[PATCH v2 4/4] scsi: ufs: Fix up and simplify error recovery mechanism

Can Guo
2020-07-14T02:34:08Z

Error recovery can be invoked from multiple paths, including hibern8
enter/exit, some vendor vops, ufshcd_eh_host_reset_handler(), resume and
eh_work scheduled from IRQ context. Ultimately, these paths are trying to
invoke ufshcd_reset_and_restore(), in either sync or async manner.

Having both sync and async manners at the same time has some problems

- If link recovery happens during clock scaling work, acquring scaling_lock
in ufshcd_exec_dev_cmd() would cause dead lock, because scaling_lock is
already held by scaling work before link recovery happens.

- If link recovery happens during ungate work, ufshcd_hold() would be
called recursively. Although commit 53c12d0ef6fcb
("scsi: ufs: fix error recovery after the hibern8 exit failure") fixed
a deadlock due to recursive calls of ufshcd_hold() by adding a check
of eh_in_progress into ufshcd_hold(), this check added to ufshcd_hold()
allows eh_work to run in parallel when link recovery is running.

- Similar concurrency can also happen to error recovery invoked from
eh_host_reset_handler(), although it tries to protect it from happening
by flushing eh_work before start invoking reset and restore, after flush
work returns, eh_work can still be scheduled and running in parallel.

- Concurrency can even happen between eh_works. eh_work, currently queued
on system_wq, is allowed to have multiple instances running in parallel,
but we don't have proper protection for that.

To fix up and simplify error recovery mechanism, this change mainly does
below things

o Queue eh_work on a single threaded workqueue to avoid concurrency between
eh_works.

o According to the UFSHCI JEDEC spec, hibern8 enter/exit error occurs when
the link is broken. This actaully applies to any power mode change
operations. In this change, if a power mode change operation (including
AH8 enter/exit) fails, mark the link state as UIC_LINK_BROKEN_STATE and
schedule eh_work. eh_work needs to do full reset and restore to recover
the link back to active. Before the link state is recovered to active by
eh_work, any power mode change attempts just return -ENOLINK to avoid
consecutive HW error.

o To avoid concurrency between eh_work and link recovery, remove link
recovery from hibern8 enter/exit func. If hibern8 enter/exit func fails,
simply return error code and let eh_work run in parallel.

o Recover UFS hba runtime PM error in eh_work. If ufschd_suspend/resume
fails due to UFS error, e.g. hibern8 enter/exit error and SSU cmd error,
the runtime PM framework saves the error to dev.power.runtime_error.
After that, hba runtime suspend/resume would not be invoked anymore until
dev.power.runtime_error is cleared. The runtime PM error can be recovered
in eh_work by calling pm_runtime_set_active() after reset and restore
succeeds. Meanwhile, if pm_runtime_set_active() returns no error, which
means dev.power.runtime_error is cleared, we also need to explicitly
resume those scsi devices under hba in case any of them has failed to be
resumed due to hba runtime resume error.

o Fix a racing problem between eh_work and ufshcd_suspend/resume. In the
old code, it blocks scsi requests before schedules eh_work, but when
eh_work calls pm_runtime_get_sync(), if ufshcd_suspend/resume is sending
a scsi cmd, most likely the SSU cmd, pm_runtime_get_sync() will never
return because scsi requests were blocked. To fix this racing problem,
o Don't block scsi requests before schedule eh_work, but let eh_work
block scsi requests when eh_work is ready to start error recovery.
o Meanwhile, if eh_work is schueduled due to fatal error, don't requeue
the scsi cmds sent from ufshcd_suspend/resume path, but simply let the
scsi cmds fail. If the scsi cmds fail, hba runtime suspend/resume fails
too, but it does hurt since eh_work recovers hba runtime PM error.

o Move host/regs dump in ufshcd_check_errors() to eh_work because heavy
dump in IRQ context can lead to stability issues. In addition, some clean
up in ufshcd_print_host_regs() and ufshcd_print_host_state().

Signed-off-by: Can Guo <cang@codeaurora.org>
---
drivers/scsi/ufs/ufs-sysfs.c | 1 +
drivers/scsi/ufs/ufshcd.c | 442 ++++++++++++++++++++++++++-----------------
drivers/scsi/ufs/ufshcd.h | 15 ++
3 files changed, 285 insertions(+), 173 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 2d71d23..02d379f00 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -16,6 +16,7 @@ static const char *ufschd_uic_link_state_to_string(
case UIC_LINK_OFF_STATE: return "OFF";
case UIC_LINK_ACTIVE_STATE: return "ACTIVE";
case UIC_LINK_HIBERN8_STATE: return "HIBERN8";
+ case UIC_LINK_BROKEN_STATE: return "BROKEN";
default: return "UNKNOWN";
}
}
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 33214bb..6ae2f51 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -15,6 +15,8 @@
#include <linux/of.h>
#include <linux/bitfield.h>
#include <linux/blk-pm.h>
+#include <linux/blkdev.h>
+#include <scsi/scsi_device.h>
#include "ufshcd.h"
#include "ufs_quirks.h"
#include "unipro.h"
@@ -125,7 +127,8 @@ enum {
UFSHCD_STATE_RESET,
UFSHCD_STATE_ERROR,
UFSHCD_STATE_OPERATIONAL,
- UFSHCD_STATE_EH_SCHEDULED,
+ UFSHCD_STATE_EH_SCHEDULED_FATAL,
+ UFSHCD_STATE_EH_SCHEDULED_NON_FATAL,
};

