diff mbox series

[v1,2/2] scsi: ufs: qcom: Update the UIC Command Timeout

Message ID 8e5593feaac75660ff132d67ee5d9130e628fefb.1716359578.git.quic_nguyenb@quicinc.com (mailing list archive)
State Changes Requested
Headers show
Series Allow vendor drivers to update UIC command timeout | expand

Commit Message

Bao D. Nguyen May 22, 2024, 7:01 a.m. UTC
Change the UIC command timeout to 2 seconds.
This extra time is to allow the uart occasionally print long
debug messages and logging from different modules during
product development. With the default hardcoded 500ms timeout,
the uart printing with interrupt disabled may cause the UIC command
interrupt get starved, resulting in a UIC command timeout and
eventually a watchdog timeout.
When a product development completes, the vendors may
select a different UIC command timeout as desired.

Signed-off-by: Bao D. Nguyen <quic_nguyenb@quicinc.com>
---
 drivers/ufs/host/ufs-qcom.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Bart Van Assche May 22, 2024, 6:18 p.m. UTC | #1
On 5/22/24 00:01, Bao D. Nguyen wrote:
> Change the UIC command timeout to 2 seconds.
> This extra time is to allow the uart occasionally print long
> debug messages and logging from different modules during
> product development. With the default hardcoded 500ms timeout,
> the uart printing with interrupt disabled may cause the UIC command
> interrupt get starved, resulting in a UIC command timeout and
> eventually a watchdog timeout.
> When a product development completes, the vendors may
> select a different UIC command timeout as desired.
> 
> Signed-off-by: Bao D. Nguyen <quic_nguyenb@quicinc.com>
> ---
>   drivers/ufs/host/ufs-qcom.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 79f8cb3..4649e0f 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -49,6 +49,7 @@ enum {
>   
>   #define QCOM_UFS_MAX_GEAR 4
>   #define QCOM_UFS_MAX_LANE 2
> +#define QCOM_UIC_CMD_TIMEOUT_MS 2000
>   
>   enum {
>   	MODE_MIN,
> @@ -1111,6 +1112,8 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>   		dev_warn(dev, "%s: failed to configure the testbus %d\n",
>   				__func__, err);
>   
> +	hba->uic_cmd_timeout = QCOM_UIC_CMD_TIMEOUT_MS;
> +
>   	return 0;
>   
>   out_variant_clear:

Given the description of patch 1, the addressed issue is not specific to
a single vendor. Is that correct?

Since the described issue is only encountered during development, why to
modify the UIC command timeout unconditionally?

Thanks,

Bart.
Bao D. Nguyen May 22, 2024, 8:56 p.m. UTC | #2
On 5/22/2024 11:18 AM, Bart Van Assche wrote:
> On 5/22/24 00:01, Bao D. Nguyen wrote:
>> Change the UIC command timeout to 2 seconds.
>> This extra time is to allow the uart occasionally print long
>> debug messages and logging from different modules during
>> product development. With the default hardcoded 500ms timeout,
>> the uart printing with interrupt disabled may cause the UIC command
>> interrupt get starved, resulting in a UIC command timeout and
>> eventually a watchdog timeout.
>> When a product development completes, the vendors may
>> select a different UIC command timeout as desired.
>>
>> Signed-off-by: Bao D. Nguyen <quic_nguyenb@quicinc.com>
>> ---
>>   drivers/ufs/host/ufs-qcom.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
>> index 79f8cb3..4649e0f 100644
>> --- a/drivers/ufs/host/ufs-qcom.c
>> +++ b/drivers/ufs/host/ufs-qcom.c
>> @@ -49,6 +49,7 @@ enum {
>>   #define QCOM_UFS_MAX_GEAR 4
>>   #define QCOM_UFS_MAX_LANE 2
>> +#define QCOM_UIC_CMD_TIMEOUT_MS 2000
>>   enum {
>>       MODE_MIN,
>> @@ -1111,6 +1112,8 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>>           dev_warn(dev, "%s: failed to configure the testbus %d\n",
>>                   __func__, err);
>> +    hba->uic_cmd_timeout = QCOM_UIC_CMD_TIMEOUT_MS;
>> +
>>       return 0;
>>   out_variant_clear:
> 
> Given the description of patch 1, the addressed issue is not specific to
> a single vendor. Is that correct?

The issue we are trying to address is not specific to a single vendor.
Any vendor would have a freedom to choose the UIC command timeout. At 
different times during their product development, they can choose 
different UIC command timeout, or use the default 500ms. It's the 
flexibility we would like to give to vendors.

> 
> Since the described issue is only encountered during development, why to
> modify the UIC command timeout unconditionally?

The vendors can enjoy the default 500ms UIC timeout if they prefer.
As long as they don't write to hba->uic_cmd_timeout in the vendor's 
initialization routine, the default value of 500ms will be used.

