linux-kernel - [PATCH v2] scsi: ufs: qcom: avoid re-init quirk when gears match

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Date: Tue, 23 Jan 2024 14:28:57 -0500
From: Eric Chanudet <echanude@...hat.com>
To: Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	"James E.J. Bottomley" <jejb@...ux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>
Cc: linux-arm-msm@...r.kernel.org,
	linux-scsi@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Eric Chanudet <echanude@...hat.com>
Subject: [PATCH v2] scsi: ufs: qcom: avoid re-init quirk when gears match

On sa8775p-ride, probing the hba will go through the
UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH path although the power info
are same during the second init.

The REINIT quirk only applies starting with controller v4. For these,
ufs_qcom_get_hs_gear() reads the highest supported gear when setting the
host_params. After the negotiation, if the host and device are on the
same gear, it is the highest gear supported between the two. Skip REINIT
to save some time.

Signed-off-by: Eric Chanudet <echanude@...hat.com>
---

v1 -> v2:
* drop test against host->hw_ver.major >= 4 and amend description as a
  result (Andrew/Mani)
* add comment, test device gear against host->phy_gear and reset
  host->phy_gear only if necessary (Mani)
* Link to v1: https://lore.kernel.org/linux-arm-msm/20240119185537.3091366-11-echanude@redhat.com/

trace_event=ufs:ufshcd_init reports the time spent in ufshcd_probe_hba
where the re-init quirk is performed:
Currently:
0.355879: ufshcd_init: 1d84000.ufs: took 103377 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0
With this patch:
0.297676: ufshcd_init: 1d84000.ufs: took 43553 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0

 drivers/ufs/host/ufs-qcom.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 39eef470f8fa..f7dba7236c6e 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -738,8 +738,17 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
 		 * 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 (hba->ufshcd_state == UFSHCD_STATE_RESET)
-			host->phy_gear = dev_req_params->gear_tx;
+		if (hba->ufshcd_state == UFSHCD_STATE_RESET) {
+			/*
+			 * Skip REINIT if the negotiated gear matches with the
+			 * initial phy_gear. Otherwise, update the phy_gear to
+			 * program the optimal gear setting during REINIT.
+			 */
+			if (host->phy_gear == dev_req_params->gear_tx)
+				hba->quirks &= ~UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
+			else
+				host->phy_gear = dev_req_params->gear_tx;
+		}
 
 		/* enable the device ref clock before changing to HS mode */
 		if (!ufshcd_is_hs_mode(&hba->pwr_info) &&
-- 
2.43.0