This is a cache of https://discuss.96boards.org/t/robotics-rb5-ufs-storage-device-doesnt-work-at-gear4-after-switching-to-aosp/11870. It is a snapshot of the page at 2024-09-28T14:23:17.466+0000.
Robotics RB5 UFS storage device doesn't work at gear4 after switching to AOSP - Qualcomm RB5 - 96Boards Forum

Robotics RB5 UFS storage device doesn't work at gear4 after switching to AOSP

Products Support Qualcomm RB5
#1

Hi,

The RB5 board has preinstalled Yocto OS (kernel 4.19.125). The UFS storage device works in gear 4 with version (see the attachment #1). After switching to AOSP (the AOSP project is compiled and flashed using device/linaro/dragonboard/installer/rv5/flash-all-aosp.sh), the storage is limited to gear 3 (see the attachment #2).

With UFS protocol analyzer we’d discovered that gear limitation comes from the UFS controller

I’ve recompiled the kernel, but it doesn’t help (and I couldn’t find any UFS controller gear limitations in DTS anyway)

How can I solve this problem?

Thank you

Stanislav

rb5 after burning AOSP
rb5 after burning AOSP1920×1080 448 KB

RB5-Gear4
RB5-Gear41592×573 75.3 KB

#2

hey! thanks for reporting the issue! Looks like it’s a legit problem… the Yocto build that comes with the device is provided by QCOM/Thundercomm, based on Qualcomm 4.19 product kernel, and has proper support for gear 4.

The AOSP build provided by Android/Linaro is based on a different Linux kernel, e.g. the mainline/upstream kernel. What you’ve identified is a bug (or missing feature) in the upstream UFS qcom driver, which does not support gear 4. we made a quick test to enable gear 4, and it didn’t work out of the box. we will need to investigate a bit more…

#3

Hi,
Are there plans to fix this issue? If not, please, could you provide a link to a git repository with RB5 kernel where UFS device gear 4 is supported.
Thank you.
Stanislav

#4

hey,

I am not aware of any progress…we took note of the problem, but nobody has looked into it yet. What we noticed is that in the upstream kernel, ufshcd_init_pwr_dev_param() specifies G3 to be the max gear for the platform in hs-mode, which is why G3 is used. So definitely support for G4 is missing.

The vendor kernel for 8250/RB5 is the Qualcomm msm-4.19 kernel, and it’s available here

The UFS driver in the vendor kernel is quite different from upstream…

#5

Hi Nicolas,
Thank you for the fast response. Any idea which branch contains the vendor code? I couldn’t find in the list of branches something related to RB5 and the default branch contains code very similar to the 4.19 mainline.
Regards
Stanislav

#6

The link I shared includes points to the proper branch (e.g. it’s branch msm-4.19 in the git tree called msm-4.19).

#7

@Stas I’ve added the UFS Gear4 support in RB5 and pushed the commits to ufs_gear4 branch:
https://git.linaro.org/people/manivannan.sadhasivam/linux.git/log/?h=ufs_gear4

With this branch, I could confirm that the UFS in RB5 operates at HS-G4-B:

[    5.813039] ufshcd-qcom 1d84000.ufshc: ufshcd_print_pwr_info:[RX, TX]: gear=[1, 1], lane[1, 1], pwr[SLOWAUTO_MODE, SLOWAUTO_MODE], rate = 0
[    5.890181] ufshcd-qcom 1d84000.ufshc: ufshcd_print_pwr_info:[RX, TX]: gear=[4, 4], lane[2, 2], pwr[FAST MODE, FAST MODE], rate = 2

This branch is on top of linux-next/master as of 2022-08-22 and the patches will be submitted to the mailing list very soon.

Thanks,
Mani

#8

Hi Mani,
The patches work well. Thank you very much.
Regards
Stas