scsi: ufs: ufs-qcom: Restore HS/LS link startup mode for Qualcomm UFS controller v6.2+

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The link startup mode (HS LSS - high-speed link startup, or LS LSS -
low-speed link startup) is decided in the boot stage based on the
bootconfig GPIO. This selection is carried forward through the secondary
stage bootloaders and finally to HLOS via the spare configuration
register (REG_UFS_DEBUG_SPARE_CFG).

On Qualcomm UFS controller v6.2 and later, bit 31 in the spare
configuration register indicates the high-speed link startup mode
selection, as per the Hardware Programming Guide (HPG).

The spare register value is read during host driver initialization but
gets cleared after UFS reset. Preserve the spare register value during
initialization and restore it during link startup to maintain the
bootloader-configured link startup mode.

Signed-off-by: Nitin Rawat <nitin.rawat@oss.qualcomm.com>
Tested-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://patch.msgid.link/20260825145203.265579-2-nitin.rawat@oss.qualcomm.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>

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This commit is contained in:

Nitin Rawat 2026-08-25 20:22:02 +05:30 • committed by Martin K. Petersen (Oracle)

parent 9a69cc5f19

commit a3756f53ba

2 changed files with 13 additions and 3 deletions

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15

drivers/ufs/host/ufs-qcom.c

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1

drivers/ufs/host/ufs-qcom.h

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