[PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[Sayali Lokhande]

From: Subhash Jadavani <subhashj@codeaurora.org>

UFS host supplies the reference clock to UFS device and UFS device
specification allows host to provide one of the 4 frequencies (19.2 MHz,
26 MHz, 38.4 MHz, 52 MHz) for reference clock. Host should set the
device reference clock frequency setting in the device based on what
frequency it is supplying to UFS device.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
---
 drivers/scsi/ufs/ufs.h           | 14 +++++++
 drivers/scsi/ufs/ufshcd-pltfrm.c |  2 +
 drivers/scsi/ufs/ufshcd.c        | 87 ++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.h        |  2 +
 4 files changed, 105 insertions(+)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 14e5bf7..a2e76b1 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -378,6 +378,20 @@ enum query_opcode {
 	UPIU_QUERY_OPCODE_TOGGLE_FLAG	= 0x8,
 };
 
+/* bRefClkFreq attribute values */
+enum ufs_ref_clk_freq {
+	REF_CLK_FREQ_19_2_MHZ	= 0,
+	REF_CLK_FREQ_26_MHZ	= 1,
+	REF_CLK_FREQ_38_4_MHZ	= 2,
+	REF_CLK_FREQ_52_MHZ	= 3,
+	REF_CLK_FREQ_INVAL	= -1,
+};
+
+struct ufs_ref_clk {
+	u32 freq_hz;
+	enum ufs_ref_clk_freq val;
+};
+
 /* Query response result code */
 enum {
 	QUERY_RESULT_SUCCESS                    = 0x00,
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index e82bde0..0953563 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -343,6 +343,8 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
+	ufshcd_parse_dev_ref_clk_freq(hba);
+
 	ufshcd_init_lanes_per_dir(hba);
 
 	err = ufshcd_init(hba, mmio_base, irq);
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c5b1bf1..64c62db 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6296,6 +6296,86 @@ static void ufshcd_def_desc_sizes(struct ufs_hba *hba)
 	hba->desc_size.hlth_desc = QUERY_DESC_HEALTH_DEF_SIZE;
 }
 
+static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
+	{19200000, REF_CLK_FREQ_19_2_MHZ},
+	{26000000, REF_CLK_FREQ_26_MHZ},
+	{38400000, REF_CLK_FREQ_38_4_MHZ},
+	{52000000, REF_CLK_FREQ_52_MHZ},
+	{0, REF_CLK_FREQ_INVAL},
+};
+
+static inline enum ufs_ref_clk_freq
+ufs_get_bref_clk_from_hz(u32 freq)
+{
+	int i = 0;
+
+	while (ufs_ref_clk_freqs[i].freq_hz != freq) {
+		if (!ufs_ref_clk_freqs[i].freq_hz)
+			return REF_CLK_FREQ_INVAL;
+		i++;
+	}
+
+	return ufs_ref_clk_freqs[i].val;
+}
+
+void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba)
+{
+	struct device *dev = hba->dev;
+	struct device_node *np = dev->of_node;
+	struct clk *refclk = NULL;
+	u32 freq = 0;
+
+	if (!np)
+		return;
+
+	refclk = of_clk_get_by_name(np, "ref_clk");
+	if (!refclk)
+		return;
+
+	freq = clk_get_rate(refclk);
+
+	hba->dev_ref_clk_freq =
+		ufs_get_bref_clk_from_hz(freq);
+
+	if (hba->dev_ref_clk_freq == REF_CLK_FREQ_INVAL)
+		dev_err(hba->dev,
+		"%s: invalid ref_clk setting = %d\n",
+		__func__, freq);
+}
+
+static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba)
+{
+	int err, ref_clk = -1;
+	u32 freq = hba->dev_ref_clk_freq;
+
+	err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+			QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &ref_clk);
+
+	if (err) {
+		dev_err(hba->dev, "%s: failed reading bRefClkFreq. err = %d\n",
+			 __func__, err);
+		goto out;
+	}
+
+	if (ref_clk == hba->dev_ref_clk_freq)
+		goto out; /* nothing to update */
+
+	err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
+			QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &freq);
+
+	if (err) {
+		dev_err(hba->dev, "%s: bRefClkFreq setting to %u Hz failed\n",
+		__func__, ufs_ref_clk_freqs[freq].freq_hz);
+		goto out;
+	}
+
+	dev_dbg(hba->dev, "%s: bRefClkFreq setting to %u Hz succeeded\n",
+		__func__, ufs_ref_clk_freqs[freq].freq_hz);
+
+out:
+	return err;
+}
+
 /**
  * ufshcd_probe_hba - probe hba to detect device and initialize
  * @hba: per-adapter instance
@@ -6361,6 +6441,12 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 			"%s: Failed getting max supported power mode\n",
 			__func__);
 	} else {
+		/*
+		 * Set the right value to bRefClkFreq before attempting to
+		 * switch to HS gears.
+		 */
+		if (hba->dev_ref_clk_freq != REF_CLK_FREQ_INVAL)
+			ufshcd_set_dev_ref_clk(hba);
 		ret = ufshcd_config_pwr_mode(hba, &hba->max_pwr_info.info);
 		if (ret) {
 			dev_err(hba->dev, "%s: Failed setting power mode, err = %d\n",
@@ -7690,6 +7776,7 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle)
 	hba->host = host;
 	hba->dev = dev;
 	*hba_handle = hba;
+	hba->dev_ref_clk_freq = REF_CLK_FREQ_INVAL;
 
 	INIT_LIST_HEAD(&hba->clk_list_head);
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 8110dcd..45013b6 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -548,6 +548,7 @@ struct ufs_hba {
 	void *priv;
 	unsigned int irq;
 	bool is_irq_enabled;
+	enum ufs_ref_clk_freq dev_ref_clk_freq;
 
 	/* Interrupt aggregation support is broken */
 	#define UFSHCD_QUIRK_BROKEN_INTR_AGGR			0x1
@@ -746,6 +747,7 @@ static inline void ufshcd_rmwl(struct ufs_hba *hba, u32 mask, u32 val, u32 reg)
 int ufshcd_wait_for_register(struct ufs_hba *hba, u32 reg, u32 mask,
 				u32 val, unsigned long interval_us,
 				unsigned long timeout_ms, bool can_sleep);
+void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba);
 
 static inline void check_upiu_size(void)
 {
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Sayali Lokhande]

This patch adds configfs support to provision UFS device at
runtime. This feature can be primarily useful in factory or
assembly line as some devices may be required to be configured
multiple times during initial system development phase.
Configuration Descriptors can be written multiple times until
bConfigDescrLock attribute is zero.

