1 /*
2 * Copyright (c) 2023 Intel Corporation
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/kernel.h>
8
9 #define DATA_SIZE_K(n) (n * 1024u)
10 #define RSDP_SIGNATURE ((uint64_t)0x2052545020445352)
11 #define EBDA_ADD (0x040e)
12 #define BIOS_RODATA_ADD (0xe0000)
13 #define BIOS_EXT_DATA_LOW (0x80000UL)
14 #define BIOS_EXT_DATA_HIGH (0x100000UL)
15
bios_search_rsdp_buff(uintptr_t search_phy_add,uint32_t search_length)16 static uintptr_t bios_search_rsdp_buff(uintptr_t search_phy_add, uint32_t search_length)
17 {
18 uint64_t *search_buff;
19
20 z_phys_map((uint8_t **)&search_buff, search_phy_add, search_length, 0);
21 if (!search_buff) {
22 return 0;
23 }
24
25 for (int i = 0; i < search_length / 8u; i++) {
26 if (search_buff[i] == RSDP_SIGNATURE) {
27 z_phys_unmap((uint8_t *)search_buff, search_length);
28 return (search_phy_add + (i * 8u));
29 }
30 }
31 z_phys_unmap((uint8_t *)search_buff, search_length);
32
33 return 0;
34 }
35
bios_acpi_rsdp_get(void)36 void *bios_acpi_rsdp_get(void)
37 {
38 uint8_t *bios_ext_data, *zero_page_base;
39 uintptr_t search_phy_add, rsdp_phy_add;
40
41 z_phys_map(&zero_page_base, 0, DATA_SIZE_K(4u), 0);
42 bios_ext_data = EBDA_ADD + zero_page_base;
43 search_phy_add = (uintptr_t)((*(uint16_t *)bios_ext_data) << 4u);
44 z_phys_unmap(zero_page_base, DATA_SIZE_K(4u));
45
46 if ((search_phy_add >= BIOS_EXT_DATA_LOW) && (search_phy_add < BIOS_EXT_DATA_HIGH)) {
47 rsdp_phy_add = bios_search_rsdp_buff(search_phy_add, DATA_SIZE_K(1u));
48 if (rsdp_phy_add) {
49 return (void *)rsdp_phy_add;
50 }
51 }
52 return (void *)bios_search_rsdp_buff(BIOS_RODATA_ADD, DATA_SIZE_K(128u));
53 }
54
