exfldio.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

			 * Put together the appropriate bits of the two raw data to make a
			 * single complete field datum
			 *
			 * 1) Normalize the first datum down to bit 0
			 */
			merged_datum = (previous_raw_datum >> obj_desc->common_field.start_field_bit_offset);

			/* 2) Insert the second datum "above" the first datum */

			merged_datum |= (this_raw_datum << obj_desc->common_field.datum_valid_bits);

			if ((datum_offset >= (datum_count -1))) {
				/*
				 * This is the last iteration of the loop.  We need to clear
				 * any unused bits (bits that are not part of this field) that
				 * came from the last raw datum before we store the final
				 * merged datum into the caller buffer.
				 */
				if (obj_desc->common_field.end_buffer_valid_bits) {
					merged_datum &=
						MASK_BITS_ABOVE (obj_desc->common_field.end_buffer_valid_bits);
				}
			}
		}

		/*
		 * Store the merged field datum in the caller's buffer, according to
		 * the granularity of the field (size of each datum).
		 */
		acpi_ex_set_buffer_datum (merged_datum, buffer, obj_desc->common_field.access_byte_width,
				datum_offset);

		/*
		 * Save the raw datum that was just acquired since it may contain bits
		 * of the *next* field datum.  Update offsets
		 */
		previous_raw_datum = this_raw_datum;
		datum_offset++;
	}

	return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ex_write_field_datum
 *
 * PARAMETERS:  *Obj_desc           - Field to be set
 *              Value               - Value to store
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Store the value into the given field
 *
 ******************************************************************************/

static acpi_status
acpi_ex_write_field_datum (
	acpi_operand_object     *obj_desc,
	u32                     field_datum_byte_offset,
	u32                     value)
{
	acpi_status             status = AE_OK;
	acpi_operand_object     *rgn_desc = NULL;
	ACPI_PHYSICAL_ADDRESS   address;


	FUNCTION_TRACE_U32 ("Ex_write_field_datum", field_datum_byte_offset);


	/*
	 * Buffer_fields - Read from a Buffer
	 * Other Fields - Read from a Operation Region.
	 */
	switch (obj_desc->common.type) {
	case ACPI_TYPE_BUFFER_FIELD:

		/*
		 * For Buffer_fields, we only need to copy the data to the
		 * target buffer.  Length is the field width in bytes.
		 */
		MEMCPY ((obj_desc->buffer_field.buffer_obj)->buffer.pointer
				+ obj_desc->buffer_field.base_byte_offset + field_datum_byte_offset,
				&value, obj_desc->common_field.access_byte_width);
		status = AE_OK;
		break;


	case INTERNAL_TYPE_REGION_FIELD:
	case INTERNAL_TYPE_BANK_FIELD:

		/*
		 * For other fields, we need to go through an Operation Region
		 * (Only types that will get here are Region_fields and Bank_fields)
		 */
		status = acpi_ex_setup_field (obj_desc, field_datum_byte_offset);
		if (ACPI_FAILURE (status)) {
			return_ACPI_STATUS (status);
		}

		/*
		 * The physical address of this field datum is:
		 *
		 * 1) The base of the region, plus
		 * 2) The base offset of the field, plus
		 * 3) The current offset into the field
		 */
		rgn_desc = obj_desc->common_field.region_obj;
		address = rgn_desc->region.address +
				 obj_desc->common_field.base_byte_offset +
				 field_datum_byte_offset;

		ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
			"Store %X in Region %s(%X) at %8.8X%8.8X width %X\n",
			value, acpi_ut_get_region_name (rgn_desc->region.space_id),
			rgn_desc->region.space_id, HIDWORD(address), LODWORD(address),
			obj_desc->common_field.access_bit_width));

		/* Invoke the appropriate Address_space/Op_region handler */

		status = acpi_ev_address_space_dispatch (rgn_desc, ACPI_WRITE_ADR_SPACE,
				  address, obj_desc->common_field.access_bit_width, &value);

		if (status == AE_NOT_IMPLEMENTED) {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
				"**** Region type %s(%X) not implemented\n",
				acpi_ut_get_region_name (rgn_desc->region.space_id),
				rgn_desc->region.space_id));
		}

		else if (status == AE_NOT_EXIST) {
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
				"**** Region type %s(%X) does not have a handler\n",
				acpi_ut_get_region_name (rgn_desc->region.space_id),
				rgn_desc->region.space_id));
		}

		break;


	default:

