Re: [PATCH v5 06/10] scsi: ufs: ufs-qcom: Limit HS-G5 Rate-A to hosts with HW version 5

Can Guo
2023-11-28T07:48:31Z

Hi Mani,

On 11/28/2023 1:55 PM, Manivannan Sadhasivam wrote:
> On Thu, Nov 23, 2023 at 12:46:26AM -0800, Can Guo wrote:
>> Qcom UFS hosts, with HW ver 5, can only support up to HS-G5 Rate-A due to
>> HW limitations. If the HS-G5 PHY gear is used, update host_params->hs_rate
>> to Rate-A, so that the subsequent power mode changes shall stick to Rate-A.
>>
>> Signed-off-by: Can Guo <quic_cang@quicinc.com>
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>
> One question below...
>
>> ---
>> drivers/ufs/host/ufs-qcom.c | 18 +++++++++++++++++-
>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
>> index 9613ad9..6756f8d 100644
>> --- a/drivers/ufs/host/ufs-qcom.c
>> +++ b/drivers/ufs/host/ufs-qcom.c
>> @@ -442,9 +442,25 @@ static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
>> static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>> {
>> struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>> + struct ufs_host_params *host_params = &host->host_params;
>> struct phy *phy = host->generic_phy;
>> + enum phy_mode mode;
>> int ret;
>>
>> + /*
>> + * HW ver 5 can only support up to HS-G5 Rate-A due to HW limitations.
>> + * If the HS-G5 PHY gear is used, update host_params->hs_rate to Rate-A,
>> + * so that the subsequent power mode change shall stick to Rate-A.
>> + */
>> + if (host->hw_ver.major == 0x5) {
>> + if (host->phy_gear == UFS_HS_G5)
>> + host_params->hs_rate = PA_HS_MODE_A;
>> + else
>> + host_params->hs_rate = PA_HS_MODE_B;
>
> Is this 'else' part really needed? Since there wouldn't be any 2nd init, I think
> we can skip that.

We need it because, even there is only one init, if a UFS3.1 device is
attached, phy_gear is given as UFS_HS_G4 in ufs_qcom_set_phy_gear(),
hence we need to put the UFS at HS-G4 Rate B, not Rate A.

Thanks,
Can Guo.

>
> - Mani
>
>> + }
>> +
>> + mode = host_params->hs_rate == PA_HS_MODE_B ? PHY_MODE_UFS_HS_B : PHY_MODE_UFS_HS_A;
>> +
>> /* Reset UFS Host Controller and PHY */
>> ret = ufs_qcom_host_reset(hba);
>> if (ret)
>> @@ -459,7 +475,7 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>> return ret;
>> }
>>
>> - phy_set_mode_ext(phy, PHY_MODE_UFS_HS_B, host->phy_gear);
>> + phy_set_mode_ext(phy, mode, host->phy_gear);
>>
>> /* power on phy - start serdes and phy's power and clocks */
>> ret = phy_power_on(phy);
>> --
>> 2.7.4
>>
>