[PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Liu Dalin]

When an application sets and enables an alarm on Loongson RTC devices,
the alarm notification fails to propagate to userspace because the
ACPI event handler omits calling rtc_update_irq().

As a result, processes waiting via select() or poll() on RTC device
files fail to receive alarm notifications.

Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
---
 drivers/rtc/rtc-loongson.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
index 97e5625c064c..0c573f198f63 100644
--- a/drivers/rtc/rtc-loongson.c
+++ b/drivers/rtc/rtc-loongson.c
@@ -129,6 +129,8 @@ static u32 loongson_rtc_handler(void *id)
 {
 	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 
+	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+
 	spin_lock(&priv->lock);
 	/* Disable RTC alarm wakeup and interrupt */
 	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
-- 
2.33.0

Re: [PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Binbin Zhou]

Hi Dalin:

Thanks for your patch.

On 2025/4/29 14:27, Liu Dalin wrote:
> When an application sets and enables an alarm on Loongson RTC devices,
> the alarm notification fails to propagate to userspace because the
> ACPI event handler omits calling rtc_update_irq().
>
> As a result, processes waiting via select() or poll() on RTC device
> files fail to receive alarm notifications.
>
> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
> ---
>   drivers/rtc/rtc-loongson.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> index 97e5625c064c..0c573f198f63 100644
> --- a/drivers/rtc/rtc-loongson.c
> +++ b/drivers/rtc/rtc-loongson.c
> @@ -129,6 +129,8 @@ static u32 loongson_rtc_handler(void *id)
>   {
>   	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
>   
> +	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
> +
While testing the patch, I noticed that interrupts are triggered 
multiple times (/proc/interrupt), not sure if you have the same issue.

I think we need a similar operation to loongson_rtc_isr() to clear the 
interrupt:
regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
>   	spin_lock(&priv->lock);
>   	/* Disable RTC alarm wakeup and interrupt */
>   	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
Thanks.
Binbin

Re: Re: [PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[liudalin]

Hi Binbin:
   The described issue does not happened  with or without the patch by test, as the interrupt is managed by acpi. 

   The device info and test result are as follows.

1. Device info
[系统未激活][root@mail test]# dmidecode -q
BIOS Information
        Vendor: ZD-TECH
        Version: V09
        Release Date: 06/15/2022
        ROM Size: 8 MB
        Characteristics:
                PCI is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                Boot from CD is supported
                Selectable boot is supported
                BIOS ROM is socketed
                Serial services are supported (int 14h)
                USB legacy is supported
                Function key-initiated network boot is supported
                UEFI is supported
        BIOS Revision: 4.0
        Firmware Revision: 0.4

System Information
        Manufacturer: GEIT
        Product Name: UT6000-LB5
        Version: 1.0
        Serial Number: TBD by OEM
        UUID: 00112233-4455-6677-8899-aabbccddeeff
        Wake-up Type: Power Switch
        SKU Number: Loongson_SKU
        Family: Type1Family

Base Board Information
        Manufacturer: GEIT
        Product Name: GG-3A5000-02
        Version: 1.0
        Serial Number: Chassis Board Serial#To Be Filled By O.E.M
        Asset Tag: Type2 - Board Asset Tag
        Features:
                Board is a hosting board
                Board is replaceable
        Location In Chassis: Type2 - Board Chassis Location
        Type: Motherboard
...

2. The system exhibits a timeout error when waiting for alarm signal response without the patch.
[系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
21:          3          0          0          0   PCH PIC   1  acpi
[系统未激活][root@mail test]#
[系统未激活][root@mail test]# ./rtc01
RTC READ TEST:
RTC READ TEST Passed
Current RTC date/time is 8-5-2025, 05:50:05.
RTC ALARM TEST :Alarm time set to 05:50:10.
Waiting 5 seconds for the alarm...
Timed out waiting for the alarm
RTC UPDATE INTERRUPTS TEST :
RTC_UIE_ON not supported
RTC Tests Done!
[系统未激活][root@mail test]#
[系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
21:          4          0          0          0   PCH PIC   1  acpi
[系统未激活][root@mail test]#

