Commit 8043b16f authored by Valentin Caron's avatar Valentin Caron Committed by Greg Kroah-Hartman
Browse files

serial: stm32: add earlycon support 



Add early console support in stm32 uart driver.

Signed-off-by: default avatarAlexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: default avatarValentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220419085330.1178925-4-valentin.caron@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f507b3a

drivers/tty/serial/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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"

drivers/tty/serial/stm32-usart.c

+51 −0
Original line number Diff line number Diff line
@@ -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,