From a1ce5f037ee83c1addb114179a776d505be1ddd5 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 13 Jan 2015 10:16:32 -0700 Subject: [PATCH] staging: comedi: das16: introduce das16_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/das16.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c index f99796684978..09d65fcebd0b 100644 --- a/drivers/staging/comedi/drivers/das16.c +++ b/drivers/staging/comedi/drivers/das16.c @@ -475,6 +475,19 @@ static void das16_isadma_program(unsigned int dma_chan, release_dma_lock(flags); } +static unsigned int das16_isadma_disable(unsigned int dma_chan) +{ + 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; +} + static void das16_ai_enable(struct comedi_device *dev, unsigned int mode, unsigned int src) { @@ -514,23 +527,24 @@ static int disable_dma_on_even(struct comedi_device *dev) struct das16_private_struct *devpriv = dev->private; static const int disable_limit = 100; static const int enable_timeout = 100; - int residue; + unsigned long flags; + unsigned int residue; int new_residue; int i; int j; - disable_dma(devpriv->dma_chan); - residue = get_dma_residue(devpriv->dma_chan); + residue = das16_isadma_disable(devpriv->dma_chan); for (i = 0; i < disable_limit && (residue % 2); ++i) { + flags = claim_dma_lock(); enable_dma(devpriv->dma_chan); for (j = 0; j < enable_timeout; ++j) { udelay(2); new_residue = get_dma_residue(devpriv->dma_chan); + release_dma_lock(flags); if (new_residue != residue) break; } - disable_dma(devpriv->dma_chan); - residue = get_dma_residue(devpriv->dma_chan); + residue = das16_isadma_disable(devpriv->dma_chan); } if (i == disable_limit) { dev_err(dev->class_dev, @@ -548,7 +562,6 @@ static void das16_interrupt(struct comedi_device *dev) struct das16_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma]; struct das16_dma_desc *nxt_dma; unsigned long spin_flags; - unsigned long dma_flags; unsigned int nsamples; int num_bytes, residue; @@ -558,10 +571,7 @@ static void das16_interrupt(struct comedi_device *dev) return; } - dma_flags = claim_dma_lock(); - clear_dma_ff(devpriv->dma_chan); residue = disable_dma_on_even(dev); - release_dma_lock(dma_flags); /* figure out how many points to read */ if (residue > dma->size) { @@ -1001,7 +1011,6 @@ static int das16_alloc_dma(struct comedi_device *dev, unsigned int dma_chan) { struct das16_private_struct *devpriv = dev->private; struct das16_dma_desc *dma; - unsigned long flags; int i; if (!(dma_chan == 1 || dma_chan == 3)) @@ -1020,9 +1029,7 @@ static int das16_alloc_dma(struct comedi_device *dev, unsigned int dma_chan) return -ENOMEM; } - flags = claim_dma_lock(); - disable_dma(devpriv->dma_chan); - release_dma_lock(flags); + das16_isadma_disable(devpriv->dma_chan); init_timer(&devpriv->timer); devpriv->timer.function = das16_timer_interrupt; -- 2.11.0