Re: [PATCH V2 1/2] ufs: ufs-qcom: Restore HS/LS link startup mode for Qualcomm UFS controller v6.2+
Mukesh Ojha <[email protected]>
| Newsgroups | org.kernel.vger.linux-scsi,org.kernel.vger.linux-arm-msm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Tue, Aug 25, 2026 at 08:22:02PM +0530, Nitin Rawat wrote: > 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 <[email protected]> Tested-by: Mukesh Ojha <[email protected]> -Mukesh