LXR uboot/include/debug

   1/* SPDX-License-Identifier: GPL-2.0+ */
   2/*
   3 * Early debug UART support
   4 *
   5 * (C) Copyright 2014 Google, Inc
   6 * Writte by Simon Glass <sjg@chromium.org>
   7 */
   8
   9#ifndef _DEBUG_UART_H
  10#define _DEBUG_UART_H
  11
  12/*
  13 * The debug UART is intended for use very early in U-Boot to debug problems
  14 * when an ICE or other debug mechanism is not available.
  15 *
  16 * To use it you should:
  17 * - Make sure your UART supports this interface
  18 * - Enable CONFIG_DEBUG_UART
  19 * - Enable the CONFIG for your UART to tell it to provide this interface
  20 *       (e.g. CONFIG_DEBUG_UART_NS16550)
  21 * - Define the required settings as needed (see below)
  22 * - Call debug_uart_init() before use
  23 * - Call printch() to output a character
  24 *
  25 * Depending on your platform it may be possible to use this UART before a
  26 * stack is available.
  27 *
  28 * If your UART does not support this interface you can probably add support
  29 * quite easily. Remember that you cannot use driver model and it is preferred
  30 * to use no stack.
  31 *
  32 * You must not use this UART once driver model is working and the serial
  33 * drivers are up and running (done in serial_init()). Otherwise the drivers
  34 * may conflict and you will get strange output.
  35 *
  36 *
  37 * To enable the debug UART in your serial driver:
  38 *
  39 * - #include <debug_uart.h>
  40 * - Define _debug_uart_init(), trying to avoid using the stack
  41 * - Define _debug_uart_putc() as static inline (avoiding stack usage)
  42 * - Immediately afterwards, add DEBUG_UART_FUNCS to define the rest of the
  43 *     functionality (printch(), etc.)
  44 *
  45 * If your board needs additional init for the UART to work, enable
  46 * CONFIG_DEBUG_UART_BOARD_INIT and write a function called
  47 * board_debug_uart_init() to perform that init. When debug_uart_init() is
  48 * called, the init will happen automatically.
  49 */
  50
  51/**
  52 * debug_uart_init() - Set up the debug UART ready for use
  53 *
  54 * This sets up the UART with the correct baud rate, etc.
  55 *
  56 * Available CONFIG is:
  57 *
  58 *    - CONFIG_DEBUG_UART_BASE: Base address of UART
  59 *    - CONFIG_BAUDRATE: Requested baud rate
  60 *    - CONFIG_DEBUG_UART_CLOCK: Input clock for UART
  61 */
  62void debug_uart_init(void);
  63
  64#ifdef CONFIG_DEBUG_UART_BOARD_INIT
  65void board_debug_uart_init(void);
  66#else
  67static inline void board_debug_uart_init(void)
  68{
  69}
  70#endif
  71
  72/**
  73 * printch() - Output a character to the debug UART
  74 *
  75 * @ch:         Character to output
  76 */
  77void printch(int ch);
  78
  79/**
  80 * printascii() - Output an ASCII string to the debug UART
  81 *
  82 * @str:        String to output
  83 */
  84void printascii(const char *str);
  85
  86/**
  87 * printhex2() - Output a 2-digit hex value
  88 *
  89 * @value:      Value to output
  90 */
  91void printhex2(uint value);
  92
  93/**
  94 * printhex4() - Output a 4-digit hex value
  95 *
  96 * @value:      Value to output
  97 */
  98void printhex4(uint value);
  99
 100/**
 101 * printhex8() - Output a 8-digit hex value
 102 *
 103 * @value:      Value to output
 104 */
 105void printhex8(uint value);
 106
 107#ifdef CONFIG_DEBUG_UART_ANNOUNCE
 108#define _DEBUG_UART_ANNOUNCE    printascii("<debug_uart> ");
 109#else
 110#define _DEBUG_UART_ANNOUNCE
 111#endif
 112
 113#define serial_dout(reg, value) \
 114        serial_out_shift((char *)com_port + \
 115                ((char *)reg - (char *)com_port) * \
 116                        (1 << CONFIG_DEBUG_UART_SHIFT), \
 117                CONFIG_DEBUG_UART_SHIFT, value)
 118#define serial_din(reg) \
 119        serial_in_shift((char *)com_port + \
 120                ((char *)reg - (char *)com_port) * \
 121                        (1 << CONFIG_DEBUG_UART_SHIFT), \
 122                CONFIG_DEBUG_UART_SHIFT)
 123
 124/*
 125 * Now define some functions - this should be inserted into the serial driver
 126 */
 127#define DEBUG_UART_FUNCS \
 128\
 129        static inline void _printch(int ch) \
 130        { \
 131                if (ch == '\n') \
 132                        _debug_uart_putc('\r'); \
 133                _debug_uart_putc(ch); \
 134        } \
 135\
 136        void printch(int ch) \
 137        { \
 138                _printch(ch); \
 139        } \
 140\
 141        void printascii(const char *str) \
 142        { \
 143                while (*str) \
 144                        _printch(*str++); \
 145        } \
 146\
 147        static inline void printhex1(uint digit) \
 148        { \
 149                digit &= 0xf; \
 150                _debug_uart_putc(digit > 9 ? digit - 10 + 'a' : digit + '0'); \
 151        } \
 152\
 153        static inline void printhex(uint value, int digits) \
 154        { \
 155                while (digits-- > 0) \
 156                        printhex1(value >> (4 * digits)); \
 157        } \
 158\
 159        void printhex2(uint value) \
 160        { \
 161                printhex(value, 2); \
 162        } \
 163\
 164        void printhex4(uint value) \
 165        { \
 166                printhex(value, 4); \
 167        } \
 168\
 169        void printhex8(uint value) \
 170        { \
 171                printhex(value, 8); \
 172        } \
 173\
 174        void debug_uart_init(void) \
 175        { \
 176                board_debug_uart_init(); \
 177                _debug_uart_init(); \
 178                _DEBUG_UART_ANNOUNCE \
 179        } \
 180
 181#endif
 182