3. There is no error with the patch applied and the interrupts are triggered ok
[系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
21:          0          0          0          0   PCH PIC   1  acpi
[系统未激活][root@mail test]#
[系统未激活][root@mail test]# ./rtc01
RTC READ TEST:
RTC READ TEST Passed
Current RTC date/time is 8-5-2025, 06:09:03.
RTC ALARM TEST :Alarm time set to 06:09:08.
Waiting 5 seconds for the alarm...
Alarm rang.
RTC ALARM TEST Passed
RTC UPDATE INTERRUPTS TEST :
RTC_UIE_ON not supported
RTC Tests Done!
[系统未激活][root@mail test]#
[系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
21:          1          0          0          0   PCH PIC   1  acpi
[系统未激活][root@mail test]#





From: Binbin Zhou



Date: 2025-05-08 11:12



To: Liu Dalin; alexandre.belloni; wangming01



CC: chenhuacai; gaojuxin; git; jiaxun.yang; keguang.zhang; lixuefeng; linux-rtc; linux-kernel; zhoubb.aaron



Subject: Re: [PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events



Hi Dalin:



 



Thanks for your patch.



 



On 2025/4/29 14:27, Liu Dalin wrote:



> When an application sets and enables an alarm on Loongson RTC devices,



> the alarm notification fails to propagate to userspace because the



> ACPI event handler omits calling rtc_update_irq().



>



> As a result, processes waiting via select() or poll() on RTC device



> files fail to receive alarm notifications.



>



> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")



> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>



> ---



>   drivers/rtc/rtc-loongson.c | 2 ++



>   1 file changed, 2 insertions(+)



>



> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c



> index 97e5625c064c..0c573f198f63 100644



> --- a/drivers/rtc/rtc-loongson.c



> +++ b/drivers/rtc/rtc-loongson.c



> @@ -129,6 +129,8 @@ static u32 loongson_rtc_handler(void *id)



>   {



>   struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;



>  



> + rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);



> +



While testing the patch, I noticed that interrupts are triggered



multiple times (/proc/interrupt), not sure if you have the same issue.



 



I think we need a similar operation to loongson_rtc_isr() to clear the



interrupt:



regmap_write(priv->regmap, TOY_MATCH0_REG, 0);



>   spin_lock(&priv->lock);



>   /* Disable RTC alarm wakeup and interrupt */



>   writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,



Thanks.



Binbin



 



 



 

Re: Re: [PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Binbin Zhou]

Hi:

On Thu, May 8, 2025 at 2:20 PM liudalin@kylinos.com.cn
<liudalin@kylinos.com.cn> wrote:
>
> Hi Binbin:
>    The described issue does not happened  with or without the patch by test, as the interrupt is managed by acpi.

I see it.
>
> The device info and test result are as follows.
>
> 1. Device info
> [系统未激活][root@mail test]# dmidecode
> # dmidecode 3.5
> Getting SMBIOS data from sysfs.
> SMBIOS 3.2.0 present.
> Table at 0x90000000FD620000.
>
> Handle 0x0000, DMI type 0, 24 bytes
> BIOS Information
>         Vendor: ZD-TECH
>         Version: V09
>         Release Date: 06/15/2022
>         ROM Size: 8 MB
>         Characteristics:
>                 PCI is supported
>                 BIOS is upgradeable
>                 BIOS shadowing is allowed
>                 Boot from CD is supported
>                 Selectable boot is supported
>                 BIOS ROM is socketed
>                 Serial services are supported (int 14h)
>                 USB legacy is supported
>                 Function key-initiated network boot is supported
>                 UEFI is supported
>         BIOS Revision: 4.0
>         Firmware Revision: 0.4
>
> Handle 0x0001, DMI type 1, 27 bytes
> System Information
>         Manufacturer: GEIT
>         Product Name: UT6000-LB5
>         Version: 1.0
>         Serial Number: TBD by OEM
>         UUID: 00112233-4455-6677-8899-aabbccddeeff
>         Wake-up Type: Power Switch
>         SKU Number: Loongson_SKU
>         Family: Type1Family
>
> Handle 0x0002, DMI type 2, 15 bytes
> Base Board Information
>         Manufacturer: GEIT
>         Product Name: GG-3A5000-02

My machine is also Loongosn-3A5000 + 7A2000, I think this should not affect.

