a52cf086ac
Add debug UART functions to permit omap specific ns16550 to provide an early debug UART. This is mostly in common with DEBUG_UART_NS16550 except for Mode definition register which is required for selecting UART mode(16x auto-baud or 13x mode). Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Tom Rini <trini@konsulko.com>
183 lines
4.2 KiB
C
183 lines
4.2 KiB
C
/*
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* Early debug UART support
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*
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* (C) Copyright 2014 Google, Inc
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* Writte by Simon Glass <sjg@chromium.org>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef _DEBUG_UART_H
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#define _DEBUG_UART_H
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/*
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* The debug UART is intended for use very early in U-Boot to debug problems
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* when an ICE or other debug mechanism is not available.
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*
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* To use it you should:
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* - Make sure your UART supports this interface
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* - Enable CONFIG_DEBUG_UART
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* - Enable the CONFIG for your UART to tell it to provide this interface
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* (e.g. CONFIG_DEBUG_UART_NS16550)
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* - Define the required settings as needed (see below)
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* - Call debug_uart_init() before use
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* - Call printch() to output a character
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*
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* Depending on your platform it may be possible to use this UART before a
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* stack is available.
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*
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* If your UART does not support this interface you can probably add support
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* quite easily. Remember that you cannot use driver model and it is preferred
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* to use no stack.
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*
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* You must not use this UART once driver model is working and the serial
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* drivers are up and running (done in serial_init()). Otherwise the drivers
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* may conflict and you will get strange output.
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*
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*
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* To enable the debug UART in your serial driver:
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*
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* - #include <debug_uart.h>
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* - Define _debug_uart_init(), trying to avoid using the stack
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* - Define _debug_uart_putc() as static inline (avoiding stack usage)
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* - Immediately afterwards, add DEBUG_UART_FUNCS to define the rest of the
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* functionality (printch(), etc.)
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*
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* If your board needs additional init for the UART to work, enable
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* CONFIG_DEBUG_UART_BOARD_INIT and write a function called
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* board_debug_uart_init() to perform that init. When debug_uart_init() is
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* called, the init will happen automatically.
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*/
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/**
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* debug_uart_init() - Set up the debug UART ready for use
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*
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* This sets up the UART with the correct baud rate, etc.
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*
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* Available CONFIG is:
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*
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* - CONFIG_DEBUG_UART_BASE: Base address of UART
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* - CONFIG_BAUDRATE: Requested baud rate
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* - CONFIG_DEBUG_UART_CLOCK: Input clock for UART
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*/
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void debug_uart_init(void);
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#ifdef CONFIG_DEBUG_UART_BOARD_INIT
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void board_debug_uart_init(void);
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#else
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static inline void board_debug_uart_init(void)
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{
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}
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#endif
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/**
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* printch() - Output a character to the debug UART
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*
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* @ch: Character to output
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*/
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void printch(int ch);
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/**
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* printascii() - Output an ASCII string to the debug UART
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*
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* @str: String to output
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*/
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void printascii(const char *str);
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/**
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* printhex2() - Output a 2-digit hex value
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*
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* @value: Value to output
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*/
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void printhex2(uint value);
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/**
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* printhex4() - Output a 4-digit hex value
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*
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* @value: Value to output
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*/
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void printhex4(uint value);
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/**
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* printhex8() - Output a 8-digit hex value
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*
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* @value: Value to output
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*/
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void printhex8(uint value);
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#ifdef CONFIG_DEBUG_UART_ANNOUNCE
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#define _DEBUG_UART_ANNOUNCE printascii("<debug_uart> ");
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#else
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#define _DEBUG_UART_ANNOUNCE
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#endif
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#define serial_dout(reg, value) \
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serial_out_shift((char *)com_port + \
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((char *)reg - (char *)com_port) * \
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(1 << CONFIG_DEBUG_UART_SHIFT), \
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CONFIG_DEBUG_UART_SHIFT, value)
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#define serial_din(reg) \
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serial_in_shift((char *)com_port + \
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((char *)reg - (char *)com_port) * \
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(1 << CONFIG_DEBUG_UART_SHIFT), \
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CONFIG_DEBUG_UART_SHIFT)
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/*
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* Now define some functions - this should be inserted into the serial driver
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*/
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#define DEBUG_UART_FUNCS \
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\
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static inline void _printch(int ch) \
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{ \
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if (ch == '\n') \
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_debug_uart_putc('\r'); \
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_debug_uart_putc(ch); \
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} \
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\
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void printch(int ch) \
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{ \
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_printch(ch); \
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} \
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\
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void printascii(const char *str) \
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{ \
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while (*str) \
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_printch(*str++); \
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} \
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\
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static inline void printhex1(uint digit) \
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{ \
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digit &= 0xf; \
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_debug_uart_putc(digit > 9 ? digit - 10 + 'a' : digit + '0'); \
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} \
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\
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static inline void printhex(uint value, int digits) \
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{ \
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while (digits-- > 0) \
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printhex1(value >> (4 * digits)); \
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} \
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\
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void printhex2(uint value) \
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{ \
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printhex(value, 2); \
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} \
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\
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void printhex4(uint value) \
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{ \
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printhex(value, 4); \
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} \
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\
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void printhex8(uint value) \
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{ \
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printhex(value, 8); \
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} \
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\
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void debug_uart_init(void) \
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{ \
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board_debug_uart_init(); \
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_debug_uart_init(); \
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_DEBUG_UART_ANNOUNCE \
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} \
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#endif
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