 ++++++++++++++++++++++++------------------------
>  1 files changed, 29 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> index fb994e9..75637ad 100644
> --- a/drivers/rtc/rtc-s3c.c
> +++ b/drivers/rtc/rtc-s3c.c
> @@ -65,12 +65,12 @@ static void s3c_rtc_alarm_clk_enable(bool enable)
>  	spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
>  	if (enable) {
>  		if (!alarm_clk_enabled) {
> -			clk_enable(rtc_clk);
> +			clk_prepare_enable(rtc_clk);
>  			alarm_clk_enabled = true;
>  		}
>  	} else {
>  		if (alarm_clk_enabled) {
> -			clk_disable(rtc_clk);
> +			clk_disable_unprepare(rtc_clk);
>  			alarm_clk_enabled = false;
>  		}
>  	}
> @@ -83,13 +83,13 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
>  {
>  	struct rtc_device *rdev = id;
>  
> -	clk_enable(rtc_clk);
> +	clk_prepare_enable(rtc_clk);

The reason for the above failure is that clk_prepare is called from an interrupt
context. You are not supposed to use clk_prepare_enable()/clk_unprepare_disble()
like this. Instead, prepare the clock in s3c_rtc_probe() and unprepare in the
driver's remove() callback. And clk_enable()/clk_disable calls could stay untouched.

>  	rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);
>  
>  	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
>  		writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);
>  
> -	clk_disable(rtc_clk);
> +	clk_disable_unprepare(rtc_clk);
>  
>  	s3c_rtc_alarm_clk_enable(false);
>  
> @@ -100,13 +100,13 @@ static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
>  {
>  	struct rtc_device *rdev = id;
>  
> -	clk_enable(rtc_clk);
> +	clk_prepare_enable(rtc_clk);
>  	rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);
>  
>  	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
>  		writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);
>  
> -	clk_disable(rtc_clk);
> +	clk_disable_unprepare(rtc_clk);
>  	return IRQ_HANDLED;
>  }

