text: /******************************************************************************
   *
   * Module Name: amfield - ACPI AML (p-code) execution - field manipulation
   *              $Revision: 74 $
   *
   *****************************************************************************/
  
  /*
   *  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 "acdispat.h"
  #include "acinterp.h"
  #include "amlcode.h"
  #include "acnamesp.h"
  #include "achware.h"
  #include "acevents.h"
  
  
  #define _COMPONENT          INTERPRETER
  	 MODULE_NAME         ("amfield")
  
  
  /*******************************************************************************
   *
   * FUNCTION:    Acpi_aml_setup_field
   *
   * PARAMETERS:  *Obj_desc           - Field to be read or written
   *              *Rgn_desc           - Region containing field
   *              Field_bit_width     - Field Width in bits (8, 16, or 32)
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Common processing for Acpi_aml_read_field and Acpi_aml_write_field
   *
   *  ACPI SPECIFICATION REFERENCES:
   *  Each of the Type1_opcodes is defined as specified in in-line
   *  comments below. For each one, use the following definitions.
   *
   *  Def_bit_field   :=  Bit_field_op    Src_buf Bit_idx Destination
   *  Def_byte_field  :=  Byte_field_op   Src_buf Byte_idx Destination
   *  Def_create_field := Create_field_op Src_buf Bit_idx Num_bits Name_string
   *  Def_dWord_field :=  DWord_field_op  Src_buf Byte_idx Destination
   *  Def_word_field  :=  Word_field_op   Src_buf Byte_idx Destination
   *  Bit_index       :=  Term_arg=>Integer
   *  Byte_index      :=  Term_arg=>Integer
   *  Destination     :=  Name_string
   *  Num_bits        :=  Term_arg=>Integer
   *  Source_buf      :=  Term_arg=>Buffer
   *
   ******************************************************************************/
  
  ACPI_STATUS
  acpi_aml_setup_field (
  	ACPI_OPERAND_OBJECT     *obj_desc,
  	ACPI_OPERAND_OBJECT     *rgn_desc,
  	u32                     field_bit_width)
  {
  	ACPI_STATUS             status = AE_OK;
  	u32                     field_byte_width;
  
  
  	/* Parameter validation */
  
  	if (!obj_desc || !rgn_desc) {
  		return (AE_AML_NO_OPERAND);
  	}
  
  	if (ACPI_TYPE_REGION != rgn_desc->common.type) {
  		return (AE_AML_OPERAND_TYPE);
  	}
  
  
  	/*
  	 * TBD: [Future] Acpi 2.0 supports Qword fields
  	 *
  	 * Init and validate Field width
  	 * Possible values are 1, 2, 4
  	 */
  
  	field_byte_width = DIV_8 (field_bit_width);
  
  	if ((field_bit_width != 8) &&
  		(field_bit_width != 16) &&
  		(field_bit_width != 32))
  	{
  		return (AE_AML_OPERAND_VALUE);
  	}
  
  
  	/*
  	 * If the Region Address and Length have not been previously evaluated,
  	 * evaluate them and save the results.
  	 */
  	if (!(rgn_desc->region.flags & AOPOBJ_DATA_VALID)) {
  
  		status = acpi_ds_get_region_arguments (rgn_desc);
  		if (ACPI_FAILURE (status)) {
  			return (status);
  		}
  	}
  
  
  	if ((obj_desc->common.type == ACPI_TYPE_FIELD_UNIT) &&
  		(!(obj_desc->common.flags & AOPOBJ_DATA_VALID)))
  	{
  		/*
  		 * Field Buffer and Index have not been previously evaluated,
  		 */
  		return (AE_AML_INTERNAL);
  	}
  
  	if (rgn_desc->region.length <
  	   (obj_desc->field.offset & ~((u32) field_byte_width - 1)) +
  			field_byte_width)
  	{
  		/*
  		 * Offset rounded up to next multiple of field width
  		 * exceeds region length, indicate an error
  		 */
  
  		return (AE_AML_REGION_LIMIT);
  	}
  
  	return (AE_OK);
  }
  
  
  /*******************************************************************************
   *
   * FUNCTION:    Acpi_aml_access_named_field
   *
   * PARAMETERS:  Mode                - ACPI_READ or ACPI_WRITE
   *              Named_field         - Handle for field to be accessed
   *              *Buffer             - Value(s) to be read or written
   *              Buffer_length         - Number of bytes to transfer
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Read or write a named field
   *
   ******************************************************************************/
  
  ACPI_STATUS
  acpi_aml_access_named_field (
  	u32                     mode,
  	ACPI_HANDLE             named_field,
  	void                    *buffer,
  	u32                     buffer_length)
  {
  	ACPI_OPERAND_OBJECT     *obj_desc = NULL;
  	ACPI_STATUS             status = AE_OK;
  	u8                      locked = FALSE;
  	u32                     bit_granularity = 0;
  	u32                     byte_granularity;
  	u32                     datum_length;
  	u32                     actual_byte_length;
  	u32                     byte_field_length;
  
  
  	/* Basic data checking */
  	if ((!named_field) || (ACPI_READ == mode && !buffer)) {
  		return (AE_AML_INTERNAL);
  	}
  
  	/* Get the attached field object */
  
  	obj_desc = acpi_ns_get_attached_object (named_field);
  	if (!obj_desc) {
  		return (AE_AML_INTERNAL);
  	}
  
  	/* Check the type */
  
  	if (INTERNAL_TYPE_DEF_FIELD != acpi_ns_get_type (named_field)) {
  		return (AE_AML_OPERAND_TYPE);
  	}
  
  	/* Obj_desc valid and Named_field is a defined field */
  
  
  	/* Double-check that the attached object is also a field */
  
  	if (INTERNAL_TYPE_DEF_FIELD != obj_desc->common.type) {
  		return (AE_AML_OPERAND_TYPE);
  	}
  
  
  	/*
  	 * Granularity was decoded from the field access type
  	 * (Any_acc will be the same as Byte_acc)
  	 */
  
  	bit_granularity = obj_desc->field_unit.granularity;
  	byte_granularity = DIV_8 (bit_granularity);
  
  	/*
  	 * Check if request is too large for the field, and silently truncate
  	 * if necessary
  	 */
  
  	/* TBD: [Errors] should an error be returned in this case? */
  
  	byte_field_length = (u32) DIV_8 (obj_desc->field_unit.length + 7);
  
  
  	actual_byte_length = buffer_length;
  	if (buffer_length > byte_field_length) {
  		actual_byte_length = byte_field_length;
  	}
  
  	/* TBD: should these round down to a power of 2? */
  
  	if (DIV_8(bit_granularity) > byte_field_length) {
  		bit_granularity = MUL_8(byte_field_length);
  	}
  
  	if (byte_granularity > byte_field_length) {
  		byte_granularity = byte_field_length;
  	}
  
  
  	/* Convert byte count to datum count, round up if necessary */
  
  	datum_length = (actual_byte_length + (byte_granularity-1)) / byte_granularity;
  
  
  	/* Get the global lock if needed */
  
  	locked = acpi_aml_acquire_global_lock (obj_desc->field_unit.lock_rule);
  
  
  	/* Perform the actual read or write of the buffer */
  
  	switch (mode)
  	{
  	case ACPI_READ:
  
  		status = acpi_aml_read_field (obj_desc, buffer, buffer_length,
  				  actual_byte_length, datum_length,
  				  bit_granularity, byte_granularity);
  		break;
  
  
  	case ACPI_WRITE:
  
  		status = acpi_aml_write_field (obj_desc, buffer, buffer_length,
  				  actual_byte_length, datum_length,
  				  bit_granularity, byte_granularity);
  		break;
  
  
  	default:
  
  		status = AE_BAD_PARAMETER;
  		break;
  	}
  
  
  	/* Release global lock if we acquired it earlier */
  
  	acpi_aml_release_global_lock (locked);
  
  	return (status);
  }
  
  