[RFC PATCH v1 2/2] exynos-ufs: support command history

[Kiwoong Kim <kwmad.kim@samsung.com>]

This patch is to record contexts of incoming commands
in a circular queue. ufshcd.c has already some function
tracer calls to get command history but ftrace would be
gone when system dies before you get the information,
such as panic cases.

Setting EN_PRINT_UFS_LOG to one enables to print
information in the circular queue whenever ufshcd.c
invokes a dbg_register_dump callback.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/Makefile         |   2 +-
 drivers/scsi/ufs/ufs-exynos-dbg.c | 208 ++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufs-exynos-if.h  |  19 ++++
 drivers/scsi/ufs/ufs-exynos.c     |  43 ++++++++
 drivers/scsi/ufs/ufs-exynos.h     |  13 +++
 5 files changed, 284 insertions(+), 1 deletion(-)
 create mode 100644 drivers/scsi/ufs/ufs-exynos-dbg.c
 create mode 100644 drivers/scsi/ufs/ufs-exynos-if.h

diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index f0c5b95..d9e4da7 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -4,7 +4,7 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o tc-dwc-g210.
 obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-dwc-g210.o
 obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
 obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
-obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
+obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o ufs-exynos-dbg.o
 obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
 ufshcd-core-y				+= ufshcd.o ufs-sysfs.o
 ufshcd-core-$(CONFIG_SCSI_UFS_BSG)	+= ufs_bsg.o
diff --git a/drivers/scsi/ufs/ufs-exynos-dbg.c b/drivers/scsi/ufs/ufs-exynos-dbg.c
new file mode 100644
index 0000000..2265af7
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-exynos-dbg.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * UFS Exynos debugging functions
+ *
+ * Copyright (C) 2020 Samsung Electronics Co., Ltd.
+ * Author: Kiwoong Kim <kwmad.kim@samsung.com>
+ *
+ */
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include "ufshcd.h"
+#include "ufs-exynos.h"
+#include "ufs-exynos-if.h"
+
+#define EN_PRINT_UFS_LOG 1
+
+/* Structure for ufs cmd logging */
+#define MAX_CMD_LOGS    32
+
+struct cmd_data {
+	unsigned int tag;
+	unsigned int sct;
+	unsigned long lba;
+	u64 start_time;
+	u64 end_time;
+	u64 outstanding_reqs;
+	int retries;
+	unsigned char op;
+};
+
+struct ufs_cmd_info {
+	u32 total;
+	u32 last;
+	struct cmd_data data[MAX_CMD_LOGS];
+	struct cmd_data *pdata[32];	/* Currently, 32 slots */
+};
+
+#define DBG_NUM_OF_HOSTS	1
+struct ufs_s_dbg_mgr {
+	struct ufs_exynos_handle *handle;
+	int active;
+	u64 first_time;
+	u64 time;
+
+	/* cmd log */
+	struct ufs_cmd_info cmd_info;
+	struct cmd_data cmd_log;		/* temp buffer to put */
+	spinlock_t cmd_lock;
+};
+static struct ufs_s_dbg_mgr ufs_s_dbg[DBG_NUM_OF_HOSTS];
+static int ufs_s_dbg_mgr_idx;
+
+static void ufs_s_print_cmd_log(struct ufs_s_dbg_mgr *mgr, struct device *dev)
+{
+	struct ufs_cmd_info *cmd_info = &mgr->cmd_info;
+	struct cmd_data *data = cmd_info->data;
+	u32 i;
+	u32 last;
+	u32 max = MAX_CMD_LOGS;
+	unsigned long flags;
+	u32 total;
+
+	spin_lock_irqsave(&mgr->cmd_lock, flags);
+	total = cmd_info->total;
+	if (cmd_info->total < max)
+		max = cmd_info->total;
+	last = (cmd_info->last + MAX_CMD_LOGS - 1) % MAX_CMD_LOGS;
+	spin_unlock_irqrestore(&mgr->cmd_lock, flags);
+
+	dev_err(dev, ":---------------------------------------------------\n");
+	dev_err(dev, ":\t\tSCSI CMD(%u)\n", total - 1);
+	dev_err(dev, ":---------------------------------------------------\n");
+	dev_err(dev, ":OP, TAG, LBA, SCT, RETRIES, STIME, ETIME, REQS\n\n");
+
+	for (i = 0 ; i < max ; i++, data++) {
+		dev_err(dev, ": 0x%02x, %02d, 0x%08lx, 0x%04x, %d, %llu, %llu, 0x%llx %s",
+				data->op,
+				data->tag,
+				data->lba,
+				data->sct,
+				data->retries,
+				data->start_time,
+				data->end_time,
+				data->outstanding_reqs,
+				((last == i) ? "<--" : " "));
+		if (last == i)
+			dev_err(dev, "\n");
+	}
+}
+
+static void ufs_s_put_cmd_log(struct ufs_s_dbg_mgr *mgr,
+			      struct cmd_data *cmd_data)