		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "%p, wrong source type - %s\n",
			obj_desc, acpi_ut_get_type_name (obj_desc->common.type)));
		status = AE_AML_INTERNAL;
		break;
	}


	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Value written=%08X \n", value));
	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ex_write_field_datum_with_update_rule
 *
 * PARAMETERS:  *Obj_desc           - Field to be set
 *              Value               - Value to store
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Apply the field update rule to a field write
 *
 ******************************************************************************/

static acpi_status
acpi_ex_write_field_datum_with_update_rule (
	acpi_operand_object     *obj_desc,
	u32                     mask,
	u32                     field_value,
	u32                     field_datum_byte_offset)
{
	acpi_status             status = AE_OK;
	u32                     merged_value;
	u32                     current_value;


	FUNCTION_TRACE ("Ex_write_field_datum_with_update_rule");


	/* Start with the new bits  */

	merged_value = field_value;

	/* If the mask is all ones, we don't need to worry about the update rule */

	if (mask != ACPI_UINT32_MAX) {
		/* Decode the update rule */

		switch (obj_desc->common_field.update_rule) {
		case UPDATE_PRESERVE:
			/*
			 * Check if update rule needs to be applied (not if mask is all
			 * ones)  The left shift drops the bits we want to ignore.
			 */
			if ((~mask << (sizeof (mask) * 8 -
					  obj_desc->common_field.access_bit_width)) != 0) {
				/*
				 * Read the current contents of the byte/word/dword containing
				 * the field, and merge with the new field value.
				 */
				status = acpi_ex_read_field_datum (obj_desc, field_datum_byte_offset,
						  &current_value);
				merged_value |= (current_value & ~mask);
			}
			break;


		case UPDATE_WRITE_AS_ONES:

			/* Set positions outside the field to all ones */

			merged_value |= ~mask;
			break;


		case UPDATE_WRITE_AS_ZEROS:

			/* Set positions outside the field to all zeros */

			merged_value &= mask;
			break;


		default:
			ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
				"Write_with_update_rule: Unknown Update_rule setting: %x\n",
				obj_desc->common_field.update_rule));
			return_ACPI_STATUS (AE_AML_OPERAND_VALUE);
			break;
		}
	}


	/* Write the merged value */

	status = acpi_ex_write_field_datum (obj_desc, field_datum_byte_offset,
			  merged_value);

	ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD, "Mask %X Datum_offset %X Value %X, Merged_value %X\n",
		mask, field_datum_byte_offset, field_value, merged_value));

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ex_insert_into_field
 *
 * PARAMETERS:  *Obj_desc           - Field to be set
 *              Buffer              - Value to store
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Store the value into the given field
 *
 ******************************************************************************/

acpi_status
acpi_ex_insert_into_field (
	acpi_operand_object     *obj_desc,
	void                    *buffer,
	u32                     buffer_length)
{
	acpi_status             status;
	u32                     field_datum_byte_offset;
	u32                     datum_offset;
	u32                     mask;
	u32                     merged_datum;
	u32                     previous_raw_datum;
	u32                     this_raw_datum;
	u32                     byte_field_length;
	u32                     datum_count;


	FUNCTION_TRACE ("Ex_insert_into_field");


	/*
	 * Incoming buffer must be at least as long as the field, we do not
	 * allow "partial" field writes.  We do not care if the buffer is
	 * larger than the field, this typically happens when an integer is
	 * written to a field that is actually smaller than an integer.
	 */
	byte_field_length = ROUND_BITS_UP_TO_BYTES (obj_desc->common_field.bit_length);
	if (buffer_length < byte_field_length) {
		ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Buffer length %X too small for field %X\n",
			buffer_length, byte_field_length));

		/* TBD: Need a better error code */

		return_ACPI_STATUS (AE_BUFFER_OVERFLOW);
	}

	/* Convert byte count to datum count, round up if necessary */

	datum_count = ROUND_UP_TO (byte_field_length, obj_desc->common_field.access_byte_width);

	ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
		"Byte_len=%x, Datum_len=%x, Bit_gran=%x, Byte_gran=%x\n",
		byte_field_length, datum_count, obj_desc->common_field.access_bit_width,
		obj_desc->common_field.access_byte_width));

	/*
	 * Break the request into up to three parts (similar to an I/O request):
	 * 1) non-aligned part at start
	 * 2) aligned part in middle
	 * 3) non-aligned part at the end
	 */
	field_datum_byte_offset = 0;
	datum_offset= 0;