Thanks,
Bao

> 
> Thanks,
> 
> Bart.
Bart Van Assche May 22, 2024, 9:01 p.m. UTC | #3
On 5/22/24 13:56, Bao D. Nguyen wrote:
> On 5/22/2024 11:18 AM, Bart Van Assche wrote:
>> Since the described issue is only encountered during development, why to
>> modify the UIC command timeout unconditionally?
> 
> The vendors can enjoy the default 500ms UIC timeout if they prefer.
> As long as they don't write to hba->uic_cmd_timeout in the vendor's initialization routine, the default value of 500ms will be used.

Since this issue is not vendor specific, I think it would be better to
modify the UFSHCI core driver only. Has it been considered to introduce a
kernel module parameter for setting the UIC command timeout instead of the
approach of this patch? As you probably know there are multiple mechanisms
for specifying kernel module parameters, e.g. the bootargs parameter in the
device tree.

Thanks,

Bart.
Avri Altman May 23, 2024, 3:18 a.m. UTC | #4
> On 5/22/24 13:56, Bao D. Nguyen wrote:
> > On 5/22/2024 11:18 AM, Bart Van Assche wrote:
> >> Since the described issue is only encountered during development, why to
> >> modify the UIC command timeout unconditionally?
> >
> > The vendors can enjoy the default 500ms UIC timeout if they prefer.
> > As long as they don't write to hba->uic_cmd_timeout in the vendor's
> initialization routine, the default value of 500ms will be used.
> 
> Since this issue is not vendor specific, I think it would be better to
> modify the UFSHCI core driver only. Has it been considered to introduce a
> kernel module parameter for setting the UIC command timeout instead of the
> approach of this patch? As you probably know there are multiple mechanisms
> for specifying kernel module parameters, e.g. the bootargs parameter in the
> device tree.
Since the problem statement is "During product development...", why not just a debugfs?

Thanks,
Avri

> 
> Thanks,
> 
> Bart.
Bao D. Nguyen May 23, 2024, 5:34 a.m. UTC | #5
On 5/22/2024 2:01 PM, Bart Van Assche wrote:
> On 5/22/24 13:56, Bao D. Nguyen wrote:
>> On 5/22/2024 11:18 AM, Bart Van Assche wrote:
>>> Since the described issue is only encountered during development, why to
>>> modify the UIC command timeout unconditionally?
>>
>> The vendors can enjoy the default 500ms UIC timeout if they prefer.
>> As long as they don't write to hba->uic_cmd_timeout in the vendor's 
>> initialization routine, the default value of 500ms will be used.
> 
> Since this issue is not vendor specific, I think it would be better to
> modify the UFSHCI core driver only. Has it been considered to introduce a
> kernel module parameter for setting the UIC command timeout instead of the
> approach of this patch? As you probably know there are multiple mechanisms
> for specifying kernel module parameters, e.g. the bootargs parameter in the
> device tree.

The proposal here uses similar implementation as the auto hibern8 timer 
(hba->ahit). The ahit mechanism has been working well and stable, so I 
thought why not keep using it? Let see if other members have any 
comments about kernel module parameter/bootargs suggestion.

Thanks, Bao

> 
> Thanks,
> 
> Bart.
>
Bao D. Nguyen May 23, 2024, 5:42 a.m. UTC | #6
On 5/22/2024 8:18 PM, Avri Altman wrote:
>> On 5/22/24 13:56, Bao D. Nguyen wrote:
>>> On 5/22/2024 11:18 AM, Bart Van Assche wrote:
>>>> Since the described issue is only encountered during development, why to
>>>> modify the UIC command timeout unconditionally?
>>>
>>> The vendors can enjoy the default 500ms UIC timeout if they prefer.
>>> As long as they don't write to hba->uic_cmd_timeout in the vendor's
>> initialization routine, the default value of 500ms will be used.
>>
>> Since this issue is not vendor specific, I think it would be better to
>> modify the UFSHCI core driver only. Has it been considered to introduce a
>> kernel module parameter for setting the UIC command timeout instead of the
>> approach of this patch? As you probably know there are multiple mechanisms
>> for specifying kernel module parameters, e.g. the bootargs parameter in the
>> device tree.
> Since the problem statement is "During product development...", why not just a debugfs?

Hi Avri, if I am not mistaken, debugfs is not available at the initial 
stage of ufs probe/init time right?

> 
> Thanks,
> Avri
> 
>>
>> Thanks,
>>
>> Bart.
>
diff mbox series

Patch

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 79f8cb3..4649e0f 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -49,6 +49,7 @@  enum {
 
 #define QCOM_UFS_MAX_GEAR 4
 #define QCOM_UFS_MAX_LANE 2
+#define QCOM_UIC_CMD_TIMEOUT_MS 2000
 
 enum {
 	MODE_MIN,
@@ -1111,6 +1112,8 @@  static int ufs_qcom_init(struct ufs_hba *hba)
 		dev_warn(dev, "%s: failed to configure the testbus %d\n",
 				__func__, err);
 
+	hba->uic_cmd_timeout = QCOM_UIC_CMD_TIMEOUT_MS;
+
 	return 0;
 
 out_variant_clear: