diff options
| author | Valentin Caron <valentin.caron@foss.st.com> | 2022-04-19 11:53:30 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-22 17:36:23 +0300 |
| commit | 8043b16f522c9e21e2361a67514386bee3731c6e (patch) | |
| tree | 4548b40b84e1b4c702f95ee256f8ccd6ed22e877 /drivers | |
| parent | 1f507b3aecb3245177ca9012dfe08117bb7925e8 (diff) | |
| download | linux-8043b16f522c9e21e2361a67514386bee3731c6e.tar.xz | |
serial: stm32: add earlycon support
Add early console support in stm32 uart driver.
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220419085330.1178925-4-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/tty/serial/stm32-usart.c | 51 |
2 files changed, 52 insertions, 0 deletions
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index f51a8079f1f5..80321b9c4465 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1443,6 +1443,7 @@ config SERIAL_STM32_CONSOLE bool "Support for console on STM32" depends on SERIAL_STM32=y select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON config SERIAL_MVEBU_UART bool "Marvell EBU serial port support" diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 8aefb286bd88..f75691e72729 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1761,6 +1761,57 @@ static struct console stm32_console = { #define STM32_SERIAL_CONSOLE NULL #endif /* CONFIG_SERIAL_STM32_CONSOLE */ +#ifdef CONFIG_SERIAL_EARLYCON +static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch) +{ + struct stm32_usart_info *info = port->private_data; + + while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE)) + cpu_relax(); + + writel_relaxed(ch, port->membase + info->ofs.tdr); +} + +static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count) +{ + struct earlycon_device *device = console->data; + struct uart_port *port = &device->port; + + uart_console_write(port, s, count, early_stm32_usart_console_putchar); +} + +static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32h7_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32f7_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32f4_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup); +OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup); +OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup); +#endif /* CONFIG_SERIAL_EARLYCON */ + static struct uart_driver stm32_usart_driver = { .driver_name = DRIVER_NAME, .dev_name = STM32_SERIAL_NAME, |