patch-2.4.0-prerelease linux/drivers/acpi/tables/tbxfroot.c

• Lines: 215
• Date: Fri Dec 29 14:07:21 2000
• Orig file: v2.4.0-test12/linux/drivers/acpi/tables/tbxfroot.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test12/linux/drivers/acpi/tables/tbxfroot.c linux/drivers/acpi/tables/tbxfroot.c
@@ -0,0 +1,214 @@
+/******************************************************************************
+ *
+ * Module Name: tbxfroot - Find the root ACPI table (RSDT)
+ *              $Revision: 33 $
+ *
+ *****************************************************************************/
+
+/*
+ *  Copyright (C) 2000 R. Byron Moore
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+
+#include "acpi.h"
+#include "achware.h"
+#include "actables.h"
+
+
+#define _COMPONENT          TABLE_MANAGER
+	 MODULE_NAME         ("tbxfroot")
+
+#define RSDP_CHECKSUM_LENGTH 20
+
+
+/*******************************************************************************
+ *
+ * FUNCTION:    Acpi_find_root_pointer
+ *
+ * PARAMETERS:  **Rsdp_physical_address     - Where to place the RSDP address
+ *
+ * RETURN:      Status, Physical address of the RSDP
+ *
+ * DESCRIPTION: Find the RSDP
+ *
+ ******************************************************************************/
+
+ACPI_STATUS
+acpi_find_root_pointer (
+	ACPI_PHYSICAL_ADDRESS   *rsdp_physical_address)
+{
+	ACPI_TABLE_DESC         table_info;
+	ACPI_STATUS             status;
+
+
+	/* Get the RSDP */
+
+	status = acpi_tb_find_rsdp (&table_info);
+	if (ACPI_FAILURE (status)) {
+		return (AE_NO_ACPI_TABLES);
+	}
+
+	*rsdp_physical_address = table_info.physical_address;
+
+	return (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)
+{
+	u32                     offset;
+	u8                      *mem_rover;
+
+
+	/* Search from given start addr for the requested length  */
+
+	for (offset = 0, mem_rover = start_address;
+		 offset < length;
+		 offset += RSDP_SCAN_STEP, mem_rover += RSDP_SCAN_STEP)
+	{
+
+		/* The signature and checksum must both be correct */
+
+		if (STRNCMP ((NATIVE_CHAR *) mem_rover,
+				RSDP_SIG, sizeof (RSDP_SIG)-1) == 0 &&
+			acpi_tb_checksum (mem_rover, RSDP_CHECKSUM_LENGTH) == 0)
+		{
+			/* If so, we have found the RSDP */
+
+			return (mem_rover);
+		}
+	}
+
+	/* Searched entire block, no RSDP was found */
+
+	return (NULL);
+}
+
+
+/*******************************************************************************
+ *
+ * FUNCTION:    Acpi_tb_find_rsdp
+ *
+ * PARAMETERS:  *Buffer_ptr             - If == NULL, read data from buffer
+ *                                        rather than searching memory
+ *              *Table_info             - Where the table info is returned
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Search lower 1_mbyte of memory for the root system descriptor
+ *              pointer structure.  If it is found, set *RSDP to point to it.
+ *
+ *              NOTE: The RSDP must be either in the first 1_k of the Extended
+ *              BIOS Data Area or between E0000 and FFFFF (ACPI 1.0 section
+ *              5.2.2; assertion #421).
+ *
+ ******************************************************************************/
+
+ACPI_STATUS
+acpi_tb_find_rsdp (
+	ACPI_TABLE_DESC         *table_info)
+{
+	u8                      *table_ptr;
+	u8                      *mem_rover;
+	UINT64                  phys_addr;
+	ACPI_STATUS             status = AE_OK;
+
+
+	/*
+	 * Search memory for RSDP.  First map low physical memory.
+	 */
+
+	status = acpi_os_map_memory (LO_RSDP_WINDOW_BASE, LO_RSDP_WINDOW_SIZE,
+			  (void **)&table_ptr);
+
+	if (ACPI_FAILURE (status)) {
+		return (status);
+	}
+
+	/*
+	 * 1) Search EBDA (low memory) paragraphs
+	 */
+
+	mem_rover = acpi_tb_scan_memory_for_rsdp (table_ptr, LO_RSDP_WINDOW_SIZE);
+
+	/* This mapping is no longer needed */
+
+	acpi_os_unmap_memory (table_ptr, LO_RSDP_WINDOW_SIZE);
+
+	if (mem_rover) {
+		/* Found it, return the physical address */
+
+		phys_addr = LO_RSDP_WINDOW_BASE;
+		phys_addr += (mem_rover - table_ptr);
+
+		table_info->physical_address = phys_addr;
+
+		return (AE_OK);
+	}
+
+
+	/*
+	 * 2) Search upper memory: 16-byte boundaries in E0000h-F0000h
+	 */
+
+	status = acpi_os_map_memory (HI_RSDP_WINDOW_BASE, HI_RSDP_WINDOW_SIZE,
+			  (void **)&table_ptr);
+
+	if (ACPI_FAILURE (status)) {
+		return (status);
+	}
+
+	mem_rover = acpi_tb_scan_memory_for_rsdp (table_ptr, HI_RSDP_WINDOW_SIZE);
+
+	/* This mapping is no longer needed */
+
+	acpi_os_unmap_memory (table_ptr, HI_RSDP_WINDOW_SIZE);
+
+	if (mem_rover) {
+		/* Found it, return the physical address */
+
+		phys_addr = HI_RSDP_WINDOW_BASE;
+		phys_addr += (mem_rover - table_ptr);
+
+		table_info->physical_address = phys_addr;
+
+		return (AE_OK);
+	}
+
+
+	/* RSDP signature was not found */
+
+	return (AE_NOT_FOUND);
+}
+
+