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Commit cb3d0d39 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: dt282x: IRQ and DMA are needed for async command support 



This driver requires an IRQ and 2 DMA channels in order to execute async
commands.

Modify the (*attach) so that command support is only hooked up if
DMA is available. This allows removing the extra checks in the
command support functions.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ebf86ea9

drivers/staging/comedi/drivers/dt282x.c

+52 −60
Original line number Diff line number Diff line
@@ -343,7 +343,6 @@ struct dt282x_private { 
		int size;	/* size of current transfer */

	} dma[2];

	int dma_maxsize;	/* max size of DMA transfer (in bytes) */

	int usedma;		/* driver uses DMA              */

	int current_dma_index;

	int dma_dir;

};
@@ -412,11 +411,9 @@ static void dt282x_disable_dma(struct comedi_device *dev) 
{

	struct dt282x_private *devpriv = dev->private;



	if (devpriv->usedma) {

	disable_dma(devpriv->dma[0].chan);

	disable_dma(devpriv->dma[1].chan);

}

}



static int dt282x_ns_to_timer(int *nanosec, int round_mode)

{
@@ -788,13 +785,6 @@ static int dt282x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	int timer;

	int ret;



	if (devpriv->usedma == 0) {

		comedi_error(dev,

			     "driver requires 2 dma channels"

						" to execute command");

		return -EIO;

	}



	dt282x_disable_dma(dev);



	if (cmd->convert_arg < board->ai_speed)
@@ -1014,13 +1004,6 @@ static int dt282x_ao_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	int timer;

	struct comedi_cmd *cmd = &s->async->cmd;



	if (devpriv->usedma == 0) {

		comedi_error(dev,

			     "driver requires 2 dma channels"

						" to execute command");

		return -EIO;

	}



	dt282x_disable_dma(dev);



	devpriv->supcsr = DT2821_ERRINTEN | DT2821_DS1 | DT2821_DDMA;
@@ -1155,21 +1138,6 @@ static int dt282x_grab_dma(struct comedi_device *dev, int dma1, int dma2) 
	struct dt282x_private *devpriv = dev->private;

	int ret;



	devpriv->usedma = 0;



	if (!dma1 && !dma2)

		return 0;



	if (dma1 == dma2 || dma1 < 5 || dma2 < 5 || dma1 > 7 || dma2 > 7)

		return -EINVAL;



	if (dma2 < dma1) {

		int i;

		i = dma1;

		dma1 = dma2;

		dma2 = i;

	}



	ret = request_dma(dma1, "dt282x A");

	if (ret)

		return -EBUSY;
@@ -1186,11 +1154,27 @@ static int dt282x_grab_dma(struct comedi_device *dev, int dma1, int dma2) 
	if (!devpriv->dma[0].buf || !devpriv->dma[1].buf)

		return -ENOMEM;



	devpriv->usedma = 1;



	return 0;

}



static void dt282x_free_dma(struct comedi_device *dev)

{

	struct dt282x_private *devpriv = dev->private;

	int i;



	if (!devpriv)

		return;



	for (i = 0; i < 2; i++) {

		if (devpriv->dma[i].chan)

			free_dma(devpriv->dma[i].chan);

		if (devpriv->dma[i].buf)

			free_page((unsigned long)devpriv->dma[i].buf);

		devpriv->dma[i].chan = 0;

		devpriv->dma[i].buf = NULL;

	}

}



/*

   options:

   0	i/o base
@@ -1235,22 +1219,41 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it) 
	}

	/* should do board test */



	if (it->options[opt_irq] > 0) {

		ret = request_irq(it->options[opt_irq], dt282x_interrupt, 0,

				  dev->board_name, dev);

		if (ret == 0)

			dev->irq = it->options[opt_irq];

	}



	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));

	if (!devpriv)

		return -ENOMEM;



	if (dev->irq) {

		ret = dt282x_grab_dma(dev, it->options[opt_dma1],

				      it->options[opt_dma2]);

		if (ret < 0)

			return ret;

	/* an IRQ and 2 DMA channels are required for async command support */

	if (it->options[opt_irq] &&

	    it->options[opt_dma1] && it->options[opt_dma2]) {

		unsigned int irq = it->options[opt_irq];

		unsigned int dma1 = it->options[opt_dma1];

		unsigned int dma2 = it->options[opt_dma2];



		if (dma2 < dma1) {

			unsigned int swap;



			swap = dma1;

			dma1 = dma2;

			dma2 = swap;

		}



		if (dma1 != dma2 &&

		    dma1 >= 5 && dma1 <= 7 &&

		    dma2 >= 5 && dma2 <= 7) {

			ret = request_irq(irq, dt282x_interrupt, 0,

					  dev->board_name, dev);

			if (ret == 0) {

				dev->irq = irq;



				ret = dt282x_grab_dma(dev, dma1, dma2);

				if (ret < 0) {

					dt282x_free_dma(dev);

					free_irq(dev->irq, dev);

					dev->irq = 0;

				}

			}

		}

	}



	ret = comedi_alloc_subdevices(dev, 3);
@@ -1323,18 +1326,7 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it) 


static void dt282x_detach(struct comedi_device *dev)

{

	struct dt282x_private *devpriv = dev->private;



	if (dev->private) {

		if (devpriv->dma[0].chan)

			free_dma(devpriv->dma[0].chan);

		if (devpriv->dma[1].chan)

			free_dma(devpriv->dma[1].chan);

		if (devpriv->dma[0].buf)

			free_page((unsigned long)devpriv->dma[0].buf);

		if (devpriv->dma[1].buf)

			free_page((unsigned long)devpriv->dma[1].buf);

	}

	dt282x_free_dma(dev);

	comedi_legacy_detach(dev);

}