[PATCH 7/8] scsi: ufs: Add a PM notifier

Bart Van Assche
2022-09-23T20:13:03Z

Add a PM notifier to track whether or not the system is suspending. This
information will be used in a later patch to fix a deadlock between the
SCSI error handler and the suspend code.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufshcd.c | 24 ++++++++++++++++++++++++
include/ufs/ufshcd.h | 7 ++++++-
2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index d7453f788d0d..abeb120b12eb 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -9246,6 +9246,25 @@ static int ufshcd_wl_runtime_resume(struct device *dev)
}
#endif

+static int ufshcd_pm_cb(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct ufs_hba *hba = container_of(nb, typeof(*hba), pm_nb);
+
+ switch (action) {
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ hba->system_suspending = true;
+ break;
+ case PM_POST_RESTORE:
+ case PM_POST_SUSPEND:
+ hba->system_suspending = false;
+ break;
+ }
+
+ return 0;
+}
+
#ifdef CONFIG_PM_SLEEP
static int ufshcd_wl_suspend(struct device *dev)
{
@@ -9534,6 +9553,7 @@ EXPORT_SYMBOL(ufshcd_shutdown);
*/
void ufshcd_remove(struct ufs_hba *hba)
{
+ unregister_pm_notifier(&hba->pm_nb);
if (hba->ufs_device_wlun)
ufshcd_rpm_get_sync(hba);
ufs_hwmon_remove(hba);
@@ -9832,7 +9852,11 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
async_schedule(ufshcd_async_scan, hba);
ufs_sysfs_add_nodes(hba->dev);

+ hba->pm_nb = (struct notifier_block){ .notifier_call = ufshcd_pm_cb };
+ register_pm_notifier(&hba->pm_nb);
+
device_enable_async_suspend(dev);
+
return 0;

free_tmf_queue:
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 24c97e0772bb..9bc48c13006f 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -802,7 +802,10 @@ struct ufs_hba_monitor {
* @caps: bitmask with information about UFS controller capabilities
* @devfreq: frequency scaling information owned by the devfreq core
* @clk_scaling: frequency scaling information owned by the UFS driver
- * @is_sys_suspended: whether or not the entire system has been suspended
+ * @system_suspending: system suspend has been started and system resume has
+ * not yet finished.
+ * @is_sys_suspended: UFS device has been suspended because of system suspend
+ * @pm_nb: power management notifier block
* @urgent_bkops_lvl: keeps track of urgent bkops level for device
* @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
* device is known or not.
@@ -943,7 +946,9 @@ struct ufs_hba {

struct devfreq *devfreq;
struct ufs_clk_scaling clk_scaling;
+ bool system_suspending;
bool is_sys_suspended;
+ struct notifier_block pm_nb;

enum bkops_status urgent_bkops_lvl;
bool is_urgent_bkops_lvl_checked;