4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2003, 2004, 2006 Develer S.r.l. (http://www.develer.com/)
30 * Copyright 2000 Bernie Innocenti <bernie@codewiz.org>
33 * \brief Buffered serial I/O driver
35 * The serial rx interrupt buffers incoming data in a software FIFO
36 * to decouple the higher level protocols from the line speed.
37 * Outgoing data is buffered as well for better performance.
38 * This driver is not optimized for best performance, but it
39 * has proved to be fast enough to handle transfer rates up to
40 * 38400bps on a 16MHz 80196.
42 * MODULE CONFIGURATION
44 * \li \c CONFIG_SER_HWHANDSHAKE - set to 1 to enable RTS/CTS handshake.
45 * Support is incomplete/untested.
46 * \li \c CONFIG_SER_TXTIMEOUT - Enable software serial transmission timeouts
50 * \author Bernie Innocenti <bernie@codewiz.org>
57 #include "cfg/cfg_ser.h"
58 #include "cfg/cfg_kern.h"
59 #include <cfg/debug.h>
61 #include <mware/formatwr.h>
63 #include <string.h> /* memset */
66 * Sanity check for config parameters required by this module.
68 #if !defined(CONFIG_KERNEL) || ((CONFIG_KERNEL != 0) && CONFIG_KERNEL != 1)
69 #error CONFIG_KERNEL must be set to either 0 or 1 in config.h
71 #if !defined(CONFIG_SER_RXTIMEOUT)
72 #error CONFIG_SER_TXTIMEOUT missing in config.h
74 #if !defined(CONFIG_SER_RXTIMEOUT)
75 #error CONFIG_SER_RXTIMEOUT missing in config.h
77 #if !defined(CONFIG_SER_DEFBAUDRATE)
78 #error CONFIG_SER_DEFBAUDRATE missing in config.h
81 #if CONFIG_KERNEL && CONFIG_KERN_SCHED
82 #include <kern/proc.h>
84 #define proc_yield() do {} while(0)
87 #if CONFIG_SER_TXTIMEOUT != -1 || CONFIG_SER_RXTIMEOUT != -1
88 #include <drv/timer.h>
92 struct Serial *ser_handles[SER_CNT];
95 * Insert \a c in tx FIFO buffer.
96 * \note This function will switch out the calling process
97 * if the tx buffer is full. If the buffer is full
98 * and \a port->txtimeout is 0 return EOF immediatly.
100 * \return EOF on error or timeout, \a c otherwise.
102 static int ser_putchar(int c, struct Serial *port)
104 if (fifo_isfull_locked(&port->txfifo))
106 #if CONFIG_SER_TXTIMEOUT != -1
107 /* If timeout == 0 we don't want to wait */
108 if (port->txtimeout == 0)
111 ticks_t start_time = timer_clock();
114 /* Wait while buffer is full... */
117 /* Give up timeslice to other processes. */
121 #if CONFIG_SER_TXTIMEOUT != -1
122 if (timer_clock() - start_time >= port->txtimeout)
124 ATOMIC(port->status |= SERRF_TXTIMEOUT);
127 #endif /* CONFIG_SER_TXTIMEOUT */
129 while (fifo_isfull_locked(&port->txfifo));
132 fifo_push_locked(&port->txfifo, (unsigned char)c);
134 /* (re)trigger tx interrupt */
135 port->hw->table->txStart(port->hw);
137 /* Avoid returning signed extended char */
138 return (int)((unsigned char)c);
143 * Fetch a character from the rx FIFO buffer.
144 * \note This function will switch out the calling process
145 * if the rx buffer is empty. If the buffer is empty
146 * and \a port->rxtimeout is 0 return EOF immediatly.
148 * \return EOF on error or timeout, \a c otherwise.
150 static int ser_getchar(struct Serial *port)
152 if (fifo_isempty_locked(&port->rxfifo))
154 #if CONFIG_SER_RXTIMEOUT != -1
155 /* If timeout == 0 we don't want to wait for chars */
156 if (port->rxtimeout == 0)
159 ticks_t start_time = timer_clock();
162 /* Wait while buffer is empty */
165 /* Give up timeslice to other processes. */
169 #if CONFIG_SER_RXTIMEOUT != -1
170 if (timer_clock() - start_time >= port->rxtimeout)
172 ATOMIC(port->status |= SERRF_RXTIMEOUT);
175 #endif /* CONFIG_SER_RXTIMEOUT */
177 while (fifo_isempty_locked(&port->rxfifo) && (ser_getstatus(port) & SERRF_RX) == 0);
181 * Get a byte from the FIFO (avoiding sign-extension),
182 * re-enable RTS, then return result.
