diff options
Diffstat (limited to 'drivers/acpi/acpica/tbxfroot.c')
| -rw-r--r-- | drivers/acpi/acpica/tbxfroot.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/tbxfroot.c b/drivers/acpi/acpica/tbxfroot.c new file mode 100644 index 000000000..3d09e3f6b --- /dev/null +++ b/drivers/acpi/acpica/tbxfroot.c @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/****************************************************************************** + * + * Module Name: tbxfroot - Find the root ACPI table (RSDT) + * + * Copyright (C) 2000 - 2022, Intel Corp. + * + *****************************************************************************/ + +#include <acpi/acpi.h> +#include "accommon.h" +#include "actables.h" + +#define _COMPONENT ACPI_TABLES +ACPI_MODULE_NAME("tbxfroot") + +/******************************************************************************* + * + * FUNCTION: acpi_tb_get_rsdp_length + * + * PARAMETERS: rsdp - Pointer to RSDP + * + * RETURN: Table length + * + * DESCRIPTION: Get the length of the RSDP + * + ******************************************************************************/ +u32 acpi_tb_get_rsdp_length(struct acpi_table_rsdp *rsdp) +{ + + if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) { + + /* BAD Signature */ + + return (0); + } + + /* "Length" field is available if table version >= 2 */ + + if (rsdp->revision >= 2) { + return (rsdp->length); + } else { + return (ACPI_RSDP_CHECKSUM_LENGTH); + } +} + +/******************************************************************************* + * + * FUNCTION: acpi_tb_validate_rsdp + * + * PARAMETERS: rsdp - Pointer to unvalidated RSDP + * + * RETURN: Status + * + * DESCRIPTION: Validate the RSDP (ptr) + * + ******************************************************************************/ + +acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp) +{ + + /* + * The signature and checksum must both be correct + * + * Note: Sometimes there exists more than one RSDP in memory; the valid + * RSDP has a valid checksum, all others have an invalid checksum. + */ + if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) { + + /* Nope, BAD Signature */ + + return (AE_BAD_SIGNATURE); + } + + /* Check the standard checksum */ + + if (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) { + return (AE_BAD_CHECKSUM); + } + + /* Check extended checksum if table version >= 2 */ + + if ((rsdp->revision >= 2) && + (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) { + return (AE_BAD_CHECKSUM); + } + + return (AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_find_root_pointer + * + * PARAMETERS: table_address - Where the table pointer is returned + * + * RETURN: Status, RSDP physical address + * + * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor + * pointer structure. If it is found, set *RSDP to point to it. + * + * NOTE1: The RSDP must be either in the first 1K of the Extended + * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.) + * Only a 32-bit physical address is necessary. + * + * NOTE2: This function is always available, regardless of the + * initialization state of the rest of ACPI. + * + ******************************************************************************/ + +acpi_status ACPI_INIT_FUNCTION +acpi_find_root_pointer(acpi_physical_address *table_address) +{ + u8 *table_ptr; + u8 *mem_rover; + u32 physical_address; + + ACPI_FUNCTION_TRACE(acpi_find_root_pointer); + + /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */ + + table_ptr = acpi_os_map_memory((acpi_physical_address) + ACPI_EBDA_PTR_LOCATION, + ACPI_EBDA_PTR_LENGTH); + if (!table_ptr) { + ACPI_ERROR((AE_INFO, + "Could not map memory at 0x%8.8X for length %u", + ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH)); + + return_ACPI_STATUS(AE_NO_MEMORY); + } + + ACPI_MOVE_16_TO_32(&physical_address, table_ptr); + + /* Convert segment part to physical address */ + + physical_address <<= 4; + acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH); + + /* EBDA present? */ + + if (physical_address > 0x400) { + /* + * 1b) Search EBDA paragraphs (EBDA is required to be a + * minimum of 1K length) + */ + table_ptr = acpi_os_map_memory((acpi_physical_address) + physical_address, + ACPI_EBDA_WINDOW_SIZE); + if (!table_ptr) { + ACPI_ERROR((AE_INFO, + "Could not map memory at 0x%8.8X for length %u", + physical_address, ACPI_EBDA_WINDOW_SIZE)); + + return_ACPI_STATUS(AE_NO_MEMORY); + } + + mem_rover = + acpi_tb_scan_memory_for_rsdp(table_ptr, + ACPI_EBDA_WINDOW_SIZE); + acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE); + + if (mem_rover) { + + /* Return the physical address */ + + physical_address += + (u32) ACPI_PTR_DIFF(mem_rover, table_ptr); + + *table_address = + (acpi_physical_address)physical_address; + return_ACPI_STATUS(AE_OK); + } + } + + /* + * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh + */ + table_ptr = acpi_os_map_memory((acpi_physical_address) + ACPI_HI_RSDP_WINDOW_BASE, + ACPI_HI_RSDP_WINDOW_SIZE); + + if (!table_ptr) { + ACPI_ERROR((AE_INFO, + "Could not map memory at 0x%8.8X for length %u", + ACPI_HI_RSDP_WINDOW_BASE, + ACPI_HI_RSDP_WINDOW_SIZE)); + + return_ACPI_STATUS(AE_NO_MEMORY); + } + + mem_rover = + acpi_tb_scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); + acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); + + if (mem_rover) { + + /* Return the physical address */ + + physical_address = (u32) + (ACPI_HI_RSDP_WINDOW_BASE + + ACPI_PTR_DIFF(mem_rover, table_ptr)); + + *table_address = (acpi_physical_address)physical_address; + return_ACPI_STATUS(AE_OK); + } + + /* A valid RSDP was not found */ + + ACPI_BIOS_ERROR((AE_INFO, "A valid RSDP was not found")); + return_ACPI_STATUS(AE_NOT_FOUND); +} + +ACPI_EXPORT_SYMBOL_INIT(acpi_find_root_pointer) + +/******************************************************************************* + * + * FUNCTION: acpi_tb_scan_memory_for_rsdp + * + * PARAMETERS: start_address - Starting pointer for search + * length - Maximum length to search + * + * RETURN: Pointer to the RSDP if found, otherwise NULL. + * + * DESCRIPTION: Search a block of memory for the RSDP signature + * + ******************************************************************************/ +u8 *acpi_tb_scan_memory_for_rsdp(u8 *start_address, u32 length) +{ + acpi_status status; + u8 *mem_rover; + u8 *end_address; + + ACPI_FUNCTION_TRACE(tb_scan_memory_for_rsdp); + + end_address = start_address + length; + + /* Search from given start address for the requested length */ + + for (mem_rover = start_address; mem_rover < end_address; + mem_rover += ACPI_RSDP_SCAN_STEP) { + + /* The RSDP signature and checksum must both be correct */ + + status = + acpi_tb_validate_rsdp(ACPI_CAST_PTR + (struct acpi_table_rsdp, mem_rover)); + if (ACPI_SUCCESS(status)) { + + /* Sig and checksum valid, we have found a real RSDP */ + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "RSDP located at physical address %p\n", + mem_rover)); + return_PTR(mem_rover); + } + + /* No sig match or bad checksum, keep searching */ + } + + /* Searched entire block, no RSDP was found */ + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Searched entire block from %p, valid RSDP was not found\n", + start_address)); + return_PTR(NULL); +} |