Configuration descriptor buffer consists of Device and Unit
descriptor configurable parameters which are parsed from vendor
specific provisioning file and then passed via configfs node at
runtime to provision ufs device.
CONFIG_CONFIGFS_FS and CONFIG_SCSI_UFS_PROVISION needs to be enabled
for using this feature.

Usage:
1) To read current configuration descriptor with index X
   (where index X can be 0/1/2/3) :
   cat /config/<device_name>/ufs_config_desc_X

2) To write configuration descriptor with index X :
   echo <config_desc_buf> > /config/<device_name>/ufs_config_desc_X

Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
---
 Documentation/ABI/testing/configfs-driver-ufs |  12 ++
 drivers/scsi/ufs/Kconfig                      |  10 ++
 drivers/scsi/ufs/Makefile                     |   1 +
 drivers/scsi/ufs/ufs-configfs.c               | 237 ++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c                     |   3 +-
 drivers/scsi/ufs/ufshcd.h                     |  18 ++
 6 files changed, 280 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
 create mode 100644 drivers/scsi/ufs/ufs-configfs.c

diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs
new file mode 100644
index 0000000..6743ea9
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-driver-ufs
@@ -0,0 +1,12 @@
+What:		/config/*/ufs_config_desc_X
+Date:		Jun 2018
+KernelVersion:	4.20
+Description:
+		This file shows bytes of the current ufs configuration descriptor
+		with index X (where X = 0/1/2/3) set in device. This can be used to
+		provision ufs device if bConfigDescrLock is 0.
+		For more details, refer 14.1.6.3 Configuration Descriptor and
+		table 14-12 - Unit Descriptor configurable parameters from specs for
+		description and format of each configuration descriptor parameter.
+		Parameters of Configuration descriptor buffer for respective index
+		needs to be passed as bytes in space separated format.
diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
index e27b4d4..6e7ff35 100644
--- a/drivers/scsi/ufs/Kconfig
+++ b/drivers/scsi/ufs/Kconfig
@@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
 