Regards,
Sylwester
Vivek Gautam - April 9, 2013, 12:51 p.m.
Hi Sylwester,


On Tue, Apr 9, 2013 at 3:39 PM, Sylwester Nawrocki
<s.nawrocki@samsung.com> wrote:
> On 04/09/2013 11:45 AM, Vivek Gautam wrote:
>> Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
>> calls as required by common clock framework, to get rid of
>> WARN_ON on prepare_count.
>
> Hmm, do you think warnings like below are any better that WARN_ON() on wrong
> clock's prepare_count value ? :)
>
>> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
>> ---
>>
>> This fixes the warnings in the boot log coming out of enabling
>> the common clock framework in exynos platform.
>>
>> However, on doing system suspend/resume using rtc wake mechanism
>> we still get following warning dump for the first time we suspend
>> using commands:
>>     echo +10 > /sys/class/rtc/rtc0/wakealarm
>>     echo mem > /sys/power/state
>>
>> [   12.530000] ------------[ cut here ]------------
>> [   12.530000] WARNING: at kernel/mutex.c:199 __mutex_lock_slowpath+0x2c0/0x340()
>> [   12.530000] Modules linked in:
>> [   12.530000] [<80014c60>] (unwind_backtrace+0x0/0xf8) from [<8001ebd0>] (warn_slowpath_common+0x54/0x68)
>> [   12.530000] [<8001ebd0>] (warn_slowpath_common+0x54/0x68) from [<8001ec00>] (warn_slowpath_null+0x1c/0x24)
>> [   12.530000] [<8001ec00>] (warn_slowpath_null+0x1c/0x24) from [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340)
>> [   12.530000] [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) from [<8033f5d4>] (mutex_lock+0xc/0x24)
>> [   12.530000] [<8033f5d4>] (mutex_lock+0xc/0x24) from [<80299e18>] (clk_prepare+0x18/0x34)
>> [   12.530000] [<80299e18>] (clk_prepare+0x18/0x34) from [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98)
>> [   12.530000] [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) from [<8006ad78>] (handle_irq_event_percpu+0x54/0x194)
>> [   12.530000] [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) from [<8006aef4>] (handle_irq_event+0x3c/0x5c)
>> [   12.530000] [<8006aef4>] (handle_irq_event+0x3c/0x5c) from [<8006db00>] (handle_fasteoi_irq+0xa4/0x134)
>> [   12.530000] [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) from [<8006a594>] (generic_handle_irq+0x30/0x40)
>> [   12.530000] [<8006a594>] (generic_handle_irq+0x30/0x40) from [<8000f4fc>] (handle_IRQ+0x40/0x90)
>> [   12.530000] [<8000f4fc>] (handle_IRQ+0x40/0x90) from [<80008544>] (gic_handle_irq+0x38/0x68)
>> [   12.530000] [<80008544>] (gic_handle_irq+0x38/0x68) from [<8000e200>] (__irq_svc+0x40/0x70)
>> [   12.530000] Exception stack(0x8182be60 to 0x8182bea8)
>> [   12.530000] be60: 00000000 00000000 0000000c ffffffff 60000013 8049fc50 00000000 80479a10
>> [   12.530000] be80: 60000013 ee97de98 804799c0 00000001 0000000d 8182bea8 803412dc 803412e0
>> [   12.530000] bea0: 60000013 ffffffff
>> [   12.530000] [<8000e200>] (__irq_svc+0x40/0x70) from [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38)
>> [   12.530000] [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) from [<80070bc4>] (resume_irqs+0x9c/0xb8)
>> [   12.530000] [<80070bc4>] (resume_irqs+0x9c/0xb8) from [<8021d528>] (dpm_resume_start+0xc/0x18)
>> [   12.530000] [<8021d528>] (dpm_resume_start+0xc/0x18) from [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4)
>> [   12.530000] [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) from [<80054814>] (pm_suspend+0x19c/0x214)
>> [   12.530000] [<80054814>] (pm_suspend+0x19c/0x214) from [<80053a58>] (state_store+0x120/0x12c)
>> [   12.530000] [<80053a58>] (state_store+0x120/0x12c) from [<801ae9d8>] (kobj_attr_store+0x14/0x20)
>> [   12.530000] [<801ae9d8>] (kobj_attr_store+0x14/0x20) from [<801092c8>] (sysfs_write_file+0xfc/0x17c)
>> [   12.530000] [<801092c8>] (sysfs_write_file+0xfc/0x17c) from [<800b0d84>] (vfs_write+0xa8/0x138)
>> [   12.530000] [<800b0d84>] (vfs_write+0xa8/0x138) from [<800b10e4>] (sys_write+0x40/0x68)
>> [   12.530000] [<800b10e4>] (sys_write+0x40/0x68) from [<8000e600>] (ret_fast_syscall+0x0/0x30)
>> [   12.530000] ---[ end trace 8643216fba2e8cb5 ]---
>>
>>  drivers/rtc/rtc-s3c.c |   58 ++++++++++++++++++++++++------------------------
>>  1 files changed, 29 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
>> index fb994e9..75637ad 100644
>> --- a/drivers/rtc/rtc-s3c.c
>> +++ b/drivers/rtc/rtc-s3c.c
>> @@ -65,12 +65,12 @@ static void s3c_rtc_alarm_clk_enable(bool enable)
>>       spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
>>       if (enable) {
>>               if (!alarm_clk_enabled) {
>> -                     clk_enable(rtc_clk);
>> +                     clk_prepare_enable(rtc_clk);
>>                       alarm_clk_enabled = true;
>>               }
>>       } else {
>>               if (alarm_clk_enabled) {
>> -                     clk_disable(rtc_clk);
>> +                     clk_disable_unprepare(rtc_clk);
>>                       alarm_clk_enabled = false;
>>               }
>>       }
>> @@ -83,13 +83,13 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
>>  {
>>       struct rtc_device *rdev = id;
>>
>> -     clk_enable(rtc_clk);
>> +     clk_prepare_enable(rtc_clk);
>
> The reason for the above failure is that clk_prepare is called from an interrupt
> context. You are not supposed to use clk_prepare_enable()/clk_unprepare_disble()
> like this. Instead, prepare the clock in s3c_rtc_probe() and unprepare in the
> driver's remove() callback. And clk_enable()/clk_disable calls could stay untouched.

