[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 4/8] xen/gntdev: Allow mappings for DMA buffers
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.hindex 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__ */ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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