diff options
Diffstat (limited to 'drivers/staging/comedi/drivers/comedi_rt_timer.c')
| -rw-r--r-- | drivers/staging/comedi/drivers/comedi_rt_timer.c | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/comedi_rt_timer.c b/drivers/staging/comedi/drivers/comedi_rt_timer.c new file mode 100644 index 000000000000..f40c8cffd4bb --- /dev/null +++ b/drivers/staging/comedi/drivers/comedi_rt_timer.c @@ -0,0 +1,728 @@ +/* + comedi/drivers/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 <ds@schleef.org> + + 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 +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 "../comedidev.h" +#include "../comedilib.h" + +#include "comedi_fc.h" + +#ifdef CONFIG_COMEDI_RTL_V1 +#include <rtl_sched.h> +#include <asm/rt_irq.h> +#endif +#ifdef CONFIG_COMEDI_RTL +#include <rtl.h> +#include <rtl_sched.h> +#include <rtl_compat.h> +#include <asm/div64.h> + +#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 <rtai.h> +#include <rtai_sched.h> + +#if RTAI_VERSION_CODE < RTAI_MANGLE_VERSION(3,3,0) +#define comedi_rt_task_context_t int +#else +#define comedi_rt_task_context_t long +#endif + +#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(struct comedi_device * dev, struct comedi_devconfig * it); +static int timer_detach(struct comedi_device * dev); +static int timer_inttrig(struct comedi_device * dev, struct comedi_subdevice * s, + unsigned int trig_num); +static int timer_start_cmd(struct comedi_device * dev, struct comedi_subdevice * s); + +static struct 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); + +struct timer_private { + 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) (struct comedi_device * dev, struct 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 struct comedi_cmd + volatile int scan_task_active; // indicates scan_task is servicing a struct comedi_cmd + unsigned timer_running:1; +}; +#define devpriv ((struct timer_private *)dev->private) + +static int timer_cancel(struct comedi_device * dev, struct comedi_subdevice * s) +{ + devpriv->stop = 1; + + return 0; +} + +// checks for scan timing error +inline static int check_scan_timing(struct 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(struct 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(struct comedi_device * dev, struct comedi_cmd * cmd, + unsigned int index) +{ + struct comedi_subdevice *s = dev->read_subdev; + int ret; + unsigned int 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(struct comedi_device * dev, struct comedi_cmd * cmd, + unsigned int index) +{ + struct comedi_subdevice *s = dev->write_subdev; + unsigned int num_bytes; + short data; + unsigned int 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(struct comedi_device * dev, struct comedi_cmd * cmd, + unsigned int index) +{ + struct comedi_subdevice *s = dev->read_subdev; + int ret; + unsigned int 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(comedi_rt_task_context_t d) +{ + struct comedi_device *dev = (struct comedi_device *) d; + struct comedi_subdevice *s = dev->subdevices + 0; + struct comedi_async *async = s->async; + struct comedi_cmd *cmd = &async->cmd; + int i, ret; + unsigned long long n; + RTIME scan_start; + + // every struct 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 = 0; + } + + cleanup: + + comedi_unlock(devpriv->device, devpriv->subd); + async->events |= COMEDI_CB_EOA; + comedi_event(dev, s); + async->events = 0; + devpriv->scan_task_active = 0; + // suspend task until next struct comedi_cmd + rt_task_suspend(devpriv->scan_task); + } +} + +static void timer_task_func(comedi_rt_task_context_t d) +{ + struct comedi_device *dev = (struct comedi_device *) d; + struct comedi_subdevice *s = dev->subdevices + 0; + struct comedi_cmd *cmd = &s->async->cmd; + int ret; + unsigned long long n; + + // every struct 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 struct comedi_cmd + rt_task_suspend(devpriv->rt_task); + } +} + +static int timer_insn(struct comedi_device * dev, struct comedi_subdevice * s, + struct comedi_insn * insn, unsigned int * data) +{ + struct comedi_insn xinsn = *insn; + + xinsn.data = data; + xinsn.subdev = devpriv->subd; + + return comedi_do_insn(devpriv->device, &xinsn); +} + +static int cmdtest_helper(struct 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(struct comedi_device * dev, struct comedi_subdevice * s, + struct 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_arg < SPEED_LIMIT) { + cmd->scan_begin_arg = SPEED_LIMIT; + err++; + } + } + if (cmd->convert_src == TRIG_TIMER) { + if (cmd->convert_arg < SPEED_LIMIT) { + cmd->convert_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(struct comedi_device * dev, struct comedi_subdevice * s) +{ + int ret; + struct 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 struct 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(struct comedi_device * dev, struct 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(struct comedi_device * dev, struct comedi_subdevice * s) +{ + struct comedi_async *async = s->async; + struct 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(struct comedi_device * dev, struct comedi_devconfig * it) +{ + int ret; + struct comedi_subdevice *s, *emul_s; + struct 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"; + + if ((ret = alloc_subdevices(dev, 1)) < 0) + return ret; + if ((ret = alloc_private(dev, sizeof(struct 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; + s->subdev_flags |= SDF_CMD_READ; + 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; + s->subdev_flags |= SDF_CMD_WRITE; + 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; + s->subdev_flags |= SDF_CMD_READ; + 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 = kzalloc(sizeof(RT_TASK), GFP_KERNEL); + + // initialize real-time tasks + ret = rt_task_init(devpriv->rt_task, timer_task_func, + (comedi_rt_task_context_t) 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 = kzalloc(sizeof(RT_TASK), GFP_KERNEL); + + ret = rt_task_init(devpriv->scan_task, scan_task_func, + (comedi_rt_task_context_t) 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(struct 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(); + if (devpriv->device) + comedi_close(devpriv->device); + } + return 0; +} |