Messages in this thread Patch in this message | | | Date | Tue, 14 Oct 2008 15:31:09 -0700 | Subject | [PATCH] Enable console on PCI serial devices | From | donald.d.dugger@intel ... |
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The problem with using a PCI serial card for the console is that, until the PCI serial driver is loaded, output will be lost. The issue is that PCI serial devices use a non-standard I/O port address and sometimes use a non-standard crystal frequency. This patch gets around those problems by allowing you to specify both I/O port address and crystal frequency on the kernel command line. The serial console specification is enhanced to be:
BBBBPNF-III/CCC
where BBBB is the baud rate, P is the parity, N is the number of bits, F is the flow control, III is the I/O port address (prefix with 0x for hexadecimal) and CCC is the crystal frequency. -III and /CCC are optional and can be omitted although -III must be specified if you want to set /CCC. For example, the option I use is:
console=ttyS0,115200-0xe880/921600
Signed-off-by: Don Dugger <donald.d.dugger@intel.com>
Documentation/serial-console.txt | 12 ++++++++---- drivers/serial/8250.c | 2 +- drivers/serial/serial_core.c | 26 ++++++++++++++++++++++---- include/linux/serial_core.h | 2 +- 4 files changed, 32 insertions(+), 10 deletions(-)
----- cut here for patch.d/pci_serial-1014.patch ----- diff --git a/Documentation/serial-console.txt b/Documentation/serial-console.txt index 9a7bc8b..8cffce6 100644 --- a/Documentation/serial-console.txt +++ b/Documentation/serial-console.txt @@ -21,10 +21,14 @@ The format of this option is: options: depend on the driver. For the serial port this defines the baudrate/parity/bits/flow control of - the port, in the format BBBBPNF, where BBBB is the - speed, P is parity (n/o/e), N is number of bits, - and F is flow control ('r' for RTS). Default is - 9600n8. The maximum baudrate is 115200. + the port, in the format BBBBPNF-III/CCC, where BBBB + is the speed, P is parity (n/o/e), N is number of bits, + F is flow control ('r' for RTS), III is I/O port + address (prefix with 0x for hexadecimal) and CCC is + the uart crystal frequency. Default is 9600n8. The + I/O port defaults to 0x3f8 for ttyS0 and 0x2f8 for + ttyS1. The default crystal frequency is 1843200. + The maximum baudrate is 115200. You can specify multiple console= options on the kernel command line. Output will appear on all of them. The last device will be used when diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index d3ca7d3..5d59cf7 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -2632,7 +2632,7 @@ static int __init serial8250_console_setup(struct console *co, char *options) return -ENODEV; if (options) - uart_parse_options(options, &baud, &parity, &bits, &flow); + uart_parse_options(options, &baud, &parity, &bits, &flow, &port->iobase, &port->uartclk); return uart_set_options(port, co, baud, parity, bits, flow); } diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 6bdf336..31b5545 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1864,25 +1864,43 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co) * @parity: pointer to an 'int' variable for the parity. * @bits: pointer to an 'int' variable for the number of data bits. * @flow: pointer to an 'int' variable for the flow control character. + * @ioport: pointer to an 'int' variable for the I/O base for device + * @clk: pointer to an 'int' variable for the clock devisor * * uart_parse_options decodes a string containing the serial console * options. The format of the string is <baud><parity><bits><flow>, * eg: 115200n8r */ void -uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow) +uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow, int *ioport, int *clk) { char *s = options; *baud = simple_strtoul(s, NULL, 10); while (*s >= '0' && *s <= '9') s++; - if (*s) + if (*s && (*s != '-')) *parity = *s++; - if (*s) + if (*s && (*s != '-')) *bits = *s++ - '0'; - if (*s) + if (*s && (*s != '-')) *flow = *s; + if (*s && (*s != '-')) + *flow = *s++; + if (*s++ == '-') { + int b; + + if (*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')) { + s += 2; + b = 16; + } else + b = 10; + *ioport = simple_strtoul(s, NULL, b); + while (*s && (*s != '/')) + s++; + if (*s == '/') + *clk = simple_strtoul(s + 1, NULL, 10) << 4; + } } EXPORT_SYMBOL_GPL(uart_parse_options); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index e27f216..3b4fb3a 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -402,7 +402,7 @@ unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); struct uart_port *uart_get_console(struct uart_port *ports, int nr, struct console *c); void uart_parse_options(char *options, int *baud, int *parity, int *bits, - int *flow); + int *flow, int *iobase, int *clk); int uart_set_options(struct uart_port *port, struct console *co, int baud, int parity, int bits, int flow); struct tty_driver *uart_console_device(struct console *co, int *index);
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