 	  Select this if you have UFS controller on QCOM chipset.
 	  If unsure, say N.
+
+config SCSI_UFS_PROVISION
+	bool "Runtime UFS Provisioning support"
+	depends on SCSI_UFSHCD && CONFIGFS_FS
+	help
+	  This enables runtime UFS provisioning support. This can be used
+	  primarily during assembly line as some devices may be required to
+	  be configured multiple times during initial development phase.
+
+	  If unsure, say N.
diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 918f579..09880b9 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
 obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
 obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
 ufshcd-core-objs := ufshcd.o ufs-sysfs.o
+obj-$(CONFIG_SCSI_UFS_PROVISION) += ufs-configfs.o
 obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
 obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
diff --git a/drivers/scsi/ufs/ufs-configfs.c b/drivers/scsi/ufs/ufs-configfs.c
new file mode 100644
index 0000000..8f6a5d3
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-configfs.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (c) 2018, Linux Foundation.
+
+#include <linux/configfs.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+#include "ufs.h"
+#include "ufshcd.h"
+
+static inline struct ufs_hba *config_item_to_hba(struct config_item *item)
+{
+	struct config_group *group = to_config_group(item);
+	struct configfs_subsystem *subsys = to_configfs_subsystem(group);
+	struct ufs_hba *hba = container_of(subsys, struct ufs_hba, subsys);
+
+	return hba;
+}
+
+static ssize_t ufs_config_desc_show(struct config_item *item, char *buf,
+				    u8 index)
+{
+	struct ufs_hba *hba = config_item_to_hba(item);
+	u8 *desc_buf = NULL;
+	int desc_buf_len = hba->desc_size.conf_desc;
+	int i, ret, curr_len = 0;
+
+	desc_buf = kzalloc(desc_buf_len, GFP_KERNEL);
+	if (!desc_buf)
+		return -ENOMEM;
+
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+					    QUERY_DESC_IDN_CONFIGURATION, index,
+					    0, desc_buf, &desc_buf_len);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < desc_buf_len; i++)
+		curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
+				"0x%x ", desc_buf[i]);
+
+out:
+	kfree(desc_buf);
+	return ret ? ret : curr_len;
+}
+
+ssize_t ufshcd_desc_configfs_store(struct config_item *item, const char *buf,
+				   size_t count, u8 index)
+{
+	char *strbuf;
+	char *strbuf_copy;
+	struct ufs_hba *hba = config_item_to_hba(item);
+	u8 *desc_buf = NULL;
+	int desc_buf_len = hba->desc_size.conf_desc;
+	char *token;
+	int i, ret;
+	u8 value;
+	u32 config_desc_lock = 0;
+
+	desc_buf = kzalloc(desc_buf_len, GFP_KERNEL);
+	if (!desc_buf)
+		return -ENOMEM;
+
+	strbuf = kstrdup(buf, GFP_KERNEL);
+	if (!strbuf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	strbuf_copy = strbuf;
+
+	/* Just return if bConfigDescrLock is already set */
+	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+				QUERY_ATTR_IDN_CONF_DESC_LOCK, 0, 0,
+				&config_desc_lock);
+	if (ret)
+		goto out;
+
+	if (config_desc_lock) {
+		dev_err(hba->dev, "%s: bConfigDescrLock already set to %u, cannot re-provision device!\n",
+			__func__, config_desc_lock);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * First read the current configuration descriptor
+	 * and then update with user provided parameters
+	 */
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+					    QUERY_DESC_IDN_CONFIGURATION, index,
+					    0, desc_buf, &desc_buf_len);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < desc_buf_len; i++) {
+		token = strsep(&strbuf_copy, " ");
+		if (!token)
+			break;
+
+		ret = kstrtou8(token, 0, &value);
+		if (ret) {
+			dev_err(hba->dev, "%s: Invalid value %s writing UFS configuration descriptor %u\n",
+				__func__, token, index);
+			ret = -EINVAL;
+			goto out;
+		}
+		desc_buf[i] = value;
+	}
+
+	/* Write configuration descriptor to provision ufs */
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_WRITE_DESC,
+					    QUERY_DESC_IDN_CONFIGURATION, index,
+					    0, desc_buf, &desc_buf_len);
+	if (!ret)
+		dev_info(hba->dev, "%s: UFS Configuration Descriptor %u written\n",
+			 __func__, index);
+
+out:
+	kfree(strbuf);
+	kfree(desc_buf);
+	return ret ? ret : count;
+}
+
+static ssize_t ufs_config_desc_0_show(struct config_item *item, char *buf)
+{
+	return ufs_config_desc_show(item, buf, 0);
+}
+
+static ssize_t ufs_config_desc_0_store(struct config_item *item,
+				       const char *buf, size_t count)
+{
+	return ufshcd_desc_configfs_store(item, buf, count, 0);
+}
+
+static ssize_t ufs_config_desc_1_show(struct config_item *item, char *buf)
+{
+	return ufs_config_desc_show(item, buf, 1);
+}
+
+static ssize_t ufs_config_desc_1_store(struct config_item *item,
+				       const char *buf, size_t count)
+{
+	return ufshcd_desc_configfs_store(item, buf, count, 1);
+}
+
+static ssize_t ufs_config_desc_2_show(struct config_item *item, char *buf)
+{
+	return ufs_config_desc_show(item, buf, 2);
+}
+
+static ssize_t ufs_config_desc_2_store(struct config_item *item,
+				       const char *buf, size_t count)
+{
+	return ufshcd_desc_configfs_store(item, buf, count, 2);
+}
+
+static ssize_t ufs_config_desc_3_show(struct config_item *item, char *buf)
+{
+	return ufs_config_desc_show(item, buf, 3);
+}
+
+static ssize_t ufs_config_desc_3_store(struct config_item *item,
+				       const char *buf, size_t count)
+{
+	return ufshcd_desc_configfs_store(item, buf, count, 3);
+}
+
+static struct configfs_attribute ufshcd_attr_provision_0 = {
+	.ca_name	= "ufs_config_desc_0",
+	.ca_mode	= 0644,
+	.ca_owner	= THIS_MODULE,
+	.show		= ufs_config_desc_0_show,
+	.store		= ufs_config_desc_0_store,
+};
+
+static struct configfs_attribute ufshcd_attr_provision_1 = {
+	.ca_name	= "ufs_config_desc_1",
+	.ca_mode	= 0644,
+	.ca_owner	= THIS_MODULE,
+	.show		= ufs_config_desc_1_show,
+	.store		= ufs_config_desc_1_store,
+};
+
+static struct configfs_attribute ufshcd_attr_provision_2 = {
+	.ca_name	= "ufs_config_desc_2",
+	.ca_mode	= 0644,
+	.ca_owner	= THIS_MODULE,
+	.show		= ufs_config_desc_2_show,
+	.store		= ufs_config_desc_2_store,
+};
+
+static struct configfs_attribute ufshcd_attr_provision_3 = {
+	.ca_name	= "ufs_config_desc_3",
+	.ca_mode	= 0644,
+	.ca_owner	= THIS_MODULE,
+	.show		= ufs_config_desc_3_show,
+	.store		= ufs_config_desc_3_store,
+};
+
+static struct configfs_attribute *ufshcd_attrs[] = {
+	&ufshcd_attr_provision_0,
+	&ufshcd_attr_provision_1,
+	&ufshcd_attr_provision_2,
+	&ufshcd_attr_provision_3,
+	NULL,
+};
+
+static struct config_item_type ufscfg_type = {
+	.ct_attrs	= ufshcd_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+void ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
+{
+	int ret;
+	struct config_item *cg_item;
+	struct configfs_subsystem *subsys;
+
+	cg_item = &hba->subsys.su_group.cg_item;
+	snprintf(cg_item->ci_namebuf, CONFIGFS_ITEM_NAME_LEN, "%s", name);
+	cg_item->ci_type = &ufscfg_type;
+
+	subsys = &hba->subsys;
+	config_group_init(&subsys->su_group);
+	mutex_init(&subsys->su_mutex);
+	ret = configfs_register_subsystem(subsys);
+	if (ret)
+		pr_err("Error %d while registering subsystem %s\n",
+		       ret,
+		       subsys->su_group.cg_item.ci_namebuf);
+}
+
+void ufshcd_configfs_exit(struct ufs_hba *hba)
+{
+	configfs_unregister_subsystem(&hba->subsys);
+}
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 64c62db..d06fbdb 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7708,6 +7708,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 void ufshcd_remove(struct ufs_hba *hba)
 {
 	ufs_sysfs_remove_nodes(hba->dev);
+	ufshcd_configfs_exit(hba);
 	scsi_remove_host(hba->host);
 	/* disable interrupts */
 	ufshcd_disable_intr(hba, hba->intr_mask);
@@ -7962,7 +7963,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 
 	async_schedule(ufshcd_async_scan, hba);
 	ufs_sysfs_add_nodes(hba->dev);
-
+	ufshcd_configfs_init(hba, dev_name(hba->dev));
 	return 0;
 
 out_remove_scsi_host:
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 45013b6..f348b4b 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -37,6 +37,7 @@
 #ifndef _UFSHCD_H
 #define _UFSHCD_H
 
