[RESEND RFC PATCH v4 0/3] ufs: exynos: introduce the way to get cmd info

[RESEND RFC PATCH v4 0/3] ufs: exynos: introduce the way to get cmd info

[Kiwoong Kim]

v3 -> v4
seperate respective implementations of the callbacks
change the location of compl_xfer_req related stuffs
fix null pointer access

v2 -> v3
fix build errors

v1 -> v2
change callbacks
allocate memory for ufs_s_dbg_mgr dynamically, not static way


Kiwoong Kim (3):
  ufs: introduce a callback to get info of command completion
  ufs: exynos: introduce command history
  ufs: exynos: implement dbg_register_dump

 drivers/scsi/ufs/Kconfig          |  14 +++
 drivers/scsi/ufs/Makefile         |   2 +-
 drivers/scsi/ufs/ufs-exynos-dbg.c | 201 ++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufs-exynos-if.h  |  17 ++++
 drivers/scsi/ufs/ufs-exynos.c     |  61 ++++++++++++
 drivers/scsi/ufs/ufs-exynos.h     |  12 +++
 drivers/scsi/ufs/ufshcd.c         |   2 +
 drivers/scsi/ufs/ufshcd.h         |   8 ++
 8 files changed, 316 insertions(+), 1 deletion(-)
 create mode 100644 drivers/scsi/ufs/ufs-exynos-dbg.c
 create mode 100644 drivers/scsi/ufs/ufs-exynos-if.h

-- 
2.7.4

[RESEND RFC PATCH v4 1/3] ufs: introduce a callback to get info of command completion

[Kiwoong Kim]

Some SoC specific might need command history for
various reasons, such as stacking command contexts
in system memory to check for debugging in the future
or scaling some DVFS knobs to boost IO throughput.

What you would do with the information could be
variant per SoC vendor.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
Acked-By: Stanley Chu <stanley.chu@mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 2 ++
 drivers/scsi/ufs/ufshcd.h | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 52abe82..3326236 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4882,6 +4882,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
 	for_each_set_bit(index, &completed_reqs, hba->nutrs) {
 		lrbp = &hba->lrb[index];
 		cmd = lrbp->cmd;
+		ufshcd_vops_compl_xfer_req(hba, index, (cmd) ? true : false);
 		if (cmd) {
 			ufshcd_add_command_trace(hba, index, "complete");
 			result = ufshcd_transfer_rsp_status(hba, lrbp);
@@ -4890,6 +4891,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
 			/* Mark completed command as NULL in LRB */
 			lrbp->cmd = NULL;
 			lrbp->compl_time_stamp = ktime_get();
+
 			/* Do not touch lrbp after scsi done */
 			cmd->scsi_done(cmd);
 			__ufshcd_release(hba);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index c774012..e5353d6 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -294,6 +294,7 @@ struct ufs_hba_variant_ops {
 					struct ufs_pa_layer_attr *,
 					struct ufs_pa_layer_attr *);
 	void	(*setup_xfer_req)(struct ufs_hba *, int, bool);
+	void	(*compl_xfer_req)(struct ufs_hba *hba, int tag, bool is_scsi);
 	void	(*setup_task_mgmt)(struct ufs_hba *, int, u8);
 	void    (*hibern8_notify)(struct ufs_hba *, enum uic_cmd_dme,
 					enum ufs_notify_change_status);
@@ -1070,6 +1071,13 @@ static inline void ufshcd_vops_setup_xfer_req(struct ufs_hba *hba, int tag,
 		return hba->vops->setup_xfer_req(hba, tag, is_scsi_cmd);
 }
 
+static inline void ufshcd_vops_compl_xfer_req(struct ufs_hba *hba,
+					      int tag, bool is_scsi)
+{
+	if (hba->vops && hba->vops->compl_xfer_req)
+		hba->vops->compl_xfer_req(hba, tag, is_scsi);
+}
+
 static inline void ufshcd_vops_setup_task_mgmt(struct ufs_hba *hba,
 					int tag, u8 tm_function)
 {
-- 
2.7.4

