+static int carma_dma_init(struct data_buf *buf, int nr_pages)
+{
+ struct page *pg;
+ int i;
+
+ buf->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
+ if (NULL == buf->vaddr) {
+ pr_debug("vmalloc_32(%d pages) failed\n", nr_pages);
+ return -ENOMEM;
+ }
+
+ pr_debug("vmalloc is at addr 0x%08lx, size=%d\n",
+ (unsigned long)buf->vaddr,
+ nr_pages << PAGE_SHIFT);
+
+ memset(buf->vaddr, 0, nr_pages << PAGE_SHIFT);
+ buf->nr_pages = nr_pages;
+
+ buf->sglist = vzalloc(buf->nr_pages * sizeof(*buf->sglist));
+ if (NULL == buf->sglist)
+ goto vzalloc_err;
+
+ sg_init_table(buf->sglist, buf->nr_pages);
+ for (i = 0; i < buf->nr_pages; i++) {
+ pg = vmalloc_to_page(buf->vaddr + i * PAGE_SIZE);
+ if (NULL == pg)
+ goto vmalloc_to_page_err;
+ sg_set_page(&buf->sglist[i], pg, PAGE_SIZE, 0);
+ }
+ return 0;
+
+vmalloc_to_page_err:
+ vfree(buf->sglist);
+ buf->sglist = NULL;
+vzalloc_err:
+ vfree(buf->vaddr);
+ buf->vaddr = NULL;
+ return -ENOMEM;
+}
+
+static int carma_dma_map(struct device *dev, struct data_buf *buf)
+{
+ buf->sglen = dma_map_sg(dev, buf->sglist,
+ buf->nr_pages, DMA_FROM_DEVICE);
+
+ if (0 == buf->sglen) {
+ pr_warn("%s: dma_map_sg failed\n", __func__);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static int carma_dma_unmap(struct device *dev, struct data_buf *buf)
+{
+ if (!buf->sglen)
+ return 0;
+
+ dma_unmap_sg(dev, buf->sglist, buf->sglen, DMA_FROM_DEVICE);
+ buf->sglen = 0;
+ return 0;
+}
+