Commit 9335e23d authored by Cristian Ciocaltea's avatar Cristian Ciocaltea Committed by Greg Kroah-Hartman
Browse files

tty: serial: owl: Add support for kernel debugger 



Implement 'poll_put_char' and 'poll_get_char' callbacks in struct
'owl_uart_ops' that enables OWL UART to be used for kernel debugging
over serial line.

Signed-off-by: default avatarCristian Ciocaltea <cristian.ciocaltea@gmail.com>
Link: https://lore.kernel.org/r/026543195b9aeefb339d90abc5660a6ac7463c63.1610484108.git.cristian.ciocaltea@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c9cd57bf

drivers/tty/serial/owl-uart.c

+38 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/console.h>

#include <linux/delay.h>

#include <linux/io.h>

#include <linux/iopoll.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>
@@ -62,6 +63,9 @@ 
#define OWL_UART_STAT_TRFL_MASK		GENMASK(16, 11)

#define OWL_UART_STAT_UTBB		BIT(17)



#define OWL_UART_POLL_USEC		5

#define OWL_UART_TIMEOUT_USEC		10000



static struct uart_driver owl_uart_driver;



struct owl_uart_info {
@@ -461,6 +465,36 @@ static void owl_uart_config_port(struct uart_port *port, int flags) 
	}

}



#ifdef CONFIG_CONSOLE_POLL



static int owl_uart_poll_get_char(struct uart_port *port)

{

	if (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_RFEM)

		return NO_POLL_CHAR;



	return owl_uart_read(port, OWL_UART_RXDAT);

}



static void owl_uart_poll_put_char(struct uart_port *port, unsigned char ch)

{

	u32 reg;

	int ret;



	/* Wait while FIFO is full or timeout */

	ret = readl_poll_timeout_atomic(port->membase + OWL_UART_STAT, reg,

					!(reg & OWL_UART_STAT_TFFU),

					OWL_UART_POLL_USEC,

					OWL_UART_TIMEOUT_USEC);

	if (ret == -ETIMEDOUT) {

		dev_err(port->dev, "Timeout waiting while UART TX FULL\n");

		return;

	}



	owl_uart_write(port, ch, OWL_UART_TXDAT);

}



#endif /* CONFIG_CONSOLE_POLL */



static const struct uart_ops owl_uart_ops = {

	.set_mctrl = owl_uart_set_mctrl,

	.get_mctrl = owl_uart_get_mctrl,
@@ -476,6 +510,10 @@ static const struct uart_ops owl_uart_ops = { 
	.request_port = owl_uart_request_port,

	.release_port = owl_uart_release_port,

	.verify_port = owl_uart_verify_port,

#ifdef CONFIG_CONSOLE_POLL

	.poll_get_char = owl_uart_poll_get_char,

	.poll_put_char = owl_uart_poll_put_char,

#endif

};



#ifdef CONFIG_SERIAL_OWL_CONSOLE