2 comedi/drivers/comedi_rt_timer.c
3 virtual driver for using RTL timing sources
5 Authors: David A. Schleef, Frank M. Hess
7 COMEDI - Linux Control and Measurement Device Interface
8 Copyright (C) 1999,2001 David A. Schleef <ds@schleef.org>
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 **************************************************************************
27 Driver: comedi_rt_timer
28 Description: Command emulator using real-time tasks
33 This driver requires RTAI or RTLinux to work correctly. It doesn't
34 actually drive hardware directly, but calls other drivers and uses
35 a real-time task to emulate commands for drivers and devices that
36 are incapable of native commands. Thus, you can get accurately
37 timed I/O on any device.
39 Since the timing is all done in software, sampling jitter is much
40 higher than with a device that has an on-board timer, and maximum
41 sample rate is much lower.
43 Configuration options:
44 [0] - minor number of device you wish to emulate commands for
45 [1] - subdevice number you wish to emulate commands for
49 Support for digital io commands could be added, except I can't see why
50 anyone would want to use them
51 What happens if device we are emulating for is de-configured?
54 #include "../comedidev.h"
55 #include "../comedilib.h"
57 #include "comedi_fc.h"
59 #ifdef CONFIG_COMEDI_RTL_V1
60 #include <rtl_sched.h>
61 #include <asm/rt_irq.h>
63 #ifdef CONFIG_COMEDI_RTL
65 #include <rtl_sched.h>
66 #include <rtl_compat.h>
67 #include <asm/div64.h>
69 #ifndef RTLINUX_VERSION_CODE
70 #define RTLINUX_VERSION_CODE 0
72 #ifndef RTLINUX_VERSION
73 #define RTLINUX_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
76 /* begin hack to workaround broken HRT_TO_8254() function on rtlinux */
77 #if RTLINUX_VERSION_CODE <= RTLINUX_VERSION(3,0,100)
78 /* this function sole purpose is to divide a long long by 838 */
79 static inline RTIME nano2count(long long ns)
88 #define rt_get_time() nano2count(gethrtime())
92 #define nano2count(x) HRT_TO_8254(x)
96 /* rtl-rtai compatibility */
97 #define rt_task_wait_period() rt_task_wait()
98 #define rt_pend_linux_srq(irq) rtl_global_pend_irq(irq)
99 #define rt_free_srq(irq) rtl_free_soft_irq(irq)
100 #define rt_request_srq(x,y,z) rtl_get_soft_irq(y,"timer")
101 #define rt_task_init(a,b,c,d,e,f,g) rt_task_init(a,b,c,d,(e)+1)
102 #define rt_task_resume(x) rt_task_wakeup(x)
103 #define rt_set_oneshot_mode()
104 #define start_rt_timer(x)
105 #define stop_rt_timer()
108 #ifdef CONFIG_COMEDI_RTAI
110 #include <rtai_sched.h>
111 #include <rtai_version.h>
113 /* RTAI_VERSION_CODE doesn't work for rtai-3.6-cv and other strange versions.
