Lukasz Majewski lukma@denx.de 于2019年3月27日周三 下午5:34写道：
Hi Simon, Jun,
Hi Jun,
On Fri, 22 Mar 2019 at 16:02, Jun Nie jun.nie@linaro.org wrote:
Simon Glass sjg@chromium.org 于2019年3月22日周五 下午3:56写道：
Hi Jun,
On Fri, 22 Mar 2019 at 15:20, Jun Nie jun.nie@linaro.org wrote:
add skipping init option to avoid corrupt data in console if serial is already initilized when u-boot start its excution.
Signed-off-by: Jun Nie jun.nie@linaro.org
drivers/serial/Kconfig | 6 ++++++ 1 file changed, 6 insertions(+)
Could we use a device-tree property for this? Some UARTs have a 'skip-init' property.
Regards, Simon
Hi Simon,
It is a good suggestion. But device tree is board specific, while the config is boot flow specific. For ATF -> OPTEE -> U-BOOT case, initialization should be skipped. Without earlier initialization from firmware, U-boot should do it by itself. So I need find a solution that is defconfig specific, instead of device tree specific.
So you want something that is flow-specific, I think. Your thinking is that the defconfig specifies this. Is that because certain boards require ATF/Optee?
Should we consider having a way to tell U-Boot that it is running from Optee?
Could the UART driver detect that the UART is already inited?
Isn't this issue similar to: http://patchwork.ozlabs.org/patch/820824/
and
My case is that console does not emit any log when OPTEE runs into u-boot. I already root caused that there is a bug in uart clock handling. UART1_CLK_ROOT is hard coded in imx_get_uartclk() of arch/arm/mach-imx/mx7/clock.c If the console serial is not UART1, 0 may be returned and console does not work.
But when I add an IMX_UART_PORT config option in Kconfig to dynamic configure the CLK_ROOT ID as below, the expansion result is UARTCONFIG_IMX_UART_PORT_CLK_ROOT instead of UART1_CLK_ROOT. It seems macro expansion happens before the inclusion of defconfig. Do you see any better idea other than add the definition in include/configs/pico-imx7d.h directly?
#define IMX_UART_CLK_ROOT UART##CONFIG_IMX_UART_PORT##_CLK_ROOT
Current plan is to add below change so that platform can define different clock root other than UART1_CLK_ROOT.
+++ b/arch/arm/mach-imx/mx7/clock.c @@ -51,9 +51,12 @@ static u32 get_ipg_clk(void) return get_ahb_clk() / 2; }
+#ifndef UART_CLK_ROOT +#define UART_CLK_ROOT UART1_CLK_ROOT +#endif u32 imx_get_uartclk(void) { - return get_root_clk(UART1_CLK_ROOT); + return get_root_clk(UART_CLK_ROOT); }
Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Best regards,
Lukasz Majewski
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