From c92b0b29819bc2b3f504b8341b26bb7c1421ad22 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 13 Jan 2015 10:16:35 -0700 Subject: [PATCH] staging: comedi: ni_at_a2150: introduce a2150_isadma_program() Introduce a helper function to program the ISA DMA controller. Program the ISA DMA 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 | 36 ++++++++++++-------- 1 file changed, 21 insertions(+), 15 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c index 3905097ef6d8..23c59cb9412f 100644 --- a/drivers/staging/comedi/drivers/ni_at_a2150.c +++ b/drivers/staging/comedi/drivers/ni_at_a2150.c @@ -159,6 +159,19 @@ struct a2150_private { int config_bits; /* config register bits */ }; +static void a2150_isadma_program(struct a2150_dma_desc *dma) +{ + unsigned long flags; + + flags = claim_dma_lock(); + clear_dma_ff(dma->chan); + set_dma_mode(dma->chan, DMA_MODE_READ); + set_dma_addr(dma->chan, dma->hw_addr); + set_dma_count(dma->chan, dma->size); + enable_dma(dma->chan); + release_dma_lock(flags); +} + /* interrupt service routine */ static irqreturn_t a2150_interrupt(int irq, void *d) { @@ -217,6 +230,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d) * 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; if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT) num_points = devpriv->count; @@ -250,14 +264,11 @@ static irqreturn_t a2150_interrupt(int irq, void *d) } } } - /* re-enable dma */ + /* re-enable dma */ if (leftover) { - set_dma_addr(dma->chan, dma->hw_addr); - set_dma_count(dma->chan, - comedi_samples_to_bytes(s, leftover)); - enable_dma(dma->chan); + dma->size = comedi_samples_to_bytes(s, leftover); + a2150_isadma_program(dma); } - release_dma_lock(flags); comedi_handle_events(dev, s); @@ -549,13 +560,10 @@ 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; - /* enable computer's dma */ lock_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); - set_dma_addr(dma->chan, dma->hw_addr); + release_dma_lock(lock_flags); + /* set size of transfer to fill in 1/3 second */ #define ONE_THIRD_SECOND 333333333 dma->size = comedi_bytes_per_sample(s) * cmd->chanlist_len * @@ -565,9 +573,8 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) if (dma->size < comedi_bytes_per_sample(s)) dma->size = comedi_bytes_per_sample(s); dma->size -= dma->size % comedi_bytes_per_sample(s); - set_dma_count(dma->chan, dma->size); - enable_dma(dma->chan); - release_dma_lock(lock_flags); + + a2150_isadma_program(dma); /* clear dma interrupt before enabling it, to try and get rid of that * one spurious interrupt that has been happening */ @@ -724,7 +731,6 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev, devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan); disable_dma(dma_chan); - set_dma_mode(dma_chan, DMA_MODE_READ); } static void a2150_free_dma(struct comedi_device *dev) -- 2.20.1