A sysreset-gpio can be provided in an RK3399 platform's Device Tree and if U-Boot detects a "warm" boot was done, it'll toggle that GPIO to perform a reset of the PMIC, essentially forcing a cold boot to make sure there are no non-default values in SoC registers.
For now, this was only supported in SPL, probably because when this was implemented RK3399 (and specifically Puma) didn't have TPL support so SPL was the earliest stage. Now that most RK3399 boards (and specifically Puma) have TPL enabled, it makes sense to move this logic triggering this sysreset from it. It brings the following advantages: - faster boot time as we don't need to reach SPL to be able to reset the system on a condition we know is already met in TPL, - have less code to be impacted by the issue this system reset works around (that is, "unclean" SoC registers after a reboot), - less confusion around the reason for restarting. Indeed when done from SPL, the following log can be observed: """ U-Boot TPL 2025.01-rc1-00165-gd79216ca9878-dirty (Nov 05 2024 - 15:31:45) Channel 0: DDR3, 666MHz BW=32 Col=10 Bk=8 CS0 Row=16 CS=1 Die BW=16 Size=2048MB Channel 1: DDR3, 666MHz BW=32 Col=10 Bk=8 CS0 Row=16 CS=1 Die BW=16 Size=2048MB 256B stride Trying to boot from BOOTROM Returning to boot ROM... U-Boot SPL 2025.01-rc1-00165-gd79216ca9878-dirty (Nov 05 2024 - 15:31:45 +0100) Trying to boot from MMC2 U-Boot TPL 2025.01-rc1-00165-gd79216ca9878-dirty (Nov 05 2024 - 15:31:45) """ possibly hinting at an issue within the SPL when loading the fitImage from MMC2 instead of the normal course of events (a system reset). For this to be possible, a weak callback is added in the TPL main C code so that we can hook this sysreset function within the TPL code path. @Cc Paul since he's trying to add support for this sysreset to the Firefly ROC-RK3399-PC[1] and Pine64 ROCKPro64[2]. You'll want to have gpio1 with boopth-pre-sram though so it makes it to the TPL DTB. [1] https://lore.kernel.org/u-boot/20240926183111.1324284-1-pa...@sys-base.io/ [2] https://lore.kernel.org/u-boot/20240926183111.1324284-2-pa...@sys-base.io/ Signed-off-by: Quentin Schulz <quentin.sch...@cherry.de> --- Changes in v2: - added Paul's Rb tags - fixed "an TPL" typos - removed SPL support (merging patches 4 and 5 from v1 for bisectability) - removed indentation in # if defined and their trailing comments - Link to v1: https://lore.kernel.org/r/20241105-rk3399-sysreset-gpio-tpl-v1-0-12caff07a...@cherry.de --- Quentin Schulz (4): pinctrl: rockchip: allow to build for TPL rockchip: rk3399: merge CRU check within rk3399_force_power_on_reset rockchip: tpl: allow to call board/SoC-specific code before DRAM init rockchip: rk3399: move sysreset-gpio logic to TPL arch/arm/mach-rockchip/rk3399/rk3399.c | 56 ++++++++++++++++++---------------- arch/arm/mach-rockchip/tpl.c | 6 ++++ configs/puma-rk3399_defconfig | 3 ++ drivers/pinctrl/Kconfig | 8 +++++ drivers/pinctrl/rockchip/Kconfig | 7 +++++ 5 files changed, 54 insertions(+), 26 deletions(-) --- base-commit: 56accc56b9aab87ef4809ccc588e1257969cd271 change-id: 20241105-rk3399-sysreset-gpio-tpl-50620781cdd9 Best regards, -- Quentin Schulz <quentin.sch...@cherry.de>