+#include <linux/configfs.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -515,6 +516,9 @@ struct ufs_hba {
 
 	struct Scsi_Host *host;
 	struct device *dev;
+#ifdef CONFIG_SCSI_UFS_PROVISION
+	struct configfs_subsystem subsys;
+#endif
 	/*
 	 * This field is to keep a reference to "scsi_device" corresponding to
 	 * "UFS device" W-LU.
@@ -868,6 +872,20 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
 int ufshcd_hold(struct ufs_hba *hba, bool async);
 void ufshcd_release(struct ufs_hba *hba);
 
+/* Expose UFS configfs API's */
+#ifndef CONFIG_SCSI_UFS_PROVISION
+static inline void ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
+{
+}
+
+static inline void ufshcd_configfs_exit(struct ufs_hba *hba)
+{
+}
+#else
+void ufshcd_configfs_init(struct ufs_hba *hba, const char *name);
+void ufshcd_configfs_exit(struct ufs_hba *hba);
+#endif
+
 int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
 	int *desc_length);
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[Avri Altman]

>+static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
>+       {19200000, REF_CLK_FREQ_19_2_MHZ},
>+       {26000000, REF_CLK_FREQ_26_MHZ},
>+       {38400000, REF_CLK_FREQ_38_4_MHZ},
>+       {52000000, REF_CLK_FREQ_52_MHZ},
>+       {0, REF_CLK_FREQ_INVAL},
>+};
>+
>+static inline enum ufs_ref_clk_freq
>+ufs_get_bref_clk_from_hz(u32 freq)
>+{
>+       int i = 0;
>+
>+       while (ufs_ref_clk_freqs[i].freq_hz != freq) {
>+               if (!ufs_ref_clk_freqs[i].freq_hz)
>+                       return REF_CLK_FREQ_INVAL;
Is the if clause really needed?
you will return REF_CLK_FREQ_INVAL anyway

>+               i++;
You might overrun here if freq is not what you've expected

>+       }
>+
>+       return ufs_ref_clk_freqs[i].val;
>+}

Re: [PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[Sayali Lokhande]

On 9/24/2018 1:28 PM, Avri Altman wrote:
>> +static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
>> +       {19200000, REF_CLK_FREQ_19_2_MHZ},
>> +       {26000000, REF_CLK_FREQ_26_MHZ},
>> +       {38400000, REF_CLK_FREQ_38_4_MHZ},
>> +       {52000000, REF_CLK_FREQ_52_MHZ},
>> +       {0, REF_CLK_FREQ_INVAL},
>> +};
>> +
>> +static inline enum ufs_ref_clk_freq
>> +ufs_get_bref_clk_from_hz(u32 freq)
>> +{
>> +       int i = 0;
>> +
>> +       while (ufs_ref_clk_freqs[i].freq_hz != freq) {
>> +               if (!ufs_ref_clk_freqs[i].freq_hz)
>> +                       return REF_CLK_FREQ_INVAL;
> Is the if clause really needed?
> you will return REF_CLK_FREQ_INVAL anyway
Yes. the if condition makes sure to return REF_CLK_FREQ_INVAL if freq is 
not what we expect.
>
>> +               i++;
> You might overrun here if freq is not what you've expected
Above if condition "if (!ufs_ref_clk_freqs[i].freq_hz)" prevents such 
overrun
as we will reach end of ufs_ref_clk_freqs[] (i.e upto  0, 
REF_CLK_FREQ_INVAL) when there is no match and thus we will return 
REF_CLK_FREQ_INVAL.
>> +       }
>> +
>> +       return ufs_ref_clk_freqs[i].val;
>> +}

Re: [PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Avri Altman]

> obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>ufshcd-core-objs := ufshcd.o ufs-sysfs.o
>+obj-$(CONFIG_SCSI_UFS_PROVISION) += ufs-configfs.o
Isn't ufs-configfs should be part of ufshcd-core? like ufs-sysfs ?


>+static ssize_t ufs_config_desc_show(struct config_item *item, char *buf,
>+                                   u8 index)
>+{
The read part already exist in ufs-sysfs.


>+ssize_t ufshcd_desc_configfs_store(struct config_item *item, const char *buf,
>+                                  size_t count, u8 index)
>+{


>+
>+       /*
>+        * First read the current configuration descriptor
>+        * and then update with user provided parameters
>+        */
if originally only lun0 was configured, and you want to configure a new set of luns - 
luns 8 to 15 (config index 0x1) - won't the read fail in that case?

Thanks,
Avri

Re: [PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Evan Green]

On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande <sayalil@codeaurora.org> wrote:
>
> This patch adds configfs support to provision UFS device at
> runtime. This feature can be primarily useful in factory or
> assembly line as some devices may be required to be configured
> multiple times during initial system development phase.
> Configuration Descriptors can be written multiple times until
> bConfigDescrLock attribute is zero.
>
> Configuration descriptor buffer consists of Device and Unit
> descriptor configurable parameters which are parsed from vendor
> specific provisioning file and then passed via configfs node at
> runtime to provision ufs device.
> CONFIG_CONFIGFS_FS and CONFIG_SCSI_UFS_PROVISION needs to be enabled
> for using this feature.
>
> Usage:
> 1) To read current configuration descriptor with index X
>    (where index X can be 0/1/2/3) :
>    cat /config/<device_name>/ufs_config_desc_X
>
> 2) To write configuration descriptor with index X :
>    echo <config_desc_buf> > /config/<device_name>/ufs_config_desc_X
>
> Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
> ---
>  Documentation/ABI/testing/configfs-driver-ufs |  12 ++
>  drivers/scsi/ufs/Kconfig                      |  10 ++
>  drivers/scsi/ufs/Makefile                     |   1 +
>  drivers/scsi/ufs/ufs-configfs.c               | 237 ++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.c                     |   3 +-
>  drivers/scsi/ufs/ufshcd.h                     |  18 ++
>  6 files changed, 280 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
>  create mode 100644 drivers/scsi/ufs/ufs-configfs.c
>

