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Commit 42c44682 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: das16: use comedi_async 'scans_done' to detect EOA 



Refactor das16_interrupt() to use the comedi_async 'scans_done' member to
detect the End-of-Acquisition for the async command. Use the helper function
comedi_nsamples_left() to determine if DMA needs to be restarted.

This allows the removal of the private data 'adc_byte_count' and fixes a
possible integer overflow issue when that value is calculated.

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 29538110

drivers/staging/comedi/drivers/das16.c

+16 −21
Original line number Diff line number Diff line
@@ -440,7 +440,6 @@ struct das16_private_struct { 
	struct comedi_isadma	*dma;

	unsigned int		clockbase;

	unsigned int		ctrl_reg;

	unsigned long		adc_byte_count;

	unsigned int		divisor1;

	unsigned int		divisor2;

	struct timer_list	timer;
@@ -458,8 +457,9 @@ static void das16_interrupt(struct comedi_device *dev) 
	struct comedi_isadma *dma = devpriv->dma;

	struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];

	unsigned long spin_flags;

	unsigned int residue;

	unsigned int nbytes;

	unsigned int nsamples;

	int num_bytes, residue;



	spin_lock_irqsave(&dev->spinlock, spin_flags);

	if (!(devpriv->ctrl_reg & DAS16_CTRL_DMAE)) {
@@ -475,36 +475,33 @@ static void das16_interrupt(struct comedi_device *dev) 
	residue = comedi_isadma_disable_on_sample(desc->chan,

						  comedi_bytes_per_sample(s));



	/*  figure out how many points to read */

	/* figure out how many samples to read */

	if (residue > desc->size) {

		dev_err(dev->class_dev, "residue > transfer size!\n");

		async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA;

		num_bytes = 0;

	} else

		num_bytes = desc->size - residue;



	if (cmd->stop_src == TRIG_COUNT &&

					num_bytes >= devpriv->adc_byte_count) {

		num_bytes = devpriv->adc_byte_count;

		async->events |= COMEDI_CB_EOA;

		async->events |= COMEDI_CB_ERROR;

		nbytes = 0;

	} else {

		nbytes = desc->size - residue;

	}

	nsamples = comedi_bytes_to_samples(s, nbytes);



	dma->cur_dma = 1 - dma->cur_dma;

	devpriv->adc_byte_count -= num_bytes;



	/* re-enable dma */

	if (!(async->events & COMEDI_CB_CANCEL_MASK)) {

		struct comedi_isadma_desc *nxt_desc = &dma->desc[dma->cur_dma];

	/* restart DMA if more samples are needed */

	if (nsamples && nsamples < comedi_nsamples_left(s, nsamples + 1)) {

		struct comedi_isadma_desc *nxt_desc;



		dma->cur_dma = 1 - dma->cur_dma;

		nxt_desc = &dma->desc[dma->cur_dma];

		nxt_desc->size = nxt_desc->maxsize;

		comedi_isadma_program(nxt_desc);

	}



	spin_unlock_irqrestore(&dev->spinlock, spin_flags);



	nsamples = comedi_bytes_to_samples(s, num_bytes);

	comedi_buf_write_samples(s, desc->virt_addr, nsamples);



	if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg)

		async->events |= COMEDI_CB_EOA;



	comedi_handle_events(dev, s);

}
@@ -688,8 +685,6 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s) 
		return -1;

	}



	devpriv->adc_byte_count = cmd->stop_arg * comedi_bytes_per_scan(s);



	if (devpriv->can_burst)

		outb(DAS1600_CONV_DISABLE, dev->iobase + DAS1600_CONV_REG);