--- /dev/null
+/*
+ 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()
+
+#define comedi_rt_task_context_t int
+
+#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(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(comedi_rt_task_context_t 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 = 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 comedi_cmd
+ rt_task_suspend(devpriv->scan_task);
+ }
+}
+
+static void timer_task_func(comedi_rt_task_context_t 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_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(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";
+
+ if ((ret = alloc_subdevices(dev, 1)) < 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;
+ 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(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;
+}
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff