/* module/comedi_rt_timer.c virtual driver for using RTL timing sources Authors: David A. Schleef, Frank M. Hess COMEDI - Linux Control and Measurement Device Interface Copyright (C) 1999,2001 David A. Schleef This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. ************************************************************************** */ /* Driver: comedi_rt_timer.o Description: Command emulator using real-time tasks Author: ds, fmhess Devices: Status: works This driver requires RTAI or RTLinux to work correctly. It doesn't actually drive hardware directly, but calls other drivers and uses a real-time task to emulate commands for drivers and devices that are incapable of native commands. Thus, you can get accurately timed I/O on any device. Since the timing is all done in software, sampling jitter is much higher than with a device that has an on-board timer, and maximum sample rate is much lower. Configuration options: [0] - minor number of device you wish to emulate commands for [1] - subdevice number you wish to emulate commands for */ /* TODO: Support for digital io commands could be added, except I can't see why anyone would want to use them What happens if device we are emulating for is de-configured? */ #include #include #include "comedi_fc.h" #ifdef CONFIG_COMEDI_RTL_V1 #include #include #endif #ifdef CONFIG_COMEDI_RTL #include #include #include #include #ifndef RTLINUX_VERSION_CODE #define RTLINUX_VERSION_CODE 0 #endif #ifndef RTLINUX_VERSION #define RTLINUX_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) #endif // begin hack to workaround broken HRT_TO_8254() function on rtlinux #if RTLINUX_VERSION_CODE <= RTLINUX_VERSION(3,0,100) // this function sole purpose is to divide a long long by 838 static inline RTIME nano2count(long long ns) { do_div(ns, 838); return ns; } #ifdef rt_get_time() #undef rt_get_time() #endif #define rt_get_time() nano2count(gethrtime()) #else #define nano2count(x) HRT_TO_8254(x) #endif // end hack // rtl-rtai compatibility #define rt_task_wait_period() rt_task_wait() #define rt_pend_linux_srq(irq) rtl_global_pend_irq(irq) #define rt_free_srq(irq) rtl_free_soft_irq(irq) #define rt_request_srq(x,y,z) rtl_get_soft_irq(y,"timer") #define rt_task_init(a,b,c,d,e,f,g) rt_task_init(a,b,c,d,(e)+1) #define rt_task_resume(x) rt_task_wakeup(x) #define rt_set_oneshot_mode() #define start_rt_timer(x) #define stop_rt_timer() #endif #ifdef CONFIG_COMEDI_RTAI #include #include #endif /* This defines the fastest speed we will emulate. Note that * without a watchdog (like in RTAI), we could easily overrun our * task period because analog input tends to be slow. */ #define SPEED_LIMIT 100000 /* in nanoseconds */ static int timer_attach(comedi_device *dev,comedi_devconfig *it); static int timer_detach(comedi_device *dev); static int timer_inttrig(comedi_device *dev, comedi_subdevice *s, unsigned int trig_num); static int timer_start_cmd(comedi_device *dev, comedi_subdevice *s); static comedi_driver driver_timer={ module: THIS_MODULE, driver_name: "comedi_rt_timer", attach: timer_attach, detach: timer_detach, // open: timer_open, }; COMEDI_INITCLEANUP(driver_timer); typedef struct{ comedi_t *device; // device we are emulating commands for int subd; // subdevice we are emulating commands for RT_TASK *rt_task; // rt task that starts scans RT_TASK *scan_task; // rt task that controls conversion timing in a scan /* io_function can point to either an input or output function * depending on what kind of subdevice we are emulating for */ int (*io_function)(comedi_device *dev, comedi_cmd *cmd, unsigned int index); // RTIME has units of 1 = 838 nanoseconds // time at which first scan started, used to check scan timing RTIME start; // time between scans RTIME scan_period; // time between conversions in a scan RTIME convert_period; // flags volatile int stop; // indicates we should stop volatile int rt_task_active; // indicates rt_task is servicing a comedi_cmd volatile int scan_task_active; // indicates scan_task is servicing a comedi_cmd unsigned timer_running : 1; }timer_private; #define devpriv ((timer_private *)dev->private) static int timer_cancel(comedi_device *dev,comedi_subdevice *s) { devpriv->stop = 1; return 0; } // checks for scan timing error inline static int check_scan_timing(comedi_device *dev, unsigned long long scan) { RTIME now, timing_error; now = rt_get_time(); timing_error = now - (devpriv->start + scan * devpriv->scan_period); if(timing_error > devpriv->scan_period){ comedi_error(dev, "timing error"); rt_printk("scan started %i ns late\n", timing_error * 838); return -1; } return 0; } // checks for conversion timing error inline static int check_conversion_timing(comedi_device *dev, RTIME scan_start, unsigned int conversion) { RTIME now, timing_error; now = rt_get_time(); timing_error = now - (scan_start + conversion * devpriv->convert_period); if(timing_error > devpriv->convert_period){ comedi_error(dev, "timing error"); rt_printk("conversion started %i ns late\n", timing_error * 838); return -1; } return 0; } // devpriv->io_function for an input subdevice static int timer_data_read(comedi_device *dev, comedi_cmd *cmd, unsigned int index) { comedi_subdevice *s = dev->read_subdev; int ret; lsampl_t data; ret = comedi_data_read(devpriv->device, devpriv->subd, CR_CHAN(cmd->chanlist[index]), CR_RANGE(cmd->chanlist[index]), CR_AREF(cmd->chanlist[index]), &data); if(ret<0){ comedi_error(dev, "read error"); return -EIO; } if( s->flags & SDF_LSAMPL ){ cfc_write_long_to_buffer( s, data ); }else{ comedi_buf_put( s->async, data ); } return 0; } // devpriv->io_function for an output subdevice static int timer_data_write(comedi_device *dev, comedi_cmd *cmd, unsigned int index) { comedi_subdevice *s = dev->write_subdev; unsigned int num_bytes; sampl_t data; lsampl_t long_data; int ret; if( s->flags & SDF_LSAMPL ) { num_bytes = cfc_read_array_from_buffer( s, &long_data, sizeof( long_data ) ); }else{ num_bytes = cfc_read_array_from_buffer( s, &data, sizeof( data ) ); long_data = data; } if(num_bytes == 0) { comedi_error(dev, "buffer underrun"); return -EAGAIN; } ret = comedi_data_write(devpriv->device, devpriv->subd, CR_CHAN(cmd->chanlist[index]), CR_RANGE(cmd->chanlist[index]), CR_AREF(cmd->chanlist[index]), long_data); if(ret<0){ comedi_error(dev, "write error"); return -EIO; } return 0; } // devpriv->io_function for DIO subdevices static int timer_dio_read(comedi_device *dev, comedi_cmd *cmd, unsigned int index) { comedi_subdevice *s = dev->read_subdev; int ret; lsampl_t data; ret = comedi_dio_bitfield(devpriv->device, devpriv->subd, 0, &data); if(ret<0){ comedi_error(dev, "read error"); return -EIO; } if( s->flags & SDF_LSAMPL ) cfc_write_long_to_buffer( s, data ); else cfc_write_to_buffer( s, data ); return 0; } // performs scans static void scan_task_func(int d) { comedi_device *dev=(comedi_device *)d; comedi_subdevice *s = dev->subdevices + 0; comedi_async *async = s->async; comedi_cmd *cmd = &async->cmd; int i, ret; unsigned long long n; RTIME scan_start; // every comedi_cmd causes one execution of while loop while(1){ devpriv->scan_task_active = 1; // each for loop completes one scan for(n = 0; n < cmd->stop_arg || cmd->stop_src == TRIG_NONE; n++){ if(n){ // suspend task until next scan ret = rt_task_suspend(devpriv->scan_task); if(ret < 0){ comedi_error(dev, "error suspending scan task"); async->events |= COMEDI_CB_ERROR; goto cleanup; } } // check if stop flag was set (by timer_cancel()) if(devpriv->stop) goto cleanup; ret = check_scan_timing(dev, n); if(ret < 0){ async->events |= COMEDI_CB_ERROR; goto cleanup; } scan_start = rt_get_time(); for(i = 0; i < cmd->scan_end_arg; i++){ // conversion timing if(cmd->convert_src == TRIG_TIMER && i){ rt_task_wait_period(); ret = check_conversion_timing(dev, scan_start, i); if(ret < 0){ async->events |= COMEDI_CB_ERROR; goto cleanup; } } ret = devpriv->io_function(dev, cmd, i); if(ret < 0){ async->events |= COMEDI_CB_ERROR; goto cleanup; } } s->async->events |= COMEDI_CB_BLOCK; comedi_event(dev,s,s->async->events); s->async->events = 0; } cleanup: comedi_unlock(devpriv->device,devpriv->subd); async->events |= COMEDI_CB_EOA; comedi_event(dev, s, async->events); async->events = 0; devpriv->scan_task_active = 0; // suspend task until next comedi_cmd rt_task_suspend(devpriv->scan_task); } } static void timer_task_func(int d) { comedi_device *dev=(comedi_device *)d; comedi_subdevice *s = dev->subdevices + 0; comedi_cmd *cmd=&s->async->cmd; int ret; unsigned long long n; // every comedi_cmd causes one execution of while loop while(1){ devpriv->rt_task_active = 1; devpriv->scan_task_active = 1; devpriv->start = rt_get_time(); for(n = 0; n < cmd->stop_arg || cmd->stop_src == TRIG_NONE; n++){ // scan timing if(n) rt_task_wait_period(); if(devpriv->scan_task_active == 0){ goto cleanup; } ret = rt_task_make_periodic(devpriv->scan_task, devpriv->start + devpriv->scan_period * n, devpriv->convert_period); if(ret < 0){ comedi_error(dev, "bug!"); } } cleanup: devpriv->rt_task_active = 0; // suspend until next comedi_cmd rt_task_suspend(devpriv->rt_task); } } static int timer_insn(comedi_device *dev,comedi_subdevice *s, comedi_insn *insn,lsampl_t *data) { comedi_insn xinsn = *insn; xinsn.data = data; xinsn.subdev = devpriv->subd; return comedi_do_insn(devpriv->device,&xinsn); } static int cmdtest_helper(comedi_cmd *cmd, unsigned int start_src, unsigned int scan_begin_src, unsigned int convert_src, unsigned int scan_end_src, unsigned int stop_src) { int err = 0; int tmp; tmp = cmd->start_src; cmd->start_src &= start_src; if(!cmd->start_src || tmp!=cmd->start_src)err++; tmp = cmd->scan_begin_src; cmd->scan_begin_src &= scan_begin_src; if(!cmd->scan_begin_src || tmp!=cmd->scan_begin_src)err++; tmp = cmd->convert_src; cmd->convert_src &= convert_src; if(!cmd->convert_src || tmp!=cmd->convert_src)err++; tmp = cmd->scan_end_src; cmd->scan_end_src &= scan_end_src; if(!cmd->scan_end_src || tmp!=cmd->scan_end_src)err++; tmp = cmd->stop_src; cmd->stop_src &= stop_src; if(!cmd->stop_src || tmp!=cmd->stop_src)err++; return err; } static int timer_cmdtest(comedi_device *dev,comedi_subdevice *s,comedi_cmd *cmd) { int err = 0; unsigned int start_src = 0; if(s->type == COMEDI_SUBD_AO) start_src = TRIG_INT; else start_src = TRIG_NOW; err = cmdtest_helper(cmd, start_src, /* start_src */ TRIG_TIMER | TRIG_FOLLOW, /* scan_begin_src */ TRIG_NOW | TRIG_TIMER, /* convert_src */ TRIG_COUNT, /* scan_end_src */ TRIG_COUNT | TRIG_NONE); /* stop_src */ if(err)return 1; /* step 2: make sure trigger sources are unique and mutually * compatible */ if(cmd->start_src != TRIG_NOW && cmd->start_src != TRIG_INT) err++; if(cmd->scan_begin_src != TRIG_TIMER && cmd->scan_begin_src != TRIG_FOLLOW) err++; if(cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_NOW) err++; if(cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE) err++; if(cmd->scan_begin_src == TRIG_FOLLOW && cmd->convert_src != TRIG_TIMER) err++; if(cmd->convert_src == TRIG_NOW && cmd->scan_begin_src != TRIG_TIMER) err++; if(err)return 2; /* step 3: make sure arguments are trivially compatible */ // limit frequency, this is fairly arbitrary if(cmd->scan_begin_src == TRIG_TIMER){ if(cmd->scan_begin_argscan_begin_arg=SPEED_LIMIT; err++; } } if(cmd->convert_src == TRIG_TIMER){ if(cmd->convert_argconvert_arg=SPEED_LIMIT; err++; } } // make sure conversion and scan frequencies are compatible if(cmd->convert_src == TRIG_TIMER && cmd->scan_begin_src == TRIG_TIMER){ if(cmd->convert_arg * cmd->scan_end_arg > cmd->scan_begin_arg){ cmd->scan_begin_arg = cmd->convert_arg * cmd->scan_end_arg; err++; } } if(err)return 3; /* step 4: fix up and arguments */ if(err)return 4; return 0; } static int timer_cmd(comedi_device *dev,comedi_subdevice *s) { int ret; comedi_cmd *cmd = &s->async->cmd; /* hack attack: drivers are not supposed to do this: */ dev->rt = 1; // make sure tasks have finished cleanup of last comedi_cmd if(devpriv->rt_task_active || devpriv->scan_task_active) return -EBUSY; ret = comedi_lock(devpriv->device,devpriv->subd); if(ret<0) { comedi_error(dev, "failed to obtain lock"); return ret; } switch(cmd->scan_begin_src){ case TRIG_TIMER: devpriv->scan_period = nano2count(cmd->scan_begin_arg); break; case TRIG_FOLLOW: devpriv->scan_period = nano2count(cmd->convert_arg * cmd->scan_end_arg); break; default: comedi_error(dev, "bug setting scan period!"); return -1; break; } switch(cmd->convert_src){ case TRIG_TIMER: devpriv->convert_period = nano2count(cmd->convert_arg); break; case TRIG_NOW: devpriv->convert_period = 1; break; default: comedi_error(dev, "bug setting conversion period!"); return -1; break; } if(cmd->start_src == TRIG_NOW) return timer_start_cmd(dev, s); s->async->inttrig = timer_inttrig; return 0; } static int timer_inttrig(comedi_device *dev, comedi_subdevice *s, unsigned int trig_num) { if(trig_num != 0) return -EINVAL; s->async->inttrig = NULL; return timer_start_cmd(dev, s); } static int timer_start_cmd(comedi_device *dev, comedi_subdevice *s) { comedi_async *async = s->async; comedi_cmd *cmd = &async->cmd; RTIME now, delay, period; int ret; devpriv->stop = 0; s->async->events = 0; if(cmd->start_src == TRIG_NOW) delay = nano2count(cmd->start_arg); else delay = 0; now=rt_get_time(); /* Using 'period' this way gets around some weird bug in gcc-2.95.2 * that generates the compile error 'internal error--unrecognizable insn' * when rt_task_make_period() is called (observed with rtlinux-3.1, linux-2.2.19). * - fmhess */ period = devpriv->scan_period; ret = rt_task_make_periodic(devpriv->rt_task, now + delay, period); if(ret < 0) { comedi_error(dev, "error starting rt_task"); return ret; } return 0; } static int timer_attach(comedi_device *dev,comedi_devconfig *it) { int ret; comedi_subdevice *s, *emul_s; comedi_device *emul_dev; /* These should probably be devconfig options[] */ const int timer_priority = 4; const int scan_priority = timer_priority + 1; char path[20]; printk("comedi%d: timer: ",dev->minor); dev->board_name="timer"; dev->n_subdevices=1; if((ret=alloc_subdevices(dev))<0) return ret; if((ret=alloc_private(dev,sizeof(timer_private)))<0) return ret; sprintf(path,"/dev/comedi%d",it->options[0]); devpriv->device = comedi_open(path); devpriv->subd=it->options[1]; printk("emulating commands for minor %i, subdevice %d\n", it->options[0], devpriv->subd); emul_dev = devpriv->device; emul_s = emul_dev->subdevices+devpriv->subd; // input or output subdevice s=dev->subdevices+0; s->type=emul_s->type; s->subdev_flags = emul_s->subdev_flags; /* SDF_GROUND (to fool check_driver) */ s->n_chan=emul_s->n_chan; s->len_chanlist=1024; s->do_cmd=timer_cmd; s->do_cmdtest=timer_cmdtest; s->cancel=timer_cancel; s->maxdata=emul_s->maxdata; s->range_table=emul_s->range_table; s->range_table_list=emul_s->range_table_list; switch(emul_s->type){ case COMEDI_SUBD_AI: s->insn_read=timer_insn; dev->read_subdev = s; devpriv->io_function = timer_data_read; break; case COMEDI_SUBD_AO: s->insn_write=timer_insn; s->insn_read=timer_insn; dev->write_subdev = s; devpriv->io_function = timer_data_write; break; case COMEDI_SUBD_DIO: s->insn_write=timer_insn; s->insn_read=timer_insn; s->insn_bits=timer_insn; dev->read_subdev = s; devpriv->io_function = timer_dio_read; break; default: comedi_error(dev, "failed to determine subdevice type!"); return -EINVAL; } rt_set_oneshot_mode(); start_rt_timer( 1 ); devpriv->timer_running = 1; devpriv->rt_task = kmalloc(sizeof(RT_TASK),GFP_KERNEL); memset(devpriv->rt_task,0,sizeof(RT_TASK)); // initialize real-time tasks ret = rt_task_init(devpriv->rt_task, timer_task_func,(int)dev, 3000, timer_priority, 0, 0); if(ret < 0) { comedi_error(dev, "error initalizing rt_task"); kfree(devpriv->rt_task); devpriv->rt_task = 0; return ret; } devpriv->scan_task = kmalloc(sizeof(RT_TASK),GFP_KERNEL); memset(devpriv->scan_task,0,sizeof(RT_TASK)); ret = rt_task_init(devpriv->scan_task, scan_task_func, (int)dev, 3000, scan_priority, 0, 0); if(ret < 0){ comedi_error(dev, "error initalizing scan_task"); kfree(devpriv->scan_task); devpriv->scan_task = 0; return ret; } return 1; } // free allocated resources static int timer_detach(comedi_device *dev) { printk("comedi%d: timer: remove\n",dev->minor); if(devpriv){ if(devpriv->rt_task){ rt_task_delete(devpriv->rt_task); kfree(devpriv->rt_task); } if(devpriv->scan_task){ rt_task_delete(devpriv->scan_task); kfree(devpriv->scan_task); } if( devpriv->timer_running ) stop_rt_timer(); } return 0; }