LXR linux/arch/x86/kernel/cpu/mtrr/centaur.c

   1#include <linux/init.h>
   2#include <linux/mm.h>
   3
   4#include <asm/mtrr.h>
   5#include <asm/msr.h>
   6
   7#include "mtrr.h"
   8
   9static struct {
  10        unsigned long high;
  11        unsigned long low;
  12} centaur_mcr[8];
  13
  14static u8 centaur_mcr_reserved;
  15static u8 centaur_mcr_type;     /* 0 for winchip, 1 for winchip2 */
  16
  17/**
  18 * centaur_get_free_region - Get a free MTRR.
  19 *
  20 * @base: The starting (base) address of the region.
  21 * @size: The size (in bytes) of the region.
  22 *
  23 * Returns: the index of the region on success, else -1 on error.
  24 */
  25static int
  26centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
  27{
  28        unsigned long lbase, lsize;
  29        mtrr_type ltype;
  30        int i, max;
  31
  32        max = num_var_ranges;
  33        if (replace_reg >= 0 && replace_reg < max)
  34                return replace_reg;
  35
  36        for (i = 0; i < max; ++i) {
  37                if (centaur_mcr_reserved & (1 << i))
  38                        continue;
  39                mtrr_if->get(i, &lbase, &lsize, &ltype);
  40                if (lsize == 0)
  41                        return i;
  42        }
  43
  44        return -ENOSPC;
  45}
  46
  47/*
  48 * Report boot time MCR setups
  49 */
  50void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
  51{
  52        centaur_mcr[mcr].low = lo;
  53        centaur_mcr[mcr].high = hi;
  54}
  55
  56static void
  57centaur_get_mcr(unsigned int reg, unsigned long *base,
  58                unsigned long *size, mtrr_type * type)
  59{
  60        *base = centaur_mcr[reg].high >> PAGE_SHIFT;
  61        *size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
  62        *type = MTRR_TYPE_WRCOMB;               /* write-combining  */
  63
  64        if (centaur_mcr_type == 1 && ((centaur_mcr[reg].low & 31) & 2))
  65                *type = MTRR_TYPE_UNCACHABLE;
  66        if (centaur_mcr_type == 1 && (centaur_mcr[reg].low & 31) == 25)
  67                *type = MTRR_TYPE_WRBACK;
  68        if (centaur_mcr_type == 0 && (centaur_mcr[reg].low & 31) == 31)
  69                *type = MTRR_TYPE_WRBACK;
  70}
  71
  72static void
  73centaur_set_mcr(unsigned int reg, unsigned long base,
  74                unsigned long size, mtrr_type type)
  75{
  76        unsigned long low, high;
  77
  78        if (size == 0) {
  79                /* Disable */
  80                high = low = 0;
  81        } else {
  82                high = base << PAGE_SHIFT;
  83                if (centaur_mcr_type == 0) {
  84                        /* Only support write-combining... */
  85                        low = -size << PAGE_SHIFT | 0x1f;
  86                } else {
  87                        if (type == MTRR_TYPE_UNCACHABLE)
  88                                low = -size << PAGE_SHIFT | 0x02; /* NC */
  89                        else
  90                                low = -size << PAGE_SHIFT | 0x09; /* WWO, WC */
  91                }
  92        }
  93        centaur_mcr[reg].high = high;
  94        centaur_mcr[reg].low = low;
  95        wrmsr(MSR_IDT_MCR0 + reg, low, high);
  96}
  97
  98static int
  99centaur_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
 100{
 101        /*
 102         * FIXME: Winchip2 supports uncached
 103         */
 104        if (type != MTRR_TYPE_WRCOMB &&
 105            (centaur_mcr_type == 0 || type != MTRR_TYPE_UNCACHABLE)) {
 106                pr_warning("mtrr: only write-combining%s supported\n",
 107                           centaur_mcr_type ? " and uncacheable are" : " is");
 108                return -EINVAL;
 109        }
 110        return 0;
 111}
 112
 113static const struct mtrr_ops centaur_mtrr_ops = {
 114        .vendor            = X86_VENDOR_CENTAUR,
 115        .set               = centaur_set_mcr,
 116        .get               = centaur_get_mcr,
 117        .get_free_region   = centaur_get_free_region,
 118        .validate_add_page = centaur_validate_add_page,
 119        .have_wrcomb       = positive_have_wrcomb,
 120};
 121
 122int __init centaur_init_mtrr(void)
 123{
 124        set_mtrr_ops(&centaur_mtrr_ops);
 125        return 0;
 126}
 127