From f2d937f3bf00665ccf048b3b6616ef95859b0945 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 17 Apr 2008 20:05:37 +0200 Subject: consoles: polling support, kgdboc polled console handling support, to access a console in an irq-less way while in debug or irq context. absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled. (which is the default) [ jan.kiszka@siemens.com: lots of cleanups ] [ mingo@elte.hu: redesign, splitups, cleanups. ] Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar Signed-off-by: Jan Kiszka Reviewed-by: Thomas Gleixner --- drivers/serial/8250.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'drivers/serial/8250.c') diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 77f7a7f0646..96a585e1cee 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits) } } +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context. + */ + +static int serial8250_get_poll_char(struct uart_port *port) +{ + struct uart_8250_port *up = (struct uart_8250_port *)port; + unsigned char lsr = serial_inp(up, UART_LSR); + + while (!(lsr & UART_LSR_DR)) + lsr = serial_inp(up, UART_LSR); + + return serial_inp(up, UART_RX); +} + + +static void serial8250_put_poll_char(struct uart_port *port, + unsigned char c) +{ + unsigned int ier; + struct uart_8250_port *up = (struct uart_8250_port *)port; + + /* + * First save the IER then disable the interrupts + */ + ier = serial_in(up, UART_IER); + if (up->capabilities & UART_CAP_UUE) + serial_out(up, UART_IER, UART_IER_UUE); + else + serial_out(up, UART_IER, 0); + + wait_for_xmitr(up, BOTH_EMPTY); + /* + * Send the character out. + * If a LF, also do CR... + */ + serial_out(up, UART_TX, c); + if (c == 10) { + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_TX, 13); + } + + /* + * Finally, wait for transmitter to become empty + * and restore the IER + */ + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_IER, ier); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static int serial8250_startup(struct uart_port *port) { struct uart_8250_port *up = (struct uart_8250_port *)port; @@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = { .request_port = serial8250_request_port, .config_port = serial8250_config_port, .verify_port = serial8250_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif }; static struct uart_8250_port serial8250_ports[UART_NR]; -- cgit v1.2.3-70-g09d2 From e991a2bd4fa0b2f475b67dfe8f33e8ecbdcbb40b Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 28 Apr 2008 02:14:06 -0700 Subject: Fix tty speed handling on 8250 We try and write the correct speed back but the serial midlayer already mangles the speed on us and that means if we request B0 we report back B9600 when we should not. For now we'll hack around this in the drivers and serial code, pending a better long term solution. Signed-off-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/serial/8250.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/serial/8250.c') diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 96a585e1cee..6d0ce64163e 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -2228,7 +2228,9 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios, } serial8250_set_mctrl(&up->port, up->port.mctrl); spin_unlock_irqrestore(&up->port.lock, flags); - tty_termios_encode_baud_rate(termios, baud, baud); + /* Don't rewrite B0 */ + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); } static void -- cgit v1.2.3-70-g09d2 From 01c194d9278efc15d4785ff205643e9c0bdcef53 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 28 Apr 2008 02:14:09 -0700 Subject: serial 8250: tighten test for using backup timer Thomas Koeller had reported an issue where a device that had been making use of the UART_BUG_TXEN code in the 8250 driver was mistakenly being caught by the backup timer test, causing the device to work improperly. To fix this, tighten the test requirements to enable the backup timer workaround. The backup timer is really meant to catch UARTs that don't re-assert the THRE interrupt. The expectation is that they do initially assert THRE. This patch clarifies the test. Signed-off-by: Alex Williamson Cc: Thomas Koeller Cc: Russell King Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/serial/8250.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/serial/8250.c') diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 6d0ce64163e..ea41f262645 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1868,6 +1868,7 @@ static int serial8250_startup(struct uart_port *port) } if (is_real_interrupt(up->port.irq)) { + unsigned char iir1; /* * Test for UARTs that do not reassert THRE when the * transmitter is idle and the interrupt has already @@ -1881,7 +1882,7 @@ static int serial8250_startup(struct uart_port *port) wait_for_xmitr(up, UART_LSR_THRE); serial_out_sync(up, UART_IER, UART_IER_THRI); udelay(1); /* allow THRE to set */ - serial_in(up, UART_IIR); + iir1 = serial_in(up, UART_IIR); serial_out(up, UART_IER, 0); serial_out_sync(up, UART_IER, UART_IER_THRI); udelay(1); /* allow a working UART time to re-assert THRE */ @@ -1894,7 +1895,7 @@ static int serial8250_startup(struct uart_port *port) * If the interrupt is not reasserted, setup a timer to * kick the UART on a regular basis. */ - if (iir & UART_IIR_NO_INT) { + if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) { pr_debug("ttyS%d - using backup timer\n", port->line); up->timer.function = serial8250_backup_timeout; up->timer.data = (unsigned long)up; -- cgit v1.2.3-70-g09d2