Aah !! actually missed a similar patch from Thomas Abraham :(
doing the same as suggested by you.
Its available at:
http://patchwork.ozlabs.org/patch/188687/

>
>>       rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);
>>
>>       if (s3c_rtc_cpu_type == TYPE_S3C64XX)
>>               writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);
>>
>> -     clk_disable(rtc_clk);
>> +     clk_disable_unprepare(rtc_clk);
>>
>>       s3c_rtc_alarm_clk_enable(false);
>>
>> @@ -100,13 +100,13 @@ static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
>>  {
>>       struct rtc_device *rdev = id;
>>
>> -     clk_enable(rtc_clk);
>> +     clk_prepare_enable(rtc_clk);
>>       rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);
>>
>>       if (s3c_rtc_cpu_type == TYPE_S3C64XX)
>>               writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);
>>
>> -     clk_disable(rtc_clk);
>> +     clk_disable_unprepare(rtc_clk);
>>       return IRQ_HANDLED;
>>  }
>
Vivek Gautam - April 9, 2013, 1:34 p.m.
Hi Sylwester,


On Tue, Apr 9, 2013 at 6:21 PM, Vivek Gautam <gautamvivek1987@gmail.com> wrote:
> Hi Sylwester,
>
>
> On Tue, Apr 9, 2013 at 3:39 PM, Sylwester Nawrocki
> <s.nawrocki@samsung.com> wrote:
>> On 04/09/2013 11:45 AM, Vivek Gautam wrote:
>>> Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
>>> calls as required by common clock framework, to get rid of
>>> WARN_ON on prepare_count.
>>
>> Hmm, do you think warnings like below are any better that WARN_ON() on wrong
>> clock's prepare_count value ? :)
>>
>>> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
>>> ---
>>>
>>> This fixes the warnings in the boot log coming out of enabling
>>> the common clock framework in exynos platform.
>>>
>>> However, on doing system suspend/resume using rtc wake mechanism
>>> we still get following warning dump for the first time we suspend
>>> using commands:
>>>     echo +10 > /sys/class/rtc/rtc0/wakealarm
>>>     echo mem > /sys/power/state
>>>
>>> [   12.530000] ------------[ cut here ]------------
>>> [   12.530000] WARNING: at kernel/mutex.c:199 __mutex_lock_slowpath+0x2c0/0x340()
>>> [   12.530000] Modules linked in:
>>> [   12.530000] [<80014c60>] (unwind_backtrace+0x0/0xf8) from [<8001ebd0>] (warn_slowpath_common+0x54/0x68)
>>> [   12.530000] [<8001ebd0>] (warn_slowpath_common+0x54/0x68) from [<8001ec00>] (warn_slowpath_null+0x1c/0x24)
>>> [   12.530000] [<8001ec00>] (warn_slowpath_null+0x1c/0x24) from [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340)
>>> [   12.530000] [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) from [<8033f5d4>] (mutex_lock+0xc/0x24)
>>> [   12.530000] [<8033f5d4>] (mutex_lock+0xc/0x24) from [<80299e18>] (clk_prepare+0x18/0x34)
>>> [   12.530000] [<80299e18>] (clk_prepare+0x18/0x34) from [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98)
>>> [   12.530000] [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) from [<8006ad78>] (handle_irq_event_percpu+0x54/0x194)
>>> [   12.530000] [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) from [<8006aef4>] (handle_irq_event+0x3c/0x5c)
>>> [   12.530000] [<8006aef4>] (handle_irq_event+0x3c/0x5c) from [<8006db00>] (handle_fasteoi_irq+0xa4/0x134)
>>> [   12.530000] [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) from [<8006a594>] (generic_handle_irq+0x30/0x40)
>>> [   12.530000] [<8006a594>] (generic_handle_irq+0x30/0x40) from [<8000f4fc>] (handle_IRQ+0x40/0x90)
