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

From: Can Guo
Date: Tue Nov 28 2023 - 02:48:31 EST


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@xxxxxxxxxxx>

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

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