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soc/ti/am335x: Enable MMU in bootblock 

Enables the MMU primarily to allow the unaligned word reads that the
FMAP code requires. Without enabling this, the chip gets data access
exceptions.

Enabling the MMU also gives some advantages in allowing the icache and
dcache to be enabled, so is probably worth doing regardless.

Change-Id: Ic571570cc44b0696ea61cc76e3bce7167a3256cf
Signed-off-by: Sam Lewis <sam.vr.lewis@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44382
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
This commit is contained in:
Sam Lewis 2020-08-03 21:14:26 +10:00 committed by Patrick Georgi
parent be34afad6f
commit b5353965e1
3 changed files with 21 additions and 11 deletions
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22
src/soc/ti/am335x/bootblock.c
View File

@ -4,13 +4,25 @@
#include <arch/cache.h>
#include <bootblock_common.h>
#include <symbols.h>
#define SRAM_START ((uintptr_t)_sram / MiB)
#define SRAM_END (DIV_ROUND_UP((uintptr_t)_esram, MiB))
#define DRAM_START ((uintptr_t)_dram / MiB)
#define DRAM_SIZE (CONFIG_DRAM_SIZE_MB)
void bootblock_soc_init(void)
{
uint32_t sctlr;
mmu_init();
/* enable dcache */
sctlr = read_sctlr();
sctlr |= SCTLR_C;
write_sctlr(sctlr);
/* Map everything strongly ordered by default */
mmu_config_range(0, 4096, DCACHE_OFF);
mmu_config_range(SRAM_START, SRAM_END - SRAM_START,
DCACHE_WRITEBACK);
mmu_config_range(DRAM_START, DRAM_SIZE, DCACHE_WRITEBACK);
dcache_mmu_enable();
}

1
src/soc/ti/am335x/bootblock_media.c
View File

@ -3,7 +3,6 @@
#include <boot_device.h>
#include <symbols.h>
/* FIXME: No idea how big the internal SRAM actually is. */
static const struct mem_region_device boot_dev =
MEM_REGION_DEV_RO_INIT(_sram, CONFIG_ROM_SIZE);

9
src/soc/ti/am335x/memlayout.ld
View File

@ -8,17 +8,16 @@ SECTIONS
{
SRAM_START(0x402f0400)
BOOTBLOCK(0x402f0400, 20K)
ROMSTAGE(0x402f5400, 88K)
FMAP_CACHE(0x4030b400, 2K)
FMAP_CACHE(0x402f0400+20K, 2K)
TTB(0x402F8000, 16K)
ROMSTAGE(0x402F8000+16K, 40K)
STACK(0x4030be00, 4K)
SRAM_END(0x40310000)
DRAM_START(0x80000000)
RAMSTAGE(0x80200000, 192K)
/* TODO: Implement MMU support and move TTB to a better location. */
TTB(0x81000000, 16K)
#ifdef OMAP_HEADER
.header : {
*(.header);