1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*****************************************************************************/
3 
4 /*
5  *	baycom_par.c  -- baycom par96 and picpar radio modem driver.
6  *
7  *	Copyright (C) 1996-2000  Thomas Sailer (sailer@ife.ee.ethz.ch)
8  *
9  *  Please note that the GPL allows you to use the driver, NOT the radio.
10  *  In order to use the radio, you need a license from the communications
11  *  authority of your country.
12  *
13  *  Supported modems
14  *
15  *  par96:  This is a modem for 9600 baud FSK compatible to the G3RUH standard.
16  *          The modem does all the filtering and regenerates the receiver clock.
17  *          Data is transferred from and to the PC via a shift register.
18  *          The shift register is filled with 16 bits and an interrupt is
19  *          signalled. The PC then empties the shift register in a burst. This
20  *          modem connects to the parallel port, hence the name. The modem
21  *          leaves the implementation of the HDLC protocol and the scrambler
22  *          polynomial to the PC. This modem is no longer available (at least
23  *          from Baycom) and has been replaced by the PICPAR modem (see below).
24  *          You may however still build one from the schematics published in
25  *          cq-DL :-).
26  *
27  *  picpar: This is a redesign of the par96 modem by Henning Rech, DF9IC. The
28  *          modem is protocol compatible to par96, but uses only three low
29  *          power ICs and can therefore be fed from the parallel port and
30  *          does not require an additional power supply. It features
31  *          built in DCD circuitry. The driver should therefore be configured
32  *          for hardware DCD.
33  *
34  *  Command line options (insmod command line)
35  *
36  *  mode     driver mode string. Valid choices are par96 and picpar.
37  *  iobase   base address of the port; common values are 0x378, 0x278, 0x3bc
38  *
39  *  History:
40  *   0.1  26.06.1996  Adapted from baycom.c and made network driver interface
41  *        18.10.1996  Changed to new user space access routines (copy_{to,from}_user)
42  *   0.3  26.04.1997  init code/data tagged
43  *   0.4  08.07.1997  alternative ser12 decoding algorithm (uses delta CTS ints)
44  *   0.5  11.11.1997  split into separate files for ser12/par96
45  *   0.6  03.08.1999  adapt to Linus' new __setup/__initcall
46  *                    removed some pre-2.2 kernel compatibility cruft
47  *   0.7  10.08.1999  Check if parport can do SPP and is safe to access during interrupt contexts
48  *   0.8  12.02.2000  adapted to softnet driver interface
49  *                    removed direct parport access, uses parport driver methods
50  *   0.9  03.07.2000  fix interface name handling
51  */
52 
53 /*****************************************************************************/
54 
55 #include <linux/module.h>
56 #include <linux/kernel.h>
57 #include <linux/types.h>
58 #include <linux/fcntl.h>
59 #include <linux/interrupt.h>
60 #include <linux/ioport.h>
61 #include <linux/in.h>
62 #include <linux/string.h>
63 #include <linux/init.h>
64 #include <linux/delay.h>
65 #include <linux/errno.h>
66 #include <linux/netdevice.h>
67 #include <linux/hdlcdrv.h>
68 #include <linux/baycom.h>
69 #include <linux/parport.h>
70 #include <linux/bitops.h>
71 #include <linux/jiffies.h>
72 
73 #include <linux/uaccess.h>
74 
75 /* --------------------------------------------------------------------- */
76 
77 #define BAYCOM_DEBUG
78 
79 /*
80  * modem options; bit mask
81  */
82 #define BAYCOM_OPTIONS_SOFTDCD  1
83 
84 /* --------------------------------------------------------------------- */
85 
86 static const char bc_drvname[] = "baycom_par";
87 static const char bc_drvinfo[] = KERN_INFO "baycom_par: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA\n"
88 "baycom_par: version 0.9\n";
89 
90 /* --------------------------------------------------------------------- */
91 
92 #define NR_PORTS 4
93 
94 static struct net_device *baycom_device[NR_PORTS];
95 
96 /* --------------------------------------------------------------------- */
97 
98 #define PAR96_BURSTBITS 16
99 #define PAR96_BURST     4
100 #define PAR96_PTT       2
101 #define PAR96_TXBIT     1
102 #define PAR96_ACK       0x40
103 #define PAR96_RXBIT     0x20
104 #define PAR96_DCD       0x10
105 #define PAR97_POWER     0xf8
106 
107 /* ---------------------------------------------------------------------- */
108 /*
109  * Information that need to be kept for each board.
