253 lines
7 KiB
C
253 lines
7 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2000,2001,2002,2003,2004,2005,2007,2008,2009,2010 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/machine/memory.h>
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#include <grub/serial.h>
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#include <grub/ns8250.h>
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#include <grub/types.h>
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#include <grub/dl.h>
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#include <grub/misc.h>
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#include <grub/cpu/io.h>
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#include <grub/mm.h>
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#ifdef GRUB_MACHINE_PCBIOS
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static const unsigned short *serial_hw_io_addr = (const unsigned short *) GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
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#define GRUB_SERIAL_PORT_NUM 4
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#else
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#include <grub/machine/serial.h>
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static const grub_port_t serial_hw_io_addr[] = GRUB_MACHINE_SERIAL_PORTS;
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#define GRUB_SERIAL_PORT_NUM (ARRAY_SIZE(serial_hw_io_addr))
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#endif
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/* Convert speed to divisor. */
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static unsigned short
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serial_get_divisor (unsigned int speed)
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{
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unsigned int i;
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/* The structure for speed vs. divisor. */
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struct divisor
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{
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unsigned int speed;
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unsigned short div;
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};
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/* The table which lists common configurations. */
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/* 1843200 / (speed * 16) */
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static struct divisor divisor_tab[] =
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{
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{ 2400, 0x0030 },
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{ 4800, 0x0018 },
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{ 9600, 0x000C },
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{ 19200, 0x0006 },
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{ 38400, 0x0003 },
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{ 57600, 0x0002 },
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{ 115200, 0x0001 }
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};
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/* Set the baud rate. */
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for (i = 0; i < ARRAY_SIZE (divisor_tab); i++)
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if (divisor_tab[i].speed == speed)
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/* UART in Yeeloong runs twice the usual rate. */
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#ifdef GRUB_MACHINE_MIPS_YEELOONG
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return 2 * divisor_tab[i].div;
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#else
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return divisor_tab[i].div;
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#endif
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return 0;
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}
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static void
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do_real_config (struct grub_serial_port *port)
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{
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int divisor;
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unsigned char status = 0;
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const unsigned char parities[] = {
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[GRUB_SERIAL_PARITY_NONE] = UART_NO_PARITY,
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[GRUB_SERIAL_PARITY_ODD] = UART_ODD_PARITY,
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[GRUB_SERIAL_PARITY_EVEN] = UART_EVEN_PARITY
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};
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const unsigned char stop_bits[] = {
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[GRUB_SERIAL_STOP_BITS_1] = UART_1_STOP_BIT,
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[GRUB_SERIAL_STOP_BITS_2] = UART_2_STOP_BITS,
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};
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if (port->configured)
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return;
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divisor = serial_get_divisor (port->config.speed);
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/* Turn off the interrupt. */
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grub_outb (0, port->port + UART_IER);
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/* Set DLAB. */
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grub_outb (UART_DLAB, port->port + UART_LCR);
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/* Set the baud rate. */
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grub_outb (divisor & 0xFF, port->port + UART_DLL);
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grub_outb (divisor >> 8, port->port + UART_DLH);
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/* Set the line status. */
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status |= (parities[port->config.parity]
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| (port->config.word_len - 5)
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| stop_bits[port->config.stop_bits]);
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grub_outb (status, port->port + UART_LCR);
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/* In Yeeloong serial port has only 3 wires. */
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#ifndef GRUB_MACHINE_MIPS_YEELOONG
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/* Enable the FIFO. */
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grub_outb (UART_ENABLE_FIFO_TRIGGER1, port->port + UART_FCR);
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/* Turn on DTR and RTS. */
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grub_outb (UART_ENABLE_DTRRTS, port->port + UART_MCR);
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#else
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/* Enable the FIFO. */
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grub_outb (UART_ENABLE_FIFO_TRIGGER14, port->port + UART_FCR);
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/* Turn on DTR, RTS, and OUT2. */
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grub_outb (UART_ENABLE_DTRRTS | UART_ENABLE_OUT2, port->port + UART_MCR);
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#endif
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/* Drain the input buffer. */
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while (grub_inb (port->port + UART_LSR) & UART_DATA_READY)
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grub_inb (port->port + UART_RX);
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port->configured = 1;
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}
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/* Fetch a key. */
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static int
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serial_hw_fetch (struct grub_serial_port *port)
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{
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do_real_config (port);
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if (grub_inb (port->port + UART_LSR) & UART_DATA_READY)
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return grub_inb (port->port + UART_RX);
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return -1;
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}
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/* Put a character. */
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static void
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serial_hw_put (struct grub_serial_port *port, const int c)
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{
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unsigned int timeout = 100000;
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do_real_config (port);
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/* Wait until the transmitter holding register is empty. */
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while ((grub_inb (port->port + UART_LSR) & UART_EMPTY_TRANSMITTER) == 0)
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{
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if (--timeout == 0)
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/* There is something wrong. But what can I do? */
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return;
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}
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grub_outb (c, port->port + UART_TX);
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}
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/* Initialize a serial device. PORT is the port number for a serial device.