184 if (ser_getstatus(port) & SERRF_RX)
186 return (int)(unsigned char)fifo_pop_locked(&port->rxfifo);
190 * Fetch a character from the rx FIFO buffer.
191 * If the buffer is empty, ser_getchar_nowait() returns
193 * \note Deprecated, use ser_getchar with rx_timeout set to 0.
195 int ser_getchar_nowait(struct Serial *fd)
197 if (fifo_isempty_locked(&fd->rxfifo))
200 /* NOTE: the double cast prevents unwanted sign extension */
201 return (int)(unsigned char)fifo_pop_locked(&fd->rxfifo);
207 * Read at most \a size bytes from \a port and put them in \a buf
209 * \return number of bytes actually read.
211 static size_t ser_read(struct KFile *fd, void *_buf, size_t size)
213 Serial *fds = SERIAL_CAST(fd);
216 char *buf = (char *)_buf;
221 if ((c = ser_getchar(fds)) == EOF)
230 * \brief Write a buffer to serial.
232 * \return 0 if OK, EOF in case of error.
234 * \todo Optimize with fifo_pushblock()
236 static size_t ser_write(struct KFile *fd, const void *_buf, size_t size)
238 Serial *fds = SERIAL_CAST(fd);
239 const char *buf = (const char *)_buf;
244 if (ser_putchar(*buf++, fds) == EOF)
252 #if CONFIG_SER_RXTIMEOUT != -1 || CONFIG_SER_TXTIMEOUT != -1
253 void ser_settimeouts(struct Serial *fd, mtime_t rxtimeout, mtime_t txtimeout)
255 fd->rxtimeout = ms_to_ticks(rxtimeout);
256 fd->txtimeout = ms_to_ticks(txtimeout);
258 #endif /* CONFIG_SER_RXTIMEOUT || CONFIG_SER_TXTIMEOUT */
260 #if CONFIG_SER_RXTIMEOUT != -1
262 * Discard input to resynchronize with remote end.
264 * Discard incoming data until the port stops receiving
265 * characters for at least \a delay milliseconds.
267 * \note Serial errors are reset before and after executing the purge.
269 void ser_resync(struct Serial *fd, mtime_t delay)
271 mtime_t old_rxtimeout = ticks_to_ms(fd->rxtimeout);
273 ser_settimeouts(fd, delay, ticks_to_ms(fd->txtimeout));
276 ser_setstatus(fd, 0);
279 while (!(ser_getstatus(fd) & SERRF_RXTIMEOUT));
281 /* Restore port to an usable status */
282 ser_setstatus(fd, 0);
283 ser_settimeouts(fd, old_rxtimeout, ticks_to_ms(fd->txtimeout));
285 #endif /* CONFIG_SER_RXTIMEOUT */
288 void ser_setbaudrate(struct Serial *fd, unsigned long rate)
290 fd->hw->table->setBaudrate(fd->hw, rate);
294 void ser_setparity(struct Serial *fd, int parity)
296 fd->hw->table->setParity(fd->hw, parity);
299 static int ser_error(struct KFile *fd)
301 Serial *fds = SERIAL_CAST(fd);
302 return ser_getstatus(fds);
305 static void ser_clearerr(struct KFile *fd)
307 Serial *fds = SERIAL_CAST(fd);
308 ser_setstatus(fds, 0);
314 * Flush both the RX and TX buffers.
316 void ser_purge(struct Serial *fd)
325 void ser_purgeRx(struct Serial *fd)
327 fifo_flush_locked(&fd->rxfifo);
333 void ser_purgeTx(struct Serial *fd)
335 fifo_flush_locked(&fd->txfifo);
340 * Wait until all pending output is completely
341 * transmitted to the other end.
343 * \note The current implementation only checks the
344 * software transmission queue. Any hardware
347 static int ser_flush(struct KFile *fd)
349 Serial *fds = SERIAL_CAST(fd);
352 * Wait until the FIFO becomes empty, and then until the byte currently in
353 * the hardware register gets shifted out.
