scsi: ufs: add debugfs for ufs

Adding debugfs capability for ufshcd. This patch also implements
command tag statistics enabling, disabling, printing and resetting.

Change-Id: Idea0323391029c446a0a75aa5bea7070e3ab8125
Signed-off-by: Lee Susman <lsusman@codeaurora.org>
[gbroner@codeaurora.org: fix minor merge conflict]
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
[subhashj@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>

5 files changed, 264 insertions, 0 deletions

diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 0352e47b8397..9cddfaaa60a3 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_SCSI_UFSHCD) += ufshcd.o
 obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
 obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
 obj-$(CONFIG_SCSI_UFS_TEST) += ufs_test.o
+obj-$(CONFIG_DEBUG_FS) += debugfs.o
diff --git a/drivers/scsi/ufs/debugfs.c b/drivers/scsi/ufs/debugfs.c
new file mode 100644
index 000000000000..5c515a0da3c8
--- /dev/null
+++ b/drivers/scsi/ufs/debugfs.c
@@ -0,0 +1,184 @@
+/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * UFS debugfs - add debugfs interface to the ufshcd.
+ * This is currently used for statistics collection and exporting from the
+ * UFS driver.
+ * This infrastructure can be used for debugging or direct tweaking
+ * of the driver from userspace.
+ *
+ */
+
+#include "debugfs.h"
+
+static int ufsdbg_tag_stats_show(struct seq_file *file, void *data)
+{
+	struct ufs_hba *hba = (struct ufs_hba *)file->private;
+	struct ufs_stats *ufs_stats;
+	int i;
+	int max_depth;
+	bool is_tag_empty = true;
+
+	if (!hba)
+		goto exit;
+
+	ufs_stats = &hba->ufs_stats;
+
+	if (!ufs_stats->enabled) {
+		pr_debug("%s: ufs statistics are disabled\n", __func__);
+		goto exit;
+	}
+
+	max_depth = hba->nutrs;
+
+	mutex_lock(&ufs_stats->lock);
+
+	pr_debug("%s: UFS tag statistics:\n", __func__);
+	pr_debug("%s: Max tagged command queue depth is %d",
+		__func__, max_depth);
+
+	for (i = 0 ; i < max_depth ; ++i) {
+		if (hba->ufs_stats.tag_stats[i] != 0) {
+			is_tag_empty = false;
+			seq_printf(file,
+				 "%s: Dispatched tag %d - %llu times\n",
+				__func__, i, ufs_stats->tag_stats[i]);
+
+			pr_debug("%s: Dispatched tag %d - %llu times\n",
+				__func__, i, ufs_stats->tag_stats[i]);
+		}
+	}
+	mutex_unlock(&ufs_stats->lock);
+
+	if (is_tag_empty)
+		pr_debug("%s: All tags statistics are empty", __func__);
+
+exit:
+	return 0;
+}
+
+static int ufsdbg_tag_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ufsdbg_tag_stats_show, inode->i_private);
+}
+
+static ssize_t ufsdbg_tag_stats_write(struct file *filp,
+				      const char __user *ubuf, size_t cnt,
+				       loff_t *ppos)
+{
+	struct ufs_hba *hba = filp->f_mapping->host->i_private;
+	struct ufs_stats *ufs_stats;
+	int val = 0;
+	int ret;
+
+	ret = kstrtoint_from_user(ubuf, cnt, 0, &val);
+	if (ret) {
+		dev_err(hba->dev, "%s: Invalid argument\n", __func__);
+		return ret;
+	}
+
+	ufs_stats = &hba->ufs_stats;
+	mutex_lock(&ufs_stats->lock);
+
+	if (!val) {
+		ufs_stats->enabled = false;
+		pr_debug("%s: Disabling UFS tag statistics", __func__);
+	} else {