RE: [RESEND RFC PATCH v4 1/3] ufs: introduce a callback to get info of command completion

[Avri Altman]

 
> 
> Some SoC specific might need command history for
> various reasons, such as stacking command contexts
> in system memory to check for debugging in the future
> or scaling some DVFS knobs to boost IO throughput.
> 
> What you would do with the information could be
> variant per SoC vendor.
> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> Acked-By: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>

It will require another spin however, because you'll need to rebase it
After Stanley's (scsi: ufs: Fix and simplify setup_xfer_req vop and request's completion timestamp)
Is accepted.

Thanks,
Avri

RE: [RESEND RFC PATCH v4 1/3] ufs: introduce a callback to get info of command completion

[Kiwoong Kim]

> > Some SoC specific might need command history for various reasons, such
> > as stacking command contexts in system memory to check for debugging
> > in the future or scaling some DVFS knobs to boost IO throughput.
> >
> > What you would do with the information could be variant per SoC
> > vendor.
> >
> > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> > Acked-By: Stanley Chu <stanley.chu@mediatek.com>
> Reviewed-by: Avri Altman <avri.altman@wdc.com>
> 
> It will require another spin however, because you'll need to rebase it
> After Stanley's (scsi: ufs: Fix and simplify setup_xfer_req vop and
> request's completion timestamp) Is accepted.
> 
> Thanks,
> Avri

Got it.
And is there any way that you can recommend to rebase, not by hand?
I tried to find how but failed.

Thanks.
Kiwoong Kim

[RESEND RFC PATCH v4 2/3] ufs: exynos: introduce command history

[Kiwoong Kim]

This includes functions 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.

This patch also implements callbacks compl_xfer_req
to store IO contexts at completion times.

When you turn on CONFIG_SCSI_UFS_EXYNOS_CMD_LOG,
the driver collects the information from incoming commands
in the circular queue.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/Kconfig          |  14 +++
 drivers/scsi/ufs/Makefile         |   2 +-
 drivers/scsi/ufs/ufs-exynos-dbg.c | 201 ++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufs-exynos-if.h  |  17 ++++
 drivers/scsi/ufs/ufs-exynos.c     |  37 +++++++
 drivers/scsi/ufs/ufs-exynos.h     |  12 +++
 6 files changed, 282 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/Kconfig b/drivers/scsi/ufs/Kconfig
index 8cd9026..ebab446 100644
--- a/drivers/scsi/ufs/Kconfig
+++ b/drivers/scsi/ufs/Kconfig
@@ -172,3 +172,17 @@ config SCSI_UFS_EXYNOS
 
 	  Select this if you have UFS host controller on EXYNOS chipset.
 	  If unsure, say N.
+
+config SCSI_UFS_EXYNOS_CMD_LOG
+	bool "EXYNOS specific command log"
+	default n
+	depends on SCSI_UFS_EXYNOS
+	help
+	  This selects EXYNOS specific functions to get and even print
+	  some information to see what's happening at both command
+	  issue time completion time.
+	  The information may contain gerernal things as well as
+	  EXYNOS specific, such as vendor specific hardware contexts.
+
+	  Select this if you want to get and print the information.
+	  If unsure, say N.
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..0663026
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-exynos-dbg.c
@@ -0,0 +1,201 @@
+// 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-if.h"
+
+#define MAX_CMD_LOGS    32
+
+struct cmd_data {
+	unsigned int tag;
+	unsigned int sct;
+	u64 lba;
+	u64 start_time;
+	u64 end_time;
+	u64 outstanding_reqs;
+	int retries;
+	u8 op;
+};
+
+struct ufs_cmd_info {
+	u32 total;
+	u32 last;
+	struct cmd_data data[MAX_CMD_LOGS];
+	struct cmd_data *pdata[MAX_CMD_LOGS];
+};
+
+/*
+ * This structure points out several contexts on debugging
+ * per one host instant.
+ * Now command history exists in here but later handle may
+ * contains some mmio base addresses including vendor specific
+ * regions to get hardware contexts.
+ */
+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 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%08llx, 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());
+
+#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_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 */
+	u64 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 device *dev)
+{
+	struct ufs_s_dbg_mgr *mgr;
+
+	mgr = devm_kzalloc(dev, sizeof(struct ufs_s_dbg_mgr), GFP_KERNEL);
+	if (!mgr)
+		return -ENOMEM;
+	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..c746f59
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-exynos-if.h
@@ -0,0 +1,17 @@
+/* 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_
+
+/* 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..8c60f7d 100644
--- a/drivers/scsi/ufs/ufs-exynos.c
+++ b/drivers/scsi/ufs/ufs-exynos.c
@@ -700,11 +700,31 @@ static int exynos_ufs_post_pwr_mode(struct ufs_hba *hba,
 	return 0;
 }
 
