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scsi: ufs: core: Replace hard coded vcc-off delay with a variable

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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>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Link: https://patch.msgid.link/72fa649406a0bf02271575b7d58f22c968aa5d7e.1760383740.git.quic_nguyenb@quicinc.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bao D. Nguyen
2025-10-13 12:38:16 -07:00
committed by Martin K. Petersen
parent f8e82ae65e
commit 4760b639b4
2 changed files with 11 additions and 1 deletions
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10
drivers/ufs/core/ufshcd.c
View File

@@ -9777,7 +9777,8 @@ 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
@@ -10704,6 +10705,13 @@ 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);

2
include/ufs/ufshcd.h
View File

@@ -1117,6 +1117,8 @@ struct ufs_hba {
int critical_health_count;
atomic_t dev_lvl_exception_count;
u64 dev_lvl_exception_id;
u32 vcc_off_delay_us;
};
/**