110  */
111 
112 struct baycom_state {
113 	struct hdlcdrv_state hdrv;
114 
115 	struct pardevice *pdev;
116 	unsigned int options;
117 
118 	struct modem_state {
119 		short arb_divider;
120 		unsigned char flags;
121 		unsigned int shreg;
122 		struct modem_state_par96 {
123 			int dcd_count;
124 			unsigned int dcd_shreg;
125 			unsigned long descram;
126 			unsigned long scram;
127 		} par96;
128 	} modem;
129 
130 #ifdef BAYCOM_DEBUG
131 	struct debug_vals {
132 		unsigned long last_jiffies;
133 		unsigned cur_intcnt;
134 		unsigned last_intcnt;
135 		int cur_pllcorr;
136 		int last_pllcorr;
137 	} debug_vals;
138 #endif /* BAYCOM_DEBUG */
139 };
140 
141 /* --------------------------------------------------------------------- */
142 
baycom_int_freq(struct baycom_state * bc)143 static inline void baycom_int_freq(struct baycom_state *bc)
144 {
145 #ifdef BAYCOM_DEBUG
146 	unsigned long cur_jiffies = jiffies;
147 	/*
148 	 * measure the interrupt frequency
149 	 */
150 	bc->debug_vals.cur_intcnt++;
151 	if (time_after_eq(cur_jiffies, bc->debug_vals.last_jiffies + HZ)) {
152 		bc->debug_vals.last_jiffies = cur_jiffies;
153 		bc->debug_vals.last_intcnt = bc->debug_vals.cur_intcnt;
154 		bc->debug_vals.cur_intcnt = 0;
155 		bc->debug_vals.last_pllcorr = bc->debug_vals.cur_pllcorr;
156 		bc->debug_vals.cur_pllcorr = 0;
157 	}
158 #endif /* BAYCOM_DEBUG */
159 }
160 
161 /* --------------------------------------------------------------------- */
162 /*
163  * ===================== PAR96 specific routines =========================
164  */
165 
166 #define PAR96_DESCRAM_TAP1 0x20000
167 #define PAR96_DESCRAM_TAP2 0x01000
168 #define PAR96_DESCRAM_TAP3 0x00001
169 
170 #define PAR96_DESCRAM_TAPSH1 17
171 #define PAR96_DESCRAM_TAPSH2 12
172 #define PAR96_DESCRAM_TAPSH3 0
173 
174 #define PAR96_SCRAM_TAP1 0x20000 /* X^17 */
175 #define PAR96_SCRAM_TAPN 0x00021 /* X^0+X^5 */
176 
177 /* --------------------------------------------------------------------- */
178 
par96_tx(struct net_device * dev,struct baycom_state * bc)179 static inline void par96_tx(struct net_device *dev, struct baycom_state *bc)
180 {
181 	int i;
182 	unsigned int data = hdlcdrv_getbits(&bc->hdrv);
183 	struct parport *pp = bc->pdev->port;
184 
185 	for(i = 0; i < PAR96_BURSTBITS; i++, data >>= 1) {
186 		unsigned char val = PAR97_POWER;
187 		bc->modem.par96.scram = ((bc->modem.par96.scram << 1) |
188 					 (bc->modem.par96.scram & 1));
189 		if (!(data & 1))
190 			bc->modem.par96.scram ^= 1;
191 		if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 1))
192 			bc->modem.par96.scram ^=
193 				(PAR96_SCRAM_TAPN << 1);
194 		if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 2))
195 			val |= PAR96_TXBIT;
196 		pp->ops->write_data(pp, val);
197 		pp->ops->write_data(pp, val | PAR96_BURST);
198 	}
199 }
200 
201 /* --------------------------------------------------------------------- */
202 
par96_rx(struct net_device * dev,struct baycom_state * bc)203 static inline void par96_rx(struct net_device *dev, struct baycom_state *bc)
204 {
