13f66507af
MMIO operations are arch-agnostic so the include path should not be arch/. Change-Id: I0fd70f5aeca02e98e96b980c3aca0819f5c44b98 Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-on: https://review.coreboot.org/c/31691 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <stddef.h>
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#include <cbmem.h>
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#include <symbols.h>
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#include <device/mmio.h>
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#include "mainboard.h"
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#define PATTERN1 0x55
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#define PATTERN2 0xaa
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/* Returns 1 if mebibyte mb is present and 0 otherwise. */
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static int probe_mb(int mb)
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{
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char *ptr = (char *) 0x60000000 + (mb << 20) + 0xfffff;
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char old;
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if (ptr < (char *) &_eprogram) {
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/* Don't probe below _end to avoid accidentally clobering
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oneself. */
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return 1;
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}
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old = read8(ptr);
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write8(ptr, PATTERN1);
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if (read8(ptr) != PATTERN1)
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return 0;
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write8(ptr, PATTERN2);
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if (read8(ptr) != PATTERN2)
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return 0;
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write8(ptr, old);
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return 1;
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}
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int probe_ramsize(void)
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{
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int i;
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int discovered = 0;
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static int saved_result;
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if (saved_result)
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return saved_result;
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/* Compact binary search. */
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/* 1 GiB is the largest supported RAM by this machine. */
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for (i = 9; i >= 0; i--)
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if (probe_mb(discovered | (1 << i)))
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discovered |= (1 << i);
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discovered++;
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saved_result = discovered;
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return discovered;
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}
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void *cbmem_top(void)
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{
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return _dram + (probe_ramsize() << 20);
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}
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