53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <stdint.h>
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#include <acpi/acpi.h>
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#include <arch/ebda.h>
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#include <commonlib/endian.h>
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#include <console/console.h>
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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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void setup_default_ebda(void)
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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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