205 	int i;
206 	unsigned int data, mask, mask2, descx;
207 	struct parport *pp = bc->pdev->port;
208 
209 	/*
210 	 * do receiver; differential decode and descramble on the fly
211 	 */
212 	for(data = i = 0; i < PAR96_BURSTBITS; i++) {
213 		bc->modem.par96.descram = (bc->modem.par96.descram << 1);
214 		if (pp->ops->read_status(pp) & PAR96_RXBIT)
215 			bc->modem.par96.descram |= 1;
216 		descx = bc->modem.par96.descram ^
217 			(bc->modem.par96.descram >> 1);
218 		/* now the diff decoded data is inverted in descram */
219 		pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT);
220 		descx ^= ((descx >> PAR96_DESCRAM_TAPSH1) ^
221 			  (descx >> PAR96_DESCRAM_TAPSH2));
222 		data >>= 1;
223 		if (!(descx & 1))
224 			data |= 0x8000;
225 		pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT | PAR96_BURST);
226 	}
227 	hdlcdrv_putbits(&bc->hdrv, data);
228 	/*
229 	 * do DCD algorithm
230 	 */
231 	if (bc->options & BAYCOM_OPTIONS_SOFTDCD) {
232 		bc->modem.par96.dcd_shreg = (bc->modem.par96.dcd_shreg >> 16)
233 			| (data << 16);
234 		/* search for flags and set the dcd counter appropriately */
235 		for(mask = 0x1fe00, mask2 = 0xfc00, i = 0;
236 		    i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
237 			if ((bc->modem.par96.dcd_shreg & mask) == mask2)
238 				bc->modem.par96.dcd_count = HDLCDRV_MAXFLEN+4;
239 		/* check for abort/noise sequences */
240 		for(mask = 0x1fe00, mask2 = 0x1fe00, i = 0;
241 		    i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
242 			if (((bc->modem.par96.dcd_shreg & mask) == mask2) &&
243 			    (bc->modem.par96.dcd_count >= 0))
244 				bc->modem.par96.dcd_count -= HDLCDRV_MAXFLEN-10;
245 		/* decrement and set the dcd variable */
246 		if (bc->modem.par96.dcd_count >= 0)
247 			bc->modem.par96.dcd_count -= 2;
248 		hdlcdrv_setdcd(&bc->hdrv, bc->modem.par96.dcd_count > 0);
249 	} else {
250 		hdlcdrv_setdcd(&bc->hdrv, !!(pp->ops->read_status(pp) & PAR96_DCD));
251 	}
252 }
253 
254 /* --------------------------------------------------------------------- */
255 
par96_interrupt(void * dev_id)256 static void par96_interrupt(void *dev_id)
257 {
258 	struct net_device *dev = dev_id;
259 	struct baycom_state *bc = netdev_priv(dev);
260 
261 	baycom_int_freq(bc);
262 	/*
263 	 * check if transmitter active
264 	 */
265 	if (hdlcdrv_ptt(&bc->hdrv))
266 		par96_tx(dev, bc);
267 	else {
268 		par96_rx(dev, bc);
269 		if (--bc->modem.arb_divider <= 0) {
270 			bc->modem.arb_divider = 6;
271 			local_irq_enable();
272 			hdlcdrv_arbitrate(dev, &bc->hdrv);
273 		}
274 	}
275 	local_irq_enable();
276 	hdlcdrv_transmitter(dev, &bc->hdrv);
277 	hdlcdrv_receiver(dev, &bc->hdrv);
278         local_irq_disable();
279 }
280 
281 /* --------------------------------------------------------------------- */
282 
par96_wakeup(void * handle)283 static void par96_wakeup(void *handle)
284 {
285         struct net_device *dev = (struct net_device *)handle;
286 	struct baycom_state *bc = netdev_priv(dev);
287 
288 	printk(KERN_DEBUG "baycom_par: %s: why am I being woken up?\n", dev->name);