>>> [   12.530000] [<8000f4fc>] (handle_IRQ+0x40/0x90) from [<80008544>] (gic_handle_irq+0x38/0x68)
>>> [   12.530000] [<80008544>] (gic_handle_irq+0x38/0x68) from [<8000e200>] (__irq_svc+0x40/0x70)
>>> [   12.530000] Exception stack(0x8182be60 to 0x8182bea8)
>>> [   12.530000] be60: 00000000 00000000 0000000c ffffffff 60000013 8049fc50 00000000 80479a10
>>> [   12.530000] be80: 60000013 ee97de98 804799c0 00000001 0000000d 8182bea8 803412dc 803412e0
>>> [   12.530000] bea0: 60000013 ffffffff
>>> [   12.530000] [<8000e200>] (__irq_svc+0x40/0x70) from [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38)
>>> [   12.530000] [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) from [<80070bc4>] (resume_irqs+0x9c/0xb8)
>>> [   12.530000] [<80070bc4>] (resume_irqs+0x9c/0xb8) from [<8021d528>] (dpm_resume_start+0xc/0x18)
>>> [   12.530000] [<8021d528>] (dpm_resume_start+0xc/0x18) from [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4)
>>> [   12.530000] [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) from [<80054814>] (pm_suspend+0x19c/0x214)
>>> [   12.530000] [<80054814>] (pm_suspend+0x19c/0x214) from [<80053a58>] (state_store+0x120/0x12c)
>>> [   12.530000] [<80053a58>] (state_store+0x120/0x12c) from [<801ae9d8>] (kobj_attr_store+0x14/0x20)
>>> [   12.530000] [<801ae9d8>] (kobj_attr_store+0x14/0x20) from [<801092c8>] (sysfs_write_file+0xfc/0x17c)
>>> [   12.530000] [<801092c8>] (sysfs_write_file+0xfc/0x17c) from [<800b0d84>] (vfs_write+0xa8/0x138)
>>> [   12.530000] [<800b0d84>] (vfs_write+0xa8/0x138) from [<800b10e4>] (sys_write+0x40/0x68)
>>> [   12.530000] [<800b10e4>] (sys_write+0x40/0x68) from [<8000e600>] (ret_fast_syscall+0x0/0x30)
>>> [   12.530000] ---[ end trace 8643216fba2e8cb5 ]---
>>>
>>>  drivers/rtc/rtc-s3c.c |   58 ++++++++++++++++++++++++------------------------
>>>  1 files changed, 29 insertions(+), 29 deletions(-)
>>>
>>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
>>> index fb994e9..75637ad 100644
>>> --- a/drivers/rtc/rtc-s3c.c
>>> +++ b/drivers/rtc/rtc-s3c.c
>>> @@ -65,12 +65,12 @@ static void s3c_rtc_alarm_clk_enable(bool enable)
>>>       spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
>>>       if (enable) {
>>>               if (!alarm_clk_enabled) {
>>> -                     clk_enable(rtc_clk);
>>> +                     clk_prepare_enable(rtc_clk);
>>>                       alarm_clk_enabled = true;
>>>               }
>>>       } else {
>>>               if (alarm_clk_enabled) {
>>> -                     clk_disable(rtc_clk);
>>> +                     clk_disable_unprepare(rtc_clk);
>>>                       alarm_clk_enabled = false;
>>>               }
>>>       }
>>> @@ -83,13 +83,13 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
>>>  {
>>>       struct rtc_device *rdev = id;
>>>
>>> -     clk_enable(rtc_clk);
>>> +     clk_prepare_enable(rtc_clk);
>>
>> The reason for the above failure is that clk_prepare is called from an interrupt
>> context. You are not supposed to use clk_prepare_enable()/clk_unprepare_disble()
>> like this. Instead, prepare the clock in s3c_rtc_probe() and unprepare in the
>> driver's remove() callback. And clk_enable()/clk_disable calls could stay untouched.
>
> Aah !! actually missed a similar patch from Thomas Abraham :(
> doing the same as suggested by you.
> Its available at:
> http://patchwork.ozlabs.org/patch/188687/