114 * These are characterized by CONFIG_RTAI_REVISION_LEVEL being defined as an
115 * empty macro and CONFIG_RTAI_VERSION_MINOR being defined as something like
116 * '6-cv' or '7-test1'. The problem has been noted by the RTAI folks and they
117 * promise not to do it again. :-) Try and work around it here. */
118 #if !(CONFIG_RTAI_REVISION_LEVEL + 0)
119 #undef CONFIG_RTAI_REVISION_LEVEL
120 #define CONFIG_RTAI_REVISION_LEVEL 0
127 #if RTAI_VERSION_CODE < RTAI_MANGLE_VERSION(3,3,0)
128 #define comedi_rt_task_context_t int
130 #define comedi_rt_task_context_t long
133 /* Finished checking RTAI_VERSION_CODE. */
141 /* This defines the fastest speed we will emulate. Note that
142 * without a watchdog (like in RTAI), we could easily overrun our
143 * task period because analog input tends to be slow. */
144 #define SPEED_LIMIT 100000 /* in nanoseconds */
146 static int timer_attach(struct comedi_device * dev, struct comedi_devconfig * it);
147 static int timer_detach(struct comedi_device * dev);
148 static int timer_inttrig(struct comedi_device * dev, struct comedi_subdevice * s,
149 unsigned int trig_num);
150 static int timer_start_cmd(struct comedi_device * dev, struct comedi_subdevice * s);
152 static struct comedi_driver driver_timer = {
154 driver_name:"comedi_rt_timer",
157 /* open: timer_open, */
160 COMEDI_INITCLEANUP(driver_timer);
162 struct timer_private {
163 comedi_t *device; /* device we are emulating commands for */
164 int subd; /* subdevice we are emulating commands for */
165 RT_TASK *rt_task; /* rt task that starts scans */
166 RT_TASK *scan_task; /* rt task that controls conversion timing in a scan */
167 /* io_function can point to either an input or output function
168 * depending on what kind of subdevice we are emulating for */
169 int (*io_function) (struct comedi_device * dev, struct comedi_cmd * cmd,
172 * RTIME has units of 1 = 838 nanoseconds time at which first scan
173 * started, used to check scan timing
176 /* time between scans */
178 /* time between conversions in a scan */
179 RTIME convert_period;
181 volatile int stop; /* indicates we should stop */
182 volatile int rt_task_active; /* indicates rt_task is servicing a struct comedi_cmd */
183 volatile int scan_task_active; /* indicates scan_task is servicing a struct comedi_cmd */
184 unsigned timer_running:1;
186 #define devpriv ((struct timer_private *)dev->private)
188 static int timer_cancel(struct comedi_device * dev, struct comedi_subdevice * s)
195 /* checks for scan timing error */
196 inline static int check_scan_timing(struct comedi_device * dev,
197 unsigned long long scan)
199 RTIME now, timing_error;
202 timing_error = now - (devpriv->start + scan * devpriv->scan_period);
203 if (timing_error > devpriv->scan_period) {
204 comedi_error(dev, "timing error");
205 rt_printk("scan started %i ns late\n", timing_error * 838);
212 /* checks for conversion timing error */
213 inline static int check_conversion_timing(struct comedi_device * dev,
214 RTIME scan_start, unsigned int conversion)
216 RTIME now, timing_error;
220 now - (scan_start + conversion * devpriv->convert_period);
221 if (timing_error > devpriv->convert_period) {
222 comedi_error(dev, "timing error");
223 rt_printk("conversion started %i ns late\n",
231 /* devpriv->io_function for an input subdevice */
232 static int timer_data_read(struct comedi_device * dev, struct comedi_cmd * cmd,
235 struct comedi_subdevice *s = dev->read_subdev;
239 ret = comedi_data_read(devpriv->device, devpriv->subd,
240 CR_CHAN(cmd->chanlist[index]),
241 CR_RANGE(cmd->chanlist[index]),
242 CR_AREF(cmd->chanlist[index]), &data);
244 comedi_error(dev, "read error");
247 if (s->flags & SDF_LSAMPL) {
248 cfc_write_long_to_buffer(s, data);
250 comedi_buf_put(s->async, data);
256 /* devpriv->io_function for an output subdevice */
