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Commit 75fbdbf6 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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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: default avatarIan Abbott <abbotti@mev.co.uk>
Reviewed-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f39f87e9

drivers/staging/comedi/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/staging/comedi/drivers/adl_pci9118.c

+10 −10
Original line number Diff line number Diff line
@@ -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);

		}

	}

}