From 38a7d4999a68af0c18216279971fa7acd8ec7345 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Mon, 12 Jan 2015 10:56:12 -0700 Subject: [PATCH] staging: comedi: das16: introduce struct das16_dma_desc For aesthetics, introduce a struct to hold the DMA descriptor data. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/das16.c | 48 ++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 22 deletions(-) diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c index 64b0ada..1c32cbc 100644 --- a/drivers/staging/comedi/drivers/das16.c +++ b/drivers/staging/comedi/drivers/das16.c @@ -439,6 +439,11 @@ static inline int timer_period(void) return HZ / 20; } +struct das16_dma_desc { + uint16_t *virt_addr; /* virtual address of DMA buffer */ + dma_addr_t hw_addr; /* hardware (bus) address of DMA buffer */ +}; + struct das16_private_struct { unsigned int clockbase; unsigned int ctrl_reg; @@ -446,9 +451,8 @@ struct das16_private_struct { unsigned int divisor1; unsigned int divisor2; unsigned int dma_chan; - uint16_t *dma_buffer[2]; - dma_addr_t dma_buffer_addr[2]; - unsigned int current_buffer; + struct das16_dma_desc dma_desc[2]; + unsigned int cur_dma; unsigned int dma_transfer_size; struct comedi_lrange *user_ai_range_table; struct comedi_lrange *user_ao_range_table; @@ -528,11 +532,12 @@ static void das16_interrupt(struct comedi_device *dev) struct comedi_subdevice *s = dev->read_subdev; struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; + 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; - int buffer_index; spin_lock_irqsave(&dev->spinlock, spin_flags); if (!(devpriv->ctrl_reg & DAS16_CTRL_DMAE)) { @@ -558,14 +563,13 @@ static void das16_interrupt(struct comedi_device *dev) async->events |= COMEDI_CB_EOA; } - buffer_index = devpriv->current_buffer; - devpriv->current_buffer = (devpriv->current_buffer + 1) % 2; + devpriv->cur_dma = 1 - devpriv->cur_dma; devpriv->adc_byte_count -= num_bytes; /* re-enable dma */ if ((async->events & COMEDI_CB_EOA) == 0) { - set_dma_addr(devpriv->dma_chan, - devpriv->dma_buffer_addr[devpriv->current_buffer]); + nxt_dma = &devpriv->dma_desc[devpriv->cur_dma]; + set_dma_addr(devpriv->dma_chan, nxt_dma->hw_addr); set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size); enable_dma(devpriv->dma_chan); } @@ -574,8 +578,7 @@ static void das16_interrupt(struct comedi_device *dev) spin_unlock_irqrestore(&dev->spinlock, spin_flags); nsamples = comedi_bytes_to_samples(s, num_bytes); - comedi_buf_write_samples(s, devpriv->dma_buffer[buffer_index], - nsamples); + comedi_buf_write_samples(s, dma->virt_addr, nsamples); comedi_handle_events(dev, s); } @@ -746,6 +749,7 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s) { const struct das16_board *board = dev->board_ptr; struct das16_private_struct *devpriv = dev->private; + struct das16_dma_desc *dma = &devpriv->dma_desc[0]; struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; unsigned int byte; @@ -800,9 +804,8 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s) /* clear flip-flop to make sure 2-byte registers for * count and address get set correctly */ clear_dma_ff(devpriv->dma_chan); - devpriv->current_buffer = 0; - set_dma_addr(devpriv->dma_chan, - devpriv->dma_buffer_addr[devpriv->current_buffer]); + devpriv->cur_dma = 0; + set_dma_addr(devpriv->dma_chan, dma->hw_addr); devpriv->dma_transfer_size = DAS16_DMA_SIZE; set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size); enable_dma(devpriv->dma_chan); @@ -1067,13 +1070,13 @@ static int das16_attach(struct comedi_device *dev, struct comedi_devconfig *it) /* allocate dma buffers */ for (i = 0; i < 2; i++) { - void *p; + struct das16_dma_desc *dma = &devpriv->dma_desc[i]; - p = pci_alloc_consistent(NULL, DAS16_DMA_SIZE, - &devpriv->dma_buffer_addr[i]); - if (!p) + dma->virt_addr = pci_alloc_consistent(NULL, + DAS16_DMA_SIZE, + &dma->hw_addr); + if (!dma->virt_addr) return -ENOMEM; - devpriv->dma_buffer[i] = p; } flags = claim_dma_lock(); @@ -1219,6 +1222,7 @@ static void das16_detach(struct comedi_device *dev) { const struct das16_board *board = dev->board_ptr; struct das16_private_struct *devpriv = dev->private; + struct das16_dma_desc *dma; int i; if (devpriv) { @@ -1228,11 +1232,11 @@ static void das16_detach(struct comedi_device *dev) das16_reset(dev); for (i = 0; i < 2; i++) { - if (devpriv->dma_buffer[i]) + dma = &devpriv->dma_desc[i]; + if (dma->virt_addr) pci_free_consistent(NULL, DAS16_DMA_SIZE, - devpriv->dma_buffer[i], - devpriv-> - dma_buffer_addr[i]); + dma->virt_addr, + dma->hw_addr); } if (devpriv->dma_chan) free_dma(devpriv->dma_chan); -- 2.7.4