From 29eb955c2eba7846a4970ac491bcc0035fda1b2d Mon Sep 17 00:00:00 2001 From: Nitin Rawat Date: Mon, 1 Jun 2026 05:20:10 +0530 Subject: [PATCH 1/2] FROMLIST: scsi: ufs: core: Add UFSHCD_QUIRK_SKIP_DEVICE_RESET quirk Add a new host quirk UFSHCD_QUIRK_SKIP_DEVICE_RESET to allow host controller drivers to skip asserting device reset during UFS power down. When RST_N is asserted, the UFS device firmware wakes up and executes its internal reset routine. This routine initializes multiple hardware blocks and causing the device to draw a large curreny during this time. If the power rail transitions to LPM (Low Power Mode) while the device is still drawing this elevated current, it may trigger an OCP (Over Current Protection) fault in the regulator. For some UFS devices (e.g., Micron), the elevated current draw persists until the reset line is deasserted, making a fixed delay insufficient to prevent OCP. This quirk allows such devices to skip device reset during UFS power down. The device reset will instead be asserted as part of the platform shutdown sequence. Link: https://lore.kernel.org/linux-scsi/20260531235011.1052706-2-nitin.rawat@oss.qualcomm.com/ Signed-off-by: Nitin Rawat Signed-off-by: Pradeep P V K --- include/ufs/ufshcd.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index 17fe07dac6a7e..9ebeff5886feb 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -695,6 +695,20 @@ enum ufshcd_quirks { * because it causes link startup to become unreliable. */ UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE = 1 << 26, + + /* + * Some UFS devices keep drawing larger current after reset is + * asserted until it is deasserted. Asserting device reset + * during UFS power down causes the device firmware to wake up and + * execute its reset routine, drawing current beyond the permissible + * limit for low-power mode (LPM). This may trigger an OCP fault on + * the regulator supplying power to UFS. + * + * Enable this quirk to skip asserting device reset during UFS power + * down. This is handled only in shutdown; the device reset will be + * asserted as part of the platform shutdown sequence. + */ + UFSHCD_QUIRK_SKIP_DEVICE_RESET = 1 << 27, }; enum ufshcd_caps { From 7714c548be1606a4d4e05cb11f08a0101e8c4f30 Mon Sep 17 00:00:00 2001 From: Nitin Rawat Date: Mon, 1 Jun 2026 05:20:11 +0530 Subject: [PATCH 2/2] FROMLIST: scsi: ufs: ufs-qcom: Enable SKIP DEVICE RESET Quirk A previous fix [1] addressed an OCP (Over Current Protection) issue during UFS power down (PC=3) by adding a 10ms delay after asserting HWRST. The delay allows the UFS device to complete its reset routine before the power rail transitions to LPM (Low Power Mode). However, this fix is insufficient for certain Micron UFS parts. Unlike other vendors whose reset routine completes within ~10ms, Micron parts continue to draw current beyond the LPM threshold for a longer duration after reset is asserted, specifically until the reset is deasserted (RST_N goes high). No fixed delay can reliably cover this window since there is currently no mechanism for the host to query whether the device reset routine has completed. Enable the UFSHCD_QUIRK_SKIP_DEVICE_RESET quirk to skip device assert reset during UFS power down for Micron parts. For all other vendors, the existing behavior (assert reset + 10ms delay) is preserved. This quirk is applicable only during shutdown. The device reset will be asserted as part of the platform shutdown sequences. [1] commit 5127be409c6c ("scsi: ufs: ufs-qcom: Fix UFS OCP issue during UFS power down (PC=3)") Link: https://lore.kernel.org/linux-scsi/20260531235011.1052706-3-nitin.rawat@oss.qualcomm.com/ Signed-off-by: Nitin Rawat Signed-off-by: Pradeep P V K --- drivers/ufs/host/ufs-qcom.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c index 07e6f0ece6ef6..1e347092a7d8d 100644 --- a/drivers/ufs/host/ufs-qcom.c +++ b/drivers/ufs/host/ufs-qcom.c @@ -753,9 +753,17 @@ static int ufs_qcom_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op, if (!ufs_qcom_is_link_active(hba)) ufs_qcom_disable_lane_clks(host); - - /* reset the connected UFS device during power down */ - if (ufs_qcom_is_link_off(hba) && host->device_reset) { + /* + * For some UFS vendors, skip asserting device reset here. + * These vendor parts keep drawing larger current after reset + * is asserted until it is deasserted, and the 10ms delay is + * not sufficient to prevent OCP (Over Current Protection) + * on the regulator. This is for the powerdown case, so + * the device reset can be asserted later as part of the + * platform shutdown sequence. + */ + if (ufs_qcom_is_link_off(hba) && host->device_reset && + !(hba->quirks & UFSHCD_QUIRK_SKIP_DEVICE_RESET)) { ufs_qcom_device_reset_ctrl(hba, true); /* * After sending the SSU command, asserting the rst_n @@ -1068,6 +1076,19 @@ static struct ufs_dev_quirk ufs_qcom_dev_fixups[] = { static void ufs_qcom_fixup_dev_quirks(struct ufs_hba *hba) { ufshcd_fixup_dev_quirks(hba, ufs_qcom_dev_fixups); + + /* + * Some UFS parts keep drawing larger current after reset is asserted + * until it is deasserted. The 10ms delay added after asserting HWRST + * (as done for other vendors) is not sufficient for these parts. + * + * Skip asserting device reset during UFS power down for these parts + * to prevent OCP (Over Current Protection) fault on the regulator. + * This is handled only in shutdown; the device reset will be asserted + * as part of the platform shutdown sequence. + */ + if (hba->dev_info.wmanufacturerid == UFS_VENDOR_MICRON) + hba->quirks |= UFSHCD_QUIRK_SKIP_DEVICE_RESET; } static u32 ufs_qcom_get_ufs_hci_version(struct ufs_hba *hba)