[PATCH 15/17] dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods

Christoph Hellwig
2020-09-14T15:20:41Z

This will allow IOMMU drivers to allocate non-contigous memory and
return a vmapped virtual address.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/dma-mapping.h | 5 +++++
kernel/dma/mapping.c | 33 +++++++++++++++++++++++++++------
2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index bf592cf0db4acb..b4b5d75260d6dc 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -80,6 +80,11 @@ struct dma_map_ops {
gfp_t gfp);
void (*free_pages)(struct device *dev, size_t size, struct page *vaddr,
dma_addr_t dma_handle, enum dma_data_direction dir);
+ void* (*alloc_noncoherent)(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir,
+ gfp_t gfp);
+ void (*free_noncoherent)(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, enum dma_data_direction dir);
int (*mmap)(struct device *, struct vm_area_struct *,
void *, dma_addr_t, size_t,
unsigned long attrs);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 6f86c925b8251d..8614d7d2ee59a9 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -502,19 +502,40 @@ EXPORT_SYMBOL_GPL(dma_free_pages);
void *dma_alloc_noncoherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
{
- struct page *page;
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+ void *vaddr;

- page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
- if (!page)
- return NULL;
- return page_address(page);
+ if (!ops || !ops->alloc_noncoherent) {
+ struct page *page;
+
+ page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
+ if (!page)
+ return NULL;
+ return page_address(page);
+ }
+
+ size = PAGE_ALIGN(size);
+ vaddr = ops->alloc_noncoherent(dev, size, dma_handle, dir, gfp);
+ if (vaddr)
+ debug_dma_map_page(dev, virt_to_page(vaddr), 0, size, dir,
+ *dma_handle);
+ return vaddr;
}
EXPORT_SYMBOL_GPL(dma_alloc_noncoherent);

void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle, enum dma_data_direction dir)
{
- dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+
+ if (!ops || !ops->free_noncoherent) {
+ dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+ return;
+ }
+
+ size = PAGE_ALIGN(size);
+ debug_dma_unmap_page(dev, dma_handle, size, dir);
+ ops->free_noncoherent(dev, size, vaddr, dma_handle, dir);
}
EXPORT_SYMBOL_GPL(dma_free_noncoherent);

--
2.28.0