/* UFSHCD error handling flags */
@@ -228,6 +231,11 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up);
static irqreturn_t ufshcd_intr(int irq, void *__hba);
static int ufshcd_change_power_mode(struct ufs_hba *hba,
struct ufs_pa_layer_attr *pwr_mode);
+static void ufshcd_schedule_eh_work(struct ufs_hba *hba);
+static int ufshcd_setup_hba_vreg(struct ufs_hba *hba, bool on);
+static int ufshcd_setup_vreg(struct ufs_hba *hba, bool on);
+static inline int ufshcd_config_vreg_hpm(struct ufs_hba *hba,
+ struct ufs_vreg *vreg);
static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba);
static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba);
static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);
@@ -411,15 +419,6 @@ static void ufshcd_print_err_hist(struct ufs_hba *hba,
static void ufshcd_print_host_regs(struct ufs_hba *hba)
{
ufshcd_dump_regs(hba, 0, UFSHCI_REG_SPACE_SIZE, "host_regs: ");
- dev_err(hba->dev, "hba->ufs_version = 0x%x, hba->capabilities = 0x%x\n",
- hba->ufs_version, hba->capabilities);
- dev_err(hba->dev,
- "hba->outstanding_reqs = 0x%x, hba->outstanding_tasks = 0x%x\n",
- (u32)hba->outstanding_reqs, (u32)hba->outstanding_tasks);
- 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),
- hba->ufs_stats.hibern8_exit_cnt);

ufshcd_print_err_hist(hba, &hba->ufs_stats.pa_err, "pa_err");
ufshcd_print_err_hist(hba, &hba->ufs_stats.dl_err, "dl_err");
@@ -499,6 +498,8 @@ static void ufshcd_print_tmrs(struct ufs_hba *hba, unsigned long bitmap)

static void ufshcd_print_host_state(struct ufs_hba *hba)
{
+ struct scsi_device *sdev_ufs = hba->sdev_ufs_device;
+
dev_err(hba->dev, "UFS Host state=%d\n", hba->ufshcd_state);
dev_err(hba->dev, "outstanding reqs=0x%lx tasks=0x%lx\n",
hba->outstanding_reqs, hba->outstanding_tasks);
@@ -511,12 +512,22 @@ static void ufshcd_print_host_state(struct ufs_hba *hba)
dev_err(hba->dev, "Auto BKOPS=%d, Host self-block=%d\n",
hba->auto_bkops_enabled, hba->host->host_self_blocked);
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),
+ 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),
+ 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);
- dev_err(hba->dev, "Host capabilities=0x%x, caps=0x%x\n",
- hba->capabilities, hba->caps);
+ dev_err(hba->dev, "hba->ufs_version=0x%x, Host capabilities=0x%x, caps=0x%x\n",
+ hba->ufs_version, hba->capabilities, hba->caps);
dev_err(hba->dev, "quirks=0x%x, dev. quirks=0x%x\n", hba->quirks,
hba->dev_quirks);
+ if (sdev_ufs)
+ dev_err(hba->dev, "UFS dev info: %.8s %.16s rev %.4s\n",
+ sdev_ufs->vendor, sdev_ufs->model, sdev_ufs->rev);
}

/**
@@ -1568,11 +1579,6 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
spin_lock_irqsave(hba->host->host_lock, flags);
hba->clk_gating.active_reqs++;

- if (ufshcd_eh_in_progress(hba)) {
- spin_unlock_irqrestore(hba->host->host_lock, flags);
- return 0;
- }
-
start:
switch (hba->clk_gating.state) {
case CLKS_ON:
@@ -1647,6 +1653,7 @@ EXPORT_SYMBOL_GPL(ufshcd_hold);

static void ufshcd_gate_work(struct work_struct *work)
{
+ int ret;
struct ufs_hba *hba = container_of(work, struct ufs_hba,
clk_gating.gate_work.work);
unsigned long flags;
@@ -1676,8 +1683,11 @@ static void ufshcd_gate_work(struct work_struct *work)