289 	if (!parport_claim(bc->pdev))
290 		printk(KERN_DEBUG "baycom_par: %s: I'm broken.\n", dev->name);
291 }
292 
293 /* --------------------------------------------------------------------- */
294 
par96_open(struct net_device * dev)295 static int par96_open(struct net_device *dev)
296 {
297 	struct baycom_state *bc = netdev_priv(dev);
298 	struct pardev_cb par_cb;
299 	struct parport *pp;
300 	int i;
301 
302 	if (!dev || !bc)
303 		return -ENXIO;
304 	pp = parport_find_base(dev->base_addr);
305 	if (!pp) {
306 		printk(KERN_ERR "baycom_par: parport at 0x%lx unknown\n", dev->base_addr);
307 		return -ENXIO;
308 	}
309 	if (pp->irq < 0) {
310 		printk(KERN_ERR "baycom_par: parport at 0x%lx has no irq\n", pp->base);
311 		parport_put_port(pp);
312 		return -ENXIO;
313 	}
314 	if ((~pp->modes) & (PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT)) {
315 		printk(KERN_ERR "baycom_par: parport at 0x%lx cannot be used\n", pp->base);
316 		parport_put_port(pp);
317 		return -ENXIO;
318 	}
319 	memset(&bc->modem, 0, sizeof(bc->modem));
320 	bc->hdrv.par.bitrate = 9600;
321 	memset(&par_cb, 0, sizeof(par_cb));
322 	par_cb.wakeup = par96_wakeup;
323 	par_cb.irq_func = par96_interrupt;
324 	par_cb.private = (void *)dev;
325 	par_cb.flags = PARPORT_DEV_EXCL;
326 	for (i = 0; i < NR_PORTS; i++)
327 		if (baycom_device[i] == dev)
328 			break;
329 
330 	if (i == NR_PORTS) {
331 		pr_err("%s: no device found\n", bc_drvname);
332 		parport_put_port(pp);
333 		return -ENODEV;
334 	}
335 	bc->pdev = parport_register_dev_model(pp, dev->name, &par_cb, i);
336 	parport_put_port(pp);
337 	if (!bc->pdev) {
338 		printk(KERN_ERR "baycom_par: cannot register parport at 0x%lx\n", dev->base_addr);
339 		return -ENXIO;
340 	}
341 	if (parport_claim(bc->pdev)) {
342 		printk(KERN_ERR "baycom_par: parport at 0x%lx busy\n", pp->base);
343 		parport_unregister_device(bc->pdev);
344 		return -EBUSY;
345 	}
346 	pp = bc->pdev->port;
347 	dev->irq = pp->irq;
348 	pp->ops->data_forward(pp);
349         bc->hdrv.par.bitrate = 9600;
350 	pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER); /* switch off PTT */
351 	pp->ops->enable_irq(pp);
352 	printk(KERN_INFO "%s: par96 at iobase 0x%lx irq %u options 0x%x\n",
353 	       bc_drvname, dev->base_addr, dev->irq, bc->options);
354 	return 0;
355 }
356 
357 /* --------------------------------------------------------------------- */
358 
par96_close(struct net_device * dev)359 static int par96_close(struct net_device *dev)
360 {
361 	struct baycom_state *bc = netdev_priv(dev);
362 	struct parport *pp;
363 
364 	if (!dev || !bc)
365 		return -EINVAL;
366 	pp = bc->pdev->port;
367 	/* disable interrupt */
368 	pp->ops->disable_irq(pp);
369 	/* switch off PTT */
370 	pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER);
371 	parport_release(bc->pdev);
372 	parport_unregister_device(bc->pdev);
373 	printk(KERN_INFO "%s: close par96 at iobase 0x%lx irq %u\n",
374 	       bc_drvname, dev->base_addr, dev->irq);
375 	return 0;
376 }
377 
378 /* --------------------------------------------------------------------- */
