diff options
Diffstat (limited to 'grub-core/term/ns8250.c')
| -rw-r--r-- | grub-core/term/ns8250.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/grub-core/term/ns8250.c b/grub-core/term/ns8250.c new file mode 100644 index 0000000..4be528d --- /dev/null +++ b/grub-core/term/ns8250.c @@ -0,0 +1,278 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2000,2001,2002,2003,2004,2005,2007,2008,2009,2010 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/serial.h> +#include <grub/ns8250.h> +#include <grub/types.h> +#include <grub/dl.h> +#include <grub/misc.h> +#include <grub/cpu/io.h> +#include <grub/mm.h> +#include <grub/time.h> + +#ifdef GRUB_MACHINE_PCBIOS +#include <grub/machine/memory.h> +static const unsigned short *serial_hw_io_addr = (const unsigned short *) GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR; +#define GRUB_SERIAL_PORT_NUM 4 +#else +#include <grub/machine/serial.h> +static const grub_port_t serial_hw_io_addr[] = GRUB_MACHINE_SERIAL_PORTS; +#define GRUB_SERIAL_PORT_NUM (ARRAY_SIZE(serial_hw_io_addr)) +#endif + +/* Convert speed to divisor. */ +static unsigned short +serial_get_divisor (unsigned int speed) +{ + unsigned int i; + + /* The structure for speed vs. divisor. */ + struct divisor + { + unsigned int speed; + unsigned short div; + }; + + /* The table which lists common configurations. */ + /* 1843200 / (speed * 16) */ + static struct divisor divisor_tab[] = + { + { 2400, 0x0030 }, + { 4800, 0x0018 }, + { 9600, 0x000C }, + { 19200, 0x0006 }, + { 38400, 0x0003 }, + { 57600, 0x0002 }, + { 115200, 0x0001 } + }; + + /* Set the baud rate. */ + for (i = 0; i < ARRAY_SIZE (divisor_tab); i++) + if (divisor_tab[i].speed == speed) + /* UART in Yeeloong runs twice the usual rate. */ +#ifdef GRUB_MACHINE_MIPS_YEELOONG + return 2 * divisor_tab[i].div; +#else + return divisor_tab[i].div; +#endif + return 0; +} + +static void +do_real_config (struct grub_serial_port *port) +{ + int divisor; + unsigned char status = 0; + const unsigned char parities[] = { + [GRUB_SERIAL_PARITY_NONE] = UART_NO_PARITY, + [GRUB_SERIAL_PARITY_ODD] = UART_ODD_PARITY, + [GRUB_SERIAL_PARITY_EVEN] = UART_EVEN_PARITY + }; + const unsigned char stop_bits[] = { + [GRUB_SERIAL_STOP_BITS_1] = UART_1_STOP_BIT, + [GRUB_SERIAL_STOP_BITS_2] = UART_2_STOP_BITS, + }; + + if (port->configured) + return; + + port->broken = 0; + + divisor = serial_get_divisor (port->config.speed); + + /* Turn off the interrupt. */ + grub_outb (0, port->port + UART_IER); + + /* Set DLAB. */ + grub_outb (UART_DLAB, port->port + UART_LCR); + + /* Set the baud rate. */ + grub_outb (divisor & 0xFF, port->port + UART_DLL); + grub_outb (divisor >> 8, port->port + UART_DLH); + + /* Set the line status. */ + status |= (parities[port->config.parity] + | (port->config.word_len - 5) + | stop_bits[port->config.stop_bits]); + grub_outb (status, port->port + UART_LCR); + + /* In Yeeloong serial port has only 3 wires. */ +#ifndef GRUB_MACHINE_MIPS_YEELOONG + /* Enable the FIFO. */ + grub_outb (UART_ENABLE_FIFO_TRIGGER1, port->port + UART_FCR); + + /* Turn on DTR and RTS. */ + grub_outb (UART_ENABLE_DTRRTS, port->port + UART_MCR); +#else + /* Enable the FIFO. */ + grub_outb (UART_ENABLE_FIFO_TRIGGER14, port->port + UART_FCR); + + /* Turn on DTR, RTS, and OUT2. */ + grub_outb (UART_ENABLE_DTRRTS | UART_ENABLE_OUT2, port->port + UART_MCR); +#endif + + /* Drain the input buffer. */ + while (grub_inb (port->port + UART_LSR) & UART_DATA_READY) + grub_inb (port->port + UART_RX); + + port->configured = 1; +} + +/* Fetch a key. */ +static int +serial_hw_fetch (struct grub_serial_port *port) +{ + do_real_config (port); + if (grub_inb (port->port + UART_LSR) & UART_DATA_READY) + return grub_inb (port->port + UART_RX); + + return -1; +} + +/* Put a character. */ +static void +serial_hw_put (struct grub_serial_port *port, const int c) +{ + grub_uint64_t endtime; + + do_real_config (port); + + if (port->broken > 5) + endtime = grub_get_time_ms (); + else if (port->broken > 1) + endtime = grub_get_time_ms () + 50; + else + endtime = grub_get_time_ms () + 200; + /* Wait until the transmitter holding register is empty. */ + while ((grub_inb (port->port + UART_LSR) & UART_EMPTY_TRANSMITTER) == 0) + { + if (grub_get_time_ms () > endtime) + { + port->broken++; + /* There is something wrong. But what can I do? */ + return; + } + } + + if (port->broken) + port->broken--; + + grub_outb (c, port->port + UART_TX); +} + +/* Initialize a serial device. PORT is the port number for a serial device. + SPEED is a DTE-DTE speed which must be one of these: 2400, 4800, 9600, + 19200, 38400, 57600 and 115200. WORD_LEN is the word length to be used + for the device. Likewise, PARITY is the type of the parity and + STOP_BIT_LEN is the length of the stop bit. The possible values for + WORD_LEN, PARITY and STOP_BIT_LEN are defined in the header file as + macros. */ +static grub_err_t +serial_hw_configure (struct grub_serial_port *port, + struct grub_serial_config *config) +{ + unsigned short divisor; + + divisor = serial_get_divisor (config->speed); + if (divisor == 0) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "bad speed"); + + if (config->parity != GRUB_SERIAL_PARITY_NONE + && config->parity != GRUB_SERIAL_PARITY_ODD + && config->parity != GRUB_SERIAL_PARITY_EVEN) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported parity"); + + if (config->stop_bits != GRUB_SERIAL_STOP_BITS_1 + && config->stop_bits != GRUB_SERIAL_STOP_BITS_2) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported stop bits"); + + if (config->word_len < 5 || config->word_len > 8) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported word length"); + + port->config = *config; + port->configured = 0; + + /* FIXME: should check if the serial terminal was found. */ + + return GRUB_ERR_NONE; +} + +struct grub_serial_driver grub_ns8250_driver = + { + .configure = serial_hw_configure, + .fetch = serial_hw_fetch, + .put = serial_hw_put + }; + +static char com_names[GRUB_SERIAL_PORT_NUM][20]; +static struct grub_serial_port com_ports[GRUB_SERIAL_PORT_NUM]; + +void +grub_ns8250_init (void) +{ + unsigned i; + for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++) + if (serial_hw_io_addr[i]) + { + grub_err_t err; + grub_snprintf (com_names[i], sizeof (com_names[i]), "com%d", i); + com_ports[i].name = com_names[i]; + com_ports[i].driver = &grub_ns8250_driver; + com_ports[i].port = serial_hw_io_addr[i]; + err = grub_serial_config_defaults (&com_ports[i]); + if (err) + grub_print_error (); + + grub_serial_register (&com_ports[i]); + } +} + +/* Return the port number for the UNITth serial device. */ +grub_port_t +grub_ns8250_hw_get_port (const unsigned int unit) +{ + if (unit < GRUB_SERIAL_PORT_NUM) + return serial_hw_io_addr[unit]; + else + return 0; +} + +char * +grub_serial_ns8250_add_port (grub_port_t port) +{ + struct grub_serial_port *p; + unsigned i; + for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++) + if (com_ports[i].port == port) + return com_names[i]; + p = grub_malloc (sizeof (*p)); + if (!p) + return NULL; + p->name = grub_xasprintf ("port%lx", (unsigned long) port); + if (!p->name) + { + grub_free (p); + return NULL; + } + p->driver = &grub_ns8250_driver; + grub_serial_config_defaults (p); + p->port = port; + grub_serial_register (p); + + return p->name; +} |