[U-Boot] [PATCH 1/2] serial: add skipping init option
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(+)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 887cd68..7aeaffb 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -459,6 +459,12 @@ config DEBUG_UART_NS16550_CHECK_ENABLED Note that this does not work for every ns16550-compatible UART and so has to be enabled carefully or you might notice lost characters.
+config UART_SKIP_INIT + bool "Skip UART initialization" + help + Select this if the UART you want to use for output is already + initialized by the time U-Boot starts its execution. + config ALTERA_JTAG_UART bool "Altera JTAG UART support" depends on DM_SERIAL
Skip uart initilization if CONFIG_UART_SKIP_INIT is defined. That's means earlier firmware already initialized the uart.
Signed-off-by: Jun Nie jun.nie@linaro.org --- drivers/serial/serial_mxc.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c index 476df25..01c97a4 100644 --- a/drivers/serial/serial_mxc.c +++ b/drivers/serial/serial_mxc.c @@ -231,9 +231,11 @@ static int mxc_serial_tstc(void) */ static int mxc_serial_init(void) { +#ifndef CONFIG_UART_SKIP_INIT _mxc_serial_init(mxc_base, false);
serial_setbrg(); +#endif
return 0; } @@ -276,7 +278,9 @@ static int mxc_serial_probe(struct udevice *dev) { struct mxc_serial_platdata *plat = dev->platdata;
+#ifndef CONFIG_UART_SKIP_INIT _mxc_serial_init(plat->reg, plat->use_dte); +#endif
return 0; }
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
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.
Regards. 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?
Regards, Simon
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
http://patchwork.ozlabs.org/patch/865963/
Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Hi Jun,
On Wed, 27 Mar 2019 at 03:55, Jun Nie jun.nie@linaro.org wrote:
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);}
I'm not very knowledgeable on this platform. This seems OK to me but you should send a patch for iMX people to review.
Regards, Simon
Hi Lukasz,
On Wed, 27 Mar 2019 at 03:34, Lukasz Majewski lukma@denx.de wrote:
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
Yes. But in the case of this patch I'm hoping we don't need it.
Regards, Simon
Simon Glass sjg@chromium.org 于2019年3月31日周日 上午5:19写道：
Hi Lukasz,
On Wed, 27 Mar 2019 at 03:34, Lukasz Majewski lukma@denx.de wrote:
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
Yes. But in the case of this patch I'm hoping we don't need it.
Regards, Simon
Right, we do not need patch here to skip the initialization. I already add the fix in imx clock side to imx patch set. Thank for suggestion!
Jun
participants (3)
-
Jun Nie -
Lukasz Majewski -
Simon Glass