There's a change required in the above mentioned patch, so possibly
Thomas can go ahead and post the next version
of that.
Sylwester Nawrocki - April 9, 2013, 1:59 p.m.
On 04/09/2013 03:34 PM, Vivek Gautam wrote:
>> Aah !! actually missed a similar patch from Thomas Abraham :(
>> > doing the same as suggested by you.
>> > Its available at:
>> > http://patchwork.ozlabs.org/patch/188687/
> There's a change required in the above mentioned patch, so possibly
> Thomas can go ahead and post the next version
> of that.

Why not make that change yourself if you need it ? That patch is
really old, maybe Thomas is busy with other things now.

Thanks,
Sylwester
Vivek Gautam - April 9, 2013, 2:20 p.m.
On Tue, Apr 9, 2013 at 7:29 PM, Sylwester Nawrocki
<s.nawrocki@samsung.com> wrote:
> On 04/09/2013 03:34 PM, Vivek Gautam wrote:
>>> Aah !! actually missed a similar patch from Thomas Abraham :(
>>> > doing the same as suggested by you.
>>> > Its available at:
>>> > http://patchwork.ozlabs.org/patch/188687/
>> There's a change required in the above mentioned patch, so possibly
>> Thomas can go ahead and post the next version
>> of that.
>
> Why not make that change yourself if you need it ? That patch is
> really old, maybe Thomas is busy with other things now.

Sure, will post a patch fixing this. :-)

Patch

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index fb994e9..75637ad 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -65,12 +65,12 @@  static void s3c_rtc_alarm_clk_enable(bool enable)
 	spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
 	if (enable) {
 		if (!alarm_clk_enabled) {
-			clk_enable(rtc_clk);
+			clk_prepare_enable(rtc_clk);
 			alarm_clk_enabled = true;
 		}
 	} else {
 		if (alarm_clk_enabled) {
-			clk_disable(rtc_clk);
+			clk_disable_unprepare(rtc_clk);
 			alarm_clk_enabled = false;
 		}
 	}
@@ -83,13 +83,13 @@  static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
 {
 	struct rtc_device *rdev = id;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);
 
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 		writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	s3c_rtc_alarm_clk_enable(false);
 
@@ -100,13 +100,13 @@  static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
 {
 	struct rtc_device *rdev = id;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);
 
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 		writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 	return IRQ_HANDLED;
 }
 
@@ -117,14 +117,14 @@  static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 
 	dev_dbg(dev, "%s: aie=%d\n", __func__, enabled);
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
 
 	if (enabled)
 		tmp |= S3C2410_RTCALM_ALMEN;
 
 	writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	s3c_rtc_alarm_clk_enable(enabled);
 
@@ -141,7 +141,7 @@  static int s3c_rtc_setfreq(struct device *dev, int freq)
 	if (!is_power_of_2(freq))
 		return -EINVAL;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	spin_lock_irq(&s3c_rtc_pie_lock);
 
 	if (s3c_rtc_cpu_type != TYPE_S3C64XX) {
@@ -163,7 +163,7 @@  static int s3c_rtc_setfreq(struct device *dev, int freq)
 
 	writel(tmp, s3c_rtc_base + S3C2410_TICNT);
 	spin_unlock_irq(&s3c_rtc_pie_lock);
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return 0;
 }
@@ -175,7 +175,7 @@  static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 	unsigned int have_retried = 0;
 	void __iomem *base = s3c_rtc_base;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
  retry_get_time:
 	rtc_tm->tm_min  = readb(base + S3C2410_RTCMIN);
 	rtc_tm->tm_hour = readb(base + S3C2410_RTCHOUR);
@@ -209,7 +209,7 @@  static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 
 	rtc_tm->tm_mon -= 1;
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 	return rtc_valid_tm(rtc_tm);
 }
 
