LXR uboot/include/debug

   1/*
   2 * Early debug UART support
   3 *
   4 * (C) Copyright 2014 Google, Inc
   5 * Writte by Simon Glass <sjg@chromium.org>
   6 *
   7 * SPDX-License-Identifier:     GPL-2.0+
   8 */
   9
  10#ifndef _DEBUG_UART_H
  11#define _DEBUG_UART_H
  12
  13/*
  14 * The debug UART is intended for use very early in U-Boot to debug problems
  15 * when an ICE or other debug mechanism is not available.
  16 *
  17 * To use it you should:
  18 * - Make sure your UART supports this interface
  19 * - Enable CONFIG_DEBUG_UART
  20 * - Enable the CONFIG for your UART to tell it to provide this interface
  21 *       (e.g. CONFIG_DEBUG_UART_NS16550)
  22 * - Define the required settings as needed (see below)
  23 * - Call debug_uart_init() before use
  24 * - Call printch() to output a character
  25 *
  26 * Depending on your platform it may be possible to use this UART before a
  27 * stack is available.
  28 *
  29 * If your UART does not support this interface you can probably add support
  30 * quite easily. Remember that you cannot use driver model and it is preferred
  31 * to use no stack.
  32 *
  33 * You must not use this UART once driver model is working and the serial
  34 * drivers are up and running (done in serial_init()). Otherwise the drivers
  35 * may conflict and you will get strange output.
  36 *
  37 *
  38 * To enable the debug UART in your serial driver:
  39 *
  40 * - #include <debug_uart.h>
  41 * - Define _debug_uart_init(), trying to avoid using the stack
  42 * - Define _debug_uart_putc() as static inline (avoiding stack usage)
  43 * - Immediately afterwards, add DEBUG_UART_FUNCS to define the rest of the
  44 *     functionality (printch(), etc.)
  45 *
  46 * If your board needs additional init for the UART to work, enable
  47 * CONFIG_DEBUG_UART_BOARD_INIT and write a function called
  48 * board_debug_uart_init() to perform that init. When debug_uart_init() is
  49 * called, the init will happen automatically.
  50 */
  51
  52/**
  53 * debug_uart_init() - Set up the debug UART ready for use
  54 *
  55 * This sets up the UART with the correct baud rate, etc.
  56 *
  57 * Available CONFIG is:
  58 *
  59 *    - CONFIG_DEBUG_UART_BASE: Base address of UART
  60 *    - CONFIG_BAUDRATE: Requested baud rate
  61 *    - CONFIG_DEBUG_UART_CLOCK: Input clock for UART
  62 */
  63void debug_uart_init(void);
  64
  65#ifdef CONFIG_DEBUG_UART_BOARD_INIT
  66void board_debug_uart_init(void);
  67#else
  68static inline void board_debug_uart_init(void)
  69{
  70}
  71#endif
  72
  73/**
  74 * printch() - Output a character to the debug UART
  75 *
  76 * @ch:         Character to output
  77 */
  78void printch(int ch);
  79
  80/**
  81 * printascii() - Output an ASCII string to the debug UART
  82 *
  83 * @str:        String to output
  84 */
  85void printascii(const char *str);
  86
  87/**
  88 * printhex2() - Output a 2-digit hex value
  89 *
  90 * @value:      Value to output
  91 */
  92void printhex2(uint value);
  93
  94/**
  95 * printhex4() - Output a 4-digit hex value
  96 *
  97 * @value:      Value to output
  98 */
  99void printhex4(uint value);
 100
 101/**
 102 * printhex8() - Output a 8-digit hex value
 103 *
 104 * @value:      Value to output
 105 */
 106void printhex8(uint value);
 107
 108#ifdef CONFIG_DEBUG_UART_ANNOUNCE
 109#define _DEBUG_UART_ANNOUNCE    printascii("<debug_uart> ");
 110#else
 111#define _DEBUG_UART_ANNOUNCE
 112#endif
 113
 114/*
 115 * Now define some functions - this should be inserted into the serial driver
 116 */
 117#define DEBUG_UART_FUNCS \
 118        void printch(int ch) \
 119        { \
 120                _debug_uart_putc(ch); \
 121        } \
 122\
 123        void printascii(const char *str) \
 124        { \
 125                while (*str) \
 126                        _debug_uart_putc(*str++); \
 127        } \
 128\
 129        static inline void printhex1(uint digit) \
 130        { \
 131                digit &= 0xf; \
 132                _debug_uart_putc(digit > 9 ? digit - 10 + 'a' : digit + '0'); \
 133        } \
 134\
 135        static inline void printhex(uint value, int digits) \
 136        { \
 137                while (digits-- > 0) \
 138                        printhex1(value >> (4 * digits)); \
 139        } \
 140\
 141        void printhex2(uint value) \
 142        { \
 143                printhex(value, 2); \
 144        } \
 145\
 146        void printhex4(uint value) \
 147        { \
 148                printhex(value, 4); \
 149        } \
 150\
 151        void printhex8(uint value) \
 152        { \
 153                printhex(value, 8); \
 154        } \
 155\
 156        void debug_uart_init(void) \
 157        { \
 158                board_debug_uart_init(); \
 159                _debug_uart_init(); \
 160                _DEBUG_UART_ANNOUNCE \
 161        } \
 162
 163#endif
 164