вт, 1 квіт. 2025 р. о 16:34 Artur Kowalski <[email protected]> пише: > > > W dniu 31.03.2025 o 07:51, Svyatoslav Ryhel pisze: > > нд, 30 бер. 2025 р. о 22:27 Artur Kowalski <[email protected]> пише: > >> Tegra20 has mux allowing to repurpose microSD as UART on boards which > >> use sdmmc3 controller for microSD. Add TEGRA_UARTA_MICROSD to enable > >> this feature. It is currently supported on Transformer T20, support for > >> other boards may require Device Tree changes. > >> > >> Update Transformer T20 DTS to select correct pinmux and stdout-path > >> based on TEGRA_UARTA_MICROSD. > >> > >> Signed-off-by: Artur Kowalski <[email protected]> > >> --- > >> > >> Changes in v2: > >> - added TEGRA_UARTA_MICROSD Kconfig option > >> - removed .dtsi for enabling UART over microSD > >> - modified transformer DT to use UARTA and correct pinmux when > >> TEGRA_UARTA_MICROSD is enabled; it is enough to flip a single > >> switch to enable/disable UART over microSD > >> > >> arch/arm/dts/tegra20-asus-transformer.dtsi | 24 ++++++++++++++++++++++ > >> arch/arm/mach-tegra/tegra20/Kconfig | 15 ++++++++++++++ > >> 2 files changed, 39 insertions(+) > >> > >> diff --git a/arch/arm/dts/tegra20-asus-transformer.dtsi > >> b/arch/arm/dts/tegra20-asus-transformer.dtsi > >> index 49efabbfd92..9ea323c81f3 100644 > >> --- a/arch/arm/dts/tegra20-asus-transformer.dtsi > >> +++ b/arch/arm/dts/tegra20-asus-transformer.dtsi > >> @@ -5,7 +5,13 @@ > >> > >> / { > >> chosen { > >> +#if CONFIG_IS_ENABLED(TEGRA_ENABLE_UARTA) > >> + stdout-path = &uarta; > >> +#elif CONFIG_IS_ENABLED(TEGRA_ENABLE_UARTD) > >> stdout-path = &uartd; > >> +#else > >> +#error Unsupported UART > >> +#endif > >> }; > >> > >> aliases { > >> @@ -195,10 +201,17 @@ > >> nvidia,function = "i2c1"; > >> }; > >> > >> +#if CONFIG_IS_ENABLED(TEGRA_UARTA_SDB_SDD) > >> + dbguart { > >> + nvidia,pins = "sdb", "sdd"; > >> + nvidia,function = "uarta"; > >> + }; > >> +#else > >> sdb { > >> nvidia,pins = "sdb", "sdc", "sdd", > >> "slxc", "slxk"; > >> nvidia,function = "sdio3"; > >> }; > >> +#endif > >> > >> sdio1 { > >> nvidia,pins = "sdio1"; > >> @@ -376,7 +389,13 @@ > >> }; > >> }; > >> > >> +#if CONFIG_IS_ENABLED(TEGRA_ENABLE_UARTA) > >> + uarta: serial@70006000 { > >> +#elif CONFIG_IS_ENABLED(TEGRA_ENABLE_UARTD) > >> uartd: serial@70006300 { > >> +#else > >> +#error Unsupported UART > >> +#endif > >> status = "okay"; > >> clock-frequency = <216000000>; > >> }; > >> @@ -434,7 +453,12 @@ > >> }; > >> > >> sdmmc3: sdhci@c8000400 { > >> +#if CONFIG_IS_ENABLED(TEGRA_UARTA_MICROSD) > >> + /* Can't use both at the same time */ > >> + status = "disabled"; > >> +#else > >> status = "okay"; > >> +#endif > >> bus-width = <4>; > >> > >> cd-gpios = <&gpio TEGRA_GPIO(I, 5) GPIO_ACTIVE_LOW>; > >> diff --git a/arch/arm/mach-tegra/tegra20/Kconfig > >> b/arch/arm/mach-tegra/tegra20/Kconfig > >> index 3349f1e2786..c2c51660216 100644 > >> --- a/arch/arm/mach-tegra/tegra20/Kconfig > >> +++ b/arch/arm/mach-tegra/tegra20/Kconfig > >> @@ -77,6 +77,21 @@ endchoice > >> config SYS_SOC > >> default "tegra20" > >> > >> +config TEGRA_UARTA_MICROSD > >> + bool "UARTA on MicroSD breakout board" > >> + default n > >> + depends on TEGRA_ENABLE_UARTA && TARGET_TRANSFORMER_T20 > >> + select TEGRA_UARTA_SDB_SDD > >> + help > >> + Repurpose the SD card slot for getting access to the UARTA serial > >> + console. Primarily useful only for low level u-boot debugging on > >> + tablets, where normal UARTD is difficult to access and requires > >> + device disassembly and/or soldering. Enabling this option causes > >> + UARTA TX to become exposed on SDD and RX on SDB pins which > >> correspond > >> + to microSD CLK and CMD pins respectively. Currently this is > >> supported > >> + only on Transformer T20, support for other platforms may require > >> DT > >> + and configs (from include/configs/*) updates. > >> + > >> source "board/nvidia/harmony/Kconfig" > >> source "board/avionic-design/medcom-wide/Kconfig" > >> source "board/compal/paz00/Kconfig" > >> -- > >> 2.48.1 > >> > > This is not applicable since this is a hack by nature, BUT if you > > contain this in the transformer t20 board and Kconfig (no dts > > changes), this may be applied. > Ok, then I'll drop DTS changes. I will add few words about this option > in Transformer documentation > and a note in Kconfig help to not surprise users with not booting U-Boot > as enabling this option without > changing DTS causes U-Boot to hang.
You should remove then Kconfig option as well. Add a new chapter to Transformer T20 documentation which describes this method, here[1] you may find a similar approach but info is in the commit message of tegra30 uart-e funcmux. Additionally, as I have said previously, these changes can be contained in the transformer t20 board file by using some device tree manipulations from there. --- 1 https://source.denx.de/u-boot/u-boot/-/commit/b515d7ae0de51a26f73b2ddb5ea4db0d95b67d7a