/* put the link into hibern8 mode before turning off clocks */
if (ufshcd_can_hibern8_during_gating(hba)) {
- if (ufshcd_uic_hibern8_enter(hba)) {
+ ret = ufshcd_uic_hibern8_enter(hba);
+ if (ret) {
hba->clk_gating.state = CLKS_ON;
+ dev_err(hba->dev, "%s: hibern8 enter failed %d\n",
+ __func__, ret);
trace_ufshcd_clk_gating(dev_name(hba->dev),
hba->clk_gating.state);
goto out;
@@ -1725,8 +1735,7 @@ static void __ufshcd_release(struct ufs_hba *hba)
if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
- || hba->active_uic_cmd || hba->uic_async_done
- || ufshcd_eh_in_progress(hba))
+ || hba->active_uic_cmd || hba->uic_async_done)
return;

hba->clk_gating.state = REQ_CLKS_OFF;
@@ -2505,34 +2514,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
if (!down_read_trylock(&hba->clk_scaling_lock))
return SCSI_MLQUEUE_HOST_BUSY;

- spin_lock_irqsave(hba->host->host_lock, flags);
- switch (hba->ufshcd_state) {
- case UFSHCD_STATE_OPERATIONAL:
- break;
- case UFSHCD_STATE_EH_SCHEDULED:
- case UFSHCD_STATE_RESET:
- err = SCSI_MLQUEUE_HOST_BUSY;
- goto out_unlock;
- case UFSHCD_STATE_ERROR:
- set_host_byte(cmd, DID_ERROR);
- cmd->scsi_done(cmd);
- goto out_unlock;
- default:
- dev_WARN_ONCE(hba->dev, 1, "%s: invalid state %d\n",
- __func__, hba->ufshcd_state);
- set_host_byte(cmd, DID_BAD_TARGET);
- cmd->scsi_done(cmd);
- goto out_unlock;
- }
-
- /* if error handling is in progress, don't issue commands */
- if (ufshcd_eh_in_progress(hba)) {
- set_host_byte(cmd, DID_ERROR);
- cmd->scsi_done(cmd);
- goto out_unlock;
- }
- spin_unlock_irqrestore(hba->host->host_lock, flags);
-
hba->req_abort_count = 0;

err = ufshcd_hold(hba, true);
@@ -2568,12 +2549,52 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
/* Make sure descriptors are ready before ringing the doorbell */
wmb();

- /* issue command to the controller */
spin_lock_irqsave(hba->host->host_lock, flags);
+ switch (hba->ufshcd_state) {
+ case UFSHCD_STATE_OPERATIONAL:
+ case UFSHCD_STATE_EH_SCHEDULED_NON_FATAL:
+ break;
+ case UFSHCD_STATE_EH_SCHEDULED_FATAL:
+ /*
+ * If we are here, eh_work is either scheduled or running.
+ * Before eh_work sets ufshcd_state to STATE_RESET, it flushes
+ * runtime PM ops by calling pm_runtime_get_sync(). If a scsi
+ * cmd, e.g. the SSU cmd, is sent by PM ops, it can never be
+ * finished if we let SCSI layer keep retrying it, which gets
+ * eh_work stuck forever. Neither can we let it pass, because
+ * ufs now is not in good status, so the SSU cmd may eventually
+ * time out, blocking eh_work for too long. So just let it fail.
+ */
+ if (hba->pm_op_in_progress) {
+ hba->force_reset = true;
+ set_host_byte(cmd, DID_BAD_TARGET);
+ goto out_compl_cmd;
+ }
+ /* fallthrough */
+ case UFSHCD_STATE_RESET:
+ err = SCSI_MLQUEUE_HOST_BUSY;
+ goto out_compl_cmd;
+ case UFSHCD_STATE_ERROR:
+ set_host_byte(cmd, DID_ERROR);
+ goto out_compl_cmd;
+ default:
+ dev_WARN_ONCE(hba->dev, 1, "%s: invalid state %d\n",
+ __func__, hba->ufshcd_state);
+ set_host_byte(cmd, DID_BAD_TARGET);
+ goto out_compl_cmd;
+ }
ufshcd_vops_setup_xfer_req(hba, tag, true);
ufshcd_send_command(hba, tag);
-out_unlock:
spin_unlock_irqrestore(hba->host->host_lock, flags);
+ goto out;
+
+out_compl_cmd:
+ scsi_dma_unmap(lrbp->cmd);
+ lrbp->cmd = NULL;
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ ufshcd_release(hba);
+ if (!err)
+ cmd->scsi_done(cmd);
out:
up_read(&hba->clk_scaling_lock);
return err;
@@ -3746,6 +3767,10 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
ufshcd_add_delay_before_dme_cmd(hba);

spin_lock_irqsave(hba->host->host_lock, flags);
+ if (ufshcd_is_link_broken(hba)) {
+ ret = -ENOLINK;
+ goto out_unlock;
+ }
hba->uic_async_done = &uic_async_done;
if (ufshcd_readl(hba, REG_INTERRUPT_ENABLE) & UIC_COMMAND_COMPL) {
ufshcd_disable_intr(hba, UIC_COMMAND_COMPL);
@@ -3793,6 +3818,12 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
hba->uic_async_done = NULL;
if (reenable_intr)
ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
+ if (ret) {
+ ufshcd_set_link_broken(hba);
+ ufshcd_schedule_eh_work(hba);
+ }
+
+out_unlock:
spin_unlock_irqrestore(hba->host->host_lock, flags);
mutex_unlock(&hba->uic_cmd_mutex);

