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x86: fsp: Adjust calculations for MTRR range and DRAM top

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At present the top of available DRAM is the same as the top of the range
of the low-memory MTRR.

In fact, U-Boot is allowed to use memory up until the start of the FSP
reserved memory. Use that value for low_end, since it makes more memory
available.

Keep the same calculation as before for mtrr_top, i.e. the top of
reserved memory.

A side-effect of this change is that the E820 tables have a single entry
that extends from the bottom of the memory used by U-Boot to the bottom
of the FSP reserved memory. This includes the bloblist, if ACPI tables
are placed there.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Simon Glass 2020-11-04 09:57:43 -07:00 • committed by Bin Meng
parent dd27cd6dab
commit d46c0932a9
1 changed files with 22 additions and 13 deletions
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35
arch/x86/lib/fsp/fsp_dram.c
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@ -41,8 +41,10 @@ int fsp_scan_for_ram_size(void)
int dram_init_banksize(void)
{
efi_guid_t fsp = FSP_HOB_RESOURCE_OWNER_FSP_GUID;
const struct hob_header *hdr;
struct hob_res_desc *res_desc;
phys_addr_t mtrr_top;
phys_addr_t low_end;
uint bank;
@ -54,35 +56,42 @@ int dram_init_banksize(void)
return 0;
}
low_end = 0;
low_end = 0; /* top of low memory usable by U-Boot */
mtrr_top = 0; /* top of low memory (even if reserved) */
for (bank = 1, hdr = gd->arch.hob_list;
bank < CONFIG_NR_DRAM_BANKS && !end_of_hob(hdr);
hdr = get_next_hob(hdr)) {
if (hdr->type != HOB_TYPE_RES_DESC)
continue;
res_desc = (struct hob_res_desc *)hdr;
if (!guidcmp(&res_desc->owner, &fsp))
low_end = res_desc->phys_start;
if (res_desc->type != RES_SYS_MEM &&
res_desc->type != RES_MEM_RESERVED)
continue;
if (res_desc->phys_start < (1ULL << 32)) {
low_end = max(low_end,
res_desc->phys_start + res_desc->len);
continue;
mtrr_top = max(mtrr_top,
res_desc->phys_start + res_desc->len);
} else {
gd->bd->bi_dram[bank].start = res_desc->phys_start;
gd->bd->bi_dram[bank].size = res_desc->len;
mtrr_add_request(MTRR_TYPE_WRBACK, res_desc->phys_start,
res_desc->len);
log_debug("ram %llx %llx\n",
gd->bd->bi_dram[bank].start,
gd->bd->bi_dram[bank].size);
}
gd->bd->bi_dram[bank].start = res_desc->phys_start;
gd->bd->bi_dram[bank].size = res_desc->len;
mtrr_add_request(MTRR_TYPE_WRBACK, res_desc->phys_start,
res_desc->len);
log_debug("ram %llx %llx\n", gd->bd->bi_dram[bank].start,
gd->bd->bi_dram[bank].size);
}
/* Add the memory below 4GB */
gd->bd->bi_dram[0].start = 0;
gd->bd->bi_dram[0].size = low_end;
mtrr_add_request(MTRR_TYPE_WRBACK, 0, low_end);
/*
* Set up an MTRR to the top of low, reserved memory. This is necessary
* for graphics to run at full speed in U-Boot.
*/
mtrr_add_request(MTRR_TYPE_WRBACK, 0, mtrr_top);
return 0;
}
@ -156,7 +165,7 @@ unsigned int install_e820_map(unsigned int max_entries,
#if CONFIG_IS_ENABLED(HANDOFF) && IS_ENABLED(CONFIG_USE_HOB)
int handoff_arch_save(struct spl_handoff *ho)
{
ho->arch.usable_ram_top = fsp_get_usable_lowmem_top(gd->arch.hob_list);
ho->arch.usable_ram_top = gd->bd->bi_dram[0].size;
ho->arch.hob_list = gd->arch.hob_list;
return 0;