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From:   Can Guo <cang@codeaurora.org>
To:     subhashj@codeaurora.org, asutoshd@codeaurora.org,
        vivek.gautam@codeaurora.org, rnayak@codeaurora.org,
        vinholikatti@gmail.com, jejb@linux.vnet.ibm.com,
        martin.petersen@oracle.com
Cc:     linux-scsi@vger.kernel.org, Gilad Broner <gbroner@codeaurora.org>,
        Can Guo <cang@codeaurora.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Noa Rubens <noag@codeaurora.org>,
        Sujit Reddy Thumma <sthumma@codeaurora.org>,
        Maya Erez <merez@codeaurora.org>,
        devicetree@vger.kernel.org (open list:OPEN FIRMWARE AND FLATTENED
        DEVICE TREE BINDINGS), linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] scsi: ufs-qcom: add number of lanes per direction
Date:   Mon,  5 Feb 2018 20:02:07 +0800
Message-Id: <20180205121021.11012-1-cang@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Gilad Broner <gbroner@codeaurora.org>

Different platforms may have different number of lanes for the UFS link.
Add parameter to device tree specifying how many lanes should be
configured for the UFS link. And don't print err message for clocks
that are optional, this leads to unnecessary confusion about failure.

Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>

diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
index 5357919..4cee3f9 100644
--- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
+++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
@@ -31,6 +31,9 @@ Optional properties:
 			  defined or a value in the array is "0" then it is assumed
 			  that the frequency is set by the parent clock or a
 			  fixed rate clock source.
+- lanes-per-direction:	number of lanes available per direction - either 1 or 2.
+			Note that it is assume same number of lanes is used both directions at once.
+			If not specified, default is 2 lanes per direction.
 
 Note: If above properties are not defined it can be assumed that the supply
 regulators or clocks are always on.
diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 4cdffa4..84d37e9 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -50,13 +50,10 @@ static int ufs_qcom_host_clk_get(struct device *dev,
 	int err = 0;
 
 	clk = devm_clk_get(dev, name);
-	if (IS_ERR(clk)) {
+	if (IS_ERR(clk))
 		err = PTR_ERR(clk);
-		dev_err(dev, "%s: failed to get %s err %d",
-				__func__, name, err);
-	} else {
+	else
 		*clk_out = clk;
-	}
 
 	return err;
 }
@@ -78,9 +75,11 @@ static void ufs_qcom_disable_lane_clks(struct ufs_qcom_host *host)
 	if (!host->is_lane_clks_enabled)
 		return;
 
-	clk_disable_unprepare(host->tx_l1_sync_clk);
+	if (host->tx_l1_sync_clk)
+		clk_disable_unprepare(host->tx_l1_sync_clk);
 	clk_disable_unprepare(host->tx_l0_sync_clk);
-	clk_disable_unprepare(host->rx_l1_sync_clk);
+	if (host->rx_l1_sync_clk)
+		clk_disable_unprepare(host->rx_l1_sync_clk);
 	clk_disable_unprepare(host->rx_l0_sync_clk);
 
 	host->is_lane_clks_enabled = false;
@@ -104,21 +103,21 @@ static int ufs_qcom_enable_lane_clks(struct ufs_qcom_host *host)
 	if (err)
 		goto disable_rx_l0;
 
-	err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
-		host->rx_l1_sync_clk);
-	if (err)
-		goto disable_tx_l0;
+	if (host->hba->lanes_per_direction > 1) {
+		err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
+			host->rx_l1_sync_clk);
+		if (err)
+			goto disable_tx_l0;
 
-	err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
-		host->tx_l1_sync_clk);
-	if (err)
-		goto disable_rx_l1;
+		/* The tx lane1 clk could be muxed, hence keep this optional */
+		if (host->tx_l1_sync_clk)
+			ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
+						 host->tx_l1_sync_clk);
+	}
 
 	host->is_lane_clks_enabled = true;
 	goto out;
 
