scsi: ufs: mediatek: Fix vsx/vccqx control logic

VSX (the upper layer of VCCQ/VCCQ2) should:

 1. Always set to hpm mode if ufs device is active.

 2. Enter lpm mode only if ufs device is not active.

VCCQX should:

 1. Keep hpm mode if vccq and vccq2 not set in dts.

 2. Keep hpm mode if vcc not set in dts keep vcc always on.

 3. Keep hpm if broken vcc keep vcc always on and not allow vccq lpm.

 4. Except upper case, can enter lpm mode if ufs device is not active.

Acked-by: Chun-Hung Wu <Chun-Hung.Wu@mediatek.com>
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Link: https://lore.kernel.org/r/20240315083448.7185-2-peter.wang@mediatek.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 35 insertions, 12 deletions

diff --git a/drivers/ufs/host/ufs-mediatek.c b/drivers/ufs/host/ufs-mediatek.c
index b8a8801322e2..dd27b79519be 100644
--- a/drivers/ufs/host/ufs-mediatek.c
+++ b/drivers/ufs/host/ufs-mediatek.c
@@ -118,6 +118,13 @@ static bool ufs_mtk_is_pmc_via_fastauto(struct ufs_hba *hba)
 	return !!(host->caps & UFS_MTK_CAP_PMC_VIA_FASTAUTO);
 }
 
+static bool ufs_mtk_is_allow_vccqx_lpm(struct ufs_hba *hba)
+{
+	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
+
+	return (host->caps & UFS_MTK_CAP_ALLOW_VCCQX_LPM);
+}
+
 static void ufs_mtk_cfg_unipro_cg(struct ufs_hba *hba, bool enable)
 {
 	u32 tmp;
@@ -1303,27 +1310,37 @@ static void ufs_mtk_vsx_set_lpm(struct ufs_hba *hba, bool lpm)
 
 static void ufs_mtk_dev_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
 {
-	if (!hba->vreg_info.vccq && !hba->vreg_info.vccq2)
-		return;
+	bool skip_vccqx = false;
 
-	/* Skip if VCC is assumed always-on */
-	if (!hba->vreg_info.vcc)
-		return;
-
-	/* Bypass LPM when device is still active */
+	/* Prevent entering LPM when device is still active */
 	if (lpm && ufshcd_is_ufs_dev_active(hba))
 		return;
 
-	/* Bypass LPM if VCC is enabled */
-	if (lpm && hba->vreg_info.vcc->enabled)
-		return;
+	/* Skip vccqx lpm control and control vsx only */
+	if (!hba->vreg_info.vccq && !hba->vreg_info.vccq2)
+		skip_vccqx = true;
+
+	/* VCC is always-on, control vsx only */
+	if (!hba->vreg_info.vcc)
+		skip_vccqx = true;
+
+	/* Broken vcc keep vcc always on, most case control vsx only */
+	if (lpm && hba->vreg_info.vcc && hba->vreg_info.vcc->enabled) {
+		/* Some device vccqx/vsx can enter lpm */
+		if (ufs_mtk_is_allow_vccqx_lpm(hba))
+			skip_vccqx = false;
+		else /* control vsx only */
+			skip_vccqx = true;
+	}
 
 	if (lpm) {
-		ufs_mtk_vccqx_set_lpm(hba, lpm);
+		if (!skip_vccqx)
+			ufs_mtk_vccqx_set_lpm(hba, lpm);
 		ufs_mtk_vsx_set_lpm(hba, lpm);
 	} else {
 		ufs_mtk_vsx_set_lpm(hba, lpm);
-		ufs_mtk_vccqx_set_lpm(hba, lpm);
+		if (!skip_vccqx)
+			ufs_mtk_vccqx_set_lpm(hba, lpm);
 	}
 }
 
diff --git a/drivers/ufs/host/ufs-mediatek.h b/drivers/ufs/host/ufs-mediatek.h
index fb53882f42ca..1670e2f6ce09 100644
--- a/drivers/ufs/host/ufs-mediatek.h
+++ b/drivers/ufs/host/ufs-mediatek.h
@@ -135,6 +135,12 @@ enum ufs_mtk_host_caps {
 	UFS_MTK_CAP_VA09_PWR_CTRL              = 1 << 1,
 	UFS_MTK_CAP_DISABLE_AH8                = 1 << 2,
 	UFS_MTK_CAP_BROKEN_VCC                 = 1 << 3,
+
+	/*
+	 * Override UFS_MTK_CAP_BROKEN_VCC's behavior to
+	 * allow vccqx upstream to enter LPM
+	 */
+	UFS_MTK_CAP_ALLOW_VCCQX_LPM            = 1 << 5,
 	UFS_MTK_CAP_PMC_VIA_FASTAUTO           = 1 << 6,
 };