Commit 95a1b409 authored by John Ogness's avatar John Ogness Committed by Greg Kroah-Hartman
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serial: 8250: Use high-level writing function for FIFO 



Currently serial8250_console_fifo_write() directly writes into
the UART_TX register rather than using the high-level function
serial8250_console_putchar(). This is because
serial8250_console_putchar() waits for the holding register to
become empty, which would defeat the purpose of the FIFO code.

Move the LSR_THRE waiting to a new function
serial8250_console_wait_putchar() so that the FIFO code can use
serial8250_console_putchar(). This will be particularly important
for a follow-up commit, where output bytes are inspected to track
newlines.

This is only refactoring and has no functional change.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-4-john.ogness@linutronix.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8d5cfb1f

drivers/tty/serial/8250/8250_port.c

+10 −4
Original line number Diff line number Diff line
@@ -3298,11 +3298,16 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults); 
#ifdef CONFIG_SERIAL_8250_CONSOLE



static void serial8250_console_putchar(struct uart_port *port, unsigned char ch)

{

	serial_port_out(port, UART_TX, ch);

}



static void serial8250_console_wait_putchar(struct uart_port *port, unsigned char ch)

{

	struct uart_8250_port *up = up_to_u8250p(port);



	wait_for_xmitr(up, UART_LSR_THRE);

	serial_port_out(port, UART_TX, ch);

	serial8250_console_putchar(port, ch);

}



/*
@@ -3352,6 +3357,7 @@ static void serial8250_console_fifo_write(struct uart_8250_port *up, 
{

	const char *end = s + count;

	unsigned int fifosize = up->tx_loadsz;

	struct uart_port *port = &up->port;

	unsigned int tx_count = 0;

	bool cr_sent = false;

	unsigned int i;
@@ -3362,10 +3368,10 @@ static void serial8250_console_fifo_write(struct uart_8250_port *up, 


		for (i = 0; i < fifosize && s != end; ++i) {

			if (*s == '\n' && !cr_sent) {

				serial_out(up, UART_TX, '\r');

				serial8250_console_putchar(port, '\r');

				cr_sent = true;

			} else {

				serial_out(up, UART_TX, *s++);

				serial8250_console_putchar(port, *s++);

				cr_sent = false;

			}

		}
@@ -3445,7 +3451,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, 
	if (likely(use_fifo))

		serial8250_console_fifo_write(up, s, count);

	else

		uart_console_write(port, s, count, serial8250_console_putchar);

		uart_console_write(port, s, count, serial8250_console_wait_putchar);



	/*

	 *	Finally, wait for transmitter to become empty