Hi Stanley,
On 2020-07-29 13:18, Stanley Chu wrote:
Some UFS devices require delay after VCC power rail is turned-off.
Introduce a device quirk "DELAY_AFTER_LPM" to add 5ms delays after
VCC power-off during suspend flow.
Just curious, I can understand if you want to add some delays before
turnning off VCC/VCCQ/VCCQ2, but what is the delay AFTER turnning
them off for? I mean the power has been cut by host from PMIC, how
can the delay benefit the UFS device?
Thanks,
Can Guo.
Signed-off-by: Andy Teng <andy.teng@xxxxxxxxxxxx>
Signed-off-by: Peter Wang <peter.wang@xxxxxxxxxxxx>
Signed-off-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
---
drivers/scsi/ufs/ufs_quirks.h | 7 +++++++
drivers/scsi/ufs/ufshcd.c | 11 +++++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/scsi/ufs/ufs_quirks.h
b/drivers/scsi/ufs/ufs_quirks.h
index 2a0041493e30..07f559ac5883 100644
--- a/drivers/scsi/ufs/ufs_quirks.h
+++ b/drivers/scsi/ufs/ufs_quirks.h
@@ -109,4 +109,11 @@ struct ufs_dev_fix {
*/
#define UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES (1 << 10)
+/*
+ * Some UFS devices require delay after VCC power rail is turned-off.
+ * Enable this quirk to introduce 5ms delays after VCC power-off
during
+ * suspend flow.
+ */
+#define UFS_DEVICE_QUIRK_DELAY_AFTER_LPM (1 << 11)
+
#endif /* UFS_QUIRKS_H_ */
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index acba2271c5d3..63f4e2f75aa1 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8111,6 +8111,8 @@ static int ufshcd_link_state_transition(struct
ufs_hba *hba,
static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
{
+ bool vcc_off = false;
+
/*
* It seems some UFS devices may keep drawing more than sleep current
* (atleast for 500us) from UFS rails (especially from VCCQ rail).
@@ -8139,13 +8141,22 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba
*hba)
if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba) &&
!hba->dev_info.is_lu_power_on_wp) {
ufshcd_setup_vreg(hba, false);
+ vcc_off = true;
} else if (!ufshcd_is_ufs_dev_active(hba)) {
ufshcd_toggle_vreg(hba->dev, hba->vreg_info.vcc, false);
+ vcc_off = true;
if (!ufshcd_is_link_active(hba)) {
ufshcd_config_vreg_lpm(hba, hba->vreg_info.vccq);
ufshcd_config_vreg_lpm(hba, hba->vreg_info.vccq2);
}
}
+
+ /*
+ * Some UFS devices require delay after VCC power rail is turned-off.
+ */
+ if (vcc_off && hba->vreg_info.vcc &&
+ hba->dev_quirks & UFS_DEVICE_QUIRK_DELAY_AFTER_LPM)
+ usleep_range(5000, 5100);
}
static int ufshcd_vreg_set_hpm(struct ufs_hba *hba)
