| Message ID | 20211127223253.19098-7-semen.protsenko@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | soc: samsung: Add USIv2 driver | expand |
On Sun, 28 Nov 2021 at 16:27, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Sun, Nov 28, 2021 at 12:32:51AM +0200, Sam Protsenko wrote: > > When UART is encapsulated in USIv2 block (e.g. in Exynos850), USIv2 > > driver must be loaded first, as it's preparing USI hardware for > > particular protocol use. Make it impossible for Samsung serial driver to > > be built-in when USIv2 driver is built as a module, to prevent incorrect > > booting order for those drivers. > > > > Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org> > > --- > > drivers/tty/serial/Kconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig > > index 0e5ccb25bdb1..47bc24e74041 100644 > > --- a/drivers/tty/serial/Kconfig > > +++ b/drivers/tty/serial/Kconfig > > @@ -237,6 +237,7 @@ config SERIAL_CLPS711X_CONSOLE > > config SERIAL_SAMSUNG > > tristate "Samsung SoC serial support" > > depends on PLAT_SAMSUNG || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_APPLE || COMPILE_TEST > > + depends on EXYNOS_USI_V2 || !EXYNOS_USI_V2 > > That's odd, and is not going to help if everything is built as a module > and loaded that way. > > This needs to be done properly in code to handle the issues if the > "wrong" code is loaded first. Please trigger off of the hardware type > correctly so you don't have to worry about this at all. > You are right. The only thing that should be done is "__init" should be removed from s3c24xx_serial_console_setup() and s3c24xx_serial_get_options() functions. Because in case when USIv2 driver instantiates the serial driver via of_platform_populate(), when USI_V2=m and SERIAL_SAMSUNG=y, those symbols will be thrown away already. And of course "[PATCH 5/8] tty: serial: samsung: Enable console as module" is needed as well. Correct init order (USI vs serial) is already ensured by embedding serial node in USI node (as a child node). We'll still have some weird init order in that case (USI_V2=m and SERIAL_SAMSUNG=y), like doing serial console init first (and earlycon), then registering USI driver as a module (reconfiguring USI IP-core), and then doing serial probe. But at least that doesn't crash and works fine (only causing some delay once, in the middle of dmesg output). But I guess that would be a problem of people who decided to go with such weird config. Bottom line is, this patch is not needed. I'll re-send v2 soon, excluding it from there, and will also add that mentioned "__init" removal. Thanks for review! > thanks, > > greg k-h
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 0e5ccb25bdb1..47bc24e74041 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -237,6 +237,7 @@ config SERIAL_CLPS711X_CONSOLE config SERIAL_SAMSUNG tristate "Samsung SoC serial support" depends on PLAT_SAMSUNG || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_APPLE || COMPILE_TEST + depends on EXYNOS_USI_V2 || !EXYNOS_USI_V2 select SERIAL_CORE help Support for the on-chip UARTs on the Samsung
When UART is encapsulated in USIv2 block (e.g. in Exynos850), USIv2 driver must be loaded first, as it's preparing USI hardware for particular protocol use. Make it impossible for Samsung serial driver to be built-in when USIv2 driver is built as a module, to prevent incorrect booting order for those drivers. Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org> --- drivers/tty/serial/Kconfig | 1 + 1 file changed, 1 insertion(+)