scsi: ufs-mediatek: configure and enable clk-gating

Enable clk-gating with customized delayed timer value in MediaTek Chipsets.

Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Bean Huo <beanhuo@micron.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/1577683950-1702-7-git-send-email-stanley.chu@mediatek.comReviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-mediatek.c

@@ -210,6 +210,9 @@ static int ufs_mtk_init(struct ufs_hba *hba)
 	/* Enable runtime autosuspend */
 	hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
 
+	/* Enable clock-gating */
+	hba->caps |= UFSHCD_CAP_CLK_GATING;
+
 	/*
 	 * ufshcd_vops_init() is invoked after
 	 * ufshcd_setup_clock(true) in ufshcd_hba_init() thus
@@ -298,6 +301,23 @@ static int ufs_mtk_pre_link(struct ufs_hba *hba)
 	return ret;
 }
 
+static void ufs_mtk_setup_clk_gating(struct ufs_hba *hba)
+{
+	unsigned long flags;
+	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;
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		hba->clk_gating.delay_ms = ah_ms + 5;
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+	}
+}
+
 static int ufs_mtk_post_link(struct ufs_hba *hba)
 {
 	/* disable device LCC */
@@ -313,6 +333,8 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
 			FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
 	}
 
+	ufs_mtk_setup_clk_gating(hba);
+
 	return 0;
 }