+#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
+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);
+}
+#endif
+
 static void exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
 						int tag, bool op)
 {
 	struct exynos_ufs *ufs = ufshcd_get_variant(hba);
 	u32 type;
+#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
+	struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
+
+	if (op)
+		exynos_ufs_cmd_log(hba, cmd, 1);
+#endif
 
 	type =  hci_readl(ufs, HCI_UTRL_NEXUS_TYPE);
 
@@ -714,6 +734,16 @@ static void exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
 		hci_writel(ufs, type & ~(1 << tag), HCI_UTRL_NEXUS_TYPE);
 }
 
+static void exynos_ufs_compl_xfer_req(struct ufs_hba *hba, int tag, bool op)
+{
+#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
+	struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
+
+	if (op)
+		exynos_ufs_cmd_log(hba, cmd, 2);
+#endif
+}
+
 static void exynos_ufs_specify_nexus_t_tm_req(struct ufs_hba *hba,
 						int tag, u8 func)
 {
@@ -1008,6 +1038,12 @@ 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, dev);
+	if (ret)
+		return ret;
+	spin_lock_init(&ufs->dbg_lock);
 	return 0;
 
 phy_off:
@@ -1217,6 +1253,7 @@ static struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
 	.link_startup_notify		= exynos_ufs_link_startup_notify,
 	.pwr_change_notify		= exynos_ufs_pwr_change_notify,
 	.setup_xfer_req			= exynos_ufs_specify_nexus_t_xfer_req,
+	.compl_xfer_req			= exynos_ufs_compl_xfer_req,
 	.setup_task_mgmt		= exynos_ufs_specify_nexus_t_tm_req,
 	.hibern8_notify			= exynos_ufs_hibern8_notify,
 	.suspend			= exynos_ufs_suspend,
diff --git a/drivers/scsi/ufs/ufs-exynos.h b/drivers/scsi/ufs/ufs-exynos.h
index 76d6e39..c947fd8 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 +289,11 @@ 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_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, struct device *dev);
 #endif /* _UFS_EXYNOS_H_ */
-- 
2.7.4

RE: [RESEND RFC PATCH v4 2/3] ufs: exynos: introduce command history

[Avri Altman]

 
> 
> This includes functions 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.
Maybe add one more line explaining how you are handling dump_on_oops differently

