LXR uboot/arch/i386/cpu/cpu.c

   1/*
   2 * (C) Copyright 2002
   3 * Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
   4 *
   5 * (C) Copyright 2002
   6 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7 * Marius Groeger <mgroeger@sysgo.de>
   8 *
   9 * (C) Copyright 2002
  10 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11 * Alex Zuepke <azu@sysgo.de>
  12 *
  13 * See file CREDITS for list of people who contributed to this
  14 * project.
  15 *
  16 * This program is free software; you can redistribute it and/or
  17 * modify it under the terms of the GNU General Public License as
  18 * published by the Free Software Foundation; either version 2 of
  19 * the License, or (at your option) any later version.
  20 *
  21 * This program is distributed in the hope that it will be useful,
  22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 * GNU General Public License for more details.
  25 *
  26 * You should have received a copy of the GNU General Public License
  27 * along with this program; if not, write to the Free Software
  28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  29 * MA 02111-1307 USA
  30 */
  31
  32/*
  33 * CPU specific code
  34 */
  35
  36#include <common.h>
  37#include <command.h>
  38#include <asm/interrupt.h>
  39
  40/* Constructor for a conventional segment GDT (or LDT) entry */
  41/* This is a macro so it can be used in initializers */
  42#define GDT_ENTRY(flags, base, limit)                   \
  43        ((((base)  & 0xff000000ULL) << (56-24)) |       \
  44         (((flags) & 0x0000f0ffULL) << 40) |            \
  45         (((limit) & 0x000f0000ULL) << (48-16)) |       \
  46         (((base)  & 0x00ffffffULL) << 16) |            \
  47         (((limit) & 0x0000ffffULL)))
  48
  49/* Simple and small GDT entries for booting only */
  50
  51#define GDT_ENTRY_32BIT_CS      2
  52#define GDT_ENTRY_32BIT_DS      (GDT_ENTRY_32BIT_CS + 1)
  53#define GDT_ENTRY_16BIT_CS      (GDT_ENTRY_32BIT_DS + 1)
  54#define GDT_ENTRY_16BIT_DS      (GDT_ENTRY_16BIT_CS + 1)
  55
  56/*
  57 * Set up the GDT
  58 */
  59
  60struct gdt_ptr {
  61        u16 len;
  62        u32 ptr;
  63} __attribute__((packed));
  64
  65static void reload_gdt(void)
  66{
  67        /* There are machines which are known to not boot with the GDT
  68           being 8-byte unaligned.  Intel recommends 16 byte alignment. */
  69        static const u64 boot_gdt[] __attribute__((aligned(16))) = {
  70                /* CS: code, read/execute, 4 GB, base 0 */
  71                [GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),
  72                /* DS: data, read/write, 4 GB, base 0 */
  73                [GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),
  74                /* 16-bit CS: code, read/execute, 64 kB, base 0 */
  75                [GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff),
  76                /* 16-bit DS: data, read/write, 64 kB, base 0 */
  77                [GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff),
  78        };
  79        static struct gdt_ptr gdt;
  80
  81        gdt.len = sizeof(boot_gdt)-1;
  82        gdt.ptr = (u32)&boot_gdt;
  83
  84        asm volatile("lgdtl %0\n" \
  85                     "movl $((2+1)*8), %%ecx\n" \
  86                     "movl %%ecx, %%ds\n" \
  87                     "movl %%ecx, %%es\n" \
  88                     "movl %%ecx, %%fs\n" \
  89                     "movl %%ecx, %%gs\n" \
  90                     "movl %%ecx, %%ss" \
  91                     : : "m" (gdt) : "ecx");
  92}
  93
  94
  95int cpu_init_f(void)
  96{
  97        /* initialize FPU, reset EM, set MP and NE */
  98        asm ("fninit\n" \
  99             "movl %cr0, %eax\n" \
 100             "andl $~0x4, %eax\n" \
 101             "orl  $0x22, %eax\n" \
 102             "movl %eax, %cr0\n" );
 103
 104        return 0;
 105}
 106
 107int cpu_init_r(void)
 108{
 109        reload_gdt();
 110
 111        /* Initialize core interrupt and exception functionality of CPU */
 112        cpu_init_interrupts ();
 113        return 0;
 114}
 115
 116int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 117{
 118        printf ("resetting ...\n");
 119        udelay(50000);                          /* wait 50 ms */
 120        disable_interrupts();
 121        reset_cpu(0);
 122
 123        /*NOTREACHED*/
 124        return 0;
 125}
 126
 127void  flush_cache (unsigned long dummy1, unsigned long dummy2)
 128{
 129        asm("wbinvd\n");
 130        return;
 131}
 132
 133void __attribute__ ((regparm(0))) generate_gpf(void);
 134
 135/* segment 0x70 is an arbitrary segment which does not exist */
 136asm(".globl generate_gpf\n"
 137    ".hidden generate_gpf\n"
 138    ".type generate_gpf, @function\n"
 139    "generate_gpf:\n"
 140    "ljmp   $0x70, $0x47114711\n");
 141
 142void __reset_cpu(ulong addr)
 143{
 144        printf("Resetting using i386 Triple Fault\n");
 145        set_vector(13, generate_gpf);  /* general protection fault handler */
 146        set_vector(8, generate_gpf);   /* double fault handler */
 147        generate_gpf();                /* start the show */
 148}
 149void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));
 150