c06a3f72f8
It's more consistent to re-initialize EBDA in all boot paths. That way, the data living in EBDA is cleared prior to be accessed (assuming it's after setup_ebda()). Change-Id: I05ff84f869f7b6a463e52b4cb954acc5566475cd Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/21997 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Subrata Banik <subrata.banik@intel.com>
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2012 The Chromium OS Authors. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; version 2 of
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* 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 <stdint.h>
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#include <string.h>
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#include <arch/io.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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static bool is_length_valid(size_t dlength)
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{
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/* Check if input data length is > DEFAULT_EBDA_SIZE */
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if (dlength > DEFAULT_EBDA_SIZE)
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return false;
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/* Valid data length */
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return true;
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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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/*
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* write_ebda_data is a wrapper function to write into EBDA area
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*
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* data = data to be written into EBDA area
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* length = input data size.
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*/
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void write_ebda_data(const void *data, size_t length)
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{
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void *ebda;
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if (!is_length_valid(length))
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die("Input data length is > EBDA default size (1KiB)!");
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ebda = get_ebda_start();
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memcpy(ebda, data, length);
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}
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/*
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* read_ebda_data is a wrapper function to read from EBDA area
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*
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* data = data read from EBDA area based on input size
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* length = read data size.
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*/
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void read_ebda_data(void *data, size_t length)
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{
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void *ebda;
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if (!is_length_valid(length))
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die("Input data length is > EBDA default size (1KiB)!");
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ebda = get_ebda_start();
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memcpy(data, ebda, length);
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}
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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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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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