[PATCH V11 1/2] scsi: ufs: set the device reference clock setting

[PATCH V11 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>
---
 drivers/scsi/ufs/ufs.h           | 14 +++++++
 drivers/scsi/ufs/ufshcd-pltfrm.c |  2 +
 drivers/scsi/ufs/ufshcd.c        | 90 ++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.h        |  2 +
 4 files changed, 108 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..e01cdc0 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6296,6 +6296,89 @@ 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;
+	}
+	/*
+	 * It is good to print this out here to debug any later failures
+	 * related to gear switch.
+	 */
+	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 +6444,12 @@ 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 +7779,7 @@ 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 V11 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_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/XXXX.ufshc/ufs_config_desc_X

2) To write configuration descriptor with index X :
   echo <config_desc_buf> > /config/XXXX.ufshc/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               | 228 ++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c                     |   3 +-
 drivers/scsi/ufs/ufshcd.h                     |  17 ++
 6 files changed, 270 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..75cfc9e
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-driver-ufs
@@ -0,0 +1,12 @@
+What:		/config/*/ufs_config_desc_X
+Date:		Jun 2018
+KernelVersion:	4.19
+Description:
+		This file shows 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 in space separated format.
diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
index e27b4d4..a9a0a58 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 UFS_PROVISION
+	tristate "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..00110ea 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_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..a4d26b7
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-configfs.c
@@ -0,0 +1,228 @@
+// 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 subsys ? hba : NULL;
+}
+
+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 = kmalloc(desc_buf_len, GFP_KERNEL);
+	if (!desc_buf)
+		return -ENOMEM;
+
+	memset(desc_buf, 0, desc_buf_len);
+
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+	QUERY_DESC_IDN_CONFIGURATION, index, 0, desc_buf, &desc_buf_len);
+
+	if (ret)
+		return ret;
+
+	for (i = 0; i < desc_buf_len; i++)
+		curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
+				"0x%x ", desc_buf[i]);
+
+	return 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, value;
+	u32 config_desc_lock = 0;
+
+	desc_buf = kmalloc(desc_buf_len, GFP_KERNEL);
+	if (!desc_buf)
+		return -ENOMEM;
+
+	memset(desc_buf, 0, desc_buf_len);
+
+	/* reserve one byte for null termination */
+	strbuf = kmalloc(count + 1, GFP_KERNEL);
+	if (!strbuf)
+		return -ENOMEM;
+
+	strbuf_copy = strbuf;
+	strlcpy(strbuf, buf, count + 1);
+
+	/* 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;
+	}
+
+	for (i = 0; i < desc_buf_len; i++) {
+		token = strsep(&strbuf, " ");
+		if (!token && i)
+			break;
+
+		ret = kstrtoint(token, 0, &value);
+		if (ret) {
+			dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
+				__func__, ret, token);
+			ret = -EINVAL;
+			goto out;
+		}
+		desc_buf[i] = (u8)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_copy);
+	if (ret)
+		return ret;
+	return 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;
+	sprintf(cg_item->ci_namebuf, "%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 e01cdc0..608e23e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7711,6 +7711,7 @@ 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);
@@ -7965,7 +7966,7 @@ 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..a340ca8 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_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 +872,19 @@ 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_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);
 
-- 
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Re: [PATCH V11 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Adrian Hunter]

Cc'ing Joel Becker for any suggestions about configfs

On 29/08/18 07:35, Sayali Lokhande 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_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/XXXX.ufshc/ufs_config_desc_X
> 
> 2) To write configuration descriptor with index X :
>    echo <config_desc_buf> > /config/XXXX.ufshc/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               | 228 ++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.c                     |   3 +-
>  drivers/scsi/ufs/ufshcd.h                     |  17 ++
>  6 files changed, 270 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..75cfc9e
> --- /dev/null
> +++ b/Documentation/ABI/testing/configfs-driver-ufs
> @@ -0,0 +1,12 @@
> +What:		/config/*/ufs_config_desc_X
> +Date:		Jun 2018
> +KernelVersion:	4.19
> +Description:
> +		This file shows the current ufs configuration descriptor with

Should mention that it is in bytes i.e.

	This file shows the bytes of the 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 in space separated format.

"needs to be passed as bytes in space separated format"

> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> index e27b4d4..a9a0a58 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 UFS_PROVISION
> +	tristate "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..00110ea 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_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..a4d26b7
> --- /dev/null
> +++ b/drivers/scsi/ufs/ufs-configfs.c
> @@ -0,0 +1,228 @@
> +// 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 subsys ? hba : NULL;

'subsys' won't be null unless 'item' is null, but 'item' is passed by
configfs, so that won't happen.  i.e. might just as well return 'hba; directly.

> +}
> +
> +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 = kmalloc(desc_buf_len, GFP_KERNEL);
> +	if (!desc_buf)
> +		return -ENOMEM;
> +
> +	memset(desc_buf, 0, desc_buf_len);

Just use kzalloc

> +
> +	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
> +	QUERY_DESC_IDN_CONFIGURATION, index, 0, desc_buf, &desc_buf_len);

Indenting

> +

Blank line?

> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < desc_buf_len; i++)
> +		curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
> +				"0x%x ", desc_buf[i]);

Free desc_buf

> +
> +	return 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, value;
> +	u32 config_desc_lock = 0;
> +
> +	desc_buf = kmalloc(desc_buf_len, GFP_KERNEL);
> +	if (!desc_buf)
> +		return -ENOMEM;
> +
> +	memset(desc_buf, 0, desc_buf_len);

Just use kzalloc

> +
> +	/* reserve one byte for null termination */
> +	strbuf = kmalloc(count + 1, GFP_KERNEL);
> +	if (!strbuf)
> +		return -ENOMEM;
> +
> +	strbuf_copy = strbuf;
> +	strlcpy(strbuf, buf, count + 1);
> +
> +	/* 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;
> +	}
> +
> +	for (i = 0; i < desc_buf_len; i++) {
> +		token = strsep(&strbuf, " ");
> +		if (!token && i)
> +			break;
> +
> +		ret = kstrtoint(token, 0, &value);

Why not unsigned, and also why not check the value is <= 255

> +		if (ret) {
> +			dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
> +				__func__, ret, token);
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		desc_buf[i] = (u8)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);

Indenting

> +

Blank line?