> 
> This patch also implements callbacks compl_xfer_req
> to store IO contexts at completion times.
> 
> When you turn on CONFIG_SCSI_UFS_EXYNOS_CMD_LOG,
> the driver collects the information from incoming commands
> in the circular queue.
> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> ---
>  drivers/scsi/ufs/Kconfig          |  14 +++
>  drivers/scsi/ufs/Makefile         |   2 +-
>  drivers/scsi/ufs/ufs-exynos-dbg.c | 201
> ++++++++++++++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufs-exynos-if.h  |  17 ++++
>  drivers/scsi/ufs/ufs-exynos.c     |  37 +++++++
>  drivers/scsi/ufs/ufs-exynos.h     |  12 +++
>  6 files changed, 282 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/Kconfig b/drivers/scsi/ufs/Kconfig
> index 8cd9026..ebab446 100644
> --- a/drivers/scsi/ufs/Kconfig
> +++ b/drivers/scsi/ufs/Kconfig
> @@ -172,3 +172,17 @@ config SCSI_UFS_EXYNOS
> 
>           Select this if you have UFS host controller on EXYNOS chipset.
>           If unsure, say N.
> +
> +config SCSI_UFS_EXYNOS_CMD_LOG
> +       bool "EXYNOS specific command log"
> +       default n
> +       depends on SCSI_UFS_EXYNOS
> +       help
> +         This selects EXYNOS specific functions to get and even print
> +         some information to see what's happening at both command
> +         issue time completion time.
> +         The information may contain gerernal things as well as
Typo: gerernal -> general

> +         EXYNOS specific, such as vendor specific hardware contexts.
> +
> +         Select this if you want to get and print the information.
> +         If unsure, say N.
> 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
If the key functionality depends on SCSI_UFS_EXYNOS_CMD_LOG,
Why not use it for make as well, and in your header as well?

>  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..0663026
> --- /dev/null
> +++ b/drivers/scsi/ufs/ufs-exynos-dbg.c
> @@ -0,0 +1,201 @@
> +// 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-if.h"
> +
> +#define MAX_CMD_LOGS    32
> +
> +struct cmd_data {
> +       unsigned int tag;
> +       unsigned int sct;
> +       u64 lba;
> +       u64 start_time;
> +       u64 end_time;
> +       u64 outstanding_reqs;
> +       int retries;
> +       u8 op;
> +};
> +
> +struct ufs_cmd_info {
> +       u32 total;
> +       u32 last;
> +       struct cmd_data data[MAX_CMD_LOGS];
> +       struct cmd_data *pdata[MAX_CMD_LOGS];
> +};
> +
> +/*
> + * This structure points out several contexts on debugging
> + * per one host instant.
> + * Now command history exists in here but later handle may
> + * contains some mmio base addresses including vendor specific
> + * regions to get hardware contexts.
> + */
> +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 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%08llx, 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");
> +       }
> +}
Since you cache last, why not printing from first to last instead of marking it?


> +
> +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());
> +
> +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_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
> */
> +       u64 lba = (cmd->cmnd[2] << 24) |
> +                                       (cmd->cmnd[3] << 16) |
> +                                       (cmd->cmnd[4] << 8) |
> +                                       (cmd->cmnd[5] << 0);
Use put_unaligned?

> +       unsigned int sct = (cmd->cmnd[7] << 8) |
> +                                       (cmd->cmnd[8] << 0);
ditto

> +
> +       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 device
> *dev)
> +{
> +       struct ufs_s_dbg_mgr *mgr;
> +
> +       mgr = devm_kzalloc(dev, sizeof(struct ufs_s_dbg_mgr), GFP_KERNEL);
> +       if (!mgr)
> +               return -ENOMEM;
> +       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..c746f59
> --- /dev/null
> +++ b/drivers/scsi/ufs/ufs-exynos-if.h
> @@ -0,0 +1,17 @@
> +/* 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_
> +
> +/* 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..8c60f7d 100644
> --- a/drivers/scsi/ufs/ufs-exynos.c
> +++ b/drivers/scsi/ufs/ufs-exynos.c
> @@ -700,11 +700,31 @@ static int exynos_ufs_post_pwr_mode(struct
> ufs_hba *hba,
>         return 0;
>  }
> 
> +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
> +static void exynos_ufs_cmd_log(struct ufs_hba *hba,
> +                              struct scsi_cmnd *cmd, int enter)
Maybe make it static inline in you header, e.g. ufs-exynos-if.h,
And make it empty if CONFIG_SCSI_UFS_EXYNOS_CMD_LOG is not defined?

