From: Stefano Stabellini
With some devices physical addresses are different than dma addresses.
To be able to deal with these cases, we need to call phys_to_dma on
physical addresses (including machine addresses in Xen terminology)
before returning them from xen_swiotlb_alloc_coherent and
xen_swiotlb_map_page.
We also need to convert dma addresses back to physical addresses using
dma_to_phys in xen_swiotlb_free_coherent and xen_swiotlb_unmap_page if
we want to do any operations on them.
Call dma_to_phys in is_xen_swiotlb_buffer.
Introduce xen_phys_to_dma and call phys_to_dma in its implementation.
Introduce xen_dma_to_phys and call dma_to_phys in its implementation.
Call xen_phys_to_dma/xen_dma_to_phys instead of
xen_phys_to_bus/xen_bus_to_phys through swiotlb-xen.c.
Everything is taken care of by these changes except for
xen_swiotlb_alloc_coherent and xen_swiotlb_free_coherent, which need a
few explicit phys_to_dma/dma_to_phys calls.
Signed-off-by: Stefano Stabellini
Tested-by: Corey Minyard
Tested-by: Roman Shaposhnik
---
Changes in v2:
- improve commit message
Changes in v3:
- add xen_phys_to_dma and xen_dma_to_phys in this patch
---
drivers/xen/swiotlb-xen.c | 53 +++
1 file changed, 32 insertions(+), 21 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 03d118b6c141..a6a95358a8cb 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -52,30 +52,39 @@ static unsigned long xen_io_tlb_nslabs;
* Quick lookup value of the bus address of the IOTLB.
*/
-static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
+static inline phys_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t
paddr)
{
unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
- dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT;
+ phys_addr_t baddr = (phys_addr_t)bfn << XEN_PAGE_SHIFT;
- dma |= paddr & ~XEN_PAGE_MASK;
+ baddr |= paddr & ~XEN_PAGE_MASK;
+ return baddr;
+}
- return dma;
+static inline dma_addr_t xen_phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+ return phys_to_dma(dev, xen_phys_to_bus(dev, paddr));
}
-static inline phys_addr_t xen_bus_to_phys(struct device *dev, dma_addr_t baddr)
+static inline phys_addr_t xen_bus_to_phys(struct device *dev,
+ phys_addr_t baddr)
{
unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
- dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
- phys_addr_t paddr = dma;
-
- paddr |= baddr & ~XEN_PAGE_MASK;
+ phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
+ (baddr & ~XEN_PAGE_MASK);
return paddr;
}
+static inline phys_addr_t xen_dma_to_phys(struct device *dev,
+ dma_addr_t dma_addr)
+{
+ return xen_bus_to_phys(dev, dma_to_phys(dev, dma_addr));
+}
+
static inline dma_addr_t xen_virt_to_bus(struct device *dev, void *address)
{
- return xen_phys_to_bus(dev, virt_to_phys(address));
+ return xen_phys_to_dma(dev, virt_to_phys(address));
}
static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
@@ -94,7 +103,7 @@ static inline int range_straddles_page_boundary(phys_addr_t
p, size_t size)
static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
{
- unsigned long bfn = XEN_PFN_DOWN(dma_addr);
+ unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
unsigned long xen_pfn = bfn_to_local_pfn(bfn);
phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
@@ -299,12 +308,12 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t
size,
if (hwdev && hwdev->coherent_dma_mask)
dma_mask = hwdev->coherent_dma_mask;
- /* At this point dma_handle is the physical address, next we are
+ /* At this point dma_handle is the dma address, next we are
* going to set it to the machine address.
* Do not use virt_to_phys(ret) because on ARM it doesn't correspond
* to *dma_handle. */
- phys = *dma_handle;
- dev_addr = xen_phys_to_bus(hwdev, phys);
+ phys = dma_to_phys(hwdev, *dma_handle);
+ dev_addr = xen_phys_to_dma(hwdev, phys);
if (((dev_addr + size - 1 <= dma_mask)) &&
!range_straddles_page_boundary(phys, size))
*dma_handle = dev_addr;
@@ -314,6 +323,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t
size,
xen_free_coherent_pages(hwdev, size, ret,
(dma_addr_t)phys, attrs);
return NULL;
}
+ *dma_handle = phys_to_dma(hwdev, *dma_handle);
SetPageXenRemapped(virt_to_page(ret));
}
memset(ret, 0, size);
@@ -334,7 +344,7 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t
size, void *vaddr,
/* do not use