Reviewed-by: Evan Green <evgreen@chromium.org>

Re: [PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Evan Green]

On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande <sayalil@codeaurora.org> wrote:
>
> This patch adds configfs support to provision UFS device at
> runtime. This feature can be primarily useful in factory or
> assembly line as some devices may be required to be configured
> multiple times during initial system development phase.
> Configuration Descriptors can be written multiple times until
> bConfigDescrLock attribute is zero.
>
> Configuration descriptor buffer consists of Device and Unit
> descriptor configurable parameters which are parsed from vendor
> specific provisioning file and then passed via configfs node at
> runtime to provision ufs device.
> CONFIG_CONFIGFS_FS and CONFIG_SCSI_UFS_PROVISION needs to be enabled
> for using this feature.
>
> Usage:
> 1) To read current configuration descriptor with index X
>    (where index X can be 0/1/2/3) :
>    cat /config/<device_name>/ufs_config_desc_X
>
> 2) To write configuration descriptor with index X :
>    echo <config_desc_buf> > /config/<device_name>/ufs_config_desc_X
>
> Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
> ---
>  Documentation/ABI/testing/configfs-driver-ufs |  12 ++
>  drivers/scsi/ufs/Kconfig                      |  10 ++
>  drivers/scsi/ufs/Makefile                     |   1 +
>  drivers/scsi/ufs/ufs-configfs.c               | 237 ++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.c                     |   3 +-
>  drivers/scsi/ufs/ufshcd.h                     |  18 ++
>  6 files changed, 280 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
>  create mode 100644 drivers/scsi/ufs/ufs-configfs.c
>
> diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs
> new file mode 100644
> index 0000000..6743ea9
> --- /dev/null
> +++ b/Documentation/ABI/testing/configfs-driver-ufs
> @@ -0,0 +1,12 @@
> +What:          /config/*/ufs_config_desc_X
> +Date:          Jun 2018
> +KernelVersion: 4.20
> +Description:
> +               This file shows bytes of the current ufs configuration descriptor
> +               with index X (where X = 0/1/2/3) set in device. This can be used to
> +               provision ufs device if bConfigDescrLock is 0.
> +               For more details, refer 14.1.6.3 Configuration Descriptor and
> +               table 14-12 - Unit Descriptor configurable parameters from specs for
> +               description and format of each configuration descriptor parameter.
> +               Parameters of Configuration descriptor buffer for respective index
> +               needs to be passed as bytes in space separated format.
> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> index e27b4d4..6e7ff35 100644
> --- a/drivers/scsi/ufs/Kconfig
> +++ b/drivers/scsi/ufs/Kconfig
> @@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
>
>           Select this if you have UFS controller on QCOM chipset.
>           If unsure, say N.
> +
> +config SCSI_UFS_PROVISION
> +       bool "Runtime UFS Provisioning support"
> +       depends on SCSI_UFSHCD && CONFIGFS_FS
> +       help
> +         This enables runtime UFS provisioning support. This can be used
> +         primarily during assembly line as some devices may be required to
> +         be configured multiple times during initial development phase.
> +
> +         If unsure, say N.
> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
> index 918f579..09880b9 100644
> --- a/drivers/scsi/ufs/Makefile
> +++ b/drivers/scsi/ufs/Makefile
> @@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
>  obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>  obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>  ufshcd-core-objs := ufshcd.o ufs-sysfs.o
> +obj-$(CONFIG_SCSI_UFS_PROVISION) += ufs-configfs.o

Hi Sayali,
Can you try both of your patches with "make allmodconfig". There seem
to be a few issues compiling in that configuration. Also, as it stands
this file is either not compiled in, or baked into the kernel, where
it really should go into the driver. Check out the patch below for how
Guenter patched things up in our tree:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1255524

Re: [PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Sayali Lokhande]