> +{
> +       struct exynos_ufs *ufs = ufshcd_get_variant(hba);
> +       struct ufs_exynos_handle *handle = &ufs->handle;
> +
> +       if (enter == 1)
Maybe use "start" instead of "enter"
If (start)
   ....
else
   ....

> +               exynos_ufs_cmd_log_start(handle, hba, cmd);
> +       else if (enter == 2)
> +               exynos_ufs_cmd_log_end(handle, hba, cmd);
> +}
> +#endif
> +
>  static void exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
>                                                 int tag, bool op)
>  {
>         struct exynos_ufs *ufs = ufshcd_get_variant(hba);
>         u32 type;
> +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
> +       struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
> +
> +       if (op)
> +               exynos_ufs_cmd_log(hba, cmd, 1);
> +#endif
> 
>         type =  hci_readl(ufs, HCI_UTRL_NEXUS_TYPE);
> 
> @@ -714,6 +734,16 @@ static void
> exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
>                 hci_writel(ufs, type & ~(1 << tag), HCI_UTRL_NEXUS_TYPE);
>  }
> 
> +static void exynos_ufs_compl_xfer_req(struct ufs_hba *hba, int tag, bool op)
> +{
> +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
> +       struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
> +
> +       if (op)
> +               exynos_ufs_cmd_log(hba, cmd, 2);
> +#endif
> +}
> +
>  static void exynos_ufs_specify_nexus_t_tm_req(struct ufs_hba *hba,
>                                                 int tag, u8 func)
>  {
> @@ -1008,6 +1038,12 @@ 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, dev);
> +       if (ret)
> +               return ret;
> +       spin_lock_init(&ufs->dbg_lock);
>         return 0;
> 
>  phy_off:
> @@ -1217,6 +1253,7 @@ static struct ufs_hba_variant_ops
> ufs_hba_exynos_ops = {
>         .link_startup_notify            = exynos_ufs_link_startup_notify,
>         .pwr_change_notify              = exynos_ufs_pwr_change_notify,
>         .setup_xfer_req                 = exynos_ufs_specify_nexus_t_xfer_req,
> +       .compl_xfer_req                 = exynos_ufs_compl_xfer_req,
>         .setup_task_mgmt                = exynos_ufs_specify_nexus_t_tm_req,
>         .hibern8_notify                 = exynos_ufs_hibern8_notify,
>         .suspend                        = exynos_ufs_suspend,
> diff --git a/drivers/scsi/ufs/ufs-exynos.h b/drivers/scsi/ufs/ufs-exynos.h
> index 76d6e39..c947fd8 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 +289,11 @@ 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_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, struct device
> *dev);
>  #endif /* _UFS_EXYNOS_H_ */
> --
> 2.7.4

RE: [RESEND RFC PATCH v4 2/3] ufs: exynos: introduce command history

[Kiwoong Kim]

> > This includes functions 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.
> Maybe add one more line explaining how you are handling dump_on_oops
> differently

Even dump_on_oops eventually run by software, that means there is a possibility
to access system memory. I don’t assume only conditions where memory accesses
work. In abnormal cases, methods in kernel doesn't work and you just need to dump
memory in another software after resetting system with keeping data in system memory.
Dump_on_oops doesn't guarantee those situations.

