sysinit.c

本程序是arm开发bios的实例代码

#include "board.h"
#include "utils.h"
#include "bios.h"

/*
 * Caculate system registers
 */

static unsigned long get_width_bits(unsigned long width)
{
	unsigned long bits;
	
	switch (width) {
	case 8:
		bits = 1;
		break;
	case 16:
		bits = 2;
		break;
	case 32:
		bits = 3;
		break;
	default:
		bits = 0;
	}
	
	return bits;
}

int sys_init(struct system_table_struct *system_table, unsigned long rom_base, unsigned dram_base)
{
	struct sys_regs_struct sys_regs;
	unsigned long base;
	unsigned long r;
	int i;

	sys_regs.extdbwth = 0;
	for (i = 0; i < 6; i++)
		sys_regs.extdbwth |= get_width_bits(system_table->rom_table[i].width) << (i * 2);
	for (i = 0; i < 4; i++)
		sys_regs.extdbwth |= get_width_bits(system_table->dram_table[i].width) << (i * 2 + 12);
	for (i = 0; i < 4; i++)
		sys_regs.extdbwth |= get_width_bits(system_table->ext_table[i].width) << (i * 2 + 20);

	base = rom_base;
	for (i = 0; i < 6; i++) {
		sys_regs.romcon[i] = (system_table->rom_table[i].flags & ~0x3ffffc00) |
			(((base + system_table->rom_table[i].size) & 0x03ff0000) << 4) |
			((base & 0x03ff0000) >> 6);
		base += system_table->rom_table[i].size;
	}

	base = dram_base;
	for (i = 0; i < 4; i++) {
		sys_regs.dramcon[i] = (system_table->dram_table[i].flags & ~0x3ffffc00) |
			(((base + system_table->dram_table[i].size) & 0x03ff0000) << 4) |
			((base & 0x03ff0000) >> 6);
		base += system_table->dram_table[i].size;
	}

	sys_regs.refextcon = ((system_table->ext_base & 0x03ff0000) >> 16) | 0xce298000;

	outl(sys_regs.extdbwth, EXTDBWTH);
	outl(sys_regs.romcon[0], ROMCON0);
	outl(sys_regs.romcon[1], ROMCON1);
	outl(sys_regs.romcon[2], ROMCON2);
	outl(sys_regs.romcon[3], ROMCON3);
	outl(sys_regs.romcon[4], ROMCON4);
	outl(sys_regs.romcon[5], ROMCON5);
	outl(sys_regs.dramcon[0], DRAMCON0);
	outl(sys_regs.dramcon[1], DRAMCON1);
	outl(sys_regs.dramcon[2], DRAMCON2);
	outl(sys_regs.dramcon[3], DRAMCON3);
	outl(sys_regs.refextcon, REFEXTCON);

	r = (system_table->ext_table[0].flags & 0xffff) |
		((system_table->ext_table[1].flags & 0xffff) << 16);
	outl(r, EXTACON0);
	r = (system_table->ext_table[2].flags & 0xffff) |
		((system_table->ext_table[3].flags & 0xffff) << 16);
	outl(r, EXTACON1);

	outl(system_table->iop.iopmod, IOPMOD);
	outl(system_table->iop.iopcon, IOPCON);
	outl(system_table->iop.iopdata, IOPDATA);

	return 0;
}