Commit 205b5bdd authored by Douglas Anderson's avatar Douglas Anderson Committed by Daniel Thompson
Browse files

serial: qcom_geni_serial: Support kgdboc_earlycon 



Implement the read() function in the early console driver.  With
recent kgdb patches this allows you to use kgdb to debug fairly early
into the system boot.

We only bother implementing this if polling is enabled since kgdb
can't be enabled without that.

Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200507130644.v4.10.If2deff9679a62c1ce1b8f2558a8635dc837adf8c@changeid


Signed-off-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
parent a4912303

drivers/tty/serial/qcom_geni_serial.c

+32 −0
Original line number Diff line number Diff line
@@ -1090,6 +1090,36 @@ static void qcom_geni_serial_earlycon_write(struct console *con, 
	__qcom_geni_serial_console_write(&dev->port, s, n);

}



#ifdef CONFIG_CONSOLE_POLL

static int qcom_geni_serial_earlycon_read(struct console *con,

					  char *s, unsigned int n)

{

	struct earlycon_device *dev = con->data;

	struct uart_port *uport = &dev->port;

	int num_read = 0;

	int ch;



	while (num_read < n) {

		ch = qcom_geni_serial_get_char(uport);

		if (ch == NO_POLL_CHAR)

			break;

		s[num_read++] = ch;

	}



	return num_read;

}



static void __init qcom_geni_serial_enable_early_read(struct geni_se *se,

						      struct console *con)

{

	geni_se_setup_s_cmd(se, UART_START_READ, 0);

	con->read = qcom_geni_serial_earlycon_read;

}

#else

static inline void qcom_geni_serial_enable_early_read(struct geni_se *se,

						      struct console *con) { }

#endif



static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,

								const char *opt)

{
@@ -1136,6 +1166,8 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev, 


	dev->con->write = qcom_geni_serial_earlycon_write;

	dev->con->setup = NULL;

	qcom_geni_serial_enable_early_read(&se, dev->con);



	return 0;

}

OF_EARLYCON_DECLARE(qcom_geni, "qcom,geni-debug-uart",

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