switch-coreboot/arch/x86/serial.c
Stefan Reinauer c275218a89 Add a first bit of a framework. Builds the following parts, in
accordance to the newboot document:

* reset vector (16 bytes)
* vpd (240bytes)
* boot block (8k - 256b)
* lar archive (256-8 k)

The boot block is kind of simple, still. It enables pmode, car, and
starts looking for an initram module in the lar archive.

Note: This doesnt do much at the moment,
as gas seems to produce buggy code in init.S.

Take this as a suggestion of how it might work and please provide
patches fixing it and bringing it into shape.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Ronald G. Minnich <rminnich@gmail.com>



git-svn-id: svn://coreboot.org/repository/LinuxBIOSv3@62 f3766cd6-281f-0410-b1cd-43a5c92072e9
2007-01-29 22:09:50 +00:00

110 lines
2.4 KiB
C

#include <arch/io.h>
#include <fallback.h>
/* Base Address */
#ifndef TTYS0_BASE
#define TTYS0_BASE 0x3f8
#endif
#ifndef TTYS0_BAUD
#define TTYS0_BAUD 115200
#endif
#if ((115200%TTYS0_BAUD) != 0)
#error Bad ttys0 baud rate
#endif
#define TTYS0_DIV (115200/TTYS0_BAUD)
/* Line Control Settings */
#ifndef TTYS0_LCS
/* Set 8bit, 1 stop bit, no parity */
#define TTYS0_LCS 0x3
#endif
#define UART_LCS TTYS0_LCS
#if CONFIG_USE_INIT == 0
/* Data */
#define UART_RBR 0x00
#define UART_TBR 0x00
/* Control */
#define UART_IER 0x01
#define UART_IIR 0x02
#define UART_FCR 0x02
#define UART_LCR 0x03
#define UART_MCR 0x04
#define UART_DLL 0x00
#define UART_DLM 0x01
/* Status */
#define UART_LSR 0x05
#define UART_MSR 0x06
#define UART_SCR 0x07
static int uart_can_tx_byte(void)
{
return inb(TTYS0_BASE + UART_LSR) & 0x20;
}
static void uart_wait_to_tx_byte(void)
{
while(!uart_can_tx_byte())
;
}
static void uart_wait_until_sent(void)
{
while(!(inb(TTYS0_BASE + UART_LSR) & 0x40))
;
}
static void uart_tx_byte(unsigned char data)
{
uart_wait_to_tx_byte();
outb(data, TTYS0_BASE + UART_TBR);
/* Make certain the data clears the fifos */
uart_wait_until_sent();
}
void uart_init(void)
{
/* disable interrupts */
outb(0x0, TTYS0_BASE + UART_IER);
/* enable fifo's */
outb(0x01, TTYS0_BASE + UART_FCR);
/* Set Baud Rate Divisor to 12 ==> 115200 Baud */
outb(0x80 | UART_LCS, TTYS0_BASE + UART_LCR);
#if USE_OPTION_TABLE == 1
static const unsigned char divisor[] = { 1,2,3,6,12,24,48,96 };
unsigned ttys0_div, ttys0_index;
ttys0_index = read_option(CMOS_VSTART_baud_rate, CMOS_VLEN_baud_rate, 0);
ttys0_index &= 7;
ttys0_div = divisor[ttys0_index];
outb(ttys0_div & 0xff, TTYS0_BASE + UART_DLL);
outb(0, TTYS0_BASE + UART_DLM);
#else
outb(TTYS0_DIV & 0xFF, TTYS0_BASE + UART_DLL);
outb((TTYS0_DIV >> 8) & 0xFF, TTYS0_BASE + UART_DLM);
#endif
outb(UART_LCS, TTYS0_BASE + UART_LCR);
}
#else
extern void uart8250_init(unsigned base_port, unsigned divisor, unsigned lcs);
void uart_init(void)
{
#if USE_OPTION_TABLE == 1
static const unsigned char divisor[] = { 1,2,3,6,12,24,48,96 };
unsigned ttys0_div, ttys0_index;
ttys0_index = read_option(CMOS_VSTART_baud_rate, CMOS_VLEN_baud_rate, 0);
ttys0_index &= 7;
ttys0_div = divisor[ttys0_index];
uart8250_init(TTYS0_BASE, ttys0_div, UART_LCS);
#else
uart8250_init(TTYS0_BASE, TTYS0_DIV, UART_LCS);
#endif
}
#endif