tbxfroot.c

h内核

				goto cleanup;
			}
		}
	}

	/* Did not find the table */

	status = AE_NOT_EXIST;


cleanup:
	acpi_os_unmap_memory (rsdt_info->pointer, (acpi_size) rsdt_info->pointer->length);
	ACPI_MEM_FREE (rsdt_info);

	if (header) {
		ACPI_MEM_FREE (header);
	}
	if (table_info) {
		ACPI_MEM_FREE (table_info);
	}
	return_ACPI_STATUS (status);
}
EXPORT_SYMBOL(acpi_get_firmware_table);


/* TBD: Move to a new file */

#if ACPI_MACHINE_WIDTH != 16

/*******************************************************************************
 *
 * FUNCTION:    acpi_find_root_pointer
 *
 * PARAMETERS:  **rsdp_address          - Where to place the RSDP address
 *              Flags                   - Logical/Physical addressing
 *
 * RETURN:      Status, Physical address of the RSDP
 *
 * DESCRIPTION: Find the RSDP
 *
 ******************************************************************************/

acpi_status
acpi_find_root_pointer (
	u32                             flags,
	struct acpi_pointer             *rsdp_address)
{
	struct acpi_table_desc          table_info;
	acpi_status                     status;


	ACPI_FUNCTION_TRACE ("acpi_find_root_pointer");


	/* Get the RSDP */

	status = acpi_tb_find_rsdp (&table_info, flags);
	if (ACPI_FAILURE (status)) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
			"RSDP structure not found, %s Flags=%X\n",
			acpi_format_exception (status), flags));
		return_ACPI_STATUS (AE_NO_ACPI_TABLES);
	}

	rsdp_address->pointer_type = ACPI_PHYSICAL_POINTER;
	rsdp_address->pointer.physical = table_info.physical_address;
	return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * 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)
{
	u8                              *mem_rover;
	u8                              *end_address;
	u8                              checksum;


	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 signature and checksum must both be correct */

		if (ACPI_STRNCMP ((char *) mem_rover, RSDP_SIG, sizeof (RSDP_SIG)-1) != 0) {
			/* No signature match, keep looking */

			continue;
		}

		/* Signature matches, check the appropriate checksum */

		if ((ACPI_CAST_PTR (struct rsdp_descriptor, mem_rover))->revision < 2) {
			/* ACPI version 1.0 */

			checksum = acpi_tb_checksum (mem_rover, ACPI_RSDP_CHECKSUM_LENGTH);
		}
		else {
			/* Post ACPI 1.0, use extended_checksum */

			checksum = acpi_tb_checksum (mem_rover, ACPI_RSDP_XCHECKSUM_LENGTH);
		}

		if (checksum == 0) {
			/* Checksum valid, we have found a valid RSDP */

			ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
				"RSDP located at physical address %p\n", mem_rover));
			return_PTR (mem_rover);
		}

		ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
			"Found an RSDP at physical address %p, but it has a bad checksum\n",
			mem_rover));
	}

	/* Searched entire block, no RSDP was found */

	ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
		"Searched entire block, no valid RSDP was found.\n"));
	return_PTR (NULL);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_find_rsdp
 *
 * PARAMETERS:  *table_info             - Where the table info is returned
 *              Flags                   - Current memory mode (logical vs.
 *                                        physical addressing)
 *
 * RETURN:      Status, RSDP physical address
 *
 * DESCRIPTION: search lower 1_mbyte 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 1_k 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_tb_find_rsdp (
	struct acpi_table_desc          *table_info,
	u32                             flags)
{
	u8                              *table_ptr;
	u8                              *mem_rover;
	u32                             physical_address;
	acpi_status                     status;


	ACPI_FUNCTION_TRACE ("tb_find_rsdp");


	/*
	 * Scan supports either 1) Logical addressing or 2) Physical addressing
	 */
	if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
		/*
		 * 1a) Get the location of the EBDA
		 */
		status = acpi_os_map_memory ((acpi_physical_address) ACPI_EBDA_PTR_LOCATION,
				  ACPI_EBDA_PTR_LENGTH,
				  (void *) &table_ptr);
		if (ACPI_FAILURE (status)) {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
				"Could not map memory at %8.8X for length %X\n",
				ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
			return_ACPI_STATUS (status);
		}

		ACPI_MOVE_16_TO_32 (&physical_address, table_ptr);
		physical_address <<= 4;                 /* Convert segment to physical address */
		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 1_k length)
			 */
			status = acpi_os_map_memory ((acpi_physical_address) physical_address,
					  ACPI_EBDA_WINDOW_SIZE,
					  (void *) &table_ptr);
			if (ACPI_FAILURE (status)) {
				ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
					"Could not map memory at %8.8X for length %X\n",
					physical_address, ACPI_EBDA_WINDOW_SIZE));
				return_ACPI_STATUS (status);
			}

			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) {
				/* Found it, return the physical address */

				physical_address += ACPI_PTR_DIFF (mem_rover, table_ptr);

				table_info->physical_address = (acpi_physical_address) physical_address;
				return_ACPI_STATUS (AE_OK);
			}
		}

		/*
		 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
		 */
		status = acpi_os_map_memory ((acpi_physical_address) ACPI_HI_RSDP_WINDOW_BASE,
				  ACPI_HI_RSDP_WINDOW_SIZE,
				  (void *) &table_ptr);
		if (ACPI_FAILURE (status)) {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
				"Could not map memory at %8.8X for length %X\n",
				ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
			return_ACPI_STATUS (status);
		}

		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) {
			/* Found it, return the physical address */

			physical_address = ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (mem_rover, table_ptr);

			table_info->physical_address = (acpi_physical_address) physical_address;
			return_ACPI_STATUS (AE_OK);
		}
	}

	/*
	 * Physical addressing
	 */
	else {
		/*
		 * 1a) Get the location of the EBDA
		 */
		ACPI_MOVE_16_TO_32 (&physical_address, ACPI_EBDA_PTR_LOCATION);
		physical_address <<= 4;     /* Convert segment to physical address */

		/* EBDA present? */

		if (physical_address > 0x400) {
			/*
			 * 1b) Search EBDA paragraphs (EBDa is required to be a minimum of 1_k length)
			 */
			mem_rover = acpi_tb_scan_memory_for_rsdp (ACPI_PHYSADDR_TO_PTR (physical_address),
					  ACPI_EBDA_WINDOW_SIZE);
			if (mem_rover) {
				/* Found it, return the physical address */

				table_info->physical_address = ACPI_TO_INTEGER (mem_rover);
				return_ACPI_STATUS (AE_OK);
			}
		}

		/*
		 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
		 */
		mem_rover = acpi_tb_scan_memory_for_rsdp (ACPI_PHYSADDR_TO_PTR (ACPI_HI_RSDP_WINDOW_BASE),
				  ACPI_HI_RSDP_WINDOW_SIZE);
		if (mem_rover) {
			/* Found it, return the physical address */

			table_info->physical_address = ACPI_TO_INTEGER (mem_rover);
			return_ACPI_STATUS (AE_OK);
		}
	}

	/* RSDP signature was not found */

	return_ACPI_STATUS (AE_NOT_FOUND);
}

#endif