> 
> >
> > This patch also implements callbacks compl_xfer_req to store IO
> > contexts at completion times.
> >
> > When you turn on CONFIG_SCSI_UFS_EXYNOS_CMD_LOG, the driver collects
> > the information from incoming commands in the circular queue.
> >
> > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> > ---
> >  drivers/scsi/ufs/Kconfig          |  14 +++
> >  drivers/scsi/ufs/Makefile         |   2 +-
> >  drivers/scsi/ufs/ufs-exynos-dbg.c | 201
> > ++++++++++++++++++++++++++++++++++++++
> >  drivers/scsi/ufs/ufs-exynos-if.h  |  17 ++++
> >  drivers/scsi/ufs/ufs-exynos.c     |  37 +++++++
> >  drivers/scsi/ufs/ufs-exynos.h     |  12 +++
> >  6 files changed, 282 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/Kconfig b/drivers/scsi/ufs/Kconfig index
> > 8cd9026..ebab446 100644
> > --- a/drivers/scsi/ufs/Kconfig
> > +++ b/drivers/scsi/ufs/Kconfig
> > @@ -172,3 +172,17 @@ config SCSI_UFS_EXYNOS
> >
> >           Select this if you have UFS host controller on EXYNOS chipset.
> >           If unsure, say N.
> > +
> > +config SCSI_UFS_EXYNOS_CMD_LOG
> > +       bool "EXYNOS specific command log"
> > +       default n
> > +       depends on SCSI_UFS_EXYNOS
> > +       help
> > +         This selects EXYNOS specific functions to get and even print
> > +         some information to see what's happening at both command
> > +         issue time completion time.
> > +         The information may contain gerernal things as well as
> Typo: gerernal -> general
Got it

> 
> > +         EXYNOS specific, such as vendor specific hardware contexts.
> > +
> > +         Select this if you want to get and print the information.
> > +         If unsure, say N.
> > 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
> If the key functionality depends on SCSI_UFS_EXYNOS_CMD_LOG, Why not use
> it for make as well, and in your header as well?
> 
> >  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..0663026
> > --- /dev/null
> > +++ b/drivers/scsi/ufs/ufs-exynos-dbg.c
> > @@ -0,0 +1,201 @@
> > +// 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-if.h"
> > +
> > +#define MAX_CMD_LOGS    32
> > +
> > +struct cmd_data {
> > +       unsigned int tag;
> > +       unsigned int sct;
> > +       u64 lba;
> > +       u64 start_time;
> > +       u64 end_time;
> > +       u64 outstanding_reqs;
> > +       int retries;
> > +       u8 op;
> > +};
> > +
> > +struct ufs_cmd_info {
> > +       u32 total;
> > +       u32 last;
> > +       struct cmd_data data[MAX_CMD_LOGS];
> > +       struct cmd_data *pdata[MAX_CMD_LOGS]; };
> > +
> > +/*
> > + * This structure points out several contexts on debugging
> > + * per one host instant.
> > + * Now command history exists in here but later handle may
> > + * contains some mmio base addresses including vendor specific
> > + * regions to get hardware contexts.
> > + */
> > +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 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%08llx, 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");
> > +       }
> > +}
> Since you cache last, why not printing from first to last instead of
> marking it?
Got it and this looks that because it's easy to make.

> 
> 
> > +
> > +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());
> > +
> > +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_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
> > */
> > +       u64 lba = (cmd->cmnd[2] << 24) |
> > +                                       (cmd->cmnd[3] << 16) |
> > +                                       (cmd->cmnd[4] << 8) |
> > +                                       (cmd->cmnd[5] << 0);
> Use put_unaligned?
> 
> > +       unsigned int sct = (cmd->cmnd[7] << 8) |
> > +                                       (cmd->cmnd[8] << 0);
> ditto
> 
Got it.

> > +
> > +       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
> > +device
> > *dev)
> > +{
> > +       struct ufs_s_dbg_mgr *mgr;
> > +
> > +       mgr = devm_kzalloc(dev, sizeof(struct ufs_s_dbg_mgr), GFP_KERNEL);
> > +       if (!mgr)
> > +               return -ENOMEM;
> > +       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..c746f59
> > --- /dev/null
> > +++ b/drivers/scsi/ufs/ufs-exynos-if.h
> > @@ -0,0 +1,17 @@
> > +/* 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_
> > +
> > +/* 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..8c60f7d 100644
> > --- a/drivers/scsi/ufs/ufs-exynos.c
> > +++ b/drivers/scsi/ufs/ufs-exynos.c
> > @@ -700,11 +700,31 @@ static int exynos_ufs_post_pwr_mode(struct
> > ufs_hba *hba,
> >         return 0;
> >  }
> >
> > +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG static void
> > +exynos_ufs_cmd_log(struct ufs_hba *hba,
> > +                              struct scsi_cmnd *cmd, int enter)
> Maybe make it static inline in you header, e.g. ufs-exynos-if.h, And make
> it empty if CONFIG_SCSI_UFS_EXYNOS_CMD_LOG is not defined?
> 
> > +{
> > +       struct exynos_ufs *ufs = ufshcd_get_variant(hba);
> > +       struct ufs_exynos_handle *handle = &ufs->handle;
> > +
> > +       if (enter == 1)
> Maybe use "start" instead of "enter"
> If (start)
>    ....
> else
>    ....
Got it.

