8ca8d7665d
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@784 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
93 lines
1.8 KiB
C
93 lines
1.8 KiB
C
#include <part/fallback_boot.h>
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/* Base Address */
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#ifndef TTYS0_BASE
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#define TTYS0_BASE 0x3f8
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#endif
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#ifndef TTYS0_BAUD
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#define TTYS0_BAUD 115200
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#endif
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#if ((115200%TTYS0_BAUD) != 0)
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#error Bad ttys0 baud rate
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#endif
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#define TTYS0_DIV (115200/TTYS0_BAUD)
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/* Line Control Settings */
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#ifndef TTYS0_LCS
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/* Set 8bit, 1 stop bit, no parity */
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#define TTYS0_LCS 0x3
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#endif
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#define UART_LCS TTYS0_LCS
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/* Data */
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#define UART_RBR 0x00
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#define UART_TBR 0x00
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/* Control */
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#define UART_IER 0x01
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#define UART_IIR 0x02
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#define UART_FCR 0x02
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#define UART_LCR 0x03
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#define UART_MCR 0x04
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#define UART_DLL 0x00
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#define UART_DLM 0x01
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/* Status */
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#define UART_LSR 0x05
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#define UART_MSR 0x06
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#define UART_SCR 0x07
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static int uart_can_tx_byte(void)
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{
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return inb(TTYS0_BASE + UART_LSR) & 0x20;
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}
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static void uart_wait_to_tx_byte(void)
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{
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while(!uart_can_tx_byte())
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;
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}
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static void uart_wait_until_sent(void)
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{
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while(!(inb(TTYS0_BASE + UART_LSR) & 0x40))
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;
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}
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static void uart_tx_byte(unsigned char data)
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{
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uart_wait_to_tx_byte();
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outb(data, TTYS0_BASE + UART_TBR);
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/* Make certain the data clears the fifos */
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uart_wait_until_sent();
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}
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static void uart_init(void)
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{
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/* disable interrupts */
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outb(0x0, TTYS0_BASE + UART_IER);
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/* enable fifo's */
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outb(0x01, TTYS0_BASE + UART_FCR);
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/* Set Baud Rate Divisor to 12 ==> 115200 Baud */
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outb(0x80 | UART_LCS, TTYS0_BASE + UART_LCR);
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#if 0 && USE_OPTION_TABLE == 1
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{
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static const unsigned char divisor[] = { 1,2,3,6,12,24,48,96 };
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unsigned ttys0_div, ttys0_index;
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outb(RTC_BOOT_BYTE + 1, 0x70);
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ttys0_index = inb(0x71);
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ttys0_index &= 7;
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ttys0_div = divisor[ttys0_index];
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outb(ttys0_div & 0xff, TTYS0_BASE + UART_DLL);
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outb(0, TTYS0_BASE + UART_DLM);
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}
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#else
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outb(TTYS0_DIV & 0xFF, TTYS0_BASE + UART_DLL);
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outb((TTYS0_DIV >> 8) & 0xFF, TTYS0_BASE + UART_DLM);
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#endif
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outb(UART_LCS, TTYS0_BASE + UART_LCR);
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}
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