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SPEED is a DTE-DTE speed which must be one of these: 2400, 4800, 9600,
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19200, 38400, 57600 and 115200. WORD_LEN is the word length to be used
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for the device. Likewise, PARITY is the type of the parity and
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STOP_BIT_LEN is the length of the stop bit. The possible values for
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WORD_LEN, PARITY and STOP_BIT_LEN are defined in the header file as
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macros. */
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static grub_err_t
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serial_hw_configure (struct grub_serial_port *port,
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struct grub_serial_config *config)
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{
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unsigned short divisor;
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divisor = serial_get_divisor (config->speed);
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if (divisor == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "bad speed");
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if (config->parity != GRUB_SERIAL_PARITY_NONE
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&& config->parity != GRUB_SERIAL_PARITY_ODD
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&& config->parity != GRUB_SERIAL_PARITY_EVEN)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported parity");
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if (config->stop_bits != GRUB_SERIAL_STOP_BITS_1
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&& config->stop_bits != GRUB_SERIAL_STOP_BITS_2)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported stop bits");
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if (config->word_len < 5 || config->word_len > 8)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "unsupported word length");
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port->config = *config;
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port->configured = 0;
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/* FIXME: should check if the serial terminal was found. */
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return GRUB_ERR_NONE;
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}
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struct grub_serial_driver grub_ns8250_driver =
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{
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.configure = serial_hw_configure,
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.fetch = serial_hw_fetch,
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.put = serial_hw_put
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};
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static char com_names[GRUB_SERIAL_PORT_NUM][20];
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static struct grub_serial_port com_ports[GRUB_SERIAL_PORT_NUM];
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void
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grub_ns8250_init (void)
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{
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unsigned i;
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for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
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if (serial_hw_io_addr[i])
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{
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grub_err_t err;
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grub_snprintf (com_names[i], sizeof (com_names[i]), "com%d", i);
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com_ports[i].name = com_names[i];
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com_ports[i].driver = &grub_ns8250_driver;
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com_ports[i].port = serial_hw_io_addr[i];
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err = grub_serial_config_defaults (&com_ports[i]);
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if (err)
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grub_print_error ();
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grub_serial_register (&com_ports[i]);
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}
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}
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char *
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grub_serial_ns8250_add_port (grub_port_t port)
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{
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struct grub_serial_port *p;
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unsigned i;
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for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
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if (com_ports[i].port == port)
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return com_names[i];
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p = grub_malloc (sizeof (*p));
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if (!p)
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return NULL;
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p->name = grub_xasprintf ("port%lx", (unsigned long) port);
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if (!p->name)
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{
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grub_free (p);
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return NULL;
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}
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p->driver = &grub_ns8250_driver;
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grub_serial_config_defaults (p);
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p->port = port;
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grub_serial_register (p);
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return p->name;
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}
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