After the ufs device vcc is powered off, all the ufs device
manufacturers require a minimum of 1ms of power-off time before
vcc can be powered on again. This requirement has been verified
with all the ufs device manufacturer's datasheets.
Replace the hard coded 5ms delay with a variable with a default
setting of 2ms to improve the system resume latency. The platform
drivers can override this setting as needed.
Signed-off-by: Bao D. Nguyen <quic_nguyenb@quicinc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufshcd.c | 10 +++++++++-
include/ufs/ufshcd.h | 2 ++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index e8842dc..8d4cdd5 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -9741,7 +9741,8 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
* All UFS devices require delay after VCC power rail is turned-off.
*/
if (vcc_off && hba->vreg_info.vcc && !hba->vreg_info.vcc->always_on)
- usleep_range(5000, 5100);
+ usleep_range(hba->vcc_off_delay_us,
+ hba->vcc_off_delay_us + 100);
}
#ifdef CONFIG_PM
@@ -10665,6 +10666,13 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
UFS_SLEEP_PWR_MODE,
UIC_LINK_HIBERN8_STATE);
+ /*
+ * Most ufs devices require 1ms delay after vcc is powered off before
+ * it can be powered on again. Set the default to 2ms. The platform
+ * drivers can override this setting as needed.
+ */
+ hba->vcc_off_delay_us = 2000;
+
init_completion(&hba->dev_cmd.complete);
err = ufshcd_hba_init(hba);
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 1d39437..4be32e3 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -1140,6 +1140,8 @@ struct ufs_hba {
int critical_health_count;
atomic_t dev_lvl_exception_count;
u64 dev_lvl_exception_id;
+
+ u32 vcc_off_delay_us;
};
/**
--
2.7.4