> 
> > +               exynos_ufs_cmd_log_start(handle, hba, cmd);
> > +       else if (enter == 2)
> > +               exynos_ufs_cmd_log_end(handle, hba, cmd); } #endif
> > +
> >  static void exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
> >                                                 int tag, bool op)  {
> >         struct exynos_ufs *ufs = ufshcd_get_variant(hba);
> >         u32 type;
> > +#ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
> > +       struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
> > +
> > +       if (op)
> > +               exynos_ufs_cmd_log(hba, cmd, 1); #endif
> >
> >         type =  hci_readl(ufs, HCI_UTRL_NEXUS_TYPE);
> >
> > @@ -714,6 +734,16 @@ static void
> > exynos_ufs_specify_nexus_t_xfer_req(struct ufs_hba *hba,
> >                 hci_writel(ufs, type & ~(1 << tag),
> > HCI_UTRL_NEXUS_TYPE);  }
> >
> > +static void exynos_ufs_compl_xfer_req(struct ufs_hba *hba, int tag,
> > +bool op) { #ifdef CONFIG_SCSI_UFS_EXYNOS_CMD_LOG
> > +       struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
> > +
> > +       if (op)
> > +               exynos_ufs_cmd_log(hba, cmd, 2); #endif }
> > +
> >  static void exynos_ufs_specify_nexus_t_tm_req(struct ufs_hba *hba,
> >                                                 int tag, u8 func)  {
> > @@ -1008,6 +1038,12 @@ 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, dev);
> > +       if (ret)
> > +               return ret;
> > +       spin_lock_init(&ufs->dbg_lock);
> >         return 0;
> >
> >  phy_off:
> > @@ -1217,6 +1253,7 @@ static struct ufs_hba_variant_ops
> > ufs_hba_exynos_ops = {
> >         .link_startup_notify            = exynos_ufs_link_startup_notify,
> >         .pwr_change_notify              = exynos_ufs_pwr_change_notify,
> >         .setup_xfer_req                 = exynos_ufs_specify_nexus_t_xfer_req,
> > +       .compl_xfer_req                 = exynos_ufs_compl_xfer_req,
> >         .setup_task_mgmt                = exynos_ufs_specify_nexus_t_tm_req,
> >         .hibern8_notify                 = exynos_ufs_hibern8_notify,
> >         .suspend                        = exynos_ufs_suspend,
> > diff --git a/drivers/scsi/ufs/ufs-exynos.h
> > b/drivers/scsi/ufs/ufs-exynos.h index 76d6e39..c947fd8 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 +289,11 @@ 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_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,
> > +struct device
> > *dev);
> >  #endif /* _UFS_EXYNOS_H_ */
> > --
> > 2.7.4



Thanks.
Kiwoong Kim

RE: [RESEND RFC PATCH v4 2/3] ufs: exynos: introduce command history

[Kiwoong Kim]

> > +         EXYNOS specific, such as vendor specific hardware contexts.
> > +
> > +         Select this if you want to get and print the information.
> > +         If unsure, say N.
> > 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
> If the key functionality depends on SCSI_UFS_EXYNOS_CMD_LOG, Why not use
> it for make as well, and in your header as well? 
I assume somebody including me will add dumping vendor register or another item 
in the file. That's why I did.
But currently, you're right and I will do.

