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 Bernardo Innocenti <bernie@codewiz.org>
34 * \brief Buffered serial I/O driver
36 * The serial rx interrupt buffers incoming data in a software FIFO
37 * to decouple the higher level protocols from the line speed.
38 * Outgoing data is buffered as well for better performance.
39 * This driver is not optimized for best performance, but it
40 * has proved to be fast enough to handle transfer rates up to
41 * 38400bps on a 16MHz 80196.
43 * MODULE CONFIGURATION
45 * \li \c CONFIG_SER_HWHANDSHAKE - set to 1 to enable RTS/CTS handshake.
46 * Support is incomplete/untested.
47 * \li \c CONFIG_SER_TXTIMEOUT - Enable software serial transmission timeouts
51 * \author Bernardo Innocenti <bernie@develer.com>
57 #include <mware/formatwr.h>
58 #include <cfg/debug.h>
59 #include <appconfig.h>
61 #include <string.h> /* memset */
64 * Sanity check for config parameters required by this module.
66 #if !defined(CONFIG_KERNEL) || ((CONFIG_KERNEL != 0) && CONFIG_KERNEL != 1)
67 #error CONFIG_KERNEL must be set to either 0 or 1 in config.h
69 #if !defined(CONFIG_SER_RXTIMEOUT)
70 #error CONFIG_SER_TXTIMEOUT missing in config.h
72 #if !defined(CONFIG_SER_RXTIMEOUT)
73 #error CONFIG_SER_RXTIMEOUT missing in config.h
75 #if !defined(CONFIG_SER_DEFBAUDRATE)
76 #error CONFIG_SER_DEFBAUDRATE missing in config.h
80 #include <kern/proc.h>
83 #if CONFIG_SER_TXTIMEOUT != -1 || CONFIG_SER_RXTIMEOUT != -1
84 #include <drv/timer.h>
88 /* Serial configuration parameters */
89 #define SER_CTSDELAY 70 /**< CTS line retry interval (ms) */
90 #define SER_TXPOLLDELAY 2 /**< Transmit buffer full retry interval (ms) */
91 #define SER_RXPOLLDELAY 2 /**< Receive buffer empty retry interval (ms) */
94 struct Serial ser_handles[SER_CNT];
98 * Inserisce il carattere c nel buffer di trasmissione.
99 * Questa funzione mette il processo chiamante in attesa
100 * quando il buffer e' pieno.
102 * \return EOF in caso di errore o timeout, altrimenti
103 * il carattere inviato.
105 static int ser_putchar(int c, struct Serial *port)
107 //ASSERT_VALID_FIFO(&port->txfifo);
108 if (fifo_isfull_locked(&port->txfifo))
110 #if CONFIG_SER_TXTIMEOUT != -1
111 ticks_t start_time = timer_clock();
114 /* Attende finche' il buffer e' pieno... */
118 #if CONFIG_KERNEL && CONFIG_KERN_SCHED
119 /* Give up timeslice to other processes. */
122 #if CONFIG_SER_TXTIMEOUT != -1
123 if (timer_clock() - start_time >= port->txtimeout)
125 ATOMIC(port->status |= SERRF_TXTIMEOUT);
128 #endif /* CONFIG_SER_TXTIMEOUT */
130 while (fifo_isfull_locked(&port->txfifo));
133 fifo_push_locked(&port->txfifo, (unsigned char)c);
135 /* (re)trigger tx interrupt */
136 port->hw->table->txStart(port->hw);
138 /* Avoid returning signed extended char */
139 return (int)((unsigned char)c);
144 * Preleva un carattere dal buffer di ricezione.
145 * Questa funzione mette il processo chiamante in attesa
146 * quando il buffer e' vuoto. L'attesa ha un timeout
147 * di ser_rxtimeout millisecondi.
149 * \return EOF in caso di errore o timeout, altrimenti
150 * il carattere ricevuto.
152 static int ser_getchar(struct Serial *port)
154 if (fifo_isempty_locked(&port->rxfifo))
156 #if CONFIG_SER_RXTIMEOUT != -1
157 ticks_t start_time = timer_clock();
159 /* Wait while buffer is empty */
163 #if CONFIG_KERNEL && CONFIG_KERN_SCHED
164 /* Give up timeslice to other processes. */
167 #if CONFIG_SER_RXTIMEOUT != -1
168 if (timer_clock() - start_time >= port->rxtimeout)
170 ATOMIC(port->status |= SERRF_RXTIMEOUT);
173 #endif /* CONFIG_SER_RXTIMEOUT */
175 while (fifo_isempty_locked(&port->rxfifo) && (ser_getstatus(port) & SERRF_RX) == 0);
179 * Get a byte from the FIFO (avoiding sign-extension),
180 * re-enable RTS, then return result.
