2022-08-03 21:00:19

by Daniil Lunev

[permalink] [raw]
Subject: [PATCH v5] ufs: core: ufshcd: use local_clock() for debugging timestamps

CLOCK_MONOTONIC is not advanced when the system is in suspend. This
becomes problematic when debugging issues related to suspend-resume:
the timestamps printed by ufshcd_print_trs can not be correlated with
dmesg entries, which are timestamped with local_clock().

This CL changes the used clock to local_clock() for the informational
timestamp variables and adds mirroring *_local_clock instances for
variables used in subsequent derevations (to not change the semantics of
those derevations).

Signed-off-by: Daniil Lunev <[email protected]>
Acked-by: Stanley Chu <[email protected]>
Acked-by: Avri Altman <[email protected]>

---

Changes in v5:
- Bring over "acks" from the previous iterations

Changes in v4:
- Use div_u64 instead of "/"

Changes in v3:
- Add missing header

Changes in v2:
- Use local clock to better align with dmesg
- Correct commit message

drivers/ufs/core/ufshcd.c | 20 ++++++++++++--------
include/ufs/ufshcd.h | 14 +++++++++-----
2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index ce86d1b790c05..3b3c011d81e36 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -21,6 +21,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
+#include <linux/sched/clock.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_driver.h>
@@ -460,7 +461,7 @@ static void ufshcd_print_evt(struct ufs_hba *hba, u32 id,
if (e->tstamp[p] == 0)
continue;
dev_err(hba->dev, "%s[%d] = 0x%x at %lld us\n", err_name, p,
- e->val[p], ktime_to_us(e->tstamp[p]));
+ e->val[p], div_u64(e->tstamp[p], 1000));
found = true;
}

@@ -505,9 +506,9 @@ void ufshcd_print_trs(struct ufs_hba *hba, unsigned long bitmap, bool pr_prdt)
lrbp = &hba->lrb[tag];

dev_err(hba->dev, "UPIU[%d] - issue time %lld us\n",
- tag, ktime_to_us(lrbp->issue_time_stamp));
+ tag, div_u64(lrbp->issue_time_stamp_local_clock, 1000));
dev_err(hba->dev, "UPIU[%d] - complete time %lld us\n",
- tag, ktime_to_us(lrbp->compl_time_stamp));
+ tag, div_u64(lrbp->compl_time_stamp_local_clock, 1000));
dev_err(hba->dev,
"UPIU[%d] - Transfer Request Descriptor phys@0x%llx\n",
tag, (u64)lrbp->utrd_dma_addr);
@@ -569,10 +570,10 @@ static void ufshcd_print_host_state(struct ufs_hba *hba)
dev_err(hba->dev, "Clk gate=%d\n", hba->clk_gating.state);
dev_err(hba->dev,
"last_hibern8_exit_tstamp at %lld us, hibern8_exit_cnt=%d\n",
- ktime_to_us(hba->ufs_stats.last_hibern8_exit_tstamp),
+ div_u64(hba->ufs_stats.last_hibern8_exit_tstamp, 1000),
hba->ufs_stats.hibern8_exit_cnt);
dev_err(hba->dev, "last intr at %lld us, last intr status=0x%x\n",
- ktime_to_us(hba->ufs_stats.last_intr_ts),
+ div_u64(hba->ufs_stats.last_intr_ts, 1000),
hba->ufs_stats.last_intr_status);
dev_err(hba->dev, "error handling flags=0x%x, req. abort count=%d\n",
hba->eh_flags, hba->req_abort_count);
@@ -2142,7 +2143,9 @@ void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag)
unsigned long flags;

lrbp->issue_time_stamp = ktime_get();
+ lrbp->issue_time_stamp_local_clock = local_clock();
lrbp->compl_time_stamp = ktime_set(0, 0);
+ lrbp->compl_time_stamp_local_clock = 0;
ufshcd_add_command_trace(hba, task_tag, UFS_CMD_SEND);
ufshcd_clk_scaling_start_busy(hba);
if (unlikely(ufshcd_should_inform_monitor(hba, lrbp)))
@@ -4199,7 +4202,7 @@ int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
} else {
ufshcd_vops_hibern8_notify(hba, UIC_CMD_DME_HIBER_EXIT,
POST_CHANGE);
- hba->ufs_stats.last_hibern8_exit_tstamp = ktime_get();
+ hba->ufs_stats.last_hibern8_exit_tstamp = local_clock();
hba->ufs_stats.hibern8_exit_cnt++;
}