Hi Evan,


On 10/3/2018 11:31 PM, Evan Green wrote:
> On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande <sayalil@codeaurora.org> wrote:
>> This patch adds configfs support to provision UFS device at
>> runtime. This feature can be primarily useful in factory or
>> assembly line as some devices may be required to be configured
>> multiple times during initial system development phase.
>> Configuration Descriptors can be written multiple times until
>> bConfigDescrLock attribute is zero.
>>
>> Configuration descriptor buffer consists of Device and Unit
>> descriptor configurable parameters which are parsed from vendor
>> specific provisioning file and then passed via configfs node at
>> runtime to provision ufs device.
>> CONFIG_CONFIGFS_FS and CONFIG_SCSI_UFS_PROVISION needs to be enabled
>> for using this feature.
>>
>> Usage:
>> 1) To read current configuration descriptor with index X
>>     (where index X can be 0/1/2/3) :
>>     cat /config/<device_name>/ufs_config_desc_X
>>
>> 2) To write configuration descriptor with index X :
>>     echo <config_desc_buf> > /config/<device_name>/ufs_config_desc_X
>>
>> Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
>> ---
>>   Documentation/ABI/testing/configfs-driver-ufs |  12 ++
>>   drivers/scsi/ufs/Kconfig                      |  10 ++
>>   drivers/scsi/ufs/Makefile                     |   1 +
>>   drivers/scsi/ufs/ufs-configfs.c               | 237 ++++++++++++++++++++++++++
>>   drivers/scsi/ufs/ufshcd.c                     |   3 +-
>>   drivers/scsi/ufs/ufshcd.h                     |  18 ++
>>   6 files changed, 280 insertions(+), 1 deletion(-)
>>   create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
>>   create mode 100644 drivers/scsi/ufs/ufs-configfs.c
>>
>> diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs
>> new file mode 100644
>> index 0000000..6743ea9
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/configfs-driver-ufs
>> @@ -0,0 +1,12 @@
>> +What:          /config/*/ufs_config_desc_X
>> +Date:          Jun 2018
>> +KernelVersion: 4.20
>> +Description:
>> +               This file shows bytes of the current ufs configuration descriptor
>> +               with index X (where X = 0/1/2/3) set in device. This can be used to
>> +               provision ufs device if bConfigDescrLock is 0.
>> +               For more details, refer 14.1.6.3 Configuration Descriptor and
>> +               table 14-12 - Unit Descriptor configurable parameters from specs for
>> +               description and format of each configuration descriptor parameter.
>> +               Parameters of Configuration descriptor buffer for respective index
>> +               needs to be passed as bytes in space separated format.
>> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
>> index e27b4d4..6e7ff35 100644
>> --- a/drivers/scsi/ufs/Kconfig
>> +++ b/drivers/scsi/ufs/Kconfig
>> @@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
>>
>>            Select this if you have UFS controller on QCOM chipset.
>>            If unsure, say N.
>> +
>> +config SCSI_UFS_PROVISION
>> +       bool "Runtime UFS Provisioning support"
>> +       depends on SCSI_UFSHCD && CONFIGFS_FS
>> +       help
>> +         This enables runtime UFS provisioning support. This can be used
>> +         primarily during assembly line as some devices may be required to
>> +         be configured multiple times during initial development phase.
>> +
>> +         If unsure, say N.
>> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
>> index 918f579..09880b9 100644
>> --- a/drivers/scsi/ufs/Makefile
>> +++ b/drivers/scsi/ufs/Makefile
>> @@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
>>   obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>>   obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>>   ufshcd-core-objs := ufshcd.o ufs-sysfs.o
>> +obj-$(CONFIG_SCSI_UFS_PROVISION) += ufs-configfs.o
> Hi Sayali,
> Can you try both of your patches with "make allmodconfig". There seem
> to be a few issues compiling in that configuration. Also, as it stands
> this file is either not compiled in, or baked into the kernel, where
> it really should go into the driver. Check out the patch below for how
> Guenter patched things up in our tree:
>
> shttps://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1255524
[Sayali] : the change pointed by you above looks good to me and will 
update it in my patch as well. ufs-configfs should be part of ufshcd-core.
I tried using "make allmodconfig".(basically updating like below for 
test) + include change pointed above and it works fine.
+CONFIG_CONFIGFS_FS=y

+CONFIG_SCSI_UFSHCD=m
+CONFIG_SCSI_UFSHCD_PLATFORM=m
+CONFIG_SCSI_UFS_PROVISION=y

Re: [PATCH V14 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Sayali Lokhande]

On 9/24/2018 3:33 PM, Avri Altman wrote:
>> obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>> obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>> ufshcd-core-objs := ufshcd.o ufs-sysfs.o
>> +obj-$(CONFIG_SCSI_UFS_PROVISION) += ufs-configfs.o
> Isn't ufs-configfs should be part of ufshcd-core? like ufs-sysfs ?
Agree. Will update.
>
>
>> +static ssize_t ufs_config_desc_show(struct config_item *item, char *buf,
>> +                                   u8 index)
>> +{
> The read part already exist in ufs-sysfs.
User can just read the existing desc here and update the required fields 
as per need and write updated buffer to same configfs path.
I think its better to have both r/w functionality here.
>
>> +ssize_t ufshcd_desc_configfs_store(struct config_item *item, const char *buf,
>> +                                  size_t count, u8 index)
>> +{
>
>> +
>> +       /*
>> +        * First read the current configuration descriptor
>> +        * and then update with user provided parameters
>> +        */
> if originally only lun0 was configured, and you want to configure a new set of luns -
> luns 8 to 15 (config index 0x1) - won't the read fail in that case?
Let me try it out on my setup internally and update once I test this 
scenario
>
> Thanks,
> Avri

Re: [PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[Doug Anderson]

Hi,

On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande <sayalil@codeaurora.org> wrote:
> +static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
> +       {19200000, REF_CLK_FREQ_19_2_MHZ},
> +       {26000000, REF_CLK_FREQ_26_MHZ},
> +       {38400000, REF_CLK_FREQ_38_4_MHZ},
> +       {52000000, REF_CLK_FREQ_52_MHZ},
> +       {0, REF_CLK_FREQ_INVAL},
> +};
> +
> +static inline enum ufs_ref_clk_freq

Please don't specify inline.  Let the compiler decide whether inline is better.


> +ufs_get_bref_clk_from_hz(u32 freq)
> +{
> +       int i = 0;
> +
> +       while (ufs_ref_clk_freqs[i].freq_hz != freq) {
> +               if (!ufs_ref_clk_freqs[i].freq_hz)
> +                       return REF_CLK_FREQ_INVAL;
> +               i++;
> +       }
> +
> +       return ufs_ref_clk_freqs[i].val;

I think you'll have less confusion if you write the above as this (untested):

for (i = 0; ufs_ref_clk_freqs[i].freq_hz; i++) {
  if (ufs_ref_clk_freqs[i].freq_hz == freq)
    return ufs_ref_clk_freqs[i].val;
}

return REF_CLK_FREQ_INVAL;

Now it looks like a normal iteration till a normal stop condition
(NULL term array).


> +void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba)

Shouldn't this return an error code so that if there's a problem it
can return back to the caller?  Right now you print error messages but
ufshcd_pltfrm_init() will plow merrily along after.


> +{
> +       struct device *dev = hba->dev;
> +       struct device_node *np = dev->of_node;
> +       struct clk *refclk = NULL;
> +       u32 freq = 0;

"freq" should be "unsigned long" to match clk_get_rate(), not u32.
Similarly all the places you pass it to and store it in should be
"unsigned long" too.  Save "u32" for values which are being programmed
into 32-bit hardware registers.


> +       if (!np)
> +               return;

You don't need to check for (!np).  If you do clk_get() and there's no
np you'll get get an error back.  Handle it there.


