270 lines
9.1 KiB
C
270 lines
9.1 KiB
C
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/*******************************************************************************
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Copyright (c) 2006-2009 Tensilica Inc.
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be included
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in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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--------------------------------------------------------------------------------
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xtbsp.h Xtensa Board Support Package API
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This API defines a minimal set of board-support functions that every supported
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Xtensa board is expected to provide in the board-support-package (BSP) library
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associated with the board-specific LSP. Only basic board functions are provided
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in this board-independent API. API functions not applicable to a board must be
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stubbed in its BSP library. More complex operations must use a board-specific
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interface. Functions are grouped by type of peripheral device.
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*******************************************************************************/
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#ifndef _XTBSP_H_
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#define _XTBSP_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*******************************************************************************
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BOARD INITIALIZATION.
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The board with all its devices is initialized by xtbsp_board_init().
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Individual devices represented by this API can be reinitialized at any
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time by calling their inidividual device init functions (grouped with
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other device functions). This might be useful to (say) change the baud
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rate of the UART.
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*/
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/*
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Initialize the board. Must call before any other API function.
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Iniitializes BSP, board in general, and all devices on the board.
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*/
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extern void xtbsp_board_init(void);
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/*******************************************************************************
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BOARD CHARACTERISTICS and CONVENIENCE FUNCTIONS.
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Board support functions not associated with a particular peripheral device.
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*/
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/*
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Return a short string representing the type of board.
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If the board has a display, the string must fit on a single line.
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*/
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extern const char * xtbsp_board_name(void);
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/*
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Hardware reset the entire board (if possible). Does not return if successful.
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If this function returns, it is stubbed out or not possible with this board.
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*/
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extern void xtbsp_board_reset(void);
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/*
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Return the clock frequency in Hertz. May be constant or computed.
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*/
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extern unsigned xtbsp_clock_freq_hz(void);
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/*
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Return the clock period in picoseconds. May be constant or computed.
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*/
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extern unsigned xtbsp_clock_period_ps(void);
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/*
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Spin (at least) a number of cycles per the processor's CCOUNT register.
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Unlike a s/w delay loop, the duration is not affected by compiler
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optimization or interrupts completed within the delay period.
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If the processor doesn't have CCOUNT, a s/w delay loop is used to obtain
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a rough approximation of the cycle count.
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*/
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extern void xtbsp_delay_cycles(unsigned cycles);
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/*
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Spin at least a number of nanoseconds (approximate and err in the high side).
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BSP implementation should do this efficiently, avoiding integer overflow or
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excessive loss of precision, run-time division or floating point.
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Function implementation (vs. macro) allows BSP to optimize for the clock
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frequency by pre-computing (or using constant) scale factors.
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*/
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extern void xtbsp_delay_ns(unsigned ns);
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/*******************************************************************************
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C LIBRARY SUPPORT.
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These functions are called by the C library libgloss interface.
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Their names are predetermined apart from this BSP API.
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*/
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/*
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Initialize the board. Called by C library initialization code.
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Usually simply calls xtbsp_board_init().
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*/
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extern void board_init(void);
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/*
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(Wait for and) Input a single byte from the default character I/O
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device. Return -1 if there is no input device.
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This device is usually a UART and this function calls xtbsp_uart_getchar().
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On some boards (eg.) it might be a directly connected keyboard.
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*/
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extern int inbyte(void);
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/*
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Output a single char to the default character I/O device (and wait
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until it's been taken).
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This device is usually a UART and this function calls xtbsp_uart_putchar().
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On some boards (eg.) it might be a directly connected bit-mapped screen.
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*/
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extern void outbyte(int c);
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/*******************************************************************************
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UART (SERIAL I/O).
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Supports a single UART in a simple polling mode and provides control of
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receiver and transmitter data interrupts (client must provide handler).
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Provides a mapping to processor interrupt number which can be used with
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the HAL to control processor interrupt enable (INTENABLE) etc.
