diff mbox series

[v6,04/10] scsi: ufs: ufs-qcom: Allow the first init start with the maximum supported gear

Message ID 1701246516-11626-5-git-send-email-quic_cang@quicinc.com
State New
Headers
Series Enable HS-G5 support on SM8550 |

Commit Message

Can Guo Nov. 29, 2023, 8:28 a.m. UTC 
  During host driver init, the phy_gear is set to the minimum supported gear
(HS_G2). Then, during the first power mode change, the negotiated gear, say
HS-G4, is updated to the phy_gear variable so that in the second init the
updated phy_gear can be used to program the PHY.

But the current code only allows update the phy_gear to a higher value. If
one wants to start the first init with the maximum support gear, say HS-G4,
the phy_gear is not updated to HS-G3 if the device only supports HS-G3.

The original check added there is intend to make sure the phy_gear won't be
updated when gear is scaled down (during clock scaling). Update the check
so that one can start the first init with the maximum support gear without
breaking the original fix by checking the ufshcd_state, that is, allow
update to phy_gear only if power mode change is invoked from
ufshcd_probe_hba().

This change is a preparation patch for the next patches in the same series.

Signed-off-by: Can Guo <quic_cang@quicinc.com>
---
 drivers/ufs/host/ufs-qcom.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Manivannan Sadhasivam Nov. 30, 2023, 6:42 a.m. UTC | #1 
On Wed, Nov 29, 2023 at 12:28:29AM -0800, Can Guo wrote:
> During host driver init, the phy_gear is set to the minimum supported gear
> (HS_G2). Then, during the first power mode change, the negotiated gear, say
> HS-G4, is updated to the phy_gear variable so that in the second init the
> updated phy_gear can be used to program the PHY.
> 
> But the current code only allows update the phy_gear to a higher value. If
> one wants to start the first init with the maximum support gear, say HS-G4,
> the phy_gear is not updated to HS-G3 if the device only supports HS-G3.
> 
> The original check added there is intend to make sure the phy_gear won't be
> updated when gear is scaled down (during clock scaling). Update the check
> so that one can start the first init with the maximum support gear without
> breaking the original fix by checking the ufshcd_state, that is, allow
> update to phy_gear only if power mode change is invoked from
> ufshcd_probe_hba().
> 
> This change is a preparation patch for the next patches in the same series.

If you happen to respin the series, please remove this line. When the patches
get merged, there will be no concept of patches/series as all will be git
commits.

You can have this information in the comment section (below --- line) though.

> 
> Signed-off-by: Can Guo <quic_cang@quicinc.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
>  drivers/ufs/host/ufs-qcom.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 9a90019..81056b9 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -916,11 +916,12 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
>  		}
>  
>  		/*
> -		 * Update phy_gear only when the gears are scaled to a higher value. This is
> -		 * because, the PHY gear settings are backwards compatible and we only need to
> -		 * change the PHY gear settings while scaling to higher gears.
> +		 * During UFS driver probe, always update the PHY gear to match the negotiated
> +		 * gear, so that, if quirk UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH is enabled,
> +		 * the second init can program the optimal PHY settings. This allows one to start
> +		 * the first init with either the minimum or the maximum support gear.
>  		 */
> -		if (dev_req_params->gear_tx > host->phy_gear)
> +		if (hba->ufshcd_state == UFSHCD_STATE_RESET)
>  			host->phy_gear = dev_req_params->gear_tx;
>  
>  		/* enable the device ref clock before changing to HS mode */
> -- 
> 2.7.4
> 
>
Can Guo Nov. 30, 2023, 7:44 a.m. UTC | #2 
On 11/30/2023 2:42 PM, Manivannan Sadhasivam wrote:
> On Wed, Nov 29, 2023 at 12:28:29AM -0800, Can Guo wrote:
>> During host driver init, the phy_gear is set to the minimum supported gear
>> (HS_G2). Then, during the first power mode change, the negotiated gear, say
>> HS-G4, is updated to the phy_gear variable so that in the second init the
>> updated phy_gear can be used to program the PHY.
>>
>> But the current code only allows update the phy_gear to a higher value. If
>> one wants to start the first init with the maximum support gear, say HS-G4,
>> the phy_gear is not updated to HS-G3 if the device only supports HS-G3.
>>
>> The original check added there is intend to make sure the phy_gear won't be
>> updated when gear is scaled down (during clock scaling). Update the check
>> so that one can start the first init with the maximum support gear without
>> breaking the original fix by checking the ufshcd_state, that is, allow
>> update to phy_gear only if power mode change is invoked from
>> ufshcd_probe_hba().
>>
>> This change is a preparation patch for the next patches in the same series.
> 
> If you happen to respin the series, please remove this line. When the patches
> get merged, there will be no concept of patches/series as all will be git
> commits.
> 
> You can have this information in the comment section (below --- line) though.
> 

Sure, will remove it in next version.

Thanks,
Can Guo.

>>
>> Signed-off-by: Can Guo <quic_cang@quicinc.com>
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> 
> - Mani
> 
>> ---
>>   drivers/ufs/host/ufs-qcom.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
>> index 9a90019..81056b9 100644
>> --- a/drivers/ufs/host/ufs-qcom.c
>> +++ b/drivers/ufs/host/ufs-qcom.c
>> @@ -916,11 +916,12 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
>>   		}
>>   
>>   		/*
>> -		 * Update phy_gear only when the gears are scaled to a higher value. This is
>> -		 * because, the PHY gear settings are backwards compatible and we only need to
>> -		 * change the PHY gear settings while scaling to higher gears.
>> +		 * During UFS driver probe, always update the PHY gear to match the negotiated
>> +		 * gear, so that, if quirk UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH is enabled,
>> +		 * the second init can program the optimal PHY settings. This allows one to start
>> +		 * the first init with either the minimum or the maximum support gear.
>>   		 */
>> -		if (dev_req_params->gear_tx > host->phy_gear)
>> +		if (hba->ufshcd_state == UFSHCD_STATE_RESET)
>>   			host->phy_gear = dev_req_params->gear_tx;
>>   
>>   		/* enable the device ref clock before changing to HS mode */
>> -- 
>> 2.7.4
>>
>>
>
diff mbox series

Patch

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 9a90019..81056b9 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -916,11 +916,12 @@  static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
 		}
 
 		/*
-		 * Update phy_gear only when the gears are scaled to a higher value. This is
-		 * because, the PHY gear settings are backwards compatible and we only need to
-		 * change the PHY gear settings while scaling to higher gears.
+		 * During UFS driver probe, always update the PHY gear to match the negotiated
+		 * gear, so that, if quirk UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH is enabled,
+		 * the second init can program the optimal PHY settings. This allows one to start
+		 * the first init with either the minimum or the maximum support gear.
 		 */
-		if (dev_req_params->gear_tx > host->phy_gear)
+		if (hba->ufshcd_state == UFSHCD_STATE_RESET)
 			host->phy_gear = dev_req_params->gear_tx;
 
 		/* enable the device ref clock before changing to HS mode */