From 0156b06a6b3ee8c42c7c404a2a8a5921b74c69f5 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 13 Jan 2015 10:16:34 -0700 Subject: [PATCH] staging: comedi: pcl812: introduce pcl812_isadma_disable() According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be claimed before using any of the ISA DMA routines. Introduce a helper function to disable the ISA DMA controller and add the necessary locking calls. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcl812.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c index 6b38147..c67c2c7 100644 --- a/drivers/staging/comedi/drivers/pcl812.c +++ b/drivers/staging/comedi/drivers/pcl812.c @@ -547,6 +547,15 @@ static void pcl812_isadma_program(unsigned int dma_chan, release_dma_lock(flags); } +static void pcl812_isadma_disable(unsigned int dma_chan) +{ + unsigned long flags; + + flags = claim_dma_lock(); + disable_dma(dma_chan); + release_dma_lock(flags); +} + static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers) { struct pcl812_private *devpriv = dev->private; @@ -618,7 +627,7 @@ static void pcl812_ai_setup_next_dma(struct comedi_device *dev, struct pcl812_private *devpriv = dev->private; struct pcl812_dma_desc *dma; - disable_dma(devpriv->dma); + pcl812_isadma_disable(devpriv->dma); devpriv->cur_dma = 1 - devpriv->cur_dma; dma = &devpriv->dma_desc[devpriv->cur_dma]; @@ -980,7 +989,7 @@ static int pcl812_ai_cancel(struct comedi_device *dev, struct pcl812_private *devpriv = dev->private; if (devpriv->ai_dma) - disable_dma(devpriv->dma); + pcl812_isadma_disable(devpriv->dma); outb(devpriv->mode_reg_int | PCL812_CTRL_DISABLE_TRIG, dev->iobase + PCL812_CTRL_REG); -- 2.7.4