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staging: comedi: addi_apci_3120: 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.

Note: `struct addi_private` is used by some other ADDI-DATA drivers as
well, but this is the only one using the affected members.

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>
This commit is contained in:
Ian Abbott 2014-09-12 12:19:56 +01:00 committed by Greg Kroah-Hartman
parent 9c97e588d8
commit fbfd9c8a17
3 changed files with 15 additions and 16 deletions
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2
drivers/staging/comedi/Kconfig
View File

@ -677,7 +677,7 @@ config COMEDI_ADDI_APCI_2200
config COMEDI_ADDI_APCI_3120
tristate "ADDI-DATA APCI_3120/3001 support"
depends on VIRT_TO_BUS
depends on HAS_DMA
select COMEDI_FC
---help---
Enable support for ADDI-DATA APCI_3120/3001 cards

3
drivers/staging/comedi/drivers/addi-data/addi_common.h
View File

@ -107,10 +107,9 @@ struct addi_private {
unsigned char b_DmaDoubleBuffer; /* we can use double buffering */
unsigned int ui_DmaActualBuffer; /* which buffer is used now */
unsigned short *ul_DmaBufferVirtual[2]; /* pointers to DMA buffer */
unsigned int ul_DmaBufferHw[2]; /* hw address of DMA buff */
dma_addr_t ul_DmaBufferHw[2]; /* hw address of DMA buff */
unsigned int ui_DmaBufferSize[2]; /* size of dma buffer in bytes */
unsigned int ui_DmaBufferUsesize[2]; /* which size we may now used for transfer */
unsigned int ui_DmaBufferPageOrder[2]; /* log2 of pages in buffer */
unsigned char b_DigitalOutputRegister; /* Digital Output Register */
unsigned char b_OutputMemoryStatus;
unsigned char b_TimerSelectMode; /* Contain data written at iobase + 0C */

24
drivers/staging/comedi/drivers/addi_apci_3120.c
View File

@ -95,17 +95,16 @@ static int apci3120_auto_attach(struct comedi_device *dev,
for (i = 0; i < 2; i++) {
for (order = 2; order >= 0; order--) {
devpriv->ul_DmaBufferVirtual[i] =
(void *)__get_free_pages(GFP_KERNEL, order);
dma_alloc_coherent(dev->hw_dev, PAGE_SIZE << order,
&devpriv->ul_DmaBufferHw[i],
GFP_KERNEL);
if (devpriv->ul_DmaBufferVirtual[i])
break;
}
if (!devpriv->ul_DmaBufferVirtual[i])
break;
devpriv->ui_DmaBufferPageOrder[i] = order;
devpriv->ui_DmaBufferSize[i] = PAGE_SIZE << order;
devpriv->ul_DmaBufferHw[i] =
virt_to_bus(devpriv->ul_DmaBufferVirtual[i]);
}
if (!devpriv->ul_DmaBufferVirtual[0])
devpriv->us_UseDma = 0;
@ -198,15 +197,16 @@ static void apci3120_detach(struct comedi_device *dev)
apci3120_reset(dev);
comedi_pci_detach(dev);
if (devpriv) {
if (devpriv->ul_DmaBufferVirtual[0]) {
free_pages((unsigned long)devpriv->
ul_DmaBufferVirtual[0],
devpriv->ui_DmaBufferPageOrder[0]);
unsigned int i;
for (i = 0; i < 2; i++) {
if (devpriv->ul_DmaBufferVirtual[i]) {
dma_free_coherent(dev->hw_dev,
devpriv->ui_DmaBufferSize[i],
devpriv->
ul_DmaBufferVirtual[i],
devpriv->ul_DmaBufferHw[i]);
}
if (devpriv->ul_DmaBufferVirtual[1]) {
free_pages((unsigned long)devpriv->
ul_DmaBufferVirtual[1],
devpriv->ui_DmaBufferPageOrder[1]);
}
}
}