>         Version: 1.0
>         Serial Number: Chassis Board Serial#To Be Filled By O.E.M
>         Asset Tag: Type2 - Board Asset Tag
>         Features:
>                 Board is a hosting board
>                 Board is replaceable
>         Location In Chassis: Type2 - Board Chassis Location
>         Chassis Handle: 0xFFFF
>         Type: Motherboard
>         Contained Object Handles: 0
>
> 2. The system exhibits a timeout error when waiting for alarm signal response without the patch.
> [系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
>  21:          3          0          0          0   PCH PIC   1  acpi
> [系统未激活][root@mail test]#
> [系统未激活][root@mail test]# ./rtc01
> RTC READ TEST:
> RTC READ TEST Passed
> Current RTC date/time is 8-5-2025, 05:50:05.
> RTC ALARM TEST :Alarm time set to 05:50:10.
> Waiting 5 seconds for the alarm...
> Timed out waiting for the alarm
> RTC UPDATE INTERRUPTS TEST :
> RTC_UIE_ON not supported
> RTC Tests Done!
> [系统未激活][root@mail test]#
> [系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
>  21:          4          0          0          0   PCH PIC   1  acpi
> [系统未激活][root@mail test]#
>
Please try continuous testing to see if you get different results.

Here is my test code, it behaves fine on Loongson-2K1000, you can
compare it with yours.
https://gist.github.com/AaronDot/affafc0b861783aee128a76b34d45f55

Also, your test code can be provided to me for testing.

> 3. There is no error with the patch applied and the interrupts are triggered ok
> [系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
>  21:          0          0          0          0   PCH PIC   1  acpi
> [系统未激活][root@mail test]#
> [系统未激活][root@mail test]# ./rtc01
> RTC READ TEST:
> RTC READ TEST Passed
> Current RTC date/time is 8-5-2025, 06:09:03.
> RTC ALARM TEST :Alarm time set to 06:09:08.
> Waiting 5 seconds for the alarm...
> Alarm rang.
> RTC ALARM TEST Passed
> RTC UPDATE INTERRUPTS TEST :
> RTC_UIE_ON not supported
> RTC Tests Done!
> [系统未激活][root@mail test]#
> [系统未激活][root@mail test]# cat /proc/interrupts |grep acpi
>  21:          1          0          0          0   PCH PIC   1  acpi
> [系统未激活][root@mail test]#
>
>
> ________________________________
> liudalin@kylinos.com.cn
>
>
> From: Binbin Zhou
> Date: 2025-05-08 11:12
> To: Liu Dalin; alexandre.belloni; wangming01
> CC: chenhuacai; gaojuxin; git; jiaxun.yang; keguang.zhang; lixuefeng; linux-rtc; linux-kernel; zhoubb.aaron
> Subject: Re: [PATCH] rtc: loongson: Add missing alarm notifications for ACPI RTC events
> Hi Dalin:
>
> Thanks for your patch.
>
> On 2025/4/29 14:27, Liu Dalin wrote:
> > When an application sets and enables an alarm on Loongson RTC devices,
> > the alarm notification fails to propagate to userspace because the
> > ACPI event handler omits calling rtc_update_irq().
> >
> > As a result, processes waiting via select() or poll() on RTC device
> > files fail to receive alarm notifications.
> >
> > Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
> > Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
> > ---
> >   drivers/rtc/rtc-loongson.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> > index 97e5625c064c..0c573f198f63 100644
> > --- a/drivers/rtc/rtc-loongson.c
> > +++ b/drivers/rtc/rtc-loongson.c
> > @@ -129,6 +129,8 @@ static u32 loongson_rtc_handler(void *id)
> >   {
> >   struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
> >
> > + rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
> > +
> While testing the patch, I noticed that interrupts are triggered
> multiple times (/proc/interrupt), not sure if you have the same issue.
>
> I think we need a similar operation to loongson_rtc_isr() to clear the
> interrupt:
> regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
> >   spin_lock(&priv->lock);
> >   /* Disable RTC alarm wakeup and interrupt */
> >   writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
> Thanks.
> Binbin
>
>
>



-- 
Thanks.
Binbin

[PATCH V1] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Liu Dalin]

When an application sets and enables an alarm on Loongson RTC devices,
the alarm notification fails to propagate to userspace because the
ACPI event handler omits calling rtc_update_irq().

As a result, processes waiting via select() or poll() on RTC device
files fail to receive alarm notifications.

Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
---
 drivers/rtc/rtc-loongson.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
index 97e5625c064c..2ca7ffd5d7a9 100644
--- a/drivers/rtc/rtc-loongson.c
+++ b/drivers/rtc/rtc-loongson.c
@@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
 {
 	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 
+	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+
+	/*
+	 * The TOY_MATCH0_REG should be cleared 0 here,
+	 * otherwise the interrupt cannot be cleared.
+	 */
+	regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+
 	spin_lock(&priv->lock);
 	/* Disable RTC alarm wakeup and interrupt */
 	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
-- 
2.33.0

Re: [PATCH V1] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Binbin Zhou]

Hi:

On 2025/5/9 09:40, Liu Dalin wrote:
> When an application sets and enables an alarm on Loongson RTC devices,
> the alarm notification fails to propagate to userspace because the
> ACPI event handler omits calling rtc_update_irq().
>
> As a result, processes waiting via select() or poll() on RTC device
> files fail to receive alarm notifications.
>
> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
Technically I don't think this is a compliant patch, firstly this patch 
should be V2 and also you should add "Changlog" for describing the 
differences from the previous patch.
Anyway, it's good to me.

Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>

> ---
>   drivers/rtc/rtc-loongson.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> index 97e5625c064c..2ca7ffd5d7a9 100644
> --- a/drivers/rtc/rtc-loongson.c
> +++ b/drivers/rtc/rtc-loongson.c
> @@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
>   {
>   	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
>   
> +	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
> +
> +	/*
> +	 * The TOY_MATCH0_REG should be cleared 0 here,
> +	 * otherwise the interrupt cannot be cleared.
> +	 */
> +	regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
> +
>   	spin_lock(&priv->lock);
>   	/* Disable RTC alarm wakeup and interrupt */
>   	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
Thanks.
Binbin

Re: [PATCH V1] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Liu Dalin]

在 2025/5/9 15:12, Binbin Zhou 写道:
> Hi:
> 
> On 2025/5/9 09:40, Liu Dalin wrote:
>> When an application sets and enables an alarm on Loongson RTC devices,
>> the alarm notification fails to propagate to userspace because the
>> ACPI event handler omits calling rtc_update_irq().
>>
>> As a result, processes waiting via select() or poll() on RTC device
>> files fail to receive alarm notifications.
>>
>> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
>> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
> Technically I don't think this is a compliant patch, firstly this patch 
> should be V2 and also you should add "Changlog" for describing the 
> differences from the previous patch.
> Anyway, it's good to me.

Ok! There is another problem, if regmap_write(priv->regmap,
TOY_MATCH0_REG, 0) move to the end of loongson_rtc_handler as 
09471d8f5b39("rtc: loongson: clear TOY_MATCH0_REG in 
loongson_rtc_isr()"), the interrupt also can be triggered multiple times.

So the regmap_write(priv->regmap,TOY_MATCH0_REG, 0) is move behind of 
rtc_update_irq by me, then the interrupt was triggered OK.

Is there any problem ?

> 
> Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
> 
>> ---
>>   drivers/rtc/rtc-loongson.c | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
>> index 97e5625c064c..2ca7ffd5d7a9 100644
>> --- a/drivers/rtc/rtc-loongson.c
>> +++ b/drivers/rtc/rtc-loongson.c
>> @@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
>>   {
>>       struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
>> +    rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
>> +
>> +    /*
>> +     * The TOY_MATCH0_REG should be cleared 0 here,
>> +     * otherwise the interrupt cannot be cleared.
>> +     */
>> +    regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
>> +
>>       spin_lock(&priv->lock);
>>       /* Disable RTC alarm wakeup and interrupt */
>>       writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
> Thanks.
> Binbin
> 
> 
> 

Re: [PATCH V1] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Binbin Zhou]

On 2025/5/9 16:06, Liu Dalin wrote:
>
>
> 在 2025/5/9 15:12, Binbin Zhou 写道:
>> Hi:
>>
>> On 2025/5/9 09:40, Liu Dalin wrote:
>>> When an application sets and enables an alarm on Loongson RTC devices,
>>> the alarm notification fails to propagate to userspace because the
>>> ACPI event handler omits calling rtc_update_irq().
>>>
>>> As a result, processes waiting via select() or poll() on RTC device
>>> files fail to receive alarm notifications.
>>>
>>> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family 
>>> chips")
>>> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
>> Technically I don't think this is a compliant patch, firstly this 
>> patch should be V2 and also you should add "Changlog" for describing 
>> the differences from the previous patch.
>> Anyway, it's good to me.
>
> Ok! There is another problem, if regmap_write(priv->regmap,
> TOY_MATCH0_REG, 0) move to the end of loongson_rtc_handler as 
> 09471d8f5b39("rtc: loongson: clear TOY_MATCH0_REG in 
> loongson_rtc_isr()"), the interrupt also can be triggered multiple times.
>
> So the regmap_write(priv->regmap,TOY_MATCH0_REG, 0) is move behind of 
> rtc_update_irq by me, then the interrupt was triggered OK.
>
> Is there any problem ?