> +	if (!ret)
> +		dev_info(hba->dev, "%s: UFS Configuration Descriptor %u written\n",
> +		__func__, index);
> +
> +out:
> +	kfree(strbuf_copy);

Please arrange it so that the variable used for kfree is the same as the
variable assigned to kmalloc.

> +	if (ret)
> +		return ret;

Free desc_buf

> +	return 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;
> +	sprintf(cg_item->ci_namebuf, "%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 e01cdc0..608e23e 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -7711,6 +7711,7 @@ 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);
> @@ -7965,7 +7966,7 @@ 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..a340ca8 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_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 +872,19 @@ 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_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);
>  
> 

Re: [PATCH V11 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Sayali Lokhande]

On 8/29/2018 1:24 PM, Adrian Hunter wrote:
> Cc'ing Joel Becker for any suggestions about configfs
>
> On 29/08/18 07:35, Sayali Lokhande 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_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/XXXX.ufshc/ufs_config_desc_X
>>
>> 2) To write configuration descriptor with index X :
>>     echo <config_desc_buf> > /config/XXXX.ufshc/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               | 228 ++++++++++++++++++++++++++
>>   drivers/scsi/ufs/ufshcd.c                     |   3 +-
>>   drivers/scsi/ufs/ufshcd.h                     |  17 ++
>>   6 files changed, 270 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..75cfc9e
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/configfs-driver-ufs
>> @@ -0,0 +1,12 @@
>> +What:		/config/*/ufs_config_desc_X
>> +Date:		Jun 2018
>> +KernelVersion:	4.19
>> +Description:
>> +		This file shows the current ufs configuration descriptor with
> Should mention that it is in bytes i.e.
>
> 	This file shows the bytes of the ufs configuration descriptor with
Done.
>
>> +		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 in space separated format.
> "needs to be passed as bytes in space separated format"
Done.
>> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
>> index e27b4d4..a9a0a58 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 UFS_PROVISION
>> +	tristate "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..00110ea 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_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..a4d26b7
>> --- /dev/null
>> +++ b/drivers/scsi/ufs/ufs-configfs.c
>> @@ -0,0 +1,228 @@
>> +// 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 subsys ? hba : NULL;
> 'subsys' won't be null unless 'item' is null, but 'item' is passed by
> configfs, so that won't happen.  i.e. might just as well return 'hba; directly.
Done.
>> +}
>> +
>> +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 = kmalloc(desc_buf_len, GFP_KERNEL);
>> +	if (!desc_buf)
>> +		return -ENOMEM;
>> +
>> +	memset(desc_buf, 0, desc_buf_len);
> Just use kzalloc
Agree. will update.
>> +
>> +	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
>> +	QUERY_DESC_IDN_CONFIGURATION, index, 0, desc_buf, &desc_buf_len);
> Indenting
Done.
>> +
> Blank line?
Done.
>> +	if (ret)
>> +		return ret;
>> +
>> +	for (i = 0; i < desc_buf_len; i++)
>> +		curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
>> +				"0x%x ", desc_buf[i]);
> Free desc_buf
Done.
>> +
>> +	return 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, value;
>> +	u32 config_desc_lock = 0;
>> +
>> +	desc_buf = kmalloc(desc_buf_len, GFP_KERNEL);
>> +	if (!desc_buf)
>> +		return -ENOMEM;
>> +
>> +	memset(desc_buf, 0, desc_buf_len);
> Just use kzalloc
Done.
>> +
>> +	/* reserve one byte for null termination */
>> +	strbuf = kmalloc(count + 1, GFP_KERNEL);
>> +	if (!strbuf)
>> +		return -ENOMEM;
>> +
>> +	strbuf_copy = strbuf;
>> +	strlcpy(strbuf, buf, count + 1);
>> +
>> +	/* 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;
>> +	}
>> +
>> +	for (i = 0; i < desc_buf_len; i++) {
>> +		token = strsep(&strbuf, " ");
>> +		if (!token && i)
>> +			break;
>> +
>> +		ret = kstrtoint(token, 0, &value);
> Why not unsigned, and also why not check the value is <= 255
will use kstrtou8, which will also in-turn check for <= 255.
>> +		if (ret) {
>> +			dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
>> +				__func__, ret, token);
>> +			ret = -EINVAL;
>> +			goto out;
>> +		}
>> +		desc_buf[i] = (u8)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);
> Indenting
Done.
>> +
> Blank line?
Done.
>> +	if (!ret)
>> +		dev_info(hba->dev, "%s: UFS Configuration Descriptor %u written\n",
>> +		__func__, index);
>> +
>> +out:
>> +	kfree(strbuf_copy);
> Please arrange it so that the variable used for kfree is the same as the
> variable assigned to kmalloc.
Agree. will update.
>> +	if (ret)
>> +		return ret;
> Free desc_buf
Done.
>> +	return 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;
>> +	sprintf(cg_item->ci_namebuf, "%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 e01cdc0..608e23e 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -7711,6 +7711,7 @@ 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);
>> @@ -7965,7 +7966,7 @@ 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..a340ca8 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_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 +872,19 @@ 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_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);
>>   
>>