diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr/cyrix.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/cyrix.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/cyrix.c b/arch/x86/kernel/cpu/mtrr/cyrix.c new file mode 100644 index 000000000..4296c702a --- /dev/null +++ b/arch/x86/kernel/cpu/mtrr/cyrix.c @@ -0,0 +1,283 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/init.h> +#include <linux/io.h> +#include <linux/mm.h> + +#include <asm/processor-cyrix.h> +#include <asm/processor-flags.h> +#include <asm/mtrr.h> +#include <asm/msr.h> + +#include "mtrr.h" + +static void +cyrix_get_arr(unsigned int reg, unsigned long *base, + unsigned long *size, mtrr_type * type) +{ + unsigned char arr, ccr3, rcr, shift; + unsigned long flags; + + arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */ + + local_irq_save(flags); + + ccr3 = getCx86(CX86_CCR3); + setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */ + ((unsigned char *)base)[3] = getCx86(arr); + ((unsigned char *)base)[2] = getCx86(arr + 1); + ((unsigned char *)base)[1] = getCx86(arr + 2); + rcr = getCx86(CX86_RCR_BASE + reg); + setCx86(CX86_CCR3, ccr3); /* disable MAPEN */ + + local_irq_restore(flags); + + shift = ((unsigned char *) base)[1] & 0x0f; + *base >>= PAGE_SHIFT; + + /* + * Power of two, at least 4K on ARR0-ARR6, 256K on ARR7 + * Note: shift==0xf means 4G, this is unsupported. + */ + if (shift) + *size = (reg < 7 ? 0x1UL : 0x40UL) << (shift - 1); + else + *size = 0; + + /* Bit 0 is Cache Enable on ARR7, Cache Disable on ARR0-ARR6 */ + if (reg < 7) { + switch (rcr) { + case 1: + *type = MTRR_TYPE_UNCACHABLE; + break; + case 8: + *type = MTRR_TYPE_WRBACK; + break; + case 9: + *type = MTRR_TYPE_WRCOMB; + break; + case 24: + default: + *type = MTRR_TYPE_WRTHROUGH; + break; + } + } else { + switch (rcr) { + case 0: + *type = MTRR_TYPE_UNCACHABLE; + break; + case 8: + *type = MTRR_TYPE_WRCOMB; + break; + case 9: + *type = MTRR_TYPE_WRBACK; + break; + case 25: + default: + *type = MTRR_TYPE_WRTHROUGH; + break; + } + } +} + +/* + * cyrix_get_free_region - get a free ARR. + * + * @base: the starting (base) address of the region. + * @size: the size (in bytes) of the region. + * + * Returns: the index of the region on success, else -1 on error. +*/ +static int +cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg) +{ + unsigned long lbase, lsize; + mtrr_type ltype; + int i; + + switch (replace_reg) { + case 7: + if (size < 0x40) + break; + case 6: + case 5: + case 4: + return replace_reg; + case 3: + case 2: + case 1: + case 0: + return replace_reg; + } + /* If we are to set up a region >32M then look at ARR7 immediately */ + if (size > 0x2000) { + cyrix_get_arr(7, &lbase, &lsize, <ype); + if (lsize == 0) + return 7; + /* Else try ARR0-ARR6 first */ + } else { + for (i = 0; i < 7; i++) { + cyrix_get_arr(i, &lbase, &lsize, <ype); + if (lsize == 0) + return i; + } + /* + * ARR0-ARR6 isn't free + * try ARR7 but its size must be at least 256K + */ + cyrix_get_arr(i, &lbase, &lsize, <ype); + if ((lsize == 0) && (size >= 0x40)) + return i; + } + return -ENOSPC; +} + +static u32 cr4, ccr3; + +static void prepare_set(void) +{ + u32 cr0; + + /* Save value of CR4 and clear Page Global Enable (bit 7) */ + if (boot_cpu_has(X86_FEATURE_PGE)) { + cr4 = __read_cr4(); + __write_cr4(cr4 & ~X86_CR4_PGE); + } + + /* + * Disable and flush caches. + * Note that wbinvd flushes the TLBs as a side-effect + */ + cr0 = read_cr0() | X86_CR0_CD; + wbinvd(); + write_cr0(cr0); + wbinvd(); + + /* Cyrix ARRs - everything else was excluded at the top */ + ccr3 = getCx86(CX86_CCR3); + + /* Cyrix ARRs - everything else was excluded at the top */ + setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); +} + +static void post_set(void) +{ + /* Flush caches and TLBs */ + wbinvd(); + + /* Cyrix ARRs - everything else was excluded at the top */ + setCx86(CX86_CCR3, ccr3); + + /* Enable caches */ + write_cr0(read_cr0() & ~X86_CR0_CD); + + /* Restore value of CR4 */ + if (boot_cpu_has(X86_FEATURE_PGE)) + __write_cr4(cr4); +} + +static void cyrix_set_arr(unsigned int reg, unsigned long base, + unsigned long size, mtrr_type type) +{ + unsigned char arr, arr_type, arr_size; + + arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */ + + /* count down from 32M (ARR0-ARR6) or from 2G (ARR7) */ + if (reg >= 7) + size >>= 6; + + size &= 0x7fff; /* make sure arr_size <= 14 */ + for (arr_size = 0; size; arr_size++, size >>= 1) + ; + + if (reg < 7) { + switch (type) { + case MTRR_TYPE_UNCACHABLE: + arr_type = 1; + break; + case MTRR_TYPE_WRCOMB: + arr_type = 9; + break; + case MTRR_TYPE_WRTHROUGH: + arr_type = 24; + break; + default: + arr_type = 8; + break; + } + } else { + switch (type) { + case MTRR_TYPE_UNCACHABLE: + arr_type = 0; + break; + case MTRR_TYPE_WRCOMB: + arr_type = 8; + break; + case MTRR_TYPE_WRTHROUGH: + arr_type = 25; + break; + default: + arr_type = 9; + break; + } + } + + prepare_set(); + + base <<= PAGE_SHIFT; + setCx86(arr + 0, ((unsigned char *)&base)[3]); + setCx86(arr + 1, ((unsigned char *)&base)[2]); + setCx86(arr + 2, (((unsigned char *)&base)[1]) | arr_size); + setCx86(CX86_RCR_BASE + reg, arr_type); + + post_set(); +} + +typedef struct { + unsigned long base; + unsigned long size; + mtrr_type type; +} arr_state_t; + +static arr_state_t arr_state[8] = { + {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, + {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL} +}; + +static unsigned char ccr_state[7] = { 0, 0, 0, 0, 0, 0, 0 }; + +static void cyrix_set_all(void) +{ + int i; + + prepare_set(); + + /* the CCRs are not contiguous */ + for (i = 0; i < 4; i++) + setCx86(CX86_CCR0 + i, ccr_state[i]); + for (; i < 7; i++) + setCx86(CX86_CCR4 + i, ccr_state[i]); + + for (i = 0; i < 8; i++) { + cyrix_set_arr(i, arr_state[i].base, + arr_state[i].size, arr_state[i].type); + } + + post_set(); +} + +static const struct mtrr_ops cyrix_mtrr_ops = { + .vendor = X86_VENDOR_CYRIX, + .set_all = cyrix_set_all, + .set = cyrix_set_arr, + .get = cyrix_get_arr, + .get_free_region = cyrix_get_free_region, + .validate_add_page = generic_validate_add_page, + .have_wrcomb = positive_have_wrcomb, +}; + +int __init cyrix_init_mtrr(void) +{ + set_mtrr_ops(&cyrix_mtrr_ops); + return 0; +} |