added poll() support

diff --git a/comedi/drivers/das16m1.c b/comedi/drivers/das16m1.c
index 76a0d557df766b266016a1cea44f762bbb3569ed..46647d07565d8e234742f79bf2ce6e3c60c4b358 100644 (file)
--- a/comedi/drivers/das16m1.c
+++ b/comedi/drivers/das16m1.c
@@ -3,6 +3,7 @@
     CIO-DAS16/M1 driver
     Author: Frank Mori Hess, based on code from the das16
       driver.
+    Copyright (C) 2001 Frank Mori Hess <fmhess@users.sourceforge.net>
 
     COMEDI - Linux Control and Measurement Device Interface
     Copyright (C) 2000 David A. Schleef <ds@stm.lbl.gov>
@@ -144,7 +145,9 @@ static int das16m1_cmd_test(comedi_device *dev,comedi_subdevice *s,comedi_cmd *c
 static int das16m1_cmd_exec(comedi_device *dev,comedi_subdevice *s);
 static int das16m1_cancel(comedi_device *dev, comedi_subdevice *s);
 
+static int das16m1_poll(comedi_device *dev, comedi_subdevice *s);
 static void das16m1_interrupt(int irq, void *d, struct pt_regs *regs);
+static void das16m1_handler(comedi_device *dev, unsigned int status);
 
 static unsigned int das16m1_set_pacer(comedi_device *dev, unsigned int ns, int round_flag);
 
@@ -179,6 +182,10 @@ static comedi_driver driver_das16m1={
 struct das16m1_private_struct {
        unsigned int    control_state;
        volatile unsigned int   adc_count;      // number of samples completed
+       /* initial value in lower half of hardware conversion counter,
+        * needed to keep track of whether new count has been loaded into
+        * counter yet (loaded by first sample conversion) */
+       u16 initial_hw_count;
        unsigned int do_bits;   // saves status of digital output bits
        unsigned int divisor1;  // divides master clock to obtain conversion speed
        unsigned int divisor2;  // divides master clock to obtain conversion speed
@@ -321,10 +328,13 @@ static int das16m1_cmd_exec(comedi_device *dev,comedi_subdevice *s)
 
        // set software count
        devpriv->adc_count = 0;
-       /* initialize lower half of hardware counter, used to determine how
-        * many samples are in fifo */
+       /* Initialize lower half of hardware counter, used to determine how
+        * many samples are in fifo.  Value doesn't actually load into counter
+        * until counter's next clock (the next a/d conversion) */
        i8254_load(dev->iobase + DAS16M1_8254_FIRST, 1, 0, 2);
-
+       /* remember current reading of counter so we know when counter has
+        * actually been loaded */
+       devpriv->initial_hw_count = i8254_read(dev->iobase + DAS16M1_8254_FIRST, 1);
        /* setup channel/gain queue */
        for(i = 0; i < cmd->chanlist_len; i++)
        {
@@ -439,15 +449,24 @@ static int das16m1_do_wbits(comedi_device *dev,comedi_subdevice *s,comedi_insn *
        return 2;
 }
 
+static int das16m1_poll(comedi_device *dev, comedi_subdevice *s)
+{
+       unsigned long flags;
+       unsigned int status;
+
+       // prevent race with interrupt handler
+       comedi_spin_lock_irqsave(&dev->spinlock, flags);
+       status = inb(dev->iobase + DAS16M1_CS);
+       das16m1_handler(dev, status);
+       comedi_spin_unlock_irqrestore(&dev->spinlock, flags);
+
+       return s->async->buf_int_count - s->async->buf_user_count;
+}
+
 static void das16m1_interrupt(int irq, void *d, struct pt_regs *regs)
 {
-       int i, status;
-       sampl_t data[FIFO_SIZE];
+       int status;
        comedi_device *dev = d;
-       comedi_subdevice *s = dev->subdevices;
-       comedi_async *async;
-       comedi_cmd *cmd;
-       u16 num_samples;
 
        if(dev->attached == 0)
        {
@@ -455,20 +474,58 @@ static void das16m1_interrupt(int irq, void *d, struct pt_regs *regs)
                return;
        }
 
+       // prevent race with comedi_poll()
+       spin_lock(&dev->spinlock);
+
        status = inb(dev->iobase + DAS16M1_CS);
 
        if((status & (IRQDATA | OVRUN)) == 0)
        {
                comedi_error(dev, "spurious interrupt");
+               spin_unlock(&dev->spinlock);
                return;
        }
-       // initialize async here to avoid freak out on premature interrupt
+
+       das16m1_handler(dev, status);
+
+       /* clear interrupt */
+       outb(0, dev->iobase + DAS16M1_CLEAR_INTR);
+
+       spin_unlock(&dev->spinlock);
+}
+
+static void das16m1_handler(comedi_device *dev, unsigned int status)
+{
+       int i;
+       sampl_t data[FIFO_SIZE];
+       comedi_subdevice *s;
+       comedi_async *async;
+       comedi_cmd *cmd;
+       u16 num_samples;
+       u16 hw_counter;
+
+       s = dev->read_subdev;
        async = s->async;
        async->events = 0;
        cmd = &async->cmd;
 
        // figure out how many samples are in fifo
-       num_samples = (0x10000 - i8254_read(dev->iobase + DAS16M1_8254_FIRST, 1)) - devpriv->adc_count;
+       hw_counter = i8254_read(dev->iobase + DAS16M1_8254_FIRST, 1);
+       /* make sure hardware counter reading is not bogus due to initial value
+        * not having been loaded yet */
+       if(devpriv->adc_count == 0 && hw_counter == devpriv->initial_hw_count)
+       {
+               num_samples = 0;
+       }else
+       {
+               /* The calculation of num_samples looks odd, but it uses the following facts.
+                * 16 bit hardware counter is initialized with value of zero (which really
+                * means 0x1000).  The counter decrements by one on each conversion
+                * (when the counter decrements from zero it goes to 0xffff).  num_samples
+                * is a 16 bit variable, so it will roll over in a similar fashion to the
+                * hardware counter.  Work it out, and this is what you get. */
+               num_samples = - hw_counter - devpriv->adc_count;
+       }
        // check if we only need some of the points
        if(num_samples > cmd->stop_arg * cmd->chanlist_len)
                num_samples = cmd->stop_arg * cmd->chanlist_len;
@@ -502,8 +559,6 @@ static void das16m1_interrupt(int irq, void *d, struct pt_regs *regs)
        async->events |= COMEDI_CB_BLOCK;
        comedi_event(dev, s, async->events);
 
-       /* clear interrupt */
-       outb(0, dev->iobase + DAS16M1_CLEAR_INTR);
 }
 
 /* This function takes a time in nanoseconds and sets the     *
@@ -634,6 +689,7 @@ static int das16m1_attach(comedi_device *dev, comedi_devconfig *it)
        s->do_cmdtest = das16m1_cmd_test;
        s->do_cmd = das16m1_cmd_exec;
        s->cancel = das16m1_cancel;
+       s->poll = das16m1_poll;
 
        s = dev->subdevices + 1;
        /* di */