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/*
* Copyright © 2021-2022 The Crust Firmware Authors.
* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only
*/
#include <debug.h>
#include <mmio.h>
#include <steps.h>
#include <util.h>
#define DRAM_BASE 0x40000000
#define MIN_OFFSET sizeof(uint32_t)
#define MAX_OFFSET BIT(26) /* 64 MiB */
static uint32_t saved_checksum;
static uint32_t
dram_calc_checksum(void)
{
uint32_t checksum = 0;
for (uint32_t offset = MIN_OFFSET; offset < MAX_OFFSET; offset <<= 1) {
checksum += mmio_read_32(DRAM_BASE + 1 * offset);
checksum += mmio_read_32(DRAM_BASE + 3 * offset);
checksum += 1;
checksum *= ~offset;
}
return checksum;
}
void
dram_save_checksum(void)
{
saved_checksum = dram_calc_checksum();
}
void
dram_verify_checksum(void)
{
record_step(STEP_RESUME_DRAM_CHECKSUM);
if (dram_calc_checksum() != saved_checksum)
panic("DRAM checksum mismatch!");
}
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