@@ -3862,7 +3893,7 @@ int ufshcd_link_recovery(struct ufs_hba *hba)
}
EXPORT_SYMBOL_GPL(ufshcd_link_recovery);

-static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
+static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
{
int ret;
struct uic_command uic_cmd = {0};
@@ -3875,45 +3906,16 @@ static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
trace_ufshcd_profile_hibern8(dev_name(hba->dev), "enter",
ktime_to_us(ktime_sub(ktime_get(), start)), ret);

- if (ret) {
- int err;
-
+ if (ret)
dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d\n",
__func__, ret);
-
- /*
- * If link recovery fails then return error code returned from
- * ufshcd_link_recovery().
- * If link recovery succeeds then return -EAGAIN to attempt
- * hibern8 enter retry again.
- */
- err = ufshcd_link_recovery(hba);
- if (err) {
- dev_err(hba->dev, "%s: link recovery failed", __func__);
- ret = err;
- } else {
- ret = -EAGAIN;
- }
- } else
+ else
ufshcd_vops_hibern8_notify(hba, UIC_CMD_DME_HIBER_ENTER,
POST_CHANGE);

return ret;
}

-static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
-{
- int ret = 0, retries;
-
- for (retries = UIC_HIBERN8_ENTER_RETRIES; retries > 0; retries--) {
- ret = __ufshcd_uic_hibern8_enter(hba);
- if (!ret)
- goto out;
- }
-out:
- return ret;
-}
-
int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
{
struct uic_command uic_cmd = {0};
@@ -3930,7 +3932,6 @@ int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
if (ret) {
dev_err(hba->dev, "%s: hibern8 exit failed. ret = %d\n",
__func__, ret);
- ret = ufshcd_link_recovery(hba);
} else {
ufshcd_vops_hibern8_notify(hba, UIC_CMD_DME_HIBER_EXIT,
POST_CHANGE);
@@ -5554,6 +5555,28 @@ static bool ufshcd_quirk_dl_nac_errors(struct ufs_hba *hba)
return err_handling;
}

+/* host lock must be held before calling this func */
+static inline bool ufshcd_is_saved_err_fatal(struct ufs_hba *hba)
+{
+ return ((hba->saved_err & INT_FATAL_ERRORS) ||
+ ((hba->saved_err & UIC_ERROR) &&
+ (hba->saved_uic_err & UFSHCD_UIC_DL_PA_INIT_ERROR)));
+}
+
+/* host lock must be held before calling this func */
+static inline void ufshcd_schedule_eh_work(struct ufs_hba *hba)
+{
+ /* handle fatal errors only when link is not in error state */
+ if (hba->ufshcd_state != UFSHCD_STATE_ERROR) {
+ if (hba->force_reset || ufshcd_is_link_broken(hba) ||
+ ufshcd_is_saved_err_fatal(hba))
+ hba->ufshcd_state = UFSHCD_STATE_EH_SCHEDULED_FATAL;
+ else
+ hba->ufshcd_state = UFSHCD_STATE_EH_SCHEDULED_NON_FATAL;
+ queue_work(hba->eh_wq, &hba->eh_work);
+ }
+}
+
/**
* ufshcd_err_handler - handle UFS errors that require s/w attention
* @work: pointer to work structure
@@ -5564,21 +5587,47 @@ static void ufshcd_err_handler(struct work_struct *work)
unsigned long flags;
u32 err_xfer = 0;
u32 err_tm = 0;
- int err = 0;
+ int reset_err = -1;
int tag;
bool needs_reset = false;

hba = container_of(work, struct ufs_hba, eh_work);

+ spin_lock_irqsave(hba->host->host_lock, flags);
+ if ((hba->ufshcd_state == UFSHCD_STATE_ERROR) ||
+ (!(hba->saved_err || hba->saved_uic_err || hba->force_reset) &&
+ !ufshcd_is_link_broken(hba))) {
+ if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
+ hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ return;
+ }
+ ufshcd_set_eh_in_progress(hba);
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
pm_runtime_get_sync(hba->dev);
+ /*
+ * Don't assume anything of pm_runtime_get_sync(), if resume fails,
+ * irq and clocks can be OFF, and powers can be OFF or in LPM.
+ */
+ ufshcd_setup_vreg(hba, true);
+ ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq);
+ ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq2);
+ ufshcd_setup_hba_vreg(hba, true);
+ ufshcd_enable_irq(hba);
+
ufshcd_hold(hba, false);
+ if (!ufshcd_is_clkgating_allowed(hba))
+ ufshcd_setup_clocks(hba, true);