355 while (!fifo_isempty(&fds->txfifo)
356 || fds->hw->table->txSending(fds->hw))
358 /* Give up timeslice to other processes. */
367 * Initialize a serial port.
369 * \param fd KFile Serial struct interface.
370 * \param unit Serial unit to open. Possible values are architecture dependant.
372 static struct Serial *ser_open(struct Serial *fd, unsigned int unit)
374 ASSERT(unit < countof(ser_handles));
376 ser_handles[unit] = fd;
377 ASSERT(!fd->is_open);
378 DB(fd->is_open = true);
382 fd->hw = ser_hw_getdesc(unit);
384 /* Initialize circular buffers */
385 ASSERT(fd->hw->txbuffer);
386 ASSERT(fd->hw->rxbuffer);
387 fifo_init(&fd->txfifo, fd->hw->txbuffer, fd->hw->txbuffer_size);
388 fifo_init(&fd->rxfifo, fd->hw->rxbuffer, fd->hw->rxbuffer_size);
390 fd->hw->table->init(fd->hw, fd);
392 /* Set default values */
393 #if CONFIG_SER_RXTIMEOUT != -1 || CONFIG_SER_TXTIMEOUT != -1
394 ser_settimeouts(fd, CONFIG_SER_RXTIMEOUT, CONFIG_SER_TXTIMEOUT);
396 #if CONFIG_SER_DEFBAUDRATE
397 ser_setbaudrate(fd, CONFIG_SER_DEFBAUDRATE);
400 /* Clear error flags */
401 ser_setstatus(fd, 0);
408 * Clean up serial port, disabling the associated hardware.
410 static int ser_close(struct KFile *fd)
412 Serial *fds = SERIAL_CAST(fd);
415 ASSERT(port->is_open);
416 DB(port->is_open = false);
418 // Wait until we finish sending everything
421 port->hw->table->cleanup(port->hw);
425 * We purge the FIFO buffer only after the low-level cleanup, so that
426 * we are sure that there are no more interrupts.
433 * Reopen serial port.
435 static struct KFile *ser_reopen(struct KFile *fd)
437 Serial *fds = SERIAL_CAST(fd);
440 ser_open(fds, fds->unit);
445 * Init serial driver for \a unit.
447 void ser_init(struct Serial *fds, unsigned int unit)
449 memset(fds, 0, sizeof(*fds));
451 DB(fds->fd._type = KFT_SERIAL);
452 fds->fd.reopen = ser_reopen;
453 fds->fd.close = ser_close;
454 fds->fd.read = ser_read;
455 fds->fd.write = ser_write;
456 fds->fd.flush = ser_flush;
457 fds->fd.error = ser_error;
458 fds->fd.clearerr = ser_clearerr;
464 * Read data from SPI bus.
465 * Since we are master, we have to trigger slave by sending
466 * fake chars on the bus.
468 static size_t spimaster_read(struct KFile *fd, void *_buf, size_t size)
470 Serial *fd_spi = SERIAL_CAST(fd);
472 ser_flush(&fd_spi->fd);
476 uint8_t *buf = (uint8_t *)_buf;
482 * Send and receive chars 1 by 1, otherwise the rxfifo
485 ser_putchar(0, fd_spi);
487 if ((c = ser_getchar(fd_spi)) == EOF)
497 * Write data to SPI bus.
499 static size_t spimaster_write(struct KFile *fd, const void *buf, size_t size)
501 Serial *fd_spi = SERIAL_CAST(fd);
505 return ser_write(&fd_spi->fd, buf, size);
510 * Init SPI serial driver \a unit in master mode.
512 * This interface implements the SPI master protocol over a serial SPI
513 * driver. This is needed because normal serial driver send/receive data
514 * at the same time. SPI slaves like memories and other peripherals
515 * first receive and *then* send response back instead.
516 * To achieve this, when we are master and we are *sending*,
517 * we have to discard all incoming data. Then, when we want to
518 * receive, we must write fake data to SPI to trigger slave devices.
520 void spimaster_init(Serial *fds, unsigned int unit)
523 fds->fd.read = spimaster_read;
524 fds->fd.write = spimaster_write;