staging: comedi: das16: "timer_mode" is always used for DMA

As noted in the driver, a timer is always used by this driver to handle the
DMA due to buggy DMA controllers and the lack of a hardware fifo in some of
the supported boards.

Remove all the non-timer mode specific code.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c
index 593ec38..2dd03da 100644 (file)
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -387,7 +387,6 @@ struct das16_private_struct {
 
        struct timer_list timer;        /*  for timed interrupt */
        volatile short timer_running;
-       volatile short timer_mode;      /*  true if using timer mode */
 
        unsigned long extra_iobase;
 };
@@ -516,49 +515,6 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
        return 0;
 }
 
-/* utility function that suggests a dma transfer size in bytes */
-static unsigned int das16_suggest_transfer_size(struct comedi_device *dev,
-                                               const struct comedi_cmd *cmd)
-{
-       struct das16_private_struct *devpriv = dev->private;
-       unsigned int size;
-       unsigned int freq;
-
-       /* if we are using timer interrupt, we don't care how long it
-        * will take to complete transfer since it will be interrupted
-        * by timer interrupt */
-       if (devpriv->timer_mode)
-               return DAS16_DMA_SIZE;
-
-       /* otherwise, we are relying on dma terminal count interrupt,
-        * so pick a reasonable size */
-       if (cmd->convert_src == TRIG_TIMER)
-               freq = 1000000000 / cmd->convert_arg;
-       else if (cmd->scan_begin_src == TRIG_TIMER)
-               freq = (1000000000 / cmd->scan_begin_arg) * cmd->chanlist_len;
-       /*  return some default value */
-       else
-               freq = 0xffffffff;
-
-       if (cmd->flags & TRIG_WAKE_EOS) {
-               size = sample_size * cmd->chanlist_len;
-       } else {
-               /*  make buffer fill in no more than 1/3 second */
-               size = (freq / 3) * sample_size;
-       }
-
-       /*  set a minimum and maximum size allowed */
-       if (size > DAS16_DMA_SIZE)
-               size = DAS16_DMA_SIZE - DAS16_DMA_SIZE % sample_size;
-       else if (size < sample_size)
-               size = sample_size;
-
-       if (cmd->stop_src == TRIG_COUNT && size > devpriv->adc_byte_count)
-               size = devpriv->adc_byte_count;
-
-       return size;
-}
-
 static unsigned int das16_set_pacer(struct comedi_device *dev, unsigned int ns,
                                    int rounding_flags)
 {
@@ -585,13 +541,6 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
        unsigned long flags;
        int range;
 
-       if (devpriv->dma_chan == 0 || (dev->irq == 0
-                                      && devpriv->timer_mode == 0)) {
-               comedi_error(dev,
-                               "irq (or use of 'timer mode') dma required to "
-                                                       "execute comedi_cmd");
-               return -1;
-       }
        if (cmd->flags & TRIG_RT) {
                comedi_error(dev, "isa dma transfers cannot be performed with "
                                                        "TRIG_RT, aborting");
@@ -648,24 +597,16 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
        devpriv->current_buffer = 0;
        set_dma_addr(devpriv->dma_chan,
                     devpriv->dma_buffer_addr[devpriv->current_buffer]);
-       /*  set appropriate size of transfer */
-       devpriv->dma_transfer_size = das16_suggest_transfer_size(dev, cmd);
+       devpriv->dma_transfer_size = DAS16_DMA_SIZE;
        set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
        enable_dma(devpriv->dma_chan);
        release_dma_lock(flags);
 
        /*  set up interrupt */
-       if (devpriv->timer_mode) {
-               devpriv->timer_running = 1;
-               devpriv->timer.expires = jiffies + timer_period();
-               add_timer(&devpriv->timer);
-               devpriv->control_state &= ~DAS16_INTE;
-       } else {
-               /* clear interrupt bit */
-               outb(0x00, dev->iobase + DAS16_STATUS);
-               /* enable interrupts */
-               devpriv->control_state |= DAS16_INTE;
-       }
+       devpriv->timer_running = 1;
+       devpriv->timer.expires = jiffies + timer_period();
+       add_timer(&devpriv->timer);
+       devpriv->control_state &= ~DAS16_INTE;
        devpriv->control_state |= DMA_ENABLE;
        devpriv->control_state &= ~PACING_MASK;
        if (cmd->convert_src == TRIG_EXT)
@@ -696,7 +637,7 @@ static int das16_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
                disable_dma(devpriv->dma_chan);
 
        /*  disable SW timer */
-       if (devpriv->timer_mode && devpriv->timer_running) {
+       if (devpriv->timer_running) {
                devpriv->timer_running = 0;
                del_timer(&devpriv->timer);
        }
@@ -864,7 +805,6 @@ static int disable_dma_on_even(struct comedi_device *dev)
 
 static void das16_interrupt(struct comedi_device *dev)
 {
-       const struct das16_board *board = comedi_board(dev);
        struct das16_private_struct *devpriv = dev->private;
        unsigned long dma_flags, spin_flags;
        struct comedi_subdevice *s = dev->read_subdev;
@@ -915,21 +855,12 @@ static void das16_interrupt(struct comedi_device *dev)
        devpriv->current_buffer = (devpriv->current_buffer + 1) % 2;
        devpriv->adc_byte_count -= num_bytes;
 
-       /*  figure out how many bytes for next transfer */
-       if (cmd->stop_src == TRIG_COUNT && devpriv->timer_mode == 0 &&
-           devpriv->dma_transfer_size > devpriv->adc_byte_count)
-               devpriv->dma_transfer_size = devpriv->adc_byte_count;
-
        /*  re-enable  dma */
        if ((async->events & COMEDI_CB_EOA) == 0) {
                set_dma_addr(devpriv->dma_chan,
                             devpriv->dma_buffer_addr[devpriv->current_buffer]);
                set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
                enable_dma(devpriv->dma_chan);
-               /* reenable conversions for das1600 mode, (stupid hardware) */
-               if (board->size > 0x400 && devpriv->timer_mode == 0)
-                       outb(0x00, dev->iobase + DAS1600_CONV);
-
        }
        release_dma_lock(dma_flags);
 
@@ -1077,20 +1008,15 @@ static int das16_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        int ret;
        unsigned int irq;
        unsigned int dma_chan;
-       int timer_mode;
        unsigned long flags;
        struct comedi_krange *user_ai_range, *user_ao_range;
 
 #if 0
        irq = it->options[1];
-       timer_mode = it->options[8];
 #endif
        /* always use time_mode since using irq can drop samples while
         * waiting for dma done interrupt (due to hardware limitations) */
        irq = 0;
-       timer_mode = 1;
-       if (timer_mode)
-               irq = 0;
 
        /*  check that clock setting is valid */
        if (it->options[3]) {
@@ -1214,12 +1140,9 @@ static int das16_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                user_ao_range->flags = UNIT_volt;
        }
 
-       if (timer_mode) {
-               init_timer(&(devpriv->timer));
-               devpriv->timer.function = das16_timer_interrupt;
-               devpriv->timer.data = (unsigned long)dev;
-       }
-       devpriv->timer_mode = timer_mode ? 1 : 0;
+       init_timer(&(devpriv->timer));
+       devpriv->timer.function = das16_timer_interrupt;
+       devpriv->timer.data = (unsigned long)dev;
 
        ret = comedi_alloc_subdevices(dev, 5);
        if (ret)