On 4/6/21 6:47 PM, Yann Dirson wrote:
> From: Yann Dirson <yann@blade-group.com>
>
> TF-A runs between two u-boot stages which both uses 1500000 baud, it
> just makes no sense to use the same UART at a different rate.
>
> Here is a sample session with the successive stages, with TF-A artificially
> separated for emphasis:
>
>   [20210406-175438.135934] U-Boot TPL 2021.01 (Jan 11 2021 - 18:11:43)
>   [20210406-175438.135956] Channel 0: DDR3, 933MHz
>   [20210406-175438.236974] BW=32 Col=10 Bk=8 CS0 Row=15 CS=1 Die BW=16 Size=1024MB
>   [20210406-175438.237000] Channel 1: DDR3, 933MHz
>   [20210406-175438.237004] BW=32 Col=10 Bk=8 CS0 Row=15 CS=1 Die BW=16 Size=1024MB
>   [20210406-175438.237008] 256B stride
>   [20210406-175438.237012] Trying to boot from BOOTROM
>   [20210406-175438.237015] Returning to boot ROM...
>   [20210406-175438.237018]
>   [20210406-175438.573394] U-Boot SPL 2021.01 (Jan 11 2021 - 18:11:43 +0000)
>   [20210406-175438.573431] Trying to boot from MMC1
>
>   [20210406-175438.589254] NOTICE:  BL31: v2.3():v2.3-dirty
>   [20210406-175440.534055] NOTICE:  BL31: Built : 15:56:43, Apr 20 2020
>
>   [20210406-175441.393423] U-Boot 2021.01 (Jan 11 2021 - 18:11:43 +0000)
>   [20210406-175441.393429]
>   [20210406-175441.393433] SoC: Rockchip rk3399

Very good. TF-A should work "out of the box" in meta-rockchip, so I 
think changing it's baudrate to 1500000 makes sense at this point (at 
least until u-boot can pass the DTB)

>
> Signed-off-by: Yann Dirson <yann@blade-group.com>
> ---
>   .../files/serial-console-baudrate.patch       | 35 +++++++++++++++++++
>   .../trusted-firmware-a_%.bbappend             |  5 +++
>   2 files changed, 40 insertions(+)
>   create mode 100644 recipes-bsp/trusted-firmware-a/files/serial-console-baudrate.patch
>
> diff --git a/recipes-bsp/trusted-firmware-a/files/serial-console-baudrate.patch b/recipes-bsp/trusted-firmware-a/files/serial-console-baudrate.patch
> new file mode 100644
> index 0000000..10b5a2b
> --- /dev/null
> +++ b/recipes-bsp/trusted-firmware-a/files/serial-console-baudrate.patch
> @@ -0,0 +1,35 @@
> +From 840d6b6420e1fd8cdf6e4de7fa58a6f8de151622 Mon Sep 17 00:00:00 2001
> +From: Yann Dirson <yann@blade-group.com>
> +Date: Tue, 6 Apr 2021 17:28:45 +0200
> +Subject: [PATCH] Set serial console baudrate back to 1500000.
> +
> +TF-A runs between two u-boot stages which both uses 1500000 baud, it
> +just makes no sense to use the same UART at a different rate.
> +
> +This effectively reverts part of 0c05748bdebfad9fa43a80962186438bb8fbce62.
> +Main reason for that change stated in https://developer.trustedfirmware.org/T762
> +is ChromeOS compatibility.
> +
> +Looks like this patch may become unnecessary in the future, when
> +u-boot and TF-A get to communicate this value.

Please add Upstream-Status:


> +
> +---
> + plat/rockchip/rk3399/rk3399_def.h | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/plat/rockchip/rk3399/rk3399_def.h b/plat/rockchip/rk3399/rk3399_def.h
> +index ba83242eb..8d6ecfbe6 100644
> +--- a/plat/rockchip/rk3399/rk3399_def.h
> ++++ b/plat/rockchip/rk3399/rk3399_def.h
> +@@ -17,7 +17,7 @@
> + /**************************************************************************
> +  * UART related constants
> +  **************************************************************************/
> +-#define RK3399_BAUDRATE			115200
> ++#define RK3399_BAUDRATE			1500000
> + #define RK3399_UART_CLOCK		24000000
> +
> + /******************************************************************************
> +--
> +2.30.2
> +
> diff --git a/recipes-bsp/trusted-firmware-a/trusted-firmware-a_%.bbappend b/recipes-bsp/trusted-firmware-a/trusted-firmware-a_%.bbappend
> index 442dee8..1942c17 100644
> --- a/recipes-bsp/trusted-firmware-a/trusted-firmware-a_%.bbappend
> +++ b/recipes-bsp/trusted-firmware-a/trusted-firmware-a_%.bbappend
> @@ -4,3 +4,8 @@ DEPENDS_append_rk3399 = " virtual/arm-none-eabi-gcc-native"
>   
>   COMPATIBLE_MACHINE_append_rk3399 = "|rk3399"
>   COMPATIBLE_MACHINE_append_rk3328 = "|rk3328"
> +
> +FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
> +SRC_URI += "\
> +    file://serial-console-baudrate.patch \
> +"
>
> 
>