From 65fdfedbc06169bc49fbbdab205659237a06568c Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 13 Jan 2015 10:16:23 -0700 Subject: [PATCH] staging: comedi: pcl816: introduce pcl816_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/pcl816.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c index e0d91a18ec64..d2ce7751df93 100644 --- a/drivers/staging/comedi/drivers/pcl816.c +++ b/drivers/staging/comedi/drivers/pcl816.c @@ -147,6 +147,15 @@ static void pcl816_isadma_program(unsigned int dma_chan, release_dma_lock(flags); } +static void pcl816_isadma_disable(unsigned int dma_chan) +{ + unsigned long flags; + + flags = claim_dma_lock(); + disable_dma(dma_chan); + release_dma_lock(flags); +} + static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters) { struct pcl816_private *devpriv = dev->private; @@ -202,7 +211,7 @@ static void pcl816_ai_setup_next_dma(struct comedi_device *dev, struct comedi_cmd *cmd = &s->async->cmd; struct pcl816_dma_desc *dma; - disable_dma(devpriv->dma); + pcl816_isadma_disable(devpriv->dma); if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) { /* switch dma bufs */ devpriv->cur_dma = 1 - devpriv->cur_dma; -- 2.20.1