> +
> +       refclk = of_clk_get_by_name(np, "ref_clk");
> +       if (!refclk)
> +               return;

I can't quickly tell.  Are you intending "ref_clk" to be optional or
required?  You check against "NULL" and return with no error message,
so I'm kinda assuming it's optional.  ...but:

1. of_clk_get_by_name() doesn't return NULL when the clock wasn't
specified.  It returns "-ENOENT".  That means that (right now) anyone
who doesn't specify a "ref_clk" will get a crash when you try calling
clk_get_rate() on the error-code-clk.

2. It seems like it would be good to add a comment that
"dev_ref_clk_freq" was already initted to "REF_CLK_FREQ_INVAL in
ufshcd_alloc_host() to make it obvious how people are working that
didn't specify "ref_clk".


One note is that regardless of whether "ref_clk" is optional or
required, something about "ref_clk" should be mentioned in
"Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt" so people
know that's an important clock name.


Yet another note here is that I'm confused why you'd want to use
of_clk_get_by_name().  Why not use clk_get()?  You've already got the
"dev" node and clk_get() should be preferred since not everyone uses
device tree.


OK, one last note is that clk_get() could return -EPROBE_DEFER.  In
such a case you need to basically cancel your whole probe and
propagate the -EPROBE_DEFER.  Make sure you think about that when
you're coding things up.


OK, I lied about the previous one being the last note.  Why don't you
just add a bit of code in the ufshcd_init_clocks() loop.  If you
notice that the clock name is "ref_clk" (similar to how
__ufshcd_setup_clocks() checks) then you can grab the frequency.  Then
you can avoid dealing with all my comments above about
of_clk_get_by_name() and errors and -EPROBE_DEFER...


> +       freq = clk_get_rate(refclk);
> +
> +       hba->dev_ref_clk_freq =
> +               ufs_get_bref_clk_from_hz(freq);
> +
> +       if (hba->dev_ref_clk_freq == REF_CLK_FREQ_INVAL)
> +               dev_err(hba->dev,
> +               "%s: invalid ref_clk setting = %d\n",
> +               __func__, freq);

nit: including "__func__" in dev_xxx() calls is discouraged.  The
"dev_xxx" calls already print the device name and the string within a
given device driver should be unique enough so __func__ just adds crap
to the logs.  If you really feel that __func__ adds something for you,
try posting up a patch to make all "dev_err" functions include
__func__.  ...but I think you'd probably be rejected.


Also (more important): You're missing a clk_put().  Thus you're
leaking a reference to "ref_clk".


> +}
> +
> +static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba)
> +{
> +       int err, ref_clk = -1;
> +       u32 freq = hba->dev_ref_clk_freq;

Ugh, this is ugly.  hba->dev_ref_clk_freq could be -1 but you're
jamming it into a u32 here.  That doesn't seem so ideal.  Are you sure
-1 was the best choice for REF_CLK_FREQ_INVAL?


> +
> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> +                       QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &ref_clk);

It's not so wonderful to be passing a pointer to an "int" to a
function expecting a pointer to a "u32".  Change "ref_clk" to "u32".


> +
> +       if (err) {
> +               dev_err(hba->dev, "%s: failed reading bRefClkFreq. err = %d\n",
> +                        __func__, err);

Again, no __func__.


> +               goto out;
> +       }
> +
> +       if (ref_clk == hba->dev_ref_clk_freq)

nit: you already cached "hba->dev_ref_clk_freq in "freq".  Use it.


> +               goto out; /* nothing to update */
> +
> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> +                       QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &freq);
> +
> +       if (err) {
> +               dev_err(hba->dev, "%s: bRefClkFreq setting to %u Hz failed\n",
> +               __func__, ufs_ref_clk_freqs[freq].freq_hz);

Again, no __func__.


> +               goto out;
> +       }
> +
> +       dev_dbg(hba->dev, "%s: bRefClkFreq setting to %u Hz succeeded\n",
> +               __func__, ufs_ref_clk_freqs[freq].freq_hz);

Again, no __func__.

Re: [PATCH V14 1/2] scsi: ufs: set the device reference clock setting

[Sayali Lokhande]