+{
+	struct ufs_cmd_info *cmd_info = &mgr->cmd_info;
+	unsigned long flags;
+	struct cmd_data *pdata;
+
+	spin_lock_irqsave(&mgr->cmd_lock, flags);
+	pdata = &cmd_info->data[cmd_info->last];
+	++cmd_info->total;
+	++cmd_info->last;
+	cmd_info->last = cmd_info->last % MAX_CMD_LOGS;
+	spin_unlock_irqrestore(&mgr->cmd_lock, flags);
+
+	pdata->op = cmd_data->op;
+	pdata->tag = cmd_data->tag;
+	pdata->lba = cmd_data->lba;
+	pdata->sct = cmd_data->sct;
+	pdata->retries = cmd_data->retries;
+	pdata->start_time = cmd_data->start_time;
+	pdata->end_time = 0;
+	pdata->outstanding_reqs = cmd_data->outstanding_reqs;
+	cmd_info->pdata[cmd_data->tag] = pdata;
+}
+
+/*
+ * EXTERNAL FUNCTIONS
+ *
+ * There are two classes that are to initialize data structures for debug
+ * and to define actual behavior.
+ */
+void exynos_ufs_dump_info(struct ufs_exynos_handle *handle, struct device *dev)
+{
+	struct ufs_s_dbg_mgr *mgr = (struct ufs_s_dbg_mgr *)handle->private;
+
+	if (mgr->active == 0)
+		goto out;
+
+	mgr->time = cpu_clock(raw_smp_processor_id());
+
+#if EN_PRINT_UFS_LOG
+	ufs_s_print_cmd_log(mgr, dev);
+#endif
+
+	if (mgr->first_time == 0ULL)
+		mgr->first_time = mgr->time;
+out:
+	return;
+}
+
+void exynos_ufs_cmd_log_start(struct ufs_exynos_handle *handle,
+			      struct ufs_hba *hba, struct scsi_cmnd *cmd)
+{
+	struct ufs_s_dbg_mgr *mgr = (struct ufs_s_dbg_mgr *)handle->private;
+	int cpu = raw_smp_processor_id();
+	struct cmd_data *cmd_log = &mgr->cmd_log;	/* temp buffer to put */
+	unsigned long lba = (cmd->cmnd[2] << 24) |
+					(cmd->cmnd[3] << 16) |
+					(cmd->cmnd[4] << 8) |
+					(cmd->cmnd[5] << 0);
+	unsigned int sct = (cmd->cmnd[7] << 8) |
+					(cmd->cmnd[8] << 0);
+
+	if (mgr->active == 0)
+		return;
+
+	cmd_log->start_time = cpu_clock(cpu);
+	cmd_log->op = cmd->cmnd[0];
+	cmd_log->tag = cmd->request->tag;
+
+	/* This function runtime is protected by spinlock from outside */
+	cmd_log->outstanding_reqs = hba->outstanding_reqs;
+
+	/* unmap */
+	if (cmd->cmnd[0] != UNMAP)
+		cmd_log->lba = lba;
+
+	cmd_log->sct = sct;
+	cmd_log->retries = cmd->allowed;
+
+	ufs_s_put_cmd_log(mgr, cmd_log);
+}
+
+void exynos_ufs_cmd_log_end(struct ufs_exynos_handle *handle,
+			    struct ufs_hba *hba, struct scsi_cmnd *cmd)
+{
+	struct ufs_s_dbg_mgr *mgr = (struct ufs_s_dbg_mgr *)handle->private;
+	struct ufs_cmd_info *cmd_info = &mgr->cmd_info;
+	int cpu = raw_smp_processor_id();
+	int tag = cmd->request->tag;
+
+	if (mgr->active == 0)
+		return;
+
+	cmd_info->pdata[tag]->end_time = cpu_clock(cpu);
+}
+
+int exynos_ufs_init_dbg(struct ufs_exynos_handle *handle)
+{
+	struct ufs_s_dbg_mgr *mgr;
+
+	if (ufs_s_dbg_mgr_idx >= DBG_NUM_OF_HOSTS)
+		return -1;
+
+	mgr = &ufs_s_dbg[ufs_s_dbg_mgr_idx++];
+	handle->private = (void *)mgr;
+	mgr->handle = handle;
+	mgr->active = 1;
+
+	/* cmd log */
+	spin_lock_init(&mgr->cmd_lock);
+
+	return 0;
+}
+MODULE_AUTHOR("Kiwoong Kim <kwmad.kim@samsung.com>");
+MODULE_DESCRIPTION("Exynos UFS debug information");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");
diff --git a/drivers/scsi/ufs/ufs-exynos-if.h b/drivers/scsi/ufs/ufs-exynos-if.h
new file mode 100644
index 0000000..33f7187
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-exynos-if.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * UFS Exynos debugging functions
+ *
+ * Copyright (C) 2020 Samsung Electronics Co., Ltd.
+ * Author: Kiwoong Kim <kwmad.kim@samsung.com>
+ *
+ */
+#ifndef _UFS_EXYNOS_IF_H_
+#define _UFS_EXYNOS_IF_H_
+
+#define UFS_VS_MMIO_VER 1
+
+/* more members would be added in the future */
+struct ufs_exynos_handle {
+	void *private;
+};
+
+#endif /* _UFS_EXYNOS_IF_H_ */
diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
index 440f2af..50437db 100644
--- a/drivers/scsi/ufs/ufs-exynos.c
+++ b/drivers/scsi/ufs/ufs-exynos.c
@@ -1008,6 +1008,12 @@ static int exynos_ufs_init(struct ufs_hba *hba)
 		goto out;
 	exynos_ufs_specify_phy_time_attr(ufs);
 	exynos_ufs_config_smu(ufs);
+
+	/* init dbg */
+	ret = exynos_ufs_init_dbg(ufs->handle);
+	if (ret)
+		return ret;
+	spin_lock_init(&ufs->dbg_lock);
 	return 0;
 
