ae1ca82e87
Signed-off-by: Elyes Haouas <ehaouas@noos.fr> Change-Id: Id2db229dec2ed44333faaa8c53f3a2f9d66d52e0 Reviewed-on: https://review.coreboot.org/c/coreboot/+/68200 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <acpi/acpi.h>
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#include <bootstate.h>
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#include <commonlib/endian.h>
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#include <types.h>
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#define X86_BDA_SIZE 0x200
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#define X86_BDA_BASE ((void *)0x400)
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#define X86_EBDA_SEGMENT ((void *)0x40e)
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#define X86_EBDA_LOWMEM ((void *)0x413)
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#define DEFAULT_EBDA_LOWMEM (1024 << 10)
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#define DEFAULT_EBDA_SEGMENT 0xF600
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#define DEFAULT_EBDA_SIZE 0x400
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static void *get_ebda_start(void)
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{
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return (void *)((uintptr_t)DEFAULT_EBDA_SEGMENT << 4);
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}
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/*
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* EBDA area is representing a 1KB memory area just below
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* the top of conventional memory (below 1MB)
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*/
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static void setup_ebda(u32 low_memory_size, u16 ebda_segment, u16 ebda_size)
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{
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u16 low_memory_kb;
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u16 ebda_kb;
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void *ebda;
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if (!low_memory_size || !ebda_segment || !ebda_size)
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return;
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low_memory_kb = low_memory_size >> 10;
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ebda_kb = ebda_size >> 10;
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ebda = get_ebda_start();
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/* clear BIOS DATA AREA */
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zero_n(X86_BDA_BASE, X86_BDA_SIZE);
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/* Avoid unaligned write16() since it's undefined behavior */
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write_le16(X86_EBDA_LOWMEM, low_memory_kb);
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write_le16(X86_EBDA_SEGMENT, ebda_segment);
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/* Set up EBDA */
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zero_n(ebda, ebda_size);
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write_le16(ebda, ebda_kb);
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}
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static void setup_default_ebda(void *unused)
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{
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if (acpi_is_wakeup_s3())
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return;
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setup_ebda(DEFAULT_EBDA_LOWMEM,
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DEFAULT_EBDA_SEGMENT,
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DEFAULT_EBDA_SIZE);
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}
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/* Ensure EBDA is prepared before Option ROMs. */
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BOOT_STATE_INIT_ENTRY(BS_DEV_INIT, BS_ON_ENTRY, setup_default_ebda, NULL);
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