- spin_lock_irqsave(hba->host->host_lock, flags);
- if (hba->ufshcd_state == UFSHCD_STATE_RESET)
- goto out;
+ if (ufshcd_is_clkscaling_supported(hba)) {
+ cancel_work_sync(&hba->clk_scaling.suspend_work);
+ cancel_work_sync(&hba->clk_scaling.resume_work);
+ ufshcd_suspend_clkscaling(hba);
+ }

+ spin_lock_irqsave(hba->host->host_lock, flags);
+ ufshcd_scsi_block_requests(hba);
hba->ufshcd_state = UFSHCD_STATE_RESET;
- ufshcd_set_eh_in_progress(hba);

/* Complete requests that have door-bell cleared by h/w */
ufshcd_complete_requests(hba);
@@ -5590,17 +5639,29 @@ static void ufshcd_err_handler(struct work_struct *work)
/* release the lock as ufshcd_quirk_dl_nac_errors() may sleep */
ret = ufshcd_quirk_dl_nac_errors(hba);
spin_lock_irqsave(hba->host->host_lock, flags);
- if (!ret)
+ if (!ret && !hba->force_reset && ufshcd_is_link_active(hba))
goto skip_err_handling;
}
- if ((hba->saved_err & INT_FATAL_ERRORS) ||
- (hba->saved_err & UFSHCD_UIC_HIBERN8_MASK) ||
+
+ if (hba->force_reset || ufshcd_is_link_broken(hba) ||
+ ufshcd_is_saved_err_fatal(hba) ||
((hba->saved_err & UIC_ERROR) &&
- (hba->saved_uic_err & (UFSHCD_UIC_DL_PA_INIT_ERROR |
- UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
- UFSHCD_UIC_DL_TCx_REPLAY_ERROR))))
+ (hba->saved_uic_err & (UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
+ UFSHCD_UIC_DL_TCx_REPLAY_ERROR))))
needs_reset = true;

+ if (hba->saved_err & (INT_FATAL_ERRORS | UIC_ERROR |
+ UFSHCD_UIC_HIBERN8_MASK)) {
+ dev_err(hba->dev, "%s: saved_err 0x%x saved_uic_err 0x%x\n",
+ __func__, hba->saved_err, hba->saved_uic_err);
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ ufshcd_print_host_state(hba);
+ ufshcd_print_pwr_info(hba);
+ ufshcd_print_host_regs(hba);
+ ufshcd_print_tmrs(hba, hba->outstanding_tasks);
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ }
+
/*
* if host reset is required then skip clearing the pending
* transfers forcefully because they will get cleared during
@@ -5652,38 +5713,67 @@ static void ufshcd_err_handler(struct work_struct *work)
__ufshcd_transfer_req_compl(hba,
(1UL << (hba->nutrs - 1)));

+ hba->force_reset = false;
spin_unlock_irqrestore(hba->host->host_lock, flags);
- err = ufshcd_reset_and_restore(hba);
+ reset_err = ufshcd_reset_and_restore(hba);
spin_lock_irqsave(hba->host->host_lock, flags);
- if (err) {
+ if (reset_err)
dev_err(hba->dev, "%s: reset and restore failed\n",
__func__);
- hba->ufshcd_state = UFSHCD_STATE_ERROR;
- }
- /*
- * Inform scsi mid-layer that we did reset and allow to handle
- * Unit Attention properly.
- */
- scsi_report_bus_reset(hba->host, 0);
- hba->saved_err = 0;
- hba->saved_uic_err = 0;
}

skip_err_handling:
if (!needs_reset) {
- hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
+ if (hba->ufshcd_state == UFSHCD_STATE_RESET)
+ hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
if (hba->saved_err || hba->saved_uic_err)
dev_err_ratelimited(hba->dev, "%s: exit: saved_err 0x%x saved_uic_err 0x%x",
__func__, hba->saved_err, hba->saved_uic_err);
}

- ufshcd_clear_eh_in_progress(hba);
+#ifdef CONFIG_PM
+ if (!reset_err) {
+ struct Scsi_Host *shost = hba->host;
+ struct scsi_device *sdev;
+ struct request_queue *q;
+ int ret;

