Hi Mani,
On 11/28/2023 1:45 PM, Manivannan Sadhasivam wrote:
On Thu, Nov 23, 2023 at 12:46:24AM -0800, Can Guo wrote:
In the dual init scenario, the initial PHY gear is set to HS-G2, and the
first Power Mode Change (PMC) is meant to find the best matching PHY gear
for the 2nd init. However, for the first PMC, if the negotiated gear (say
HS-G4) is higher than the initial PHY gear, we cannot go ahead let PMC to
the negotiated gear happen, because the programmed UFS PHY settings may not
support the negotiated gear. Fix it by overwriting the negotiated gear with
the PHY gear.
I don't quite understand this patch. If the phy_gear is G2 initially and the
negotiated gear is G4, then as per this change,
phy_gear = G4;
negotiated gear = G2;
Could you please explain how this make sense?
phy_gear was G2 (in the beginning) and just now changed to G4, but the
PHY settings programmed in the beginning can only support no-G4 (not
G4). Without this change, as the negotiated gear is G4, the power mode
change is going to put UFS at HS-G4 mode, but the PHY settings
programmed is no-G4. This change is to limit the negotiated gear to
HS-G2 for the 1st init. In the 2nd init, as the new PHY gear is G4, G4
PHY settings would be programmed, it'd be safe to put the UFS at HS-G4 mode.
Thanks,
Can Guo.
- Mani
Signed-off-by: Can Guo <quic_cang@xxxxxxxxxxx>
---
drivers/ufs/host/ufs-qcom.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index cc0eb37..d4edf58 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -920,8 +920,13 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
* because, the PHY gear settings are backwards compatible and we only need to
* change the PHY gear settings while scaling to higher gears.
*/
- if (dev_req_params->gear_tx > host->phy_gear)
+ if (dev_req_params->gear_tx > host->phy_gear) {
+ u32 old_phy_gear = host->phy_gear;
+
host->phy_gear = dev_req_params->gear_tx;
+ dev_req_params->gear_tx = old_phy_gear;
+ dev_req_params->gear_rx = old_phy_gear;
+ }
/* enable the device ref clock before changing to HS mode */
if (!ufshcd_is_hs_mode(&hba->pwr_info) &&
--
2.7.4
