scsi: ufs: host: mediatek: Fix auto-hibern8 timer configuration

Move the configuration of the Auto-Hibern8 (AHIT) timer from the
post-link stage to the 'fixup_dev_quirks' function. This change allows
setting the AHIT based on the vendor requirements:

   (a) Samsung: 3.5 ms
   (b) Micron: 2 ms
   (c) Others: 1 ms

Additionally, the clock gating timer is adjusted based on the AHIT
scale, with a maximum setting of 10 ms. This ensures that the clock
gating delay is appropriately configured to match the AHIT settings.

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Link: https://lore.kernel.org/r/20250811131423.3444014-3-peter.wang@mediatek.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: ptr324

drivers/ufs/host/ufs-mediatek.c

@@ -1075,6 +1075,69 @@ static void ufs_mtk_vreg_fix_vccqx(struct ufs_hba *hba)
 	}
 }
 
+static void ufs_mtk_setup_clk_gating(struct ufs_hba *hba)
+{
+	unsigned long flags;
+	u32 ah_ms = 10;
+	u32 ah_scale, ah_timer;
+	u32 scale_us[] = {1, 10, 100, 1000, 10000, 100000};
+
+	if (ufshcd_is_clkgating_allowed(hba)) {
+		if (ufshcd_is_auto_hibern8_supported(hba) && hba->ahit) {
+			ah_scale = FIELD_GET(UFSHCI_AHIBERN8_SCALE_MASK,
+					  hba->ahit);
+			ah_timer = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK,
+					  hba->ahit);
+			if (ah_scale <= 5)
+				ah_ms = ah_timer * scale_us[ah_scale] / 1000;
+		}
+
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		hba->clk_gating.delay_ms = max(ah_ms, 10U);
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+	}
+}
+
+/* Convert microseconds to Auto-Hibernate Idle Timer register value */
+static u32 ufs_mtk_us_to_ahit(unsigned int timer)
+{
+	unsigned int scale;
+
+	for (scale = 0; timer > UFSHCI_AHIBERN8_TIMER_MASK; ++scale)
+		timer /= UFSHCI_AHIBERN8_SCALE_FACTOR;
+
+	return FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, timer) |
+	       FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, scale);
+}
+
+static void ufs_mtk_fix_ahit(struct ufs_hba *hba)
+{
+	unsigned int us;
+
+	if (ufshcd_is_auto_hibern8_supported(hba)) {
+		switch (hba->dev_info.wmanufacturerid) {
+		case UFS_VENDOR_SAMSUNG:
+			/* configure auto-hibern8 timer to 3.5 ms */
+			us = 3500;
+			break;
+
+		case UFS_VENDOR_MICRON:
+			/* configure auto-hibern8 timer to 2 ms */
+			us = 2000;
+			break;
+
+		default:
+			/* configure auto-hibern8 timer to 1 ms */
+			us = 1000;
+			break;
+		}
+
+		hba->ahit = ufs_mtk_us_to_ahit(us);
+	}
+
+	ufs_mtk_setup_clk_gating(hba);
+}
+
 static void ufs_mtk_init_mcq_irq(struct ufs_hba *hba)
 {
 	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
@@ -1369,32 +1432,10 @@ static int ufs_mtk_pre_link(struct ufs_hba *hba)
 
 	return ret;
 }
-
-static void ufs_mtk_setup_clk_gating(struct ufs_hba *hba)
-{
-	u32 ah_ms;
-
-	if (ufshcd_is_clkgating_allowed(hba)) {
-		if (ufshcd_is_auto_hibern8_supported(hba) && hba->ahit)
-			ah_ms = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK,
-					  hba->ahit);
-		else
-			ah_ms = 10;
-		ufshcd_clkgate_delay_set(hba->dev, ah_ms + 5);
-	}
-}
-
 static void ufs_mtk_post_link(struct ufs_hba *hba)
 {
 	/* enable unipro clock gating feature */
 	ufs_mtk_cfg_unipro_cg(hba, true);
-
-	/* will be configured during probe hba */
-	if (ufshcd_is_auto_hibern8_supported(hba))
-		hba->ahit = FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 10) |
-			FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3);
-
-	ufs_mtk_setup_clk_gating(hba);
 }
 
 static int ufs_mtk_link_startup_notify(struct ufs_hba *hba,
@@ -1726,6 +1767,7 @@ static void ufs_mtk_fixup_dev_quirks(struct ufs_hba *hba)
 
 	ufs_mtk_vreg_fix_vcc(hba);
 	ufs_mtk_vreg_fix_vccqx(hba);
+	ufs_mtk_fix_ahit(hba);
 }
 
 static void ufs_mtk_event_notify(struct ufs_hba *hba,