[PATCH] board: rockchip: unblock CAN bus in spl_board_init on Jaguar

[Kever Yang]

On 2025/6/17 16:42, Jakob Unterwurzacher wrote:
> GPIO0_B7 is routed to TXI of the on-board CAN transceiver. The
> line has a pull-down per SoC default.
>
> This means the CAN transceiver transmits a dominant zero
> and blocks the CAN bus until Linux boots and reconfigures the pin.
>
> Let's switch to pull-up as soon as we can (i.e. in SPL).
> This cuts down the "bus is blocked" time from 10 seconds to < 1 second.
>
> Of course, to this needs CONFIG_SPL_BOARD_INIT, so enable it
> the Jaguar defconfig.
>
> Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher at cherry.de>
Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
>   .../jaguar_rk3588/jaguar_rk3588.c             | 19 +++++++++++++++++++
>   configs/jaguar-rk3588_defconfig               |  1 +
>   2 files changed, 20 insertions(+)
>
> diff --git a/board/theobroma-systems/jaguar_rk3588/jaguar_rk3588.c b/board/theobroma-systems/jaguar_rk3588/jaguar_rk3588.c
> index a6d44f10db3..3f484646701 100644
> --- a/board/theobroma-systems/jaguar_rk3588/jaguar_rk3588.c
> +++ b/board/theobroma-systems/jaguar_rk3588/jaguar_rk3588.c
> @@ -51,3 +51,22 @@ int rockchip_early_misc_init_r(void)
>   
>   	return 0;
>   }
> +
> +#define GPIO0B7_PU_EN BIT(15)
> +
> +void spl_board_init(void)
> +{
> +	/*
> +	 * GPIO0_B7 is routed to CAN TX. This SoC pin has a pull-down per default.
> +	 * So on power-up, we block the CAN bus with a dominant zero. We want to keep
> +	 * this blocking time to a minimum, so we want to get this pin high in SPL.
> +	 *
> +	 * The CAN driver in Linux disables the pull-down and sets the pin to
> +	 * output high. We don't have a CAN driver in U-Boot and don't need one,
> +	 * so we just use the easiest way to get the pin high, which is setting a
> +	 * pull-up.
> +	 */
> +	struct rk3588_pmu2_ioc * const ioc = (void *)PMU2_IOC_BASE;
> +
> +	rk_setreg(&ioc->gpio0b_p, GPIO0B7_PU_EN);
> +}
> diff --git a/configs/jaguar-rk3588_defconfig b/configs/jaguar-rk3588_defconfig
> index 03d38274b15..272f1ca8ded 100644
> --- a/configs/jaguar-rk3588_defconfig
> +++ b/configs/jaguar-rk3588_defconfig
> @@ -27,6 +27,7 @@ CONFIG_DEFAULT_FDT_FILE="rockchip/rk3588-jaguar.dtb"
>   CONFIG_DISPLAY_BOARDINFO_LATE=y
>   CONFIG_CYCLIC=y
>   CONFIG_SPL_MAX_SIZE=0x40000
> +CONFIG_SPL_BOARD_INIT=y
>   # CONFIG_SPL_RAW_IMAGE_SUPPORT is not set
>   CONFIG_SPL_ATF=y
>   # CONFIG_BOOTM_NETBSD is not set