182 if (ser_getstatus(port) & SERRF_RX)
184 return (int)(unsigned char)fifo_pop_locked(&port->rxfifo);
189 * Preleva un carattere dal buffer di ricezione.
190 * Se il buffer e' vuoto, ser_getchar_nowait() ritorna
191 * immediatamente EOF.
193 int ser_getchar_nowait(struct Serial *port)
195 if (fifo_isempty_locked(&port->rxfifo))
198 /* NOTE: the double cast prevents unwanted sign extension */
199 return (int)(unsigned char)fifo_pop_locked(&port->rxfifo);
205 * Read at most \a size bytes from \a port and put them in \a buf
207 * \return number of bytes actually read.
209 static size_t ser_read(struct KFile *fd, void *_buf, size_t size)
211 KFileSerial *fds = KFILESERIAL(fd);
214 char *buf = (char *)_buf;
219 if ((c = ser_getchar(fds->ser)) == EOF)
228 * \brief Write a buffer to serial.
230 * \return 0 if OK, EOF in case of error.
232 * \todo Optimize with fifo_pushblock()
234 static size_t ser_write(struct KFile *fd, const void *_buf, size_t size)
236 KFileSerial *fds = KFILESERIAL(fd);
237 const char *buf = (const char *)_buf;
242 if (ser_putchar(*buf++, fds->ser) == EOF)
250 #if CONFIG_SER_RXTIMEOUT != -1 || CONFIG_SER_TXTIMEOUT != -1
251 void ser_settimeouts(struct KFileSerial *fd, mtime_t rxtimeout, mtime_t txtimeout)
253 fd->ser->rxtimeout = ms_to_ticks(rxtimeout);
254 fd->ser->txtimeout = ms_to_ticks(txtimeout);
256 #endif /* CONFIG_SER_RXTIMEOUT || CONFIG_SER_TXTIMEOUT */
258 #if CONFIG_SER_RXTIMEOUT != -1
260 * Discard input to resynchronize with remote end.
262 * Discard incoming data until the port stops receiving
263 * characters for at least \a delay milliseconds.
265 * \note Serial errors are reset before and after executing the purge.
267 void ser_resync(struct KFileSerial *fd, mtime_t delay)
269 mtime_t old_rxtimeout = ticks_to_ms(fd->ser->rxtimeout);
271 ser_settimeouts(fd, delay, ticks_to_ms(fd->ser->txtimeout));
274 ser_setstatus(fd->ser, 0);
275 ser_getchar(fd->ser);
277 while (!(ser_getstatus(fd->ser) & SERRF_RXTIMEOUT));
279 /* Restore port to an usable status */
280 ser_setstatus(fd->ser, 0);
281 ser_settimeouts(fd, old_rxtimeout, ticks_to_ms(fd->ser->txtimeout));
283 #endif /* CONFIG_SER_RXTIMEOUT */
286 void ser_setbaudrate(struct KFileSerial *fd, unsigned long rate)
288 fd->ser->hw->table->setBaudrate(fd->ser->hw, rate);
292 void ser_setparity(struct KFileSerial *fd, int parity)
294 fd->ser->hw->table->setParity(fd->ser->hw, parity);
297 static int ser_error(struct KFile *fd)
299 KFileSerial *fds = KFILESERIAL(fd);
300 return ser_getstatus(fds->ser);
303 static void ser_clearerr(struct KFile *fd)
305 KFileSerial *fds = KFILESERIAL(fd);
306 ser_setstatus(fds->ser, 0);
312 * Flush both the RX and TX buffers.
314 void ser_purge(struct KFileSerial *fd)
323 void ser_purgeRx(struct KFileSerial *fd)
325 fifo_flush_locked(&fd->ser->rxfifo);
331 void ser_purgeTx(struct KFileSerial *fd)
333 fifo_flush_locked(&fd->ser->txfifo);
338 * Wait until all pending output is completely
339 * transmitted to the other end.