379 /*
380  * ===================== hdlcdrv driver interface =========================
381  */
382 
383 static int baycom_ioctl(struct net_device *dev, void __user *data,
384 			struct hdlcdrv_ioctl *hi, int cmd);
385 
386 /* --------------------------------------------------------------------- */
387 
388 static const struct hdlcdrv_ops par96_ops = {
389 	.drvname = bc_drvname,
390 	.drvinfo = bc_drvinfo,
391 	.open    = par96_open,
392 	.close   = par96_close,
393 	.ioctl   = baycom_ioctl
394 };
395 
396 /* --------------------------------------------------------------------- */
397 
baycom_setmode(struct baycom_state * bc,const char * modestr)398 static int baycom_setmode(struct baycom_state *bc, const char *modestr)
399 {
400 	if (!strncmp(modestr, "picpar", 6))
401 		bc->options = 0;
402 	else if (!strncmp(modestr, "par96", 5))
403 		bc->options = BAYCOM_OPTIONS_SOFTDCD;
404 	else
405 		bc->options = !!strchr(modestr, '*');
406 	return 0;
407 }
408 
409 /* --------------------------------------------------------------------- */
410 
baycom_ioctl(struct net_device * dev,void __user * data,struct hdlcdrv_ioctl * hi,int cmd)411 static int baycom_ioctl(struct net_device *dev, void __user *data,
412 			struct hdlcdrv_ioctl *hi, int cmd)
413 {
414 	struct baycom_state *bc;
415 	struct baycom_ioctl bi;
416 
417 	if (!dev)
418 		return -EINVAL;
419 
420 	bc = netdev_priv(dev);
421 	BUG_ON(bc->hdrv.magic != HDLCDRV_MAGIC);
422 
423 	if (cmd != SIOCDEVPRIVATE)
424 		return -ENOIOCTLCMD;
425 	switch (hi->cmd) {
426 	default:
427 		break;
428 
429 	case HDLCDRVCTL_GETMODE:
430 		strcpy(hi->data.modename, bc->options ? "par96" : "picpar");
431 		if (copy_to_user(data, hi, sizeof(struct hdlcdrv_ioctl)))
432 			return -EFAULT;
433 		return 0;
434 
435 	case HDLCDRVCTL_SETMODE:
436 		if (netif_running(dev) || !capable(CAP_NET_ADMIN))
437 			return -EACCES;
438 		hi->data.modename[sizeof(hi->data.modename)-1] = '\0';
439 		return baycom_setmode(bc, hi->data.modename);
440 
441 	case HDLCDRVCTL_MODELIST:
442 		strcpy(hi->data.modename, "par96,picpar");
443 		if (copy_to_user(data, hi, sizeof(struct hdlcdrv_ioctl)))
444 			return -EFAULT;
445 		return 0;
446 
447 	case HDLCDRVCTL_MODEMPARMASK:
448 		return HDLCDRV_PARMASK_IOBASE;
449 
450 	}
451 
452 	if (copy_from_user(&bi, data, sizeof(bi)))
453 		return -EFAULT;
454 	switch (bi.cmd) {
455 	default:
456 		return -ENOIOCTLCMD;
457 
458 #ifdef BAYCOM_DEBUG
459 	case BAYCOMCTL_GETDEBUG:
460 		bi.data.dbg.debug1 = bc->hdrv.ptt_keyed;
461 		bi.data.dbg.debug2 = bc->debug_vals.last_intcnt;
462 		bi.data.dbg.debug3 = bc->debug_vals.last_pllcorr;
463 		break;
464 #endif /* BAYCOM_DEBUG */
465 
466 	}
467 	if (copy_to_user(data, &bi, sizeof(bi)))
468 		return -EFAULT;
469 	return 0;
470 
471 }
472 
473 /* --------------------------------------------------------------------- */
474 
475 /*
476  * command line settable parameters
477  */
478 static char *mode[NR_PORTS] = { "picpar", };
479 static int iobase[NR_PORTS] = { 0x378, };
480 