@@ -229,14 +229,14 @@  static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
 		return -EINVAL;
 	}
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	writeb(bin2bcd(tm->tm_sec),  base + S3C2410_RTCSEC);
 	writeb(bin2bcd(tm->tm_min),  base + S3C2410_RTCMIN);
 	writeb(bin2bcd(tm->tm_hour), base + S3C2410_RTCHOUR);
 	writeb(bin2bcd(tm->tm_mday), base + S3C2410_RTCDATE);
 	writeb(bin2bcd(tm->tm_mon + 1), base + S3C2410_RTCMON);
 	writeb(bin2bcd(year), base + S3C2410_RTCYEAR);
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return 0;
 }
@@ -247,7 +247,7 @@  static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	void __iomem *base = s3c_rtc_base;
 	unsigned int alm_en;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	alm_tm->tm_sec  = readb(base + S3C2410_ALMSEC);
 	alm_tm->tm_min  = readb(base + S3C2410_ALMMIN);
 	alm_tm->tm_hour = readb(base + S3C2410_ALMHOUR);
@@ -299,7 +299,7 @@  static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	else
 		alm_tm->tm_year = -1;
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 	return 0;
 }
 
@@ -309,7 +309,7 @@  static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	void __iomem *base = s3c_rtc_base;
 	unsigned int alrm_en;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	dev_dbg(dev, "s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
 		 alrm->enabled,
 		 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
@@ -339,7 +339,7 @@  static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	s3c_rtc_setaie(dev, alrm->enabled);
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 	return 0;
 }
 
@@ -347,7 +347,7 @@  static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
 {
 	unsigned int ticnt;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
 		ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);
 		ticnt &= S3C64XX_RTCCON_TICEN;
@@ -357,7 +357,7 @@  static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
 	}
 
 	seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt  ? "yes" : "no");
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 	return 0;
 }
 
@@ -378,7 +378,7 @@  static void s3c_rtc_enable(struct platform_device *pdev, int en)
 	if (s3c_rtc_base == NULL)
 		return;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	if (!en) {
 		tmp = readw(base + S3C2410_RTCCON);
 		if (s3c_rtc_cpu_type == TYPE_S3C64XX)
@@ -418,7 +418,7 @@  static void s3c_rtc_enable(struct platform_device *pdev, int en)
 				base + S3C2410_RTCCON);
 		}
 	}
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 }
 
 static int s3c_rtc_remove(struct platform_device *dev)
@@ -498,7 +498,7 @@  static int s3c_rtc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 
 	/* check to see if everything is setup correctly */
 
@@ -568,7 +568,7 @@  static int s3c_rtc_probe(struct platform_device *pdev)
 		goto err_alarm_irq;
 	}
 
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return 0;
 
@@ -578,7 +578,7 @@  static int s3c_rtc_probe(struct platform_device *pdev)
 
  err_nortc:
 	s3c_rtc_enable(pdev, 0);
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return ret;
 }
@@ -591,7 +591,7 @@  static int ticnt_save, ticnt_en_save;
 
 static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 {
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	/* save TICNT for anyone using periodic interrupts */
 	ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
@@ -606,7 +606,7 @@  static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 		else
 			dev_err(&pdev->dev, "enable_irq_wake failed\n");
 	}
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return 0;
 }
@@ -615,7 +615,7 @@  static int s3c_rtc_resume(struct platform_device *pdev)
 {
 	unsigned int tmp;
 
-	clk_enable(rtc_clk);
+	clk_prepare_enable(rtc_clk);
 	s3c_rtc_enable(pdev, 1);
 	writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX && ticnt_en_save) {
@@ -627,7 +627,7 @@  static int s3c_rtc_resume(struct platform_device *pdev)
 		disable_irq_wake(s3c_rtc_alarmno);
 		wake_en = false;
 	}
-	clk_disable(rtc_clk);
+	clk_disable_unprepare(rtc_clk);
 
 	return 0;
 }