257 static int timer_data_write(struct comedi_device * dev, struct comedi_cmd * cmd,
260 struct comedi_subdevice *s = dev->write_subdev;
261 unsigned int num_bytes;
263 unsigned int long_data;
266 if (s->flags & SDF_LSAMPL) {
268 cfc_read_array_from_buffer(s, &long_data,
271 num_bytes = cfc_read_array_from_buffer(s, &data, sizeof(data));
275 if (num_bytes == 0) {
276 comedi_error(dev, "buffer underrun");
279 ret = comedi_data_write(devpriv->device, devpriv->subd,
280 CR_CHAN(cmd->chanlist[index]),
281 CR_RANGE(cmd->chanlist[index]),
282 CR_AREF(cmd->chanlist[index]), long_data);
284 comedi_error(dev, "write error");
291 /* devpriv->io_function for DIO subdevices */
292 static int timer_dio_read(struct comedi_device * dev, struct comedi_cmd * cmd,
295 struct comedi_subdevice *s = dev->read_subdev;
299 ret = comedi_dio_bitfield(devpriv->device, devpriv->subd, 0, &data);
301 comedi_error(dev, "read error");
305 if (s->flags & SDF_LSAMPL)
306 cfc_write_long_to_buffer(s, data);
308 cfc_write_to_buffer(s, data);
314 static void scan_task_func(comedi_rt_task_context_t d)
316 struct comedi_device *dev = (struct comedi_device *) d;
317 struct comedi_subdevice *s = dev->subdevices + 0;
318 struct comedi_async *async = s->async;
319 struct comedi_cmd *cmd = &async->cmd;
321 unsigned long long n;
324 /* every struct comedi_cmd causes one execution of while loop */
326 devpriv->scan_task_active = 1;
327 /* each for loop completes one scan */
328 for (n = 0; n < cmd->stop_arg || cmd->stop_src == TRIG_NONE;
331 /* suspend task until next scan */
332 ret = rt_task_suspend(devpriv->scan_task);
335 "error suspending scan task");
336 async->events |= COMEDI_CB_ERROR;
340 /* check if stop flag was set (by timer_cancel()) */
343 ret = check_scan_timing(dev, n);
345 async->events |= COMEDI_CB_ERROR;
348 scan_start = rt_get_time();
349 for (i = 0; i < cmd->scan_end_arg; i++) {
350 /* conversion timing */
351 if (cmd->convert_src == TRIG_TIMER && i) {
352 rt_task_wait_period();
353 ret = check_conversion_timing(dev,
361 ret = devpriv->io_function(dev, cmd, i);
363 async->events |= COMEDI_CB_ERROR;
367 s->async->events |= COMEDI_CB_BLOCK;
368 comedi_event(dev, s);
369 s->async->events = 0;
374 comedi_unlock(devpriv->device, devpriv->subd);
375 async->events |= COMEDI_CB_EOA;
376 comedi_event(dev, s);
378 devpriv->scan_task_active = 0;
379 /* suspend task until next struct comedi_cmd */
380 rt_task_suspend(devpriv->scan_task);
384 static void timer_task_func(comedi_rt_task_context_t d)
386 struct comedi_device *dev = (struct comedi_device *) d;
387 struct comedi_subdevice *s = dev->subdevices + 0;
388 struct comedi_cmd *cmd = &s->async->cmd;
390 unsigned long long n;
392 /* every struct comedi_cmd causes one execution of while loop */
394 devpriv->rt_task_active = 1;
395 devpriv->scan_task_active = 1;
396 devpriv->start = rt_get_time();
398 for (n = 0; n < cmd->stop_arg || cmd->stop_src == TRIG_NONE;
402 rt_task_wait_period();
403 if (devpriv->scan_task_active == 0) {
406 ret = rt_task_make_periodic(devpriv->scan_task,
407 devpriv->start + devpriv->scan_period * n,
408 devpriv->convert_period);
410 comedi_error(dev, "bug!");
416 devpriv->rt_task_active = 0;
417 /* suspend until next struct comedi_cmd */
418 rt_task_suspend(devpriv->rt_task);
422 static int timer_insn(struct comedi_device * dev, struct comedi_subdevice * s,
423 struct comedi_insn * insn, unsigned int * data)
425 struct comedi_insn xinsn = *insn;
428 xinsn.subdev = devpriv->subd;
430 return comedi_do_insn(devpriv->device, &xinsn);
433 static int cmdtest_helper(struct comedi_cmd * cmd,
434 unsigned int start_src,
435 unsigned int scan_begin_src,
436 unsigned int convert_src,
437 unsigned int scan_end_src, unsigned int stop_src)
442 tmp = cmd->start_src;
443 cmd->start_src &= start_src;