-disable_rx_l1:
-	clk_disable_unprepare(host->rx_l1_sync_clk);
 disable_tx_l0:
 	clk_disable_unprepare(host->tx_l0_sync_clk);
 disable_rx_l0:
@@ -134,21 +133,34 @@ static int ufs_qcom_init_lane_clks(struct ufs_qcom_host *host)
 
 	err = ufs_qcom_host_clk_get(dev,
 			"rx_lane0_sync_clk", &host->rx_l0_sync_clk);
-	if (err)
+	if (err) {
+		dev_err(dev, "%s: failed to get rx_lane0_sync_clk, err %d",
+				__func__, err);
 		goto out;
+	}
 
 	err = ufs_qcom_host_clk_get(dev,
 			"tx_lane0_sync_clk", &host->tx_l0_sync_clk);
-	if (err)
+	if (err) {
+		dev_err(dev, "%s: failed to get tx_lane0_sync_clk, err %d",
+				__func__, err);
 		goto out;
+	}
 
-	err = ufs_qcom_host_clk_get(dev, "rx_lane1_sync_clk",
-		&host->rx_l1_sync_clk);
-	if (err)
-		goto out;
+	/* In case of single lane per direction, don't read lane1 clocks */
+	if (host->hba->lanes_per_direction > 1) {
+		err = ufs_qcom_host_clk_get(dev, "rx_lane1_sync_clk",
+			&host->rx_l1_sync_clk);
+		if (err) {
+			dev_err(dev, "%s: failed to get rx_lane1_sync_clk, err %d",
+					__func__, err);
+			goto out;
+		}
 
-	err = ufs_qcom_host_clk_get(dev, "tx_lane1_sync_clk",
-		&host->tx_l1_sync_clk);
+		/* The tx lane1 clk could be muxed, hence keep this optional */
+		ufs_qcom_host_clk_get(dev, "tx_lane1_sync_clk",
+					&host->tx_l1_sync_clk);
+	}
 out:
 	return err;
 }
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b0ade73..b9e1ecd 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -39,6 +39,7 @@
 
 #include <linux/async.h>
 #include <linux/devfreq.h>
+#include <linux/of.h>
 
 #include "ufshcd.h"
 #include "unipro.h"
@@ -74,6 +75,8 @@
 /* Interrupt aggregation default timeout, unit: 40us */
 #define INT_AGGR_DEF_TO	0x02
 
+#define UFSHCD_DEFAULT_LANES_PER_DIRECTION		2
+
 #define ufshcd_toggle_vreg(_dev, _vreg, _on)				\
 	({                                                              \
 		int _ret;                                               \
@@ -5530,6 +5533,21 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {
 	.get_dev_status	= ufshcd_devfreq_get_dev_status,
 };
 
+static void ufshcd_init_lanes_per_dir(struct ufs_hba *hba)
+{
+	struct device *dev = hba->dev;
+	int ret;
+
+	ret = of_property_read_u32(dev->of_node, "lanes-per-direction",
+		&hba->lanes_per_direction);
+	if (ret) {
+		dev_dbg(hba->dev,
+			"%s: failed to read lanes-per-direction, ret=%d\n",
+			__func__, ret);
+		hba->lanes_per_direction = UFSHCD_DEFAULT_LANES_PER_DIRECTION;
+	}
+}
+
 /**
  * ufshcd_init - Driver initialization routine
  * @hba: per-adapter instance
@@ -5553,6 +5571,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	hba->mmio_base = mmio_base;
 	hba->irq = irq;
 
+	ufshcd_init_lanes_per_dir(hba);
+
 	err = ufshcd_hba_init(hba);
 	if (err)
 		goto out_error;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index c40a0e7..3d9bdc7 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -500,6 +500,9 @@ struct ufs_hba {
 
 	bool wlun_dev_clr_ua;
 
+	/* Number of lanes available (1 or 2) for Rx/Tx */
+	u32 lanes_per_direction;
+
 	struct ufs_pa_layer_attr pwr_info;
 	struct ufs_pwr_mode_info max_pwr_info;
 
-- 
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