-out:
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ /*
+ * Set RPM status of hba device to RPM_ACTIVE,
+ * this also clears its runtime error.
+ */
+ ret = pm_runtime_set_active(hba->dev);
+ /*
+ * If hba device had runtime error, explicitly resume
+ * its scsi devices so that block layer can wake up
+ * those waiting in blk_queue_enter().
+ */
+ if (!ret) {
+ list_for_each_entry(sdev, &shost->__devices, siblings) {
+ q = sdev->request_queue;
+ if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
+ q->rpm_status == RPM_SUSPENDING))
+ pm_request_resume(q->dev);
+ }
+ }
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ }
+
+ /* If clk_gating is held by pm ops, release it */
+ if (pm_runtime_active(hba->dev) && hba->clk_gating.held_by_pm) {
+ hba->clk_gating.held_by_pm = false;
+ __ufshcd_release(hba);
+ }
+#endif
+
+ ufshcd_clear_eh_in_progress(hba);
spin_unlock_irqrestore(hba->host->host_lock, flags);
ufshcd_scsi_unblock_requests(hba);
ufshcd_release(hba);
- pm_runtime_put_sync(hba->dev);
+ if (ufshcd_is_clkscaling_supported(hba))
+ ufshcd_resume_clkscaling(hba);
+ pm_runtime_put_noidle(hba->dev);
}

/**
@@ -5813,6 +5903,7 @@ static irqreturn_t ufshcd_check_errors(struct ufs_hba *hba)
hba->errors, ufshcd_get_upmcrs(hba));
ufshcd_update_reg_hist(&hba->ufs_stats.auto_hibern8_err,
hba->errors);
+ ufshcd_set_link_broken(hba);
queue_eh_work = true;
}

@@ -5823,31 +5914,7 @@ static irqreturn_t ufshcd_check_errors(struct ufs_hba *hba)
*/
hba->saved_err |= hba->errors;
hba->saved_uic_err |= hba->uic_error;
-
- /* handle fatal errors only when link is functional */
- if (hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL) {
- /* block commands from scsi mid-layer */
- ufshcd_scsi_block_requests(hba);
-
- hba->ufshcd_state = UFSHCD_STATE_EH_SCHEDULED;
-
- /* dump controller state before resetting */
- if (hba->saved_err & (INT_FATAL_ERRORS | UIC_ERROR)) {
- bool pr_prdt = !!(hba->saved_err &
- SYSTEM_BUS_FATAL_ERROR);
-
- dev_err(hba->dev, "%s: saved_err 0x%x saved_uic_err 0x%x\n",
- __func__, hba->saved_err,
- hba->saved_uic_err);
-
- ufshcd_print_host_regs(hba);
- ufshcd_print_pwr_info(hba);
- ufshcd_print_tmrs(hba, hba->outstanding_tasks);
- ufshcd_print_trs(hba, hba->outstanding_reqs,
- pr_prdt);
- }
- schedule_work(&hba->eh_work);
- }
+ ufshcd_schedule_eh_work(hba);
retval |= IRQ_HANDLED;
}
/*
@@ -5951,6 +6018,8 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)

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

/*
* There could be max of hba->nutrs reqs in flight and in worst case
@@ -6589,9 +6658,6 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)

/* Establish the link again and restore the device */
err = ufshcd_probe_hba(hba, false);
-
- if (!err && (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL))
- err = -EIO;
out:
if (err)
dev_err(hba->dev, "%s: Host init failed %d\n", __func__, err);
@@ -6610,9 +6676,23 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
*/
static int ufshcd_reset_and_restore(struct ufs_hba *hba)
{
+ u32 saved_err;
+ u32 saved_uic_err;
int err = 0;
+ unsigned long flags;
int retries = MAX_HOST_RESET_RETRIES;

+ /*
+ * This is a fresh start, cache and clear saved error first,
+ * in case new error generated during reset and restore.
+ */
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ saved_err = hba->saved_err;
+ saved_uic_err = hba->saved_uic_err;
+ hba->saved_err = 0;
+ hba->saved_uic_err = 0;
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+
do {
/* Reset the attached device */
ufshcd_vops_device_reset(hba);
@@ -6620,6 +6700,19 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
err = ufshcd_host_reset_and_restore(hba);
} while (err && --retries);

+ spin_lock_irqsave(hba->host->host_lock, flags);
+ /*
+ * Inform scsi mid-layer that we did reset and allow to handle
+ * Unit Attention properly.
+ */
+ scsi_report_bus_reset(hba->host, 0);
+ if (err) {
+ hba->ufshcd_state = UFSHCD_STATE_ERROR;
+ hba->saved_err |= saved_err;
+ hba->saved_uic_err |= saved_uic_err;
+ }
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+
return err;
}

@@ -6631,48 +6724,25 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
*/
static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd)
{
- int err;
+ int err = SUCCESS;
unsigned long flags;
struct ufs_hba *hba;

hba = shost_priv(cmd->device->host);

