psargs.c

linux-2.6.15.6

/******************************************************************************
 *
 * Module Name: psargs - Parse AML opcode arguments
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2005, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include <acpi/acparser.h>
#include <acpi/amlcode.h>
#include <acpi/acnamesp.h>

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psargs")

/* Local prototypes */
static u32
acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state);

static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
						       *parser_state);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_package_length
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Decoded package length.  On completion, the AML pointer points
 *              past the length byte or bytes.
 *
 * DESCRIPTION: Decode and return a package length field
 *
 ******************************************************************************/

static u32
acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state)
{
	u32 encoded_length;
	u32 length = 0;

	ACPI_FUNCTION_TRACE("ps_get_next_package_length");

	encoded_length = (u32) ACPI_GET8(parser_state->aml);
	parser_state->aml++;

	switch (encoded_length >> 6) {	/* bits 6-7 contain encoding scheme */
	case 0:		/* 1-byte encoding (bits 0-5) */

		length = (encoded_length & 0x3F);
		break;

	case 1:		/* 2-byte encoding (next byte + bits 0-3) */

		length = ((ACPI_GET8(parser_state->aml) << 04) |
			  (encoded_length & 0x0F));
		parser_state->aml++;
		break;

	case 2:		/* 3-byte encoding (next 2 bytes + bits 0-3) */

		length = ((ACPI_GET8(parser_state->aml + 1) << 12) |
			  (ACPI_GET8(parser_state->aml) << 04) |
			  (encoded_length & 0x0F));
		parser_state->aml += 2;
		break;

	case 3:		/* 4-byte encoding (next 3 bytes + bits 0-3) */

		length = ((ACPI_GET8(parser_state->aml + 2) << 20) |
			  (ACPI_GET8(parser_state->aml + 1) << 12) |
			  (ACPI_GET8(parser_state->aml) << 04) |
			  (encoded_length & 0x0F));
		parser_state->aml += 3;
		break;

	default:

		/* Can't get here, only 2 bits / 4 cases */
		break;
	}

	return_VALUE(length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_package_end
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Pointer to end-of-package +1
 *
 * DESCRIPTION: Get next package length and return a pointer past the end of
 *              the package.  Consumes the package length field
 *
 ******************************************************************************/

u8 *acpi_ps_get_next_package_end(struct acpi_parse_state *parser_state)
{
	u8 *start = parser_state->aml;
	acpi_native_uint length;

	ACPI_FUNCTION_TRACE("ps_get_next_package_end");

	/* Function below changes parser_state->Aml */

	length =
	    (acpi_native_uint) acpi_ps_get_next_package_length(parser_state);

	return_PTR(start + length);	/* end of package */
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_namestring
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Pointer to the start of the name string (pointer points into
 *              the AML.
 *
 * DESCRIPTION: Get next raw namestring within the AML stream.  Handles all name
 *              prefix characters.  Set parser state to point past the string.
 *              (Name is consumed from the AML.)
 *
 ******************************************************************************/

char *acpi_ps_get_next_namestring(struct acpi_parse_state *parser_state)
{
	u8 *start = parser_state->aml;
	u8 *end = parser_state->aml;

	ACPI_FUNCTION_TRACE("ps_get_next_namestring");

	/* Handle multiple prefix characters */

	while (acpi_ps_is_prefix_char(ACPI_GET8(end))) {
		/* Include prefix '\\' or '^' */

		end++;
	}

	/* Decode the path */

	switch (ACPI_GET8(end)) {
	case 0:

		/* null_name */

		if (end == start) {
			start = NULL;
		}
		end++;
		break;

	case AML_DUAL_NAME_PREFIX:

		/* Two name segments */

		end += 1 + (2 * ACPI_NAME_SIZE);
		break;

	case AML_MULTI_NAME_PREFIX_OP:

		/* Multiple name segments, 4 chars each */

		end += 2 + ((acpi_size) ACPI_GET8(end + 1) * ACPI_NAME_SIZE);
		break;

	default:

