diff options
Diffstat (limited to 'src/northbridge/intel/sandybridge/ram_calc.c')
| -rw-r--r-- | src/northbridge/intel/sandybridge/ram_calc.c | 89 |
1 files changed, 88 insertions, 1 deletions
diff --git a/src/northbridge/intel/sandybridge/ram_calc.c b/src/northbridge/intel/sandybridge/ram_calc.c index 125f808fd1..026531a250 100644 --- a/src/northbridge/intel/sandybridge/ram_calc.c +++ b/src/northbridge/intel/sandybridge/ram_calc.c @@ -2,6 +2,7 @@ * This file is part of the coreboot project. * * Copyright (C) 2011 Google Inc. + * Copyright (C) 2012 ChromeOS Authors * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -15,11 +16,21 @@ #define __SIMPLE_DEVICE__ +#include <arch/cpu.h> #include <arch/io.h> #include <cbmem.h> #include <cpu/intel/romstage.h> +#include <cpu/x86/mtrr.h> +#include <program_loading.h> #include "sandybridge.h" +#if (CONFIG_SMM_TSEG_SIZE < 0x800000) +# error "CONFIG_SMM_TSEG_SIZE must at least be 8MiB" +#endif +#if ((CONFIG_SMM_TSEG_SIZE & (CONFIG_SMM_TSEG_SIZE - 1)) != 0) +# error "CONFIG_SMM_TSEG_SIZE is not a power of 2" +#endif + static uintptr_t smm_region_start(void) { /* Base of TSEG is top of usable DRAM */ @@ -32,7 +43,83 @@ void *cbmem_top(void) return (void *) smm_region_start(); } +static inline u32 *stack_push(u32 *stack, u32 value) +{ + stack = &stack[-1]; + *stack = value; + return stack; +} + +/* setup_stack_and_mtrrs() determines the stack to use after + * cache-as-ram is torn down as well as the MTRR settings to use. */ void *setup_stack_and_mtrrs(void) { - return (void*)CONFIG_RAMTOP; + int num_mtrrs; + u32 *slot; + u32 mtrr_mask_upper; + u32 top_of_ram; + + /* Top of stack needs to be aligned to a 4-byte boundary. */ + slot = (void *)romstage_ram_stack_top(); + num_mtrrs = 0; + + /* The upper bits of the MTRR mask need to set according to the number + * of physical address bits. */ + mtrr_mask_upper = (1 << (cpu_phys_address_size() - 32)) - 1; + + /* The order for each MTRR is value then base with upper 32-bits of + * each value coming before the lower 32-bits. The reasoning for + * this ordering is to create a stack layout like the following: + * +0: Number of MTRRs + * +4: MTRR base 0 31:0 + * +8: MTRR base 0 63:32 + * +12: MTRR mask 0 31:0 + * +16: MTRR mask 0 63:32 + * +20: MTRR base 1 31:0 + * +24: MTRR base 1 63:32 + * +28: MTRR mask 1 31:0 + * +32: MTRR mask 1 63:32 + */ + + /* Cache the ROM as WP just below 4GiB. */ + slot = stack_push(slot, mtrr_mask_upper); /* upper mask */ + slot = stack_push(slot, ~(CACHE_ROM_SIZE - 1) | MTRR_PHYS_MASK_VALID); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, ~(CACHE_ROM_SIZE - 1) | MTRR_TYPE_WRPROT); + num_mtrrs++; + + /* Cache RAM as WB from 0 -> CACHE_TMP_RAMTOP. */ + slot = stack_push(slot, mtrr_mask_upper); /* upper mask */ + slot = stack_push(slot, ~(CACHE_TMP_RAMTOP - 1) | MTRR_PHYS_MASK_VALID); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, 0 | MTRR_TYPE_WRBACK); + num_mtrrs++; + + top_of_ram = (uint32_t)cbmem_top(); + /* Cache 8MiB below the top of ram. On sandybridge systems the top of + * ram under 4GiB is the start of the TSEG region. It is required to + * be 8MiB aligned. Set this area as cacheable so it can be used later + * for ramstage before setting up the entire RAM as cacheable. */ + slot = stack_push(slot, mtrr_mask_upper); /* upper mask */ + slot = stack_push(slot, ~((8 << 20) - 1) | MTRR_PHYS_MASK_VALID); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, (top_of_ram - (8 << 20)) | MTRR_TYPE_WRBACK); + num_mtrrs++; + + /* Cache 8MiB at the top of ram. Top of ram on sandybridge systems + * is where the TSEG region resides. However, it is not restricted + * to SMM mode until SMM has been relocated. By setting the region + * to cacheable it provides faster access when relocating the SMM + * handler as well as using the TSEG region for other purposes. */ + slot = stack_push(slot, mtrr_mask_upper); /* upper mask */ + slot = stack_push(slot, ~((8 << 20) - 1) | MTRR_PHYS_MASK_VALID); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, top_of_ram | MTRR_TYPE_WRBACK); + num_mtrrs++; + + /* Save the number of MTRRs to setup. Return the stack location + * pointing to the number of MTRRs. */ + slot = stack_push(slot, num_mtrrs); + + return slot; } |