Hi

On 10/13/2018 4:20 AM, Doug Anderson wrote:
> Hi,
>
> On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande <sayalil@codeaurora.org> wrote:
>> +static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
>> +       {19200000, REF_CLK_FREQ_19_2_MHZ},
>> +       {26000000, REF_CLK_FREQ_26_MHZ},
>> +       {38400000, REF_CLK_FREQ_38_4_MHZ},
>> +       {52000000, REF_CLK_FREQ_52_MHZ},
>> +       {0, REF_CLK_FREQ_INVAL},
>> +};
>> +
>> +static inline enum ufs_ref_clk_freq
> Please don't specify inline.  Let the compiler decide whether inline is better.
Done
>
>> +ufs_get_bref_clk_from_hz(u32 freq)
>> +{
>> +       int i = 0;
>> +
>> +       while (ufs_ref_clk_freqs[i].freq_hz != freq) {
>> +               if (!ufs_ref_clk_freqs[i].freq_hz)
>> +                       return REF_CLK_FREQ_INVAL;
>> +               i++;
>> +       }
>> +
>> +       return ufs_ref_clk_freqs[i].val;
> I think you'll have less confusion if you write the above as this (untested):
>
> for (i = 0; ufs_ref_clk_freqs[i].freq_hz; i++) {
>    if (ufs_ref_clk_freqs[i].freq_hz == freq)
>      return ufs_ref_clk_freqs[i].val;
> }
>
> return REF_CLK_FREQ_INVAL;
>
> Now it looks like a normal iteration till a normal stop condition
> (NULL term array).
>
Will update.
>> +void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba)
> Shouldn't this return an error code so that if there's a problem it
> can return back to the caller?  Right now you print error messages but
> ufshcd_pltfrm_init() will plow merrily along after.
We need not return error if no specific device ref clk was found via DT 
parsing. Device reference clock will be already set(bRefClkFreq MDV : 
26MHz).
So no need to fail if we find invalid/no ref clk passed.
>
>> +{
>> +       struct device *dev = hba->dev;
>> +       struct device_node *np = dev->of_node;
>> +       struct clk *refclk = NULL;
>> +       u32 freq = 0;
> "freq" should be "unsigned long" to match clk_get_rate(), not u32.
> Similarly all the places you pass it to and store it in should be
> "unsigned long" too.  Save "u32" for values which are being programmed
> into 32-bit hardware registers.
>
Will update.
>> +       if (!np)
>> +               return;
> You don't need to check for (!np).  If you do clk_get() and there's no
> np you'll get get an error back.  Handle it there.
>
Will update.
>> +
>> +       refclk = of_clk_get_by_name(np, "ref_clk");
>> +       if (!refclk)
>> +               return;
> I can't quickly tell.  Are you intending "ref_clk" to be optional or
> required?  You check against "NULL" and return with no error message,
> so I'm kinda assuming it's optional.  ...but:
Explicit setting of device reference clock is not mandatory. It will be 
already set (MDV: 26Hz).
We first read the current ref clk setting in device and if host is 
passing different (but valid) ref clk freq then we go ahead and update 
it, otherwise we just return.
> 1. of_clk_get_by_name() doesn't return NULL when the clock wasn't
> specified.  It returns "-ENOENT".  That means that (right now) anyone
> who doesn't specify a "ref_clk" will get a crash when you try calling
> clk_get_rate() on the error-code-clk.
>
> 2. It seems like it would be good to add a comment that
> "dev_ref_clk_freq" was already initted to "REF_CLK_FREQ_INVAL in
> ufshcd_alloc_host() to make it obvious how people are working that
> didn't specify "ref_clk".
Will add comment to clarify that dev_ref_clk_freq is default set as 
REF_CLK_FREQ_INVA.
>
> One note is that regardless of whether "ref_clk" is optional or
> required, something about "ref_clk" should be mentioned in
> "Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt" so people
> know that's an important clock name.
>
Will check and add required documentation.
> Yet another note here is that I'm confused why you'd want to use
> of_clk_get_by_name().  Why not use clk_get()?  You've already got the
> "dev" node and clk_get() should be preferred since not everyone uses
> device tree.
Will update.
>
> OK, one last note is that clk_get() could return -EPROBE_DEFER.  In
> such a case you need to basically cancel your whole probe and
> propagate the -EPROBE_DEFER.  Make sure you think about that when
> you're coding things up.
>
>
> OK, I lied about the previous one being the last note.  Why don't you
> just add a bit of code in the ufshcd_init_clocks() loop.  If you
> notice that the clock name is "ref_clk" (similar to how
> __ufshcd_setup_clocks() checks) then you can grab the frequency.  Then
> you can avoid dealing with all my comments above about
> of_clk_get_by_name() and errors and -EPROBE_DEFER...
>
Will consider above suggestion and update.
May be I can just call ufshcd_parse_dev_ref_clk_freq (hba, ref_clk) from 
ufshcd_init_clocks() loop and pass ref_clk to it.
>> +       freq = clk_get_rate(refclk);
>> +
>> +       hba->dev_ref_clk_freq =
>> +               ufs_get_bref_clk_from_hz(freq);
>> +
>> +       if (hba->dev_ref_clk_freq == REF_CLK_FREQ_INVAL)
>> +               dev_err(hba->dev,
>> +               "%s: invalid ref_clk setting = %d\n",
>> +               __func__, freq);
> nit: including "__func__" in dev_xxx() calls is discouraged.  The
> "dev_xxx" calls already print the device name and the string within a
> given device driver should be unique enough so __func__ just adds crap
> to the logs.  If you really feel that __func__ adds something for you,
> try posting up a patch to make all "dev_err" functions include
> __func__.  ...but I think you'd probably be rejected.
will remove __func__ .
>
> Also (more important): You're missing a clk_put().  Thus you're
> leaking a reference to "ref_clk".
>
>
>> +}
>> +
>> +static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba)
>> +{
>> +       int err, ref_clk = -1;
>> +       u32 freq = hba->dev_ref_clk_freq;
> Ugh, this is ugly.  hba->dev_ref_clk_freq could be -1 but you're
> jamming it into a u32 here.  That doesn't seem so ideal.  Are you sure
> -1 was the best choice for REF_CLK_FREQ_INVAL?
ufshcd_set_dev_ref_clk() is only called if  (dev_ref_clk_freq != 
REF_CLK_FREQ_INVAL).
So we only set freq if we get a valid parsed ref clk freq (0/1/2/3h).
>
>> +
>> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
>> +                       QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &ref_clk);
> It's not so wonderful to be passing a pointer to an "int" to a
> function expecting a pointer to a "u32".  Change "ref_clk" to "u32".
done
>
>> +
>> +       if (err) {
>> +               dev_err(hba->dev, "%s: failed reading bRefClkFreq. err = %d\n",
>> +                        __func__, err);
> Again, no __func__.
>
Will remove __func__
>> +               goto out;
>> +       }
>> +
>> +       if (ref_clk == hba->dev_ref_clk_freq)
> nit: you already cached "hba->dev_ref_clk_freq in "freq".  Use it.
Will update
>
>> +               goto out; /* nothing to update */
>> +
>> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
>> +                       QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &freq);
>> +
>> +       if (err) {
>> +               dev_err(hba->dev, "%s: bRefClkFreq setting to %u Hz failed\n",
>> +               __func__, ufs_ref_clk_freqs[freq].freq_hz);
> Again, no __func__.
>
Will remove __func__
>> +               goto out;
>> +       }
>> +
>> +       dev_dbg(hba->dev, "%s: bRefClkFreq setting to %u Hz succeeded\n",
>> +               __func__, ufs_ref_clk_freqs[freq].freq_hz);
> Again, no __func__.
Will remove __func__