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*/
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/* Bitmasks to identify UART interrupts. */
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typedef enum xtbsp_uart_int {
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xtbsp_uart_int_rx = 1<<0,
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xtbsp_uart_int_tx = 1<<1,
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/* mask of all valid interrupt bits */
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xtbsp_uart_int_all = (1<<2)-1
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} xtbsp_uart_int;
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/*
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Return non-zero if the board has a UART.
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*/
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extern int xtbsp_uart_exists(void);
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/*
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Initialize the UART:
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parity = 0 (none), 1 (odd), or 2 (even).
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nstop = 1 or 2 (stop bits).
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ndata = 7 or 8 (data bits).
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Disables all UART interrupts.
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Returns non-zero if failed (perhaps due to unsupported parameter values).
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Must call before any of the following functions.
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*/
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extern int xtbsp_uart_init(unsigned baud, unsigned ndata,
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unsigned parity, unsigned nstop);
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#define xtbsp_uart_init_default() xtbsp_uart_init(38400, 8, 0, 1)
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/*
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(Wait for and) Input a single char from the UART.
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Any pending xtbsp_uart_int_rx interrupt is cleared.
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*/
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extern char xtbsp_uart_getchar(void);
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/*
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(Wait for transmitter ready and) Output a single char to the UART.
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Any pending xtbsp_uart_int_tx interrupt is cleared.
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*/
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extern void xtbsp_uart_putchar(const char c);
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/*
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Return true (non-zero) if a character has been received and is ready
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to be input by xtbsp_uart_getchar() without waiting, else return 0.
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*/
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extern int xtbsp_uart_get_isready(void);
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/*
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Return non-zero if a character may be output by xtbsp_uart_putchar()
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without waiting, else return 0.
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Any pending xtbsp_uart_int_tx interrupt is cleared.
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*/
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extern int xtbsp_uart_put_isready(void);
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/*
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Return the enable status of all UART interrupts represented by this API,
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that is those with bits defined in type xtbsp_uart_int (1 bit = enabled).
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This is the enable status at the device, not the processor's INTENABLE.
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*/
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extern xtbsp_uart_int xtbsp_uart_int_enable_status(void);
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/*
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Enable selected UART interrupts at the device.
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*/
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extern void xtbsp_uart_int_enable(const xtbsp_uart_int mask);
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/*
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Disable selected UART interrupts at the device.
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*/
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extern void xtbsp_uart_int_disable(const xtbsp_uart_int mask);
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/*
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Return the interrupt number (0..31) to which the selected UART interrupt
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is connected. May be used with the link-time HAL to obtain more information,
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eg. Xthal_intlevel_mask[xtbsp_uart_int_number(xtbsp_uart_int_rx)]
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This information can be used to control the processor's INTENABLE, etc.
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Result is -1 if not connected, undefined if mask has more than 1 bit set.
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*/
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extern int xtbsp_uart_int_number(const xtbsp_uart_int mask);
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/*******************************************************************************
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DISPLAY.
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Supports a single display that can render a series of ASCII characters.
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Functions are provided to perform generic display tasks such as display
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a string, display character by character, or blank the display.
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Chars are 7-bit printable ASCII. Strings are C style NUL \0 terminated.
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These functions busy-wait for any required timing delays so the caller does
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not have to deal with timing. Some displays require long delays which in
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some client applications warrant a board and RTOS specific approach to
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driving the display, however that is beyond the scope of this API.
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*/
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/*
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Return non-zero if board has a display.
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*/
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extern int xtbsp_display_exists(void);
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/*
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Initialize the display. Must call before any of the following functions.
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*/
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extern void xtbsp_display_init(void);
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/*
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Display a single char at position pos (0 is leftmost). Other positions are
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left untouched. Positions beyond the width of the display are ignored.
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*/
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extern void xtbsp_display_char(unsigned pos, const char c);
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/*
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Display a string. Blank-pad to or truncate at the end of the display
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(overwrites any previous string so don't need to blank display first).
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*/
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extern void xtbsp_display_string(const char *s);
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/*
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Blank (clear) the entire display.
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*/
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extern void xtbsp_display_blank(void);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _XTBSP_H_ */
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