[PATCH V5 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 needs to be enabled for using this feature.

Usage:
1) To read current configuration descriptor :
   cat /config/ufshcd/ufs_provision
2) To provision ufs device:
   echo <config_desc_buf> > /config/ufshcd/ufs_provision

Signed-off-by: Sayali Lokhande <sayalil@xxxxxxxxxxxxxx>
---
 Documentation/ABI/testing/configfs-driver-ufs |  18 +++
 drivers/scsi/ufs/Makefile                     |   1 +
 drivers/scsi/ufs/ufs-configfs.c               | 172 ++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c                     |   2 +
 drivers/scsi/ufs/ufshcd.h                     |  19 +++
 5 files changed, 212 insertions(+)
 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..dd16842
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-driver-ufs
@@ -0,0 +1,18 @@
+What:		/config/ufshcd/ufs_provision
+Date:		Jun 2018
+KernelVersion:	4.14
+Description:
+		This file shows the current ufs configuration descriptor 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 of each configuration descriptor parameter.
+		Configuration descriptor buffer needs to be passed in space separated
+		format specificied as below:
+		echo <bLength> <bDescriptorIDN> <bConfDescContinue> <bBootEnable>
+		<bDescrAccessEn> <bInitPowerMode> <bHighPriorityLUN>
+		<bSecureRemovalType> <bInitActiveICCLevel> <wPeriodicRTCUpdate>
+		<0Bh:0Fh_ReservedAs_0> <bLUEnable> <bBootLunID> <bLUWriteProtect>
+		<bMemoryType> <dNumAllocUnits> <bDataReliability> <bLogicalBlockSize>
+		<bProvisioningType> <wContextCapabilities> <0Dh:0Fh_ReservedAs_0>
+		> /config/ufshcd/ufs_provision
diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 918f579..d438e74 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_CONFIGFS_FS) += 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..7d207fc
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-configfs.c
@@ -0,0 +1,172 @@
+// 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 ? hba : NULL;
+}
+
+static ssize_t ufs_provision_show(struct config_item *item, char *buf)
+{
+	u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
+	int buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
+	int i, ret, curr_len = 0;
+	struct ufs_hba *hba = config_item_to_hba(item);
+
+	if (!hba)
+		return snprintf(buf, PAGE_SIZE, "ufs hba is NULL!\n");
+
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+		QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &buff_len);
+
+	if (ret)
+		return snprintf(buf, PAGE_SIZE,
+		"Failed reading descriptor. desc_idn %d, opcode %x ret %d\n",
+		QUERY_DESC_IDN_CONFIGURATION,
+		UPIU_QUERY_OPCODE_READ_DESC, ret);
+
+	for (i = 0; i < buff_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 ufs_hba *hba,
+		const char *buf, size_t count)
+{
+	char *strbuf;
+	char *strbuf_copy;
+	u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
+	int buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
+	char *token;
+	int i, ret, value;
+	u32 bConfigDescrLock = 0;
+
+	/* reserve one byte for null termination */
+	strbuf = kmalloc(count + 1, GFP_KERNEL);
+	if (!strbuf)
+		return -ENOMEM;
+
+	strbuf_copy = strbuf;
+	strlcpy(strbuf, buf, count + 1);
+
+	if (!hba)
+		goto out;
+
+	/* 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, &bConfigDescrLock);
+	if (ret) {
+		dev_err(hba->dev, "%s: Failed reading bConfigDescrLock %d, cannot re-provision device!\n",
+			__func__, ret);
+		goto out;
+	}
+	if (bConfigDescrLock) {
+		dev_err(hba->dev, "%s: bConfigDescrLock already set to %u, cannot re-provision device!\n",
+		__func__, bConfigDescrLock);
+		goto out;
+	}
+
+	for (i = 0; i < QUERY_DESC_CONFIGURATION_DEF_SIZE; i++) {
+		token = strsep(&strbuf, " ");
+		if (!token && i) {
+			dev_dbg(hba->dev, "%s: token %s, i %d\n",
+				__func__, token, i);
+			break;
+		}
+
+		ret = kstrtoint(token, 0, &value);
+		if (ret) {
+			dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
+				__func__, ret, token);
+			break;
+		}
+		desc_buf[i] = (u8)value;
+		dev_dbg(hba->dev, " desc_buf[%d] 0x%x", i, desc_buf[i]);
+	}
+
+	/* Write configuration descriptor to provision ufs */
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_WRITE_DESC,
+		QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &buff_len);
+
+	if (ret)
+		dev_err(hba->dev, "%s: Failed writing descriptor. desc_idn %d, opcode %x ret %d\n",
+		__func__, QUERY_DESC_IDN_CONFIGURATION,
+		UPIU_QUERY_OPCODE_WRITE_DESC, ret);
+	else
+		dev_err(hba->dev, "%s: UFS Provisioning done, reboot now!\n",
+		__func__);
+
+out:
+	kfree(strbuf_copy);
+	return count;
+}
+
+static ssize_t ufs_provision_store(struct config_item *item,
+		const char *buf, size_t count)
+{
+	struct ufs_hba *hba = config_item_to_hba(item);
+
+	return ufshcd_desc_configfs_store(hba, buf, count);
+}
+
+static struct configfs_attribute ufshcd_attr_provision = {
+	.ca_name	= "ufs_provision",
+	.ca_mode	= 0666,
+	.ca_owner	= THIS_MODULE,
+	.show		= ufs_provision_show,
+	.store		= ufs_provision_store,
+};
+
+static struct configfs_attribute *ufshcd_attrs[] = {
+	&ufshcd_attr_provision,
+	NULL,
+};
+
+static struct config_item_type ufscfg_type = {
+	.ct_attrs	= ufshcd_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct configfs_subsystem ufscfg_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "ufshcd",
+			.ci_type = &ufscfg_type,
+		},
+	},
+};
+
+int ufshcd_configfs_init(struct ufs_hba *hba)
+{
+	int ret;
+	struct configfs_subsystem *subsys = &hba->subsys;
+
+	subsys->su_group = ufscfg_subsys.su_group;
+	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);
+
+	return ret;
+}
+
+void ufshcd_configfs_exit(void)
+{
+	configfs_unregister_subsystem(&ufscfg_subsys);
+}
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 455a6ad..fb97a42 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7684,6 +7684,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 void ufshcd_remove(struct ufs_hba *hba)
 {
 	ufs_sysfs_remove_nodes(hba->dev);
+	ufshcd_configfs_exit();
 	scsi_remove_host(hba->host);
 	/* disable interrupts */
 	ufshcd_disable_intr(hba, hba->intr_mask);
@@ -7937,6 +7938,7 @@ 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);
 
 	return 0;
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 101a75c..e9081de 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_CONFIGFS_FS
+	struct configfs_subsystem subsys;
+#endif
 	/*
 	 * This field is to keep a reference to "scsi_device" corresponding to
 	 * "UFS device" W-LU.
@@ -868,6 +872,21 @@ 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 */
+#ifdef CONFIG_CONFIGFS_FS
+int ufshcd_configfs_init(struct ufs_hba *hba);
+void ufshcd_configfs_exit(void);
+#else /* CONFIG_CONFIGFS_FS */
+int ufshcd_configfs_init(struct ufs_hba *hba)
+{
+	return 0;
+}
+
+void ufshcd_configfs_exit(void)
+{
+}
+#endif /* CONFIG_CONFIGFS_FS */
+
 int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
 	int *desc_length);
 
-- 
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