+		ufs_stats->enabled = true;
+		pr_debug("%s: Enabling & Resetting UFS tag statistics",
+			 __func__);
+		memset(ufs_stats->tag_stats, 0,
+		       sizeof(unsigned int) * hba->nutrs);
+	}
+
+	mutex_unlock(&ufs_stats->lock);
+	return cnt;
+}
+
+static const struct file_operations ufsdbg_tag_stats_fops = {
+	.open		= ufsdbg_tag_stats_open,
+	.read		= seq_read,
+	.write		= ufsdbg_tag_stats_write,
+};
+
+static int ufshcd_init_tag_statistics(struct ufs_hba *hba)
+{
+	int ret = 0;
+
+	mutex_init(&hba->ufs_stats.lock);
+
+	hba->ufs_stats.tag_stats = kzalloc(hba->nutrs * sizeof(u64),
+					   GFP_KERNEL);
+	if (!hba->ufs_stats.tag_stats) {
+		dev_err(hba->dev,
+			"%s: Unable to allocate UFS tag_stats", __func__);
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	hba->ufs_stats.enabled = false;
+
+exit:
+	return ret;
+}
+
+void ufsdbg_add_debugfs(struct ufs_hba *hba)
+{
+	if (!hba) {
+		dev_err(hba->dev, "%s: NULL hba, exiting", __func__);
+		goto err_no_root;
+	}
+
+	hba->debugfs_files.debugfs_root = debugfs_create_dir("ufs", NULL);
+	if (IS_ERR(hba->debugfs_files.debugfs_root))
+		/* Don't complain -- debugfs just isn't enabled */
+		goto err_no_root;
+	if (!hba->debugfs_files.debugfs_root) {
+		/*
+		 * Complain -- debugfs is enabled, but it failed to
+		 * create the directory
+		 */
+		dev_err(hba->dev,
+			"%s: NULL debugfs root directory, exiting", __func__);
+		goto err_no_root;
+	}
+
+	hba->debugfs_files.tag_stats =
+		debugfs_create_file("tag_stats", S_IRUSR,
+					   hba->debugfs_files.debugfs_root, hba,
+					   &ufsdbg_tag_stats_fops);
+	if (!hba->debugfs_files.tag_stats) {
+		dev_err(hba->dev, "%s:  NULL tag stats file, exiting",
+			__func__);
+		goto err;
+	}
+
+	if (ufshcd_init_tag_statistics(hba)) {
+		dev_err(hba->dev, "%s: Error initializing tag stats",
+			__func__);
+		goto err;
+	}
+
+	return;
+
+err:
+	debugfs_remove_recursive(hba->debugfs_files.debugfs_root);
+	hba->debugfs_files.debugfs_root = NULL;
+err_no_root:
+	dev_err(hba->dev, "%s: failed to initialize debugfs\n", __func__);
+}
+
+void ufsdbg_remove_debugfs(struct ufs_hba *hba)
+{
+	debugfs_remove_recursive(hba->debugfs_files.debugfs_root);
+	kfree(hba->ufs_stats.tag_stats);
+
+}
diff --git a/drivers/scsi/ufs/debugfs.h b/drivers/scsi/ufs/debugfs.h
new file mode 100644
index 000000000000..9e6cd5d34c4c
--- /dev/null
+++ b/drivers/scsi/ufs/debugfs.h
@@ -0,0 +1,32 @@
+/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * UFS debugfs - add debugfs interface to the ufshcd.
+ * This is currently used for statistics collection and exporting from the
+ * UFS driver.
+ * This infrastructure can be used for debugging or direct tweaking
+ * of the driver from userspace.
+ *
+ */
+
+#ifndef _UFS_DEBUGFS_H
+#define _UFS_DEBUGFS_H
+
+#include <linux/debugfs.h>
+#include "ufshcd.h"
+
+#ifdef CONFIG_DEBUG_FS
+void ufsdbg_add_debugfs(struct ufs_hba *hba);
+
+void ufsdbg_remove_debugfs(struct ufs_hba *hba);
+#endif
+
+#endif /* End of Header */
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 65da78e0d3f7..ea4273c34999 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -42,6 +42,28 @@
 
