staging: comedi: adl_pci9118: use dma_alloc_coherent()

Use `dma_alloc_coherent()` to allocate the DMA buffers instead of
using `__get_free_pages()` to allocate and `virt_to_bus()` to get the
hardware address.  The coherent buffers are fairly small - at most 4
pages (although there are two of them).  Use of `virt_to_bus()` is
discouraged.

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

diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig
index fd5f9397af90ee3e1d437efa3a1c983f19a52d8e..9eaffd4df1542fde7cee7e7bda6978f7926fa3af 100644 (file)
--- a/drivers/staging/comedi/Kconfig
+++ b/drivers/staging/comedi/Kconfig
@@ -740,7 +740,7 @@ config COMEDI_ADL_PCI9111
 config COMEDI_ADL_PCI9118
        tristate "ADLink PCI-9118DG, PCI-9118HG, PCI-9118HR support"
        select COMEDI_FC
-       depends on VIRT_TO_BUS
+       depends on HAS_DMA
        ---help---
          Enable support for ADlink PCI-9118DG, PCI-9118HG, PCI-9118HR cards
 

diff --git a/drivers/staging/comedi/drivers/adl_pci9118.c b/drivers/staging/comedi/drivers/adl_pci9118.c
index 6ab9e0a27588de490a124021c056e11668492e15..e18fd9569a2b19cd51c59c41d065657cb98d3734 100644 (file)
--- a/drivers/staging/comedi/drivers/adl_pci9118.c
+++ b/drivers/staging/comedi/drivers/adl_pci9118.c
@@ -204,11 +204,10 @@ static const struct pci9118_boardinfo pci9118_boards[] = {
 };
 
 struct pci9118_dmabuf {
-       unsigned long virt;     /* virtual address of buffer */
-       unsigned long hw;       /* hardware (bus) address of buffer */
+       unsigned short *virt;   /* virtual address of buffer */
+       dma_addr_t hw;          /* hardware (bus) address of buffer */
        unsigned int size;      /* size of dma buffer in bytes */
        unsigned int use_size;  /* which size we may now use for transfer */
-       int order;              /* log2 number of pages in buffer */
 };
 
 struct pci9118_private {
@@ -475,12 +474,11 @@ static unsigned int defragment_dma_buffer(struct comedi_device *dev,
 
 static int move_block_from_dma(struct comedi_device *dev,
                               struct comedi_subdevice *s,
-                              unsigned long virt_addr,
+                              unsigned short *dma_buffer,
                               unsigned int num_samples)
 {
        struct pci9118_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
-       unsigned short *dma_buffer = (unsigned short *)virt_addr;
        unsigned int num_bytes;
 
        num_samples = defragment_dma_buffer(dev, s, dma_buffer, num_samples);
@@ -1485,15 +1483,15 @@ static void pci9118_alloc_dma(struct comedi_device *dev)
        for (i = 0; i < 2; i++) {
                dmabuf = &devpriv->dmabuf[i];
                for (order = 2; order >= 0; order--) {
-                       dmabuf->virt = __get_free_pages(GFP_KERNEL, order);
+                       dmabuf->virt =
+                           dma_alloc_coherent(dev->hw_dev, PAGE_SIZE << order,
+                                              &dmabuf->hw, GFP_KERNEL);
                        if (dmabuf->virt)
                                break;
                }
                if (!dmabuf->virt)
                        break;
-               dmabuf->order = order;
                dmabuf->size = PAGE_SIZE << order;
-               dmabuf->hw = virt_to_bus((void *)dmabuf->virt);
 
                if (i == 0)
                        devpriv->master = 1;
@@ -1513,8 +1511,10 @@ static void pci9118_free_dma(struct comedi_device *dev)
 
        for (i = 0; i < 2; i++) {
                dmabuf = &devpriv->dmabuf[i];
-               if (dmabuf->virt)
-                       free_pages(dmabuf->virt, dmabuf->order);
+               if (dmabuf->virt) {
+                       dma_free_coherent(dev->hw_dev, dmabuf->size,
+                                         dmabuf->virt, dmabuf->hw);
+               }
        }
 }