	/* Get a single datum from the caller's buffer */

	acpi_ex_get_buffer_datum (&previous_raw_datum, buffer,
			obj_desc->common_field.access_byte_width, datum_offset);

	/*
	 * Part1:
	 * Write a partial field datum if field does not begin on a datum boundary
	 * Note: The code in this section also handles the aligned case
	 *
	 * Construct Mask with 1 bits where the field is, 0 bits elsewhere
	 * (Only the bottom 5 bits of Bit_length are valid for a shift operation)
	 *
	 * Mask off bits that are "below" the field (if any)
	 */
	mask = MASK_BITS_BELOW (obj_desc->common_field.start_field_bit_offset);

	/* If the field fits in one datum, may need to mask upper bits */

	if ((obj_desc->common_field.access_flags & AFIELD_SINGLE_DATUM) &&
		 obj_desc->common_field.end_field_valid_bits) {
		/* There are bits above the field, mask them off also */

		mask &= MASK_BITS_ABOVE (obj_desc->common_field.end_field_valid_bits);
	}

	/* Shift and mask the value into the field position */

	merged_datum = (previous_raw_datum << obj_desc->common_field.start_field_bit_offset);
	merged_datum &= mask;

	/* Apply the update rule (if necessary) and write the datum to the field */

	status = acpi_ex_write_field_datum_with_update_rule (obj_desc, mask, merged_datum,
			   field_datum_byte_offset);
	if (ACPI_FAILURE (status)) {
		return_ACPI_STATUS (status);
	}

	/* If the entire field fits within one datum, we are done. */

	if ((datum_count == 1) &&
	   (obj_desc->common_field.access_flags & AFIELD_SINGLE_DATUM)) {
		return_ACPI_STATUS (AE_OK);
	}

	/*
	 * Part2:
	 * Write the aligned data.
	 *
	 * We don't need to worry about the update rule for these data, because
	 * all of the bits in each datum are part of the field.
	 *
	 * The last datum must be special cased because it might contain bits
	 * that are not part of the field -- therefore the "update rule" must be
	 * applied in Part3 below.
	 */
	while (datum_offset < datum_count) {
		datum_offset++;
		field_datum_byte_offset += obj_desc->common_field.access_byte_width;

		/*
		 * Get the next raw buffer datum.  It may contain bits of the previous
		 * field datum
		 */
		acpi_ex_get_buffer_datum (&this_raw_datum, buffer,
				obj_desc->common_field.access_byte_width, datum_offset);

		/* Create the field datum based on the field alignment */

		if (obj_desc->common_field.start_field_bit_offset != 0) {
			/*
			 * Put together appropriate bits of the two raw buffer data to make
			 * a single complete field datum
			 */
			merged_datum =
				(previous_raw_datum >> obj_desc->common_field.datum_valid_bits) |
				(this_raw_datum << obj_desc->common_field.start_field_bit_offset);
		}

		else {
			/* Field began aligned on datum boundary */

			merged_datum = this_raw_datum;
		}

		/*
		 * Special handling for the last datum if the field does NOT end on
		 * a datum boundary.  Update Rule must be applied to the bits outside
		 * the field.
		 */
		if (datum_offset == datum_count) {
			/*
			 * If there are dangling non-aligned bits, perform one more merged write
			 * Else - field is aligned at the end, no need for any more writes
			 */
			if (obj_desc->common_field.end_field_valid_bits) {
				/*
				 * Part3:
				 * This is the last datum and the field does not end on a datum boundary.
				 * Build the partial datum and write with the update rule.
				 *
				 * Mask off the unused bits above (after) the end-of-field
				 */
				mask = MASK_BITS_ABOVE (obj_desc->common_field.end_field_valid_bits);
				merged_datum &= mask;

				/* Write the last datum with the update rule */

				status = acpi_ex_write_field_datum_with_update_rule (obj_desc, mask,
						  merged_datum, field_datum_byte_offset);
				if (ACPI_FAILURE (status)) {
					return_ACPI_STATUS (status);
				}
			}
		}

		else {
			/* Normal case -- write the completed datum */

			status = acpi_ex_write_field_datum (obj_desc,
					  field_datum_byte_offset, merged_datum);
			if (ACPI_FAILURE (status)) {
				return_ACPI_STATUS (status);
			}
		}

		/*
		 * Save the most recent datum since it may contain bits of the *next*
		 * field datum.  Update current byte offset.
		 */
		previous_raw_datum = this_raw_datum;
	}

	return_ACPI_STATUS (status);
}