@@ -4696,7 +4699,7 @@ void ufshcd_update_evt_hist(struct ufs_hba *hba, u32 id, u32 val)

e = &hba->ufs_stats.event[id];
e->val[e->pos] = val;
- e->tstamp[e->pos] = ktime_get();
+ e->tstamp[e->pos] = local_clock();
e->cnt += 1;
e->pos = (e->pos + 1) % UFS_EVENT_HIST_LENGTH;

@@ -5329,6 +5332,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
for_each_set_bit(index, &completed_reqs, hba->nutrs) {
lrbp = &hba->lrb[index];
lrbp->compl_time_stamp = ktime_get();
+ lrbp->compl_time_stamp_local_clock = local_clock();
cmd = lrbp->cmd;
if (cmd) {
if (unlikely(ufshcd_should_inform_monitor(hba, lrbp)))
@@ -6617,7 +6621,7 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)

intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
hba->ufs_stats.last_intr_status = intr_status;
- hba->ufs_stats.last_intr_ts = ktime_get();
+ hba->ufs_stats.last_intr_ts = local_clock();

/*
* There could be max of hba->nutrs reqs in flight and in worst case
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index a92271421718e..2de73196bb779 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -160,8 +160,10 @@ struct ufs_pm_lvl_states {
* @task_tag: Task tag of the command
* @lun: LUN of the command
* @intr_cmd: Interrupt command (doesn't participate in interrupt aggregation)
- * @issue_time_stamp: time stamp for debug purposes
- * @compl_time_stamp: time stamp for statistics
+ * @issue_time_stamp: time stamp for debug purposes (CLOCK_MONOTONIC)
+ * @issue_time_stamp_local_clock: time stamp for debug purposes (local_clock)
+ * @compl_time_stamp: time stamp for statistics (CLOCK_MONOTONIC)
+ * @compl_time_stamp_local_clock: time stamp for debug purposes (local_clock)
* @crypto_key_slot: the key slot to use for inline crypto (-1 if none)
* @data_unit_num: the data unit number for the first block for inline crypto
* @req_abort_skip: skip request abort task flag
@@ -185,7 +187,9 @@ struct ufshcd_lrb {
u8 lun; /* UPIU LUN id field is only 8-bit wide */
bool intr_cmd;
ktime_t issue_time_stamp;
+ u64 issue_time_stamp_local_clock;
ktime_t compl_time_stamp;
+ u64 compl_time_stamp_local_clock;
#ifdef CONFIG_SCSI_UFS_CRYPTO
int crypto_key_slot;
u64 data_unit_num;
@@ -430,7 +434,7 @@ struct ufs_clk_scaling {
struct ufs_event_hist {
int pos;
u32 val[UFS_EVENT_HIST_LENGTH];
- ktime_t tstamp[UFS_EVENT_HIST_LENGTH];
+ u64 tstamp[UFS_EVENT_HIST_LENGTH];
unsigned long long cnt;
};

@@ -446,10 +450,10 @@ struct ufs_event_hist {
*/
struct ufs_stats {
u32 last_intr_status;
- ktime_t last_intr_ts;
+ u64 last_intr_ts;

u32 hibern8_exit_cnt;
- ktime_t last_hibern8_exit_tstamp;
+ u64 last_hibern8_exit_tstamp;
struct ufs_event_hist event[UFS_EVT_CNT];
};

--
2.31.0