- ufshcd_hold(hba, false);
- /*
- * Check if there is any race with fatal error handling.
- * If so, wait for it to complete. Even though fatal error
- * handling does reset and restore in some cases, don't assume
- * anything out of it. We are just avoiding race here.
- */
- do {
- spin_lock_irqsave(hba->host->host_lock, flags);
- if (!(work_pending(&hba->eh_work) ||
- hba->ufshcd_state == UFSHCD_STATE_RESET ||
- hba->ufshcd_state == UFSHCD_STATE_EH_SCHEDULED))
- break;
- spin_unlock_irqrestore(hba->host->host_lock, flags);
- dev_dbg(hba->dev, "%s: reset in progress\n", __func__);
- flush_work(&hba->eh_work);
- } while (1);
-
- hba->ufshcd_state = UFSHCD_STATE_RESET;
- ufshcd_set_eh_in_progress(hba);
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ hba->force_reset = true;
+ ufshcd_schedule_eh_work(hba);
+ dev_err(hba->dev, "%s: reset in progress - 1\n", __func__);
spin_unlock_irqrestore(hba->host->host_lock, flags);

- err = ufshcd_reset_and_restore(hba);
+ flush_work(&hba->eh_work);

spin_lock_irqsave(hba->host->host_lock, flags);
- if (!err) {
- err = SUCCESS;
- hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
- } else {
+ if (hba->ufshcd_state == UFSHCD_STATE_ERROR)
err = FAILED;
- hba->ufshcd_state = UFSHCD_STATE_ERROR;
- }
- ufshcd_clear_eh_in_progress(hba);
spin_unlock_irqrestore(hba->host->host_lock, flags);

- ufshcd_release(hba);
return err;
}

@@ -7393,6 +7463,7 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
static int ufshcd_probe_hba(struct ufs_hba *hba, bool async)
{
int ret;
+ unsigned long flags;
ktime_t start = ktime_get();

ret = ufshcd_link_startup(hba);
@@ -7458,7 +7529,10 @@ static int ufshcd_probe_hba(struct ufs_hba *hba, bool async)
ufshcd_set_active_icc_lvl(hba);

/* set the state as operational after switching to desired gear */
- hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ if (hba->ufshcd_state == UFSHCD_STATE_RESET)
+ hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
+ spin_unlock_irqrestore(hba->host->host_lock, flags);

ufshcd_wb_config(hba);
/* Enable Auto-Hibernate if configured */
@@ -8071,10 +8145,13 @@ static int ufshcd_link_state_transition(struct ufs_hba *hba,

if (req_link_state == UIC_LINK_HIBERN8_STATE) {
ret = ufshcd_uic_hibern8_enter(hba);
- if (!ret)
+ if (!ret) {
ufshcd_set_link_hibern8(hba);
- else
+ } else {
+ dev_err(hba->dev, "%s: hibern8 enter failed %d\n",
+ __func__, ret);
goto out;
+ }
}
/*
* If autobkops is enabled, link can't be turned off because
@@ -8090,8 +8167,11 @@ static int ufshcd_link_state_transition(struct ufs_hba *hba,
* unipro. But putting the link in hibern8 is much faster.
*/
ret = ufshcd_uic_hibern8_enter(hba);
- if (ret)
+ if (ret) {
+ dev_err(hba->dev, "%s: hibern8 enter failed %d\n",
+ __func__, ret);
goto out;
+ }
/*
* Change controller state to "reset state" which
* should also put the link in off/reset state
@@ -8226,6 +8306,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
* just gate the clocks.
*/
ufshcd_hold(hba, false);
+ hba->clk_gating.held_by_pm = true;
hba->clk_gating.is_suspended = true;

if (hba->clk_scaling.is_allowed) {
@@ -8345,6 +8426,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
hba->clk_gating.is_suspended = false;
hba->dev_info.b_rpm_dev_flush_capable = false;
ufshcd_release(hba);
+ hba->clk_gating.held_by_pm = false;
out:
if (hba->dev_info.b_rpm_dev_flush_capable) {
schedule_delayed_work(&hba->rpm_dev_flush_recheck_work,
@@ -8400,10 +8482,13 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)

if (ufshcd_is_link_hibern8(hba)) {
ret = ufshcd_uic_hibern8_exit(hba);
- if (!ret)
+ if (!ret) {
ufshcd_set_link_active(hba);
- else
+ } else {
+ dev_err(hba->dev, "%s: hibern8 exit failed %d\n",
+ __func__, ret);
goto vendor_suspend;
+ }
} else if (ufshcd_is_link_off(hba)) {
/*
* A full initialization of the host and the device is
@@ -8448,6 +8533,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)

/* Schedule clock gating in case of no access to UFS device yet */
ufshcd_release(hba);
+ hba->clk_gating.held_by_pm = false;

goto out;

