[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] Enable PCI serial devices for console messages
# HG changeset patch # User Keir Fraser <keir.fraser@xxxxxxxxxx> # Date 1224241225 -3600 # Node ID 50aaffd8f87c7dd085cc02bf471f1e4d1155dd11 # Parent 6bf61b830153010d9f3a551811469a7fbfddf023 Enable PCI serial devices for console messages The basic issue is that some PCI serial devices use a non-standard crystal to control the baud rate divisor. This patch enhances the `com' parameter to enable you to specify the crystal frequency used by the serial device. Since this parameter already allows you to specify I/O address and IRQ this is all that is needed to get a PCI serial device to work. With this patch the `com' parameter is now defined as: comN=BBB[/CCC][,NPS[,III[,IRQ]]] Where `CCC' is the crystal frequency. Note that if you specify 0 for `IRQ' Xen will run the serial device in polled mode, obviating the need for interrupts (an advantage since this is the only way I was able to get my PCI serial device to work). As an example, I am using the xen boot command: kernel /xen.gz com1=3D115200,8n1,0xe880/921600,0 console=3Dcom1 Signed-off-by: Don Dugger <donald.d.dugger@xxxxxxxxx> Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx> --- xen/drivers/char/ns16550.c | 19 ++++++++++++++----- 1 files changed, 14 insertions(+), 5 deletions(-) diff -r 6bf61b830153 -r 50aaffd8f87c xen/drivers/char/ns16550.c --- a/xen/drivers/char/ns16550.c Thu Oct 16 18:45:48 2008 +0100 +++ b/xen/drivers/char/ns16550.c Fri Oct 17 12:00:25 2008 +0100 @@ -18,17 +18,19 @@ #include <asm/io.h> /* - * Configure serial port with a string <baud>,DPS,<io-base>,<irq>. + * Configure serial port with a string: + * <baud>[/<clock_hz>][,DPS[,<io-base>[,<irq>]]]. * The tail of the string can be omitted if platform defaults are sufficient. * If the baud rate is pre-configured, perhaps by a bootloader, then 'auto' - * can be specified in place of a numeric baud rate. + * can be specified in place of a numeric baud rate. Polled mode is specified + * by requesting irq 0. */ static char opt_com1[30] = "", opt_com2[30] = ""; string_param("com1", opt_com1); string_param("com2", opt_com2); static struct ns16550 { - int baud, data_bits, parity, stop_bits, irq; + int baud, clock_hz, data_bits, parity, stop_bits, irq; unsigned long io_base; /* I/O port or memory-mapped I/O address. */ char *remapped_io_base; /* Remapped virtual address of mmap I/O. */ /* UART with IRQ line: interrupt-driven I/O. */ @@ -192,7 +194,7 @@ static void __devinit ns16550_init_preir if ( uart->baud != BAUD_AUTO ) { /* Baud rate specified: program it into the divisor latch. */ - divisor = UART_CLOCK_HZ / (uart->baud * 16); + divisor = uart->clock_hz / (uart->baud << 4); ns_write_reg(uart, DLL, (char)divisor); ns_write_reg(uart, DLM, (char)(divisor >> 8)); } @@ -201,7 +203,7 @@ static void __devinit ns16550_init_preir /* Baud rate already set: read it out from the divisor latch. */ divisor = ns_read_reg(uart, DLL); divisor |= ns_read_reg(uart, DLM) << 8; - uart->baud = UART_CLOCK_HZ / (divisor * 16); + uart->baud = uart->clock_hz / (divisor << 4); } ns_write_reg(uart, LCR, lcr); @@ -354,6 +356,12 @@ static void __init ns16550_parse_port_co } else if ( (baud = simple_strtoul(conf, &conf, 10)) != 0 ) uart->baud = baud; + + if ( *conf == '/') + { + conf++; + uart->clock_hz = simple_strtoul(conf, &conf, 0) << 4; + } if ( *conf != ',' ) goto config_parsed; @@ -408,6 +416,7 @@ void __init ns16550_init(int index, stru uart->baud = (defaults->baud ? : console_has((index == 0) ? "com1" : "com2") ? BAUD_AUTO : 0); + uart->clock_hz = UART_CLOCK_HZ; uart->data_bits = defaults->data_bits; uart->parity = parse_parity_char(defaults->parity); uart->stop_bits = defaults->stop_bits; _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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