On 05/30/2018 12:52 AM, Boris Ostrovsky wrote:
On 05/25/2018 11:33 AM, Oleksandr Andrushchenko wrote:
struct unmap_notify {
@@ -96,10 +104,28 @@ struct grant_map {
struct gnttab_unmap_grant_ref *kunmap_ops;
struct page **pages;
unsigned long pages_vm_start;
+
+#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
+ /*
+ * If dmabuf_vaddr is not NULL then this mapping is backed by DMA
+ * capable memory.
+ */
+
+ /* Device for which DMA memory is allocated. */
+ struct device *dma_dev;
+ /* Flags used to create this DMA buffer: GNTDEV_DMABUF_FLAG_XXX. */
+ bool dma_flags;
Again, I think most of the comments here can be dropped. Except possibly
for the flags.
will drop most of those
+ /* Virtual/CPU address of the DMA buffer. */
+ void *dma_vaddr;
+ /* Bus address of the DMA buffer. */
+ dma_addr_t dma_bus_addr;
+#endif
};
static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
+static struct miscdevice gntdev_miscdev;
+
/* ------------------------------------------------------------------ */
static void gntdev_print_maps(struct gntdev_priv *priv,
@@ -121,8 +147,26 @@ static void gntdev_free_map(struct grant_map *map)
if (map == NULL)
return;
+#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
+ if (map->dma_vaddr) {
+ struct gnttab_dma_alloc_args args;
+
+ args.dev = map->dma_dev;
+ args.coherent = map->dma_flags & GNTDEV_DMA_FLAG_COHERENT;
+ args.nr_pages = map->count;
+ args.pages = map->pages;
+ args.vaddr = map->dma_vaddr;
+ args.dev_bus_addr = map->dma_bus_addr;
+
+ gnttab_dma_free_pages(&args);
+ } else if (map->pages) {
+ gnttab_free_pages(map->count, map->pages);
+ }
+#else
if (map->pages)
gnttab_free_pages(map->count, map->pages);
+#endif
+
} else
#endif
if (map->pages)
gnttab_free_pages(map->count, map->pages);
(and elsewhere)
ok, just wasn't sure if it is ok to violate kernel coding style here ;)
kfree(map->pages);
kfree(map->grants);
kfree(map->map_ops);
diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h
index 6d1163456c03..2d5a4672f07c 100644
--- a/include/uapi/xen/gntdev.h
+++ b/include/uapi/xen/gntdev.h
@@ -200,4 +200,19 @@ struct ioctl_gntdev_grant_copy {
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2
+/*
+ * Flags to be used while requesting memory mapping's backing storage
+ * to be allocated with DMA API.
+ */
+
+/*
+ * The buffer is backed with memory allocated with dma_alloc_wc.
+ */
+#define GNTDEV_DMA_FLAG_WC (1 << 1)
Is there a reason you are not using bit 0?
No reason for that, will start from 0
-boris
Thank you,
Oleksandr
+
+/*
+ * The buffer is backed with memory allocated with dma_alloc_coherent.
+ */
+#define GNTDEV_DMA_FLAG_COHERENT (1 << 2)
+
#endif /* __LINUX_PUBLIC_GNTDEV_H__ */
