From f5cc425afed63820734f130fc245ba7bb11c11ac Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Mon, 17 Feb 2014 14:27:30 -0700 Subject: [PATCH] staging: comedi: pcl818: tidy up dma buffer allocation This driver uses 2 buffers for DMA. Refactor the buffer allocation to use a for loop to remove code duplication. Remove the dev_err() messages when __get_dma_pages() fails and change the errno returned from -EBUSY to -ENOMEM. Both buffers are the same size so replace the 'dmapages' and 'hwdmasize' arrays in the private data with variables to save a bit of space. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcl818.c | 61 ++++++++++++------------- 1 file changed, 28 insertions(+), 33 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c index dcc397cf45b..e2629087d09 100644 --- a/drivers/staging/comedi/drivers/pcl818.c +++ b/drivers/staging/comedi/drivers/pcl818.c @@ -320,12 +320,11 @@ static const struct pcl818_board boardtypes[] = { }; struct pcl818_private { - unsigned int dma; /* used DMA, 0=don't use DMA */ + unsigned int dmapages; + unsigned int hwdmasize; unsigned long dmabuf[2]; /* pointers to begin of DMA buffers */ - unsigned int dmapages[2]; /* len of DMA buffers in PAGE_SIZEs */ unsigned int hwdmaptr[2]; /* hardware address of DMA buffers */ - unsigned int hwdmasize[2]; /* len of DMA buffers in Bytes */ int next_dma_buf; /* which DMA buffer will be used next round */ long dma_runs_to_end; /* how many we must permorm DMA transfer to end of record */ unsigned long last_dma_run; /* how many bytes we must transfer on last DMA page */ @@ -584,13 +583,10 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d) flags = claim_dma_lock(); set_dma_addr(devpriv->dma, devpriv->hwdmaptr[devpriv->next_dma_buf]); - if (devpriv->dma_runs_to_end || devpriv->neverending_ai) { - set_dma_count(devpriv->dma, - devpriv->hwdmasize[devpriv-> - next_dma_buf]); - } else { + if (devpriv->dma_runs_to_end || devpriv->neverending_ai) + set_dma_count(devpriv->dma, devpriv->hwdmasize); + else set_dma_count(devpriv->dma, devpriv->last_dma_run); - } release_dma_lock(flags); enable_dma(devpriv->dma); } @@ -599,7 +595,7 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d) outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */ ptr = (unsigned short *)devpriv->dmabuf[1 - devpriv->next_dma_buf]; - len = devpriv->hwdmasize[0] >> 1; + len = devpriv->hwdmasize >> 1; bufptr = 0; for (i = 0; i < len; i++) { @@ -795,14 +791,14 @@ static void pcl818_ai_mode13dma_int(int mode, struct comedi_device *dev, unsigned int bytes; disable_dma(devpriv->dma); /* disable dma */ - bytes = devpriv->hwdmasize[0]; + bytes = devpriv->hwdmasize; if (!devpriv->neverending_ai) { - bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short); /* how many */ - devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize[0]; /* how many DMA pages we must fiil */ - devpriv->last_dma_run = bytes % devpriv->hwdmasize[0]; /* on last dma transfer must be moved */ + bytes = cmd->chanlist_len * cmd->stop_arg * sizeof(short); + devpriv->dma_runs_to_end = bytes / devpriv->hwdmasize; + devpriv->last_dma_run = bytes % devpriv->hwdmasize; devpriv->dma_runs_to_end--; if (devpriv->dma_runs_to_end >= 0) - bytes = devpriv->hwdmasize[0]; + bytes = devpriv->hwdmasize; } devpriv->next_dma_buf = 0; @@ -1308,9 +1304,9 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it) { const struct pcl818_board *board = comedi_board(dev); struct pcl818_private *devpriv; - int ret; - unsigned long pages; struct comedi_subdevice *s; + int ret; + int i; devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv)); if (!devpriv) @@ -1353,20 +1349,19 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it) } devpriv->dma = it->options[2]; - pages = 2; /* we need 16KB */ - devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages); - if (!devpriv->dmabuf[0]) - /* maybe experiment with try_to_free_pages() will help .... */ - return -EBUSY; /* no buffer :-( */ - devpriv->dmapages[0] = pages; - devpriv->hwdmaptr[0] = virt_to_bus((void *)devpriv->dmabuf[0]); - devpriv->hwdmasize[0] = (1 << pages) * PAGE_SIZE; - devpriv->dmabuf[1] = __get_dma_pages(GFP_KERNEL, pages); - if (!devpriv->dmabuf[1]) - return -EBUSY; - devpriv->dmapages[1] = pages; - devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]); - devpriv->hwdmasize[1] = (1 << pages) * PAGE_SIZE; + devpriv->dmapages = 2; /* we need 16KB */ + devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE; + + for (i = 0; i < 2; i++) { + unsigned long dmabuf; + + dmabuf = __get_dma_pages(GFP_KERNEL, devpriv->dmapages); + if (!dmabuf) + return -ENOMEM; + + devpriv->dmabuf[i] = dmabuf; + devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf); + } } ret = comedi_alloc_subdevices(dev, 4); @@ -1468,9 +1463,9 @@ static void pcl818_detach(struct comedi_device *dev) if (devpriv->dma) free_dma(devpriv->dma); if (devpriv->dmabuf[0]) - free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]); + free_pages(devpriv->dmabuf[0], devpriv->dmapages); if (devpriv->dmabuf[1]) - free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]); + free_pages(devpriv->dmabuf[1], devpriv->dmapages); } comedi_legacy_detach(dev); } -- 2.46.0