It is ok. That's where I added it when I suggested it before.

Thanks.
Binbin

>
>>
>> Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
>>
>>> ---
>>>   drivers/rtc/rtc-loongson.c | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
>>> index 97e5625c064c..2ca7ffd5d7a9 100644
>>> --- a/drivers/rtc/rtc-loongson.c
>>> +++ b/drivers/rtc/rtc-loongson.c
>>> @@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
>>>   {
>>>       struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
>>> +    rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
>>> +
>>> +    /*
>>> +     * The TOY_MATCH0_REG should be cleared 0 here,
>>> +     * otherwise the interrupt cannot be cleared.
>>> +     */
>>> +    regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
>>> +
>>>       spin_lock(&priv->lock);
>>>       /* Disable RTC alarm wakeup and interrupt */
>>>       writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
>> Thanks.
>> Binbin
>>
>>
>>

[PATCH V2] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Liu Dalin]

When an application sets and enables an alarm on Loongson RTC devices,
the alarm notification fails to propagate to userspace because the
ACPI event handler omits calling rtc_update_irq().

As a result, processes waiting via select() or poll() on RTC device
files fail to receive alarm notifications.

The ACPI interrupt is also triggered multiple times. In loongson_rtc_handler,
we need to clear TOY_MATCH0_REG to resolve this issue.

Fixes: 09471d8f5b39 ("rtc: loongson: clear TOY_MATCH0_REG in loongson_rtc_isr()")
Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
---
 drivers/rtc/rtc-loongson.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
index 97e5625c064c..2ca7ffd5d7a9 100644
--- a/drivers/rtc/rtc-loongson.c
+++ b/drivers/rtc/rtc-loongson.c
@@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
 {
 	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 
+	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+
+	/*
+	 * The TOY_MATCH0_REG should be cleared 0 here,
+	 * otherwise the interrupt cannot be cleared.
+	 */
+	regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+
 	spin_lock(&priv->lock);
 	/* Disable RTC alarm wakeup and interrupt */
 	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
-- 
2.33.0

Re: [PATCH V2] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Binbin Zhou]

On 2025/5/9 16:44, Liu Dalin wrote:
> When an application sets and enables an alarm on Loongson RTC devices,
> the alarm notification fails to propagate to userspace because the
> ACPI event handler omits calling rtc_update_irq().
>
> As a result, processes waiting via select() or poll() on RTC device
> files fail to receive alarm notifications.
>
> The ACPI interrupt is also triggered multiple times. In loongson_rtc_handler,
> we need to clear TOY_MATCH0_REG to resolve this issue.
>
> Fixes: 09471d8f5b39 ("rtc: loongson: clear TOY_MATCH0_REG in loongson_rtc_isr()")
> Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
> Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
> ---
>   drivers/rtc/rtc-loongson.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> index 97e5625c064c..2ca7ffd5d7a9 100644
> --- a/drivers/rtc/rtc-loongson.c
> +++ b/drivers/rtc/rtc-loongson.c
> @@ -129,6 +129,14 @@ static u32 loongson_rtc_handler(void *id)
>   {
>   	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
>   
> +	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
> +
> +	/*
> +	 * The TOY_MATCH0_REG should be cleared 0 here,
> +	 * otherwise the interrupt cannot be cleared.
> +	 */
> +	regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
> +
>   	spin_lock(&priv->lock);
>   	/* Disable RTC alarm wakeup and interrupt */
>   	writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
Thanks.
Binbin

Re: [PATCH V2] rtc: loongson: Add missing alarm notifications for ACPI RTC events

[Alexandre Belloni]

On Fri, 09 May 2025 16:44:16 +0800, Liu Dalin wrote:
> When an application sets and enables an alarm on Loongson RTC devices,
> the alarm notification fails to propagate to userspace because the
> ACPI event handler omits calling rtc_update_irq().
> 
> As a result, processes waiting via select() or poll() on RTC device
> files fail to receive alarm notifications.
> 
> [...]

Applied, thanks!

[1/1] rtc: loongson: Add missing alarm notifications for ACPI RTC events
      https://git.kernel.org/abelloni/c/5af9f1fa5768

Best regards,

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com