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path: root/drivers/staging/comedi/comedi_buf.c
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Diffstat (limited to 'drivers/staging/comedi/comedi_buf.c')
-rw-r--r--drivers/staging/comedi/comedi_buf.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
index ca709901fb3..d4be0e68509 100644
--- a/drivers/staging/comedi/comedi_buf.c
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -51,10 +51,12 @@ static void __comedi_buf_free(struct comedi_device *dev,
clear_bit(PG_reserved,
&(virt_to_page(buf->virt_addr)->flags));
if (s->async_dma_dir != DMA_NONE) {
+#ifdef CONFIG_HAS_DMA
dma_free_coherent(dev->hw_dev,
PAGE_SIZE,
buf->virt_addr,
buf->dma_addr);
+#endif
} else {
free_page((unsigned long)buf->virt_addr);
}
@@ -74,6 +76,12 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
struct comedi_buf_page *buf;
unsigned i;
+ if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
+ dev_err(dev->class_dev,
+ "dma buffer allocation not supported\n");
+ return;
+ }
+
async->buf_page_list = vzalloc(sizeof(*buf) * n_pages);
if (async->buf_page_list)
pages = vmalloc(sizeof(struct page *) * n_pages);
@@ -84,11 +92,15 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
for (i = 0; i < n_pages; i++) {
buf = &async->buf_page_list[i];
if (s->async_dma_dir != DMA_NONE)
+#ifdef CONFIG_HAS_DMA
buf->virt_addr = dma_alloc_coherent(dev->hw_dev,
PAGE_SIZE,
&buf->dma_addr,
GFP_KERNEL |
__GFP_COMP);
+#else
+ break;
+#endif
else
buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);
if (!buf->virt_addr)