		/* Single name segment */

		end += ACPI_NAME_SIZE;
		break;
	}

	parser_state->aml = (u8 *) end;
	return_PTR((char *)start);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_namepath
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *              Arg                 - Where the namepath will be stored
 *              arg_count           - If the namepath points to a control method
 *                                    the method's argument is returned here.
 *              method_call         - Whether the namepath can possibly be the
 *                                    start of a method call
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get next name (if method call, return # of required args).
 *              Names are looked up in the internal namespace to determine
 *              if the name represents a control method.  If a method
 *              is found, the number of arguments to the method is returned.
 *              This information is critical for parsing to continue correctly.
 *
 ******************************************************************************/

acpi_status
acpi_ps_get_next_namepath(struct acpi_walk_state *walk_state,
			  struct acpi_parse_state *parser_state,
			  union acpi_parse_object *arg, u8 method_call)
{
	char *path;
	union acpi_parse_object *name_op;
	acpi_status status = AE_OK;
	union acpi_operand_object *method_desc;
	struct acpi_namespace_node *node;
	union acpi_generic_state scope_info;

	ACPI_FUNCTION_TRACE("ps_get_next_namepath");

	path = acpi_ps_get_next_namestring(parser_state);

	/* Null path case is allowed */

	if (path) {
		/*
		 * Lookup the name in the internal namespace
		 */
		scope_info.scope.node = NULL;
		node = parser_state->start_node;
		if (node) {
			scope_info.scope.node = node;
		}

		/*
		 * Lookup object.  We don't want to add anything new to the namespace
		 * here, however.  So we use MODE_EXECUTE.  Allow searching of the
		 * parent tree, but don't open a new scope -- we just want to lookup the
		 * object  (MUST BE mode EXECUTE to perform upsearch)
		 */
		status = acpi_ns_lookup(&scope_info, path, ACPI_TYPE_ANY,
					ACPI_IMODE_EXECUTE,
					ACPI_NS_SEARCH_PARENT |
					ACPI_NS_DONT_OPEN_SCOPE, NULL, &node);
		if (ACPI_SUCCESS(status) && method_call) {
			if (node->type == ACPI_TYPE_METHOD) {
				/* This name is actually a control method invocation */

				method_desc = acpi_ns_get_attached_object(node);
				ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
						  "Control Method - %p Desc %p Path=%p\n",
						  node, method_desc, path));

				name_op = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
				if (!name_op) {
					return_ACPI_STATUS(AE_NO_MEMORY);
				}

				/* Change arg into a METHOD CALL and attach name to it */

				acpi_ps_init_op(arg, AML_INT_METHODCALL_OP);
				name_op->common.value.name = path;

				/* Point METHODCALL/NAME to the METHOD Node */

				name_op->common.node = node;
				acpi_ps_append_arg(arg, name_op);

				if (!method_desc) {
					ACPI_REPORT_ERROR(("ps_get_next_namepath: Control Method %p has no attached object\n", node));
					return_ACPI_STATUS(AE_AML_INTERNAL);
				}

				ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
						  "Control Method - %p Args %X\n",
						  node,
						  method_desc->method.
						  param_count));

				/* Get the number of arguments to expect */

				walk_state->arg_count =
				    method_desc->method.param_count;
				return_ACPI_STATUS(AE_OK);
			}

			/*
			 * Else this is normal named object reference.
			 * Just init the NAMEPATH object with the pathname.
			 * (See code below)
			 */
		}

		if (ACPI_FAILURE(status)) {
			/*
			 * 1) Any error other than NOT_FOUND is always severe
			 * 2) NOT_FOUND is only important if we are executing a method.
			 * 3) If executing a cond_ref_of opcode, NOT_FOUND is ok.
			 */
			if ((((walk_state->
			       parse_flags & ACPI_PARSE_MODE_MASK) ==
			      ACPI_PARSE_EXECUTE) && (status == AE_NOT_FOUND)
			     && (walk_state->op->common.aml_opcode !=
				 AML_COND_REF_OF_OP))
			    || (status != AE_NOT_FOUND)) {
				ACPI_REPORT_NSERROR(path, status);

				acpi_os_printf
				    ("search_node %p start_node %p return_node %p\n",
				     scope_info.scope.node,
				     parser_state->start_node, node);

			} else {
				/*
				 * We got a NOT_FOUND during table load or we encountered
				 * a cond_ref_of(x) where the target does not exist.
				 * Either case is ok
				 */
				status = AE_OK;
			}
		}
	}

	/*