Thanks.
Kiwoong Kim

[RESEND RFC PATCH v4 3/3] ufs: exynos: implement dbg_register_dump

[Kiwoong Kim]

At present, I just add command history print and
you can add various vendor regions.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/ufs-exynos.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
index 8c60f7d..815c361 100644
--- a/drivers/scsi/ufs/ufs-exynos.c
+++ b/drivers/scsi/ufs/ufs-exynos.c
@@ -1246,6 +1246,29 @@ 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 struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
 	.name				= "exynos_ufs",
 	.init				= exynos_ufs_init,
@@ -1258,6 +1281,7 @@ 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,
 };
 
 static int exynos_ufs_probe(struct platform_device *pdev)
-- 
2.7.4

RE: [RESEND RFC PATCH v4 3/3] ufs: exynos: implement dbg_register_dump

[Avri Altman]

 
> 
> At present, I just add command history print and
> you can add various vendor regions.
> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> ---
>  drivers/scsi/ufs/ufs-exynos.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
> index 8c60f7d..815c361 100644
> --- a/drivers/scsi/ufs/ufs-exynos.c
> +++ b/drivers/scsi/ufs/ufs-exynos.c
> @@ -1246,6 +1246,29 @@ 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)
If you would use test_and_set_bit it would save you both under_dump and dbg_lock ?

> +               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 struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
>         .name                           = "exynos_ufs",
>         .init                           = exynos_ufs_init,
> @@ -1258,6 +1281,7 @@ 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,
>  };
> 
>  static int exynos_ufs_probe(struct platform_device *pdev)
> --
> 2.7.4

RE: [RESEND RFC PATCH v4 3/3] ufs: exynos: implement dbg_register_dump

[Kiwoong Kim]

> > +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)
> If you would use test_and_set_bit it would save you both under_dump and
> dbg_lock ?


Great. Got it.

Thanks.
Kiwoong Kim

Re: [RESEND RFC PATCH v4 3/3] ufs: exynos: implement dbg_register_dump

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2445 bytes --]

Hi Kiwoong,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on scsi/for-next]
[cannot apply to mkp-scsi/for-next v5.8-rc5 next-20200717]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Kiwoong-Kim/ufs-exynos-introduce-the-way-to-get-cmd-info/20200708-103306
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git for-next
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/scsi/ufs/ufs-exynos.c: In function 'exynos_ufs_dbg_register_dump':
>> drivers/scsi/ufs/ufs-exynos.c:1263:2: error: implicit declaration of function 'exynos_ufs_dump_info'; did you mean 'exynos_ufs_suspend'? [-Werror=implicit-function-declaration]
    1263 |  exynos_ufs_dump_info(&ufs->handle, hba->dev);
         |  ^~~~~~~~~~~~~~~~~~~~
         |  exynos_ufs_suspend
   cc1: some warnings being treated as errors

vim +1263 drivers/scsi/ufs/ufs-exynos.c

  1248	
  1249	static void exynos_ufs_dbg_register_dump(struct ufs_hba *hba)
  1250	{
  1251		struct exynos_ufs *ufs = ufshcd_get_variant(hba);
  1252		unsigned long flags;
  1253	
  1254		spin_lock_irqsave(&ufs->dbg_lock, flags);
  1255		if (ufs->under_dump == 0)
  1256			ufs->under_dump = 1;
  1257		else {
  1258			spin_unlock_irqrestore(&ufs->dbg_lock, flags);
  1259			goto out;
  1260		}
  1261		spin_unlock_irqrestore(&ufs->dbg_lock, flags);
  1262	
> 1263		exynos_ufs_dump_info(&ufs->handle, hba->dev);
  1264	
  1265		spin_lock_irqsave(&ufs->dbg_lock, flags);
  1266		ufs->under_dump = 0;
  1267		spin_unlock_irqrestore(&ufs->dbg_lock, flags);
  1268	out:
  1269		return;
  1270	}
  1271	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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