 #include "ufshcd.h"
 #include "unipro.h"
+#include "debugfs.h"
+
+#ifdef CONFIG_DEBUG_FS
+#define UFSHCD_UPDATE_TAG_STATS(hba, tag)			\
+	do {							\
+		if (hba->ufs_stats.enabled) {			\
+			mutex_lock(&hba->ufs_stats.lock);	\
+			hba->ufs_stats.tag_stats[tag]++;	\
+			mutex_unlock(&hba->ufs_stats.lock);	\
+		}						\
+	} while (0);
+
+#define UFSDBG_ADD_DEBUGFS(hba)		ufsdbg_add_debugfs(hba);
+
+#define UFSDBG_REMOVE_DEBUGFS(hba)	ufsdbg_remove_debugfs(hba);
+
+#else
+#define UFSHCD_UPDATE_TAG_STATS(hba, tag)	do {} while (0);
+#define UFSDBG_ADD_DEBUGFS(hba)		do {} while (0);
+#define UFSDBG_REMOVE_DEBUGFS(hba)		do {} while (0);
+
+#endif
 
 #define UFSHCD_ENABLE_INTRS	(UTP_TRANSFER_REQ_COMPL |\
 				 UTP_TASK_REQ_COMPL |\
@@ -802,6 +824,7 @@ void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag)
 	ufshcd_clk_scaling_start_busy(hba);
 	__set_bit(task_tag, &hba->outstanding_reqs);
 	ufshcd_writel(hba, 1 << task_tag, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+	UFSHCD_UPDATE_TAG_STATS(hba, task_tag)
 }
 
 /**
@@ -5656,6 +5679,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 
 	async_schedule(ufshcd_async_scan, hba);
 
+	UFSDBG_ADD_DEBUGFS(hba)
+
 	return 0;
 
 out_remove_scsi_host:
@@ -5665,6 +5690,7 @@ exit_gating:
 out_disable:
 	hba->is_irq_enabled = false;
 	scsi_host_put(host);
+	UFSDBG_REMOVE_DEBUGFS(hba)
 	ufshcd_hba_exit(hba);
 out_error:
 	return err;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 2570d9477b37..ebc0996735fc 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -333,6 +333,19 @@ struct ufs_init_prefetch {
 	u32 icc_level;
 };
 
+#ifdef CONFIG_DEBUG_FS
+struct ufs_stats {
+	u64 *tag_stats;
+	struct mutex lock;
+	bool enabled;
+};
+
+struct debugfs_files {
+	struct dentry *debugfs_root;
+	struct dentry *tag_stats;
+};
+#endif
+
 /**
  * struct ufs_hba - per adapter private structure
  * @mmio_base: UFSHCI base register address
@@ -378,6 +391,8 @@ struct ufs_init_prefetch {
  * @dev_cmd: ufs device management command information
  * @last_dme_cmd_tstamp: time stamp of the last completed DME command
  * @auto_bkops_enabled: to track whether bkops is enabled in device
+ * @ufs_stats: ufshcd statistics to be used via debugfs
+ * @debugfs_files: debugfs files associated with the ufs stats
  * @vreg_info: UFS device voltage regulator information
  * @clk_list_head: UFS host controller clocks list node head
  * @pwr_info: holds current power mode
@@ -503,6 +518,12 @@ struct ufs_hba {
 	/* Keeps information of the UFS device connected to this host */
 	struct ufs_dev_info dev_info;
 	bool auto_bkops_enabled;
+
+#ifdef CONFIG_DEBUG_FS
+	struct ufs_stats ufs_stats;
+	struct debugfs_files debugfs_files;
+#endif
+
 	struct ufs_vreg_info vreg_info;
 	struct list_head clk_list_head;