 phy_off:
@@ -1210,6 +1216,41 @@ static int exynos_ufs_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	return 0;
 }
 
+static void exynos_ufs_dbg_register_dump(struct ufs_hba *hba)
+{
+	struct exynos_ufs *ufs = ufshcd_get_variant(hba);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ufs->dbg_lock, flags);
+	if (ufs->under_dump == 0)
+		ufs->under_dump = 1;
+	else {
+		spin_unlock_irqrestore(&ufs->dbg_lock, flags);
+		goto out;
+	}
+	spin_unlock_irqrestore(&ufs->dbg_lock, flags);
+
+	exynos_ufs_dump_info(ufs->handle, hba->dev);
+
+	spin_lock_irqsave(&ufs->dbg_lock, flags);
+	ufs->under_dump = 0;
+	spin_unlock_irqrestore(&ufs->dbg_lock, flags);
+out:
+	return;
+}
+
+static void exynos_ufs_cmd_log(struct ufs_hba *hba,
+					 struct scsi_cmnd *cmd, int enter)
+{
+	struct exynos_ufs *ufs = ufshcd_get_variant(hba);
+	struct ufs_exynos_handle *handle = ufs->handle;
+
+	if (enter == 1)
+		exynos_ufs_cmd_log_start(handle, hba, cmd);
+	else if (enter == 2)
+		exynos_ufs_cmd_log_end(handle, hba, cmd);
+}
+
 static struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
 	.name				= "exynos_ufs",
 	.init				= exynos_ufs_init,
@@ -1221,6 +1262,8 @@ static struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
 	.hibern8_notify			= exynos_ufs_hibern8_notify,
 	.suspend			= exynos_ufs_suspend,
 	.resume				= exynos_ufs_resume,
+	.dbg_register_dump		= exynos_ufs_dbg_register_dump,
+	.cmd_log			= exynos_ufs_cmd_log,
 };
 
 static int exynos_ufs_probe(struct platform_device *pdev)
diff --git a/drivers/scsi/ufs/ufs-exynos.h b/drivers/scsi/ufs/ufs-exynos.h
index 76d6e39..14347fb 100644
--- a/drivers/scsi/ufs/ufs-exynos.h
+++ b/drivers/scsi/ufs/ufs-exynos.h
@@ -8,6 +8,7 @@
 
 #ifndef _UFS_EXYNOS_H_
 #define _UFS_EXYNOS_H_
+#include "ufs-exynos-if.h"
 
 /*
  * UNIPRO registers
@@ -212,6 +213,10 @@ struct exynos_ufs {
 #define EXYNOS_UFS_OPT_BROKEN_AUTO_CLK_CTRL	BIT(2)
 #define EXYNOS_UFS_OPT_BROKEN_RX_SEL_IDX	BIT(3)
 #define EXYNOS_UFS_OPT_USE_SW_HIBERN8_TIMER	BIT(4)
+
+	struct ufs_exynos_handle *handle;
+	spinlock_t dbg_lock;
+	int under_dump;
 };
 
 #define for_each_ufs_rx_lane(ufs, i) \
@@ -284,4 +289,12 @@ struct exynos_ufs_uic_attr exynos7_uic_attr = {
 	.rx_hs_g3_prep_sync_len_cap	= PREP_LEN(0xf),
 	.pa_dbg_option_suite		= 0x30103,
 };
+
+/* public function declarations */
+void exynos_ufs_dump_info(struct ufs_exynos_handle *handle, struct device *dev);
+void exynos_ufs_cmd_log_start(struct ufs_exynos_handle *handle,
+			      struct ufs_hba *hba, struct scsi_cmnd *cmd);
+void exynos_ufs_cmd_log_end(struct ufs_exynos_handle *handle,
+			    struct ufs_hba *hba, struct scsi_cmnd *cmd);
+int exynos_ufs_init_dbg(struct ufs_exynos_handle *handle);
 #endif /* _UFS_EXYNOS_H_ */
-- 
2.7.4