54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
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/*
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* Copyright (c) 2023 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/kernel.h>
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#define DATA_SIZE_K(n) (n * 1024u)
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#define RSDP_SIGNATURE ((uint64_t)0x2052545020445352)
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#define EBDA_ADD (0x040e)
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#define BIOS_RODATA_ADD (0xe0000)
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#define BIOS_EXT_DATA_LOW (0x80000UL)
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#define BIOS_EXT_DATA_HIGH (0x100000UL)
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static uintptr_t bios_search_rsdp_buff(uintptr_t search_phy_add, uint32_t search_length)
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{
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uint64_t *search_buff;
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z_phys_map((uint8_t **)&search_buff, search_phy_add, search_length, 0);
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if (!search_buff) {
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return 0;
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}
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for (int i = 0; i < search_length / 8u; i++) {
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if (search_buff[i] == RSDP_SIGNATURE) {
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z_phys_unmap((uint8_t *)search_buff, search_length);
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return (search_phy_add + (i * 8u));
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}
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}
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z_phys_unmap((uint8_t *)search_buff, search_length);
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return 0;
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}
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void *bios_acpi_rsdp_get(void)
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{
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uint8_t *bios_ext_data, *zero_page_base;
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uintptr_t search_phy_add, rsdp_phy_add;
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z_phys_map(&zero_page_base, 0, DATA_SIZE_K(4u), 0);
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bios_ext_data = EBDA_ADD + zero_page_base;
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search_phy_add = (uintptr_t)((*(uint16_t *)bios_ext_data) << 4u);
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z_phys_unmap(zero_page_base, DATA_SIZE_K(4u));
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if ((search_phy_add >= BIOS_EXT_DATA_LOW) && (search_phy_add < BIOS_EXT_DATA_HIGH)) {
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rsdp_phy_add = bios_search_rsdp_buff(search_phy_add, DATA_SIZE_K(1u));
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if (rsdp_phy_add) {
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return (void *)rsdp_phy_add;
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}
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}
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return (void *)bios_search_rsdp_buff(BIOS_RODATA_ADD, DATA_SIZE_K(128u));
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}
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