@@ -8777,6 +8863,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
int err;
struct Scsi_Host *host = hba->host;
struct device *dev = hba->dev;
+ char eh_wq_name[sizeof("ufs_eh_wq_00")];

if (!mmio_base) {
dev_err(hba->dev,
@@ -8838,6 +8925,15 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
hba->max_pwr_info.is_valid = false;

/* Initialize work queues */
+ snprintf(eh_wq_name, sizeof(eh_wq_name), "ufs_eh_wq_%d",
+ hba->host->host_no);
+ hba->eh_wq = create_singlethread_workqueue(eh_wq_name);
+ if (!hba->eh_wq) {
+ dev_err(hba->dev, "%s: failed to create eh workqueue\n",
+ __func__);
+ err = -ENOMEM;
+ goto out_disable;
+ }
INIT_WORK(&hba->eh_work, ufshcd_err_handler);
INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);

diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 656c069..585e58b 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -90,6 +90,7 @@ enum uic_link_state {
UIC_LINK_OFF_STATE = 0, /* Link powered down or disabled */
UIC_LINK_ACTIVE_STATE = 1, /* Link is in Fast/Slow/Sleep state */
UIC_LINK_HIBERN8_STATE = 2, /* Link is in Hibernate state */
+ UIC_LINK_BROKEN_STATE = 3, /* Link is in broken state */
};

#define ufshcd_is_link_off(hba) ((hba)->uic_link_state == UIC_LINK_OFF_STATE)
@@ -97,11 +98,15 @@ enum uic_link_state {
UIC_LINK_ACTIVE_STATE)
#define ufshcd_is_link_hibern8(hba) ((hba)->uic_link_state == \
UIC_LINK_HIBERN8_STATE)
+#define ufshcd_is_link_broken(hba) ((hba)->uic_link_state == \
+ UIC_LINK_BROKEN_STATE)
#define ufshcd_set_link_off(hba) ((hba)->uic_link_state = UIC_LINK_OFF_STATE)
#define ufshcd_set_link_active(hba) ((hba)->uic_link_state = \
UIC_LINK_ACTIVE_STATE)
#define ufshcd_set_link_hibern8(hba) ((hba)->uic_link_state = \
UIC_LINK_HIBERN8_STATE)
+#define ufshcd_set_link_broken(hba) ((hba)->uic_link_state = \
+ UIC_LINK_BROKEN_STATE)

#define ufshcd_set_ufs_dev_active(h) \
((h)->curr_dev_pwr_mode = UFS_ACTIVE_PWR_MODE)
@@ -349,6 +354,7 @@ struct ufs_clk_gating {
struct device_attribute delay_attr;
struct device_attribute enable_attr;
bool is_enabled;
+ bool held_by_pm;
int active_reqs;
struct workqueue_struct *clk_gating_workq;
};
@@ -406,6 +412,8 @@ struct ufs_err_reg_hist {

/**
* struct ufs_stats - keeps usage/err statistics
+ * @last_intr_status: record the last interrupt status.
+ * @last_intr_ts: record the last interrupt timestamp.
* @hibern8_exit_cnt: Counter to keep track of number of exits,
* reset this after link-startup.
* @last_hibern8_exit_tstamp: Set time after the hibern8 exit.
@@ -425,6 +433,9 @@ struct ufs_err_reg_hist {
* @tsk_abort: tracks task abort events
*/
struct ufs_stats {
+ u32 last_intr_status;
+ ktime_t last_intr_ts;
+
u32 hibern8_exit_cnt;
ktime_t last_hibern8_exit_tstamp;

@@ -608,12 +619,14 @@ struct ufs_hba_variant_params {
* @intr_mask: Interrupt Mask Bits
* @ee_ctrl_mask: Exception event control mask
* @is_powered: flag to check if HBA is powered
+ * @eh_wq: Workqueue that eh_work works on
* @eh_work: Worker to handle UFS errors that require s/w attention
* @eeh_work: Worker to handle exception events
* @errors: HBA errors
* @uic_error: UFS interconnect layer error status
* @saved_err: sticky error mask
* @saved_uic_err: sticky UIC error mask
+ * @force_reset: flag to force eh_work perform a full reset
* @silence_err_logs: flag to silence error logs
* @dev_cmd: ufs device management command information
* @last_dme_cmd_tstamp: time stamp of the last completed DME command
@@ -702,6 +715,7 @@ struct ufs_hba {
bool is_powered;

/* Work Queues */
+ struct workqueue_struct *eh_wq;
struct work_struct eh_work;
struct work_struct eeh_work;

@@ -711,6 +725,7 @@ struct ufs_hba {
u32 saved_err;
u32 saved_uic_err;
struct ufs_stats ufs_stats;
+ bool force_reset;
bool silence_err_logs;

/* Device management request data */
--
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