From 10f3a2dca81ace26daacf26c5d79c5876576e7ea Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 13 Jan 2015 10:16:36 -0700 Subject: [PATCH] staging: comedi: ni_at_a2150: introduce a2150_isadma_disable() Introduce a helper function to disable and the ISA DMA controller and return the residue as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/ni_at_a2150.c | 42 +++++++++++--------- 1 file changed, 23 insertions(+), 19 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c index 23c59cb9412f..73768d0cbfe0 100644 --- a/drivers/staging/comedi/drivers/ni_at_a2150.c +++ b/drivers/staging/comedi/drivers/ni_at_a2150.c @@ -172,12 +172,24 @@ static void a2150_isadma_program(struct a2150_dma_desc *dma) release_dma_lock(flags); } +static unsigned int a2150_isadma_disable(struct a2150_dma_desc *dma) +{ + unsigned long flags; + unsigned int residue; + + flags = claim_dma_lock(); + disable_dma(dma->chan); + residue = get_dma_residue(dma->chan); + release_dma_lock(flags); + + return residue; +} + /* interrupt service routine */ static irqreturn_t a2150_interrupt(int irq, void *d) { int i; int status; - unsigned long flags; struct comedi_device *dev = d; struct a2150_private *devpriv = dev->private; struct a2150_dma_desc *dma = &devpriv->dma_desc; @@ -217,21 +229,16 @@ static irqreturn_t a2150_interrupt(int irq, void *d) return IRQ_HANDLED; } - flags = claim_dma_lock(); - disable_dma(dma->chan); - /* clear flip-flop to make sure 2-byte registers for - * count and address get set correctly */ - clear_dma_ff(dma->chan); - - /* figure out how many points to read */ - max_points = comedi_bytes_to_samples(s, dma->size); - /* residue is the number of points left to be done on the dma + /* + * residue is the number of bytes left to be done on the dma * transfer. It should always be zero at this point unless * the stop_src is set to external triggering. */ - residue = comedi_bytes_to_samples(s, get_dma_residue(dma->chan)); - release_dma_lock(flags); - num_points = max_points - residue; + residue = a2150_isadma_disable(dma); + + /* figure out how many points to read */ + max_points = comedi_bytes_to_samples(s, dma->size); + num_points = max_points - comedi_bytes_to_samples(s, residue); if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT) num_points = devpriv->count; @@ -288,7 +295,7 @@ static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s) outw(devpriv->irq_dma_bits, dev->iobase + IRQ_DMA_CNTRL_REG); /* disable computer's dma */ - disable_dma(dma->chan); + a2150_isadma_disable(dma); /* clear fifo and reset triggering circuitry */ outw(0, dev->iobase + FIFO_RESET_REG); @@ -524,7 +531,6 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; unsigned long timer_base = dev->iobase + I8253_BASE_REG; - unsigned long lock_flags; unsigned int old_config_bits = devpriv->config_bits; unsigned int trigger_bits; @@ -560,9 +566,7 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) /* initialize number of samples remaining */ devpriv->count = cmd->stop_arg * cmd->chanlist_len; - lock_flags = claim_dma_lock(); - disable_dma(dma->chan); - release_dma_lock(lock_flags); + a2150_isadma_disable(dma); /* set size of transfer to fill in 1/3 second */ #define ONE_THIRD_SECOND 333333333 @@ -730,7 +734,7 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev, dma->chan = dma_chan; devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan); - disable_dma(dma_chan); + a2150_isadma_disable(dma); } static void a2150_free_dma(struct comedi_device *dev) -- 2.20.1