341 * \note The current implementation only checks the
342 * software transmission queue. Any hardware
345 static int ser_flush(struct KFile *fd)
347 KFileSerial *fds = KFILESERIAL(fd);
350 * Wait until the FIFO becomes empty, and then until the byte currently in
351 * the hardware register gets shifted out.
353 while (!fifo_isempty(&fds->ser->txfifo)
354 || fds->ser->hw->table->txSending(fds->ser->hw))
356 #if CONFIG_KERNEL && CONFIG_KERN_SCHED
357 /* Give up timeslice to other processes. */
367 * Initialize a serial port.
369 * \param unit Serial unit to open. Possible values are architecture dependant.
371 static struct Serial *ser_open(struct KFileSerial *fd, unsigned int unit)
375 ASSERT(unit < countof(ser_handles));
376 port = &ser_handles[unit];
378 ASSERT(!port->is_open);
379 DB(port->is_open = true);
383 port->hw = ser_hw_getdesc(unit);
385 /* Initialize circular buffers */
386 ASSERT(port->hw->txbuffer);
387 ASSERT(port->hw->rxbuffer);
388 fifo_init(&port->txfifo, port->hw->txbuffer, port->hw->txbuffer_size);
389 fifo_init(&port->rxfifo, port->hw->rxbuffer, port->hw->rxbuffer_size);
391 port->hw->table->init(port->hw, port);
394 /* Set default values */
395 #if CONFIG_SER_RXTIMEOUT != -1 || CONFIG_SER_TXTIMEOUT != -1
396 ser_settimeouts(fd, CONFIG_SER_RXTIMEOUT, CONFIG_SER_TXTIMEOUT);
398 #if CONFIG_SER_DEFBAUDRATE
399 ser_setbaudrate(fd, CONFIG_SER_DEFBAUDRATE);
402 /* Clear error flags */
403 ser_setstatus(port, 0);
410 * Clean up serial port, disabling the associated hardware.
412 static int ser_close(struct KFile *fd)
414 KFileSerial *fds = KFILESERIAL(fd);
415 Serial *port = fds->ser;
417 ASSERT(port->is_open);
418 DB(port->is_open = false);
420 // Wait until we finish sending everything
423 port->hw->table->cleanup(port->hw);
427 * We purge the FIFO buffer only after the low-level cleanup, so that
428 * we are sure that there are no more interrupts.
435 * Reopen serial port.
437 static struct KFile *ser_reopen(struct KFile *fd)
439 KFileSerial *fds = KFILESERIAL(fd);
442 ser_open(fds, fds->ser->unit);
447 * Init serial driver for \a unit.
449 void ser_init(struct KFileSerial *fds, unsigned int unit)
451 memset(fds, 0, sizeof(*fds));
453 DB(fds->fd._type = KFT_SERIAL);
454 fds->fd.reopen = ser_reopen;
455 fds->fd.close = ser_close;
456 fds->fd.read = ser_read;
457 fds->fd.write = ser_write;
458 fds->fd.flush = ser_flush;
459 fds->fd.error = ser_error;
460 fds->fd.clearerr = ser_clearerr;
466 * Read data from SPI bus.
467 * Since we are master, we have to trigger slave by sending
468 * fake chars on the bus.
470 static size_t spimaster_read(struct KFile *fd, void *buf, size_t size)
472 KFileSerial *fd_spi = KFILESERIAL(fd);
474 ser_flush(&fd_spi->fd);
477 for (size_t i = 0; i < size; i++)
478 ser_putchar(0, fd_spi->ser);
480 return ser_read(&fd_spi->fd, buf, size);
484 * Write data to SPI bus.
486 static size_t spimaster_write(struct KFile *fd, const void *buf, size_t size)
488 KFileSerial *fd_spi = KFILESERIAL(fd);
492 return ser_write(&fd_spi->fd, buf, size);
497 * Init SPI serial driver \a unit in master mode.
499 * This interface implements the SPI master protocol over a serial SPI
500 * driver. This is needed because normal serial driver send/receive data
501 * at the same time. SPI slaves like memories and other peripherals
502 * first receive and *then* send response back instead.
503 * To achieve this, when we are master and we are *sending*,
504 * we have to discard all incoming data. Then, when we want to
505 * receive, we must write fake data to SPI to trigger slave devices.
507 void spimaster_init(KFileSerial *fds, unsigned int unit)
510 fds->fd.read = spimaster_read;
511 fds->fd.write = spimaster_write;