linux-kernel - Re: [PATCH 6/8] scsi: ufs: Add dev ref clock gating wait time support

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Date:   Thu, 06 Feb 2020 16:09:09 +0800
From:   Can Guo <cang@...eaurora.org>
To:     Avri Altman <Avri.Altman@....com>
Cc:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        hongwus@...eaurora.org, rnayak@...eaurora.org,
        linux-scsi@...r.kernel.org, kernel-team@...roid.com,
        saravanak@...gle.com, salyzyn@...gle.com,
        Alim Akhtar <alim.akhtar@...sung.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Bean Huo <beanhuo@...ron.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Colin Ian King <colin.king@...onical.com>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Bart Van Assche <bvanassche@....org>,
        Venkat Gopalakrishnan <venkatg@...eaurora.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/8] scsi: ufs: Add dev ref clock gating wait time support

On 2020-02-06 15:57, Avri Altman wrote:
>> In UFS version 3.0, a newly added attribute bRefClkGatingWaitTime 
>> defines
>> the minimum time for which the reference clock is required by device 
>> during
>> transition to LS-MODE or HIBERN8 state. Make this change to reflect 
>> the new
>> requirement by adding delays before turning off the clock.
>> 
>> Signed-off-by: Can Guo <cang@...eaurora.org>
>> Reviewed-by: Asutosh Das <asutoshd@...eaurora.org>
>> Reviewed-by: Bean Huo <beanhuo@...ron.com>
>> 
>> diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
>> index cfe3803..990cb48 100644
>> --- a/drivers/scsi/ufs/ufs.h
>> +++ b/drivers/scsi/ufs/ufs.h
>> @@ -167,6 +167,7 @@ enum attr_idn {
>>         QUERY_ATTR_IDN_FFU_STATUS               = 0x14,
>>         QUERY_ATTR_IDN_PSA_STATE                = 0x15,
>>         QUERY_ATTR_IDN_PSA_DATA_SIZE            = 0x16,
>> +       QUERY_ATTR_IDN_REF_CLK_GATING_WAIT_TIME = 0x17,
>>  };
>> 
>>  /* Descriptor idn for Query requests */
>> @@ -534,6 +535,8 @@ struct ufs_dev_info {
>>         u16 wmanufacturerid;
>>         /*UFS device Product Name */
>>         u8 *model;
>> +       u16 wspecversion;
>> +       u32 clk_gating_wait_us;
>>  };
>> 
>>  /**
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index e8f7f9d..76beaf9 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -91,6 +91,9 @@
>>  /* default delay of autosuspend: 2000 ms */
>>  #define RPM_AUTOSUSPEND_DELAY_MS 2000
>> 
>> +/* Default value of wait time before gating device ref clock */
>> +#define UFSHCD_REF_CLK_GATING_WAIT_US 0xFF /* microsecs */
>> +
>>  #define ufshcd_toggle_vreg(_dev, _vreg, _on)                          
>>  \
>>         ({                                                             
>>  \
>>                 int _ret;                                              
>>  \
>> @@ -3281,6 +3284,29 @@ static inline int
>> ufshcd_read_unit_desc_param(struct ufs_hba *hba,
>>                                       param_offset, param_read_buf, 
>> param_size);
>>  }
>> 
>> +static int ufshcd_get_ref_clk_gating_wait(struct ufs_hba *hba)
>> +{
>> +       int err = 0;
>> +       u32 gating_wait = UFSHCD_REF_CLK_GATING_WAIT_US;
>> +
>> +       if (hba->dev_info.wspecversion >= 0x300) {
>> +               err = ufshcd_query_attr_retry(hba,
>> UPIU_QUERY_OPCODE_READ_ATTR,
>> +                               
>> QUERY_ATTR_IDN_REF_CLK_GATING_WAIT_TIME, 0, 0,
>> +                               &gating_wait);
>> +               if (err)
>> +                       dev_err(hba->dev, "Failed reading 
>> bRefClkGatingWait. err =
>> %d, use default %uus\n",
>> +                                        err, gating_wait);
>> +
>> +               if (gating_wait == 0) {
>> +                       gating_wait = UFSHCD_REF_CLK_GATING_WAIT_US;
>> +                       dev_err(hba->dev, "Undefined ref clk gating 
>> wait time, use
>> default %uus\n",
>> +                                        gating_wait);
>> +               }
> 
> You forgot to set
> hba->dev_info.clk_gating_wait_us = gating_wait
> 
> Thanks,
> Avri

oops, shall add it back. Thanks.

Can Guo