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 <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c
index 64b0ada..1c32cbc 100644 (file)
--- 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);