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Diffstat (limited to 'src/soc/intel/broadwell/romstage/stack.c')
| -rw-r--r-- | src/soc/intel/broadwell/romstage/stack.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/src/soc/intel/broadwell/romstage/stack.c b/src/soc/intel/broadwell/romstage/stack.c new file mode 100644 index 0000000000..7f566295e0 --- /dev/null +++ b/src/soc/intel/broadwell/romstage/stack.c @@ -0,0 +1,124 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2014 Google Inc. + * + * 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 + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <stddef.h> +#include <stdint.h> +#include <arch/cpu.h> +#include <arch/early_variables.h> +#include <console/console.h> +#include <cbmem.h> +#include <cpu/x86/mtrr.h> +#include <broadwell/romstage.h> + +static inline uint32_t *stack_push(u32 *stack, u32 value) +{ + stack = &stack[-1]; + *stack = value; + return stack; +} + +/* Romstage needs quite a bit of stack for decompressing images since the lzma + * lib keeps its state on the stack during romstage. */ +static unsigned long choose_top_of_stack(void) +{ + unsigned long stack_top; + const unsigned long romstage_ram_stack_size = 0x5000; + + /* cbmem_add() does a find() before add(). */ + stack_top = (unsigned long)cbmem_add(CBMEM_ID_ROMSTAGE_RAM_STACK, + romstage_ram_stack_size); + stack_top += romstage_ram_stack_size; + return stack_top; +} + +/* setup_stack_and_mttrs() determines the stack to use after + * cache-as-ram is torn down as well as the MTRR settings to use. */ +void *setup_stack_and_mttrs(void) +{ + unsigned long top_of_stack; + int num_mtrrs; + uint32_t *slot; + uint32_t mtrr_mask_upper; + uint32_t top_of_ram; + + /* Top of stack needs to be aligned to a 4-byte boundary. */ + top_of_stack = choose_top_of_stack() & ~3; + slot = (void *)top_of_stack; + 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 << ((cpuid_eax(0x80000008) & 0xff) - 32)) - 1; + + /* The order for each MTTR 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: MTTR base 0 31:0 + * +8: MTTR base 0 63:32 + * +12: MTTR mask 0 31:0 + * +16: MTTR mask 0 63:32 + * +20: MTTR base 1 31:0 + * +24: MTTR base 1 63:32 + * +28: MTTR mask 1 31:0 + * +32: MTTR 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, ~(CONFIG_ROM_SIZE - 1) | MTRRphysMaskValid); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, ~(CONFIG_ROM_SIZE - 1) | MTRR_TYPE_WRPROT); + num_mtrrs++; + + /* Cache RAM as WB from 0 -> CONFIG_RAMTOP. */ + slot = stack_push(slot, mtrr_mask_upper); /* upper mask */ + slot = stack_push(slot, ~(CONFIG_RAMTOP - 1) | MTRRphysMaskValid); + 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. 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) | MTRRphysMaskValid); + 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 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) | MTRRphysMaskValid); + slot = stack_push(slot, 0); /* upper base */ + slot = stack_push(slot, top_of_ram | MTRR_TYPE_WRBACK); + num_mtrrs++; + + /* Save the number of MTTRs to setup. Return the stack location + * pointing to the number of MTRRs. */ + slot = stack_push(slot, num_mtrrs); + + return slot; +} |