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https://github.com/brain-hackers/u-boot-brain
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7e148f2ed3
It is convenient to write a length value for preceding a block of data. Of course the length is not known or is hard to calculate a priori. So add a way to mark the start on a stack, so the length can be updated when known. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Core ACPI (Advanced Configuration and Power Interface) support
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*
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* Copyright 2019 Google LLC
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*
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* Modified from coreboot file acpigen.h
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*/
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#ifndef __ACPI_ACPIGEN_H
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#define __ACPI_ACPIGEN_H
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#include <linux/types.h>
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struct acpi_ctx;
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/* Top 4 bits of the value used to indicate a three-byte length value */
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#define ACPI_PKG_LEN_3_BYTES 0x80
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/**
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* acpigen_get_current() - Get the current ACPI code output pointer
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*
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* @ctx: ACPI context pointer
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* @return output pointer
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*/
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u8 *acpigen_get_current(struct acpi_ctx *ctx);
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/**
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* acpigen_emit_byte() - Emit a byte to the ACPI code
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*
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* @ctx: ACPI context pointer
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* @data: Value to output
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*/
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void acpigen_emit_byte(struct acpi_ctx *ctx, uint data);
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/**
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* acpigen_emit_word() - Emit a 16-bit word to the ACPI code
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*
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* @ctx: ACPI context pointer
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* @data: Value to output
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*/
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void acpigen_emit_word(struct acpi_ctx *ctx, uint data);
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/**
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* acpigen_emit_dword() - Emit a 32-bit 'double word' to the ACPI code
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*
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* @ctx: ACPI context pointer
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* @data: Value to output
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*/
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void acpigen_emit_dword(struct acpi_ctx *ctx, uint data);
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/**
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* acpigen_emit_stream() - Emit a stream of bytes
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*
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* @ctx: ACPI context pointer
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* @data: Data to output
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* @size: Size of data in bytes
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*/
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void acpigen_emit_stream(struct acpi_ctx *ctx, const char *data, int size);
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/**
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* acpigen_emit_string() - Emit a string
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*
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* Emit a string with a null terminator
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*
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* @ctx: ACPI context pointer
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* @str: String to output, or NULL for an empty string
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*/
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void acpigen_emit_string(struct acpi_ctx *ctx, const char *str);
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/**
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* acpigen_write_len_f() - Write a 'forward' length placeholder
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*
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* This adds space for a length value in the ACPI stream and pushes the current
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* position (before the length) on the stack. After calling this you can write
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* some data and then call acpigen_pop_len() to update the length value.
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*
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* Usage:
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*
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* acpigen_write_len_f() ------\
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* acpigen_write...() |
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* acpigen_write...() |
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* acpigen_write_len_f() --\ |
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* acpigen_write...() | |
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* acpigen_write...() | |
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* acpigen_pop_len() ------/ |
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* acpigen_write...() |
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* acpigen_pop_len() ----------/
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*
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* See ACPI 6.3 section 20.2.4 Package Length Encoding
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*
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* This implementation always uses a 3-byte packet length for simplicity. It
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* could be adjusted to support other lengths.
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*
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* @ctx: ACPI context pointer
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*/
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void acpigen_write_len_f(struct acpi_ctx *ctx);
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/**
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* acpigen_pop_len() - Update the previously stacked length placeholder
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*
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* Call this after the data for the block has been written. It updates the
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* top length value in the stack and pops it off.
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*
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* @ctx: ACPI context pointer
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*/
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void acpigen_pop_len(struct acpi_ctx *ctx);
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#endif
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