444 if (!cmd->start_src || tmp != cmd->start_src)
447 tmp = cmd->scan_begin_src;
448 cmd->scan_begin_src &= scan_begin_src;
449 if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
452 tmp = cmd->convert_src;
453 cmd->convert_src &= convert_src;
454 if (!cmd->convert_src || tmp != cmd->convert_src)
457 tmp = cmd->scan_end_src;
458 cmd->scan_end_src &= scan_end_src;
459 if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
463 cmd->stop_src &= stop_src;
464 if (!cmd->stop_src || tmp != cmd->stop_src)
470 static int timer_cmdtest(struct comedi_device * dev, struct comedi_subdevice * s,
471 struct comedi_cmd * cmd)
474 unsigned int start_src = 0;
476 if (s->type == COMEDI_SUBD_AO)
477 start_src = TRIG_INT;
479 start_src = TRIG_NOW;
481 err = cmdtest_helper(cmd, start_src, /* start_src */
482 TRIG_TIMER | TRIG_FOLLOW, /* scan_begin_src */
483 TRIG_NOW | TRIG_TIMER, /* convert_src */
484 TRIG_COUNT, /* scan_end_src */
485 TRIG_COUNT | TRIG_NONE); /* stop_src */
489 /* step 2: make sure trigger sources are unique and mutually
492 if (cmd->start_src != TRIG_NOW && cmd->start_src != TRIG_INT)
494 if (cmd->scan_begin_src != TRIG_TIMER &&
495 cmd->scan_begin_src != TRIG_FOLLOW)
497 if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_NOW)
499 if (cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE)
501 if (cmd->scan_begin_src == TRIG_FOLLOW
502 && cmd->convert_src != TRIG_TIMER)
504 if (cmd->convert_src == TRIG_NOW && cmd->scan_begin_src != TRIG_TIMER)
510 /* step 3: make sure arguments are trivially compatible */
511 /* limit frequency, this is fairly arbitrary */
512 if (cmd->scan_begin_src == TRIG_TIMER) {
513 if (cmd->scan_begin_arg < SPEED_LIMIT) {
514 cmd->scan_begin_arg = SPEED_LIMIT;
518 if (cmd->convert_src == TRIG_TIMER) {
519 if (cmd->convert_arg < SPEED_LIMIT) {
520 cmd->convert_arg = SPEED_LIMIT;
524 /* make sure conversion and scan frequencies are compatible */
525 if (cmd->convert_src == TRIG_TIMER && cmd->scan_begin_src == TRIG_TIMER) {
526 if (cmd->convert_arg * cmd->scan_end_arg > cmd->scan_begin_arg) {
527 cmd->scan_begin_arg =
528 cmd->convert_arg * cmd->scan_end_arg;
535 /* step 4: fix up and arguments */
542 static int timer_cmd(struct comedi_device * dev, struct comedi_subdevice * s)
545 struct comedi_cmd *cmd = &s->async->cmd;
547 /* hack attack: drivers are not supposed to do this: */
550 /* make sure tasks have finished cleanup of last struct comedi_cmd */
551 if (devpriv->rt_task_active || devpriv->scan_task_active)
554 ret = comedi_lock(devpriv->device, devpriv->subd);
556 comedi_error(dev, "failed to obtain lock");
559 switch (cmd->scan_begin_src) {
561 devpriv->scan_period = nano2count(cmd->scan_begin_arg);
564 devpriv->scan_period =
565 nano2count(cmd->convert_arg * cmd->scan_end_arg);
568 comedi_error(dev, "bug setting scan period!");
572 switch (cmd->convert_src) {
574 devpriv->convert_period = nano2count(cmd->convert_arg);
577 devpriv->convert_period = 1;
580 comedi_error(dev, "bug setting conversion period!");
585 if (cmd->start_src == TRIG_NOW)
586 return timer_start_cmd(dev, s);
588 s->async->inttrig = timer_inttrig;
593 static int timer_inttrig(struct comedi_device * dev, struct comedi_subdevice * s,
594 unsigned int trig_num)
599 s->async->inttrig = NULL;
601 return timer_start_cmd(dev, s);
604 static int timer_start_cmd(struct comedi_device * dev, struct comedi_subdevice * s)
606 struct comedi_async *async = s->async;
607 struct comedi_cmd *cmd = &async->cmd;
608 RTIME now, delay, period;
612 s->async->events = 0;
614 if (cmd->start_src == TRIG_NOW)
615 delay = nano2count(cmd->start_arg);
620 /* Using 'period' this way gets around some weird bug in gcc-2.95.2
621 * that generates the compile error 'internal error--unrecognizable insn'
622 * when rt_task_make_period() is called (observed with rtlinux-3.1, linux-2.2.19).
624 period = devpriv->scan_period;
625 ret = rt_task_make_periodic(devpriv->rt_task, now + delay, period);
627 comedi_error(dev, "error starting rt_task");
633 static int timer_attach(struct comedi_device * dev, struct comedi_devconfig * it)
636 struct comedi_subdevice *s, *emul_s;
637 struct comedi_device *emul_dev;
638 /* These should probably be devconfig options[] */
639 const int timer_priority = 4;
640 const int scan_priority = timer_priority + 1;
643 printk("comedi%d: timer: ", dev->minor);
645 dev->board_name = "timer";
647 if ((ret = alloc_subdevices(dev, 1)) < 0)
649 if ((ret = alloc_private(dev, sizeof(struct timer_private))) < 0)
652 sprintf(path, "/dev/comedi%d", it->options[0]);
653 devpriv->device = comedi_open(path);
654 devpriv->subd = it->options[1];
656 printk("emulating commands for minor %i, subdevice %d\n",
657 it->options[0], devpriv->subd);
659 emul_dev = devpriv->device;
660 emul_s = emul_dev->subdevices + devpriv->subd;
662 /* input or output subdevice */
663 s = dev->subdevices + 0;
664 s->type = emul_s->type;
665 s->subdev_flags = emul_s->subdev_flags; /* SDF_GROUND (to fool check_driver) */
666 s->n_chan = emul_s->n_chan;
667 s->len_chanlist = 1024;
668 s->do_cmd = timer_cmd;
669 s->do_cmdtest = timer_cmdtest;
670 s->cancel = timer_cancel;
671 s->maxdata = emul_s->maxdata;
672 s->range_table = emul_s->range_table;
673 s->range_table_list = emul_s->range_table_list;
674 switch (emul_s->type) {
676 s->insn_read = timer_insn;
677 dev->read_subdev = s;
678 s->subdev_flags |= SDF_CMD_READ;
679 devpriv->io_function = timer_data_read;
682 s->insn_write = timer_insn;
683 s->insn_read = timer_insn;
684 dev->write_subdev = s;
685 s->subdev_flags |= SDF_CMD_WRITE;
686 devpriv->io_function = timer_data_write;
688 case COMEDI_SUBD_DIO:
689 s->insn_write = timer_insn;
690 s->insn_read = timer_insn;
691 s->insn_bits = timer_insn;
692 dev->read_subdev = s;
693 s->subdev_flags |= SDF_CMD_READ;
694 devpriv->io_function = timer_dio_read;
697 comedi_error(dev, "failed to determine subdevice type!");
701 rt_set_oneshot_mode();
703 devpriv->timer_running = 1;
705 devpriv->rt_task = kzalloc(sizeof(RT_TASK), GFP_KERNEL);
707 /* initialize real-time tasks */
708 ret = rt_task_init(devpriv->rt_task, timer_task_func,
709 (comedi_rt_task_context_t) dev, 3000, timer_priority, 0, 0);
711 comedi_error(dev, "error initalizing rt_task");
712 kfree(devpriv->rt_task);
713 devpriv->rt_task = 0;
717 devpriv->scan_task = kzalloc(sizeof(RT_TASK), GFP_KERNEL);
719 ret = rt_task_init(devpriv->scan_task, scan_task_func,
720 (comedi_rt_task_context_t) dev, 3000, scan_priority, 0, 0);
722 comedi_error(dev, "error initalizing scan_task");
723 kfree(devpriv->scan_task);
724 devpriv->scan_task = 0;
731 /* free allocated resources */
732 static int timer_detach(struct comedi_device * dev)
734 printk("comedi%d: timer: remove\n", dev->minor);
737 if (devpriv->rt_task) {
738 rt_task_delete(devpriv->rt_task);
739 kfree(devpriv->rt_task);
741 if (devpriv->scan_task) {
742 rt_task_delete(devpriv->scan_task);
743 kfree(devpriv->scan_task);
745 if (devpriv->timer_running)
748 comedi_close(devpriv->device);