481 module_param_array(mode, charp, NULL, 0);
482 MODULE_PARM_DESC(mode, "baycom operating mode; eg. par96 or picpar");
483 module_param_hw_array(iobase, int, ioport, NULL, 0);
484 MODULE_PARM_DESC(iobase, "baycom io base address");
485 
486 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
487 MODULE_DESCRIPTION("Baycom par96 and picpar amateur radio modem driver");
488 MODULE_LICENSE("GPL");
489 
490 /* --------------------------------------------------------------------- */
491 
baycom_par_probe(struct pardevice * par_dev)492 static int baycom_par_probe(struct pardevice *par_dev)
493 {
494 	struct device_driver *drv = par_dev->dev.driver;
495 	int len = strlen(drv->name);
496 
497 	if (strncmp(par_dev->name, drv->name, len))
498 		return -ENODEV;
499 
500 	return 0;
501 }
502 
503 static struct parport_driver baycom_par_driver = {
504 	.name = "bcp",
505 	.probe = baycom_par_probe,
506 	.devmodel = true,
507 };
508 
init_baycompar(void)509 static int __init init_baycompar(void)
510 {
511 	int i, found = 0, ret;
512 	char set_hw = 1;
513 
514 	printk(bc_drvinfo);
515 
516 	ret = parport_register_driver(&baycom_par_driver);
517 	if (ret)
518 		return ret;
519 
520 	/*
521 	 * register net devices
522 	 */
523 	for (i = 0; i < NR_PORTS; i++) {
524 		struct net_device *dev;
525 		struct baycom_state *bc;
526 		char ifname[IFNAMSIZ];
527 
528 		sprintf(ifname, "bcp%d", i);
529 
530 		if (!mode[i])
531 			set_hw = 0;
532 		if (!set_hw)
533 			iobase[i] = 0;
534 
535 		dev = hdlcdrv_register(&par96_ops,
536 				       sizeof(struct baycom_state),
537 				       ifname, iobase[i], 0, 0);
538 		if (IS_ERR(dev))
539 			break;
540 
541 		bc = netdev_priv(dev);
542 		if (set_hw && baycom_setmode(bc, mode[i]))
543 			set_hw = 0;
544 		found++;
545 		baycom_device[i] = dev;
546 	}
547 
548 	if (!found) {
549 		parport_unregister_driver(&baycom_par_driver);
550 		return -ENXIO;
551 	}
552 	return 0;
553 }
554 
cleanup_baycompar(void)555 static void __exit cleanup_baycompar(void)
556 {
557 	int i;
558 
559 	for(i = 0; i < NR_PORTS; i++) {
560 		struct net_device *dev = baycom_device[i];
561 
562 		if (dev)
563 			hdlcdrv_unregister(dev);
564 	}
565 	parport_unregister_driver(&baycom_par_driver);
566 }
567 
568 module_init(init_baycompar);
569 module_exit(cleanup_baycompar);
570 
571 /* --------------------------------------------------------------------- */
572 
573 #ifndef MODULE
574 
575 /*
576  * format: baycom_par=io,mode
577  * mode: par96,picpar
578  */
579 
baycom_par_setup(char * str)580 static int __init baycom_par_setup(char *str)
581 {
582         static unsigned nr_dev;
583 	int ints[2];
584 
585         if (nr_dev >= NR_PORTS)
586                 return 0;
587         str = get_options(str, 2, ints);
588         if (ints[0] < 1)
589                 return 0;
590         mode[nr_dev] = str;
591         iobase[nr_dev] = ints[1];
592 	nr_dev++;
593 	return 1;
594 }
595 
596 __setup("baycom_par=", baycom_par_setup);
597 
598 #endif /* MODULE */
599 /* --------------------------------------------------------------------- */
600