diff mbox series

[08/10] swiotlb-xen: introduce phys_to_dma/dma_to_phys translations

Message ID 20200520234520.22563-8-sstabellini@kernel.org (mailing list archive)
State Superseded
Headers show
Series fix swiotlb-xen for RPi4 | expand

Commit Message

Stefano Stabellini May 20, 2020, 11:45 p.m. UTC 
From: Stefano Stabellini <stefano.stabellini@xilinx.com>

Call dma_to_phys in is_xen_swiotlb_buffer.
Call phys_to_dma in xen_phys_to_bus.
Call dma_to_phys in xen_bus_to_phys.

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 <stefano.stabellini@xilinx.com>
---
 drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

Comments

Julien Grall May 21, 2020, 8:07 a.m. UTC | #1 
Hi,

On 21/05/2020 00:45, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
> 
> Call dma_to_phys in is_xen_swiotlb_buffer.
> Call phys_to_dma in xen_phys_to_bus.
> Call dma_to_phys in xen_bus_to_phys.
> 
> 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.

The commit message explains what the code is doing but doesn't explain 
why this is needed.

> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
> ---
>   drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
>   1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index c50448fd9b75..d011c4c7aa72 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -64,14 +64,16 @@ static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
>   
>   	dma |= paddr & ~XEN_PAGE_MASK;
>   
> -	return dma;
> +	return phys_to_dma(dev, dma);
>   }
>   
> -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,
> +					  dma_addr_t dma_addr)
>   {
> +	phys_addr_t baddr = dma_to_phys(dev, dma_addr);
>   	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;
> +	phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
> +			    (baddr & ~XEN_PAGE_MASK);
>   
>   	paddr |= baddr & ~XEN_PAGE_MASK;
>   
> @@ -99,7 +101,7 @@ 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 = XEN_PFN_PHYS(xen_pfn);
>   
> @@ -304,11 +306,11 @@ 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;
> +	phys = dma_to_phys(hwdev, *dma_handle);
>   	dev_addr = xen_phys_to_bus(hwdev, phys);
>   	if (((dev_addr + size - 1 <= dma_mask)) &&
>   	    !range_straddles_page_boundary(phys, size))
> @@ -319,6 +321,7 @@ 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);
> @@ -351,7 +354,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
>   	    TestClearPageXenRemapped(pg))
>   		xen_destroy_contiguous_region(phys, order);
>   
> -	xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
> +	xen_free_coherent_pages(hwdev, size, vaddr, phys_to_dma(hwdev, phys),
> +				attrs);
>   }
>   
>   /*
> 

Cheers,
Boris Ostrovsky May 21, 2020, 10:59 p.m. UTC | #2 
On 5/20/20 7:45 PM, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
>
> Call dma_to_phys in is_xen_swiotlb_buffer.
> Call phys_to_dma in xen_phys_to_bus.
> Call dma_to_phys in xen_bus_to_phys.
>
> 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 <stefano.stabellini@xilinx.com>
> ---
>  drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index c50448fd9b75..d011c4c7aa72 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -64,14 +64,16 @@ static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
>  
>  	dma |= paddr & ~XEN_PAGE_MASK;
>  
> -	return dma;
> +	return phys_to_dma(dev, dma);
>  }
>  
> -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,
> +					  dma_addr_t dma_addr)


Since now dma address != bus address this is no longer
xen_bus_to_phys(). (And I guess the same is rue for xen_phys_to_bus()).


>  {
> +	phys_addr_t baddr = dma_to_phys(dev, dma_addr);
>  	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;
> +	phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
> +			    (baddr & ~XEN_PAGE_MASK);
>  
>  	paddr |= baddr & ~XEN_PAGE_MASK;


This line needs to go, no?


-boris
Stefano Stabellini May 22, 2020, 5:34 p.m. UTC | #3 
On Thu, 21 May 2020, Boris Ostrovsky wrote:
> On 5/20/20 7:45 PM, Stefano Stabellini wrote:
> > From: Stefano Stabellini <stefano.stabellini@xilinx.com>
> >
> > Call dma_to_phys in is_xen_swiotlb_buffer.
> > Call phys_to_dma in xen_phys_to_bus.
> > Call dma_to_phys in xen_bus_to_phys.
> >
> > 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 <stefano.stabellini@xilinx.com>
> > ---
> >  drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
> >  1 file changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> > index c50448fd9b75..d011c4c7aa72 100644
> > --- a/drivers/xen/swiotlb-xen.c
> > +++ b/drivers/xen/swiotlb-xen.c
> > @@ -64,14 +64,16 @@ static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
> >  
> >  	dma |= paddr & ~XEN_PAGE_MASK;
> >  
> > -	return dma;
> > +	return phys_to_dma(dev, dma);
> >  }
> >  
> > -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,
> > +					  dma_addr_t dma_addr)
> 
> 
> Since now dma address != bus address this is no longer
> xen_bus_to_phys(). (And I guess the same is rue for xen_phys_to_bus()).

Should I rename them to xen_dma_to_phys and xen_phys_to_dma?

 
> >  {
> > +	phys_addr_t baddr = dma_to_phys(dev, dma_addr);
> >  	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;
> > +	phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
> > +			    (baddr & ~XEN_PAGE_MASK);
> >  
> >  	paddr |= baddr & ~XEN_PAGE_MASK;
> 
> 
> This line needs to go, no?

Yes, good point
Boris Ostrovsky May 22, 2020, 6:29 p.m. UTC | #4 
On 5/22/20 1:34 PM, Stefano Stabellini wrote:
> On Thu, 21 May 2020, Boris Ostrovsky wrote:
>> On 5/20/20 7:45 PM, Stefano Stabellini wrote:
>>> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
>>>
>>> Call dma_to_phys in is_xen_swiotlb_buffer.
>>> Call phys_to_dma in xen_phys_to_bus.
>>> Call dma_to_phys in xen_bus_to_phys.
>>>
>>> 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 <stefano.stabellini@xilinx.com>
>>> ---
>>>  drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
>>>  1 file changed, 12 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
>>> index c50448fd9b75..d011c4c7aa72 100644
>>> --- a/drivers/xen/swiotlb-xen.c
>>> +++ b/drivers/xen/swiotlb-xen.c
>>> @@ -64,14 +64,16 @@ static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
>>>  
>>>  	dma |= paddr & ~XEN_PAGE_MASK;
>>>  
>>> -	return dma;
>>> +	return phys_to_dma(dev, dma);
>>>  }
>>>  
>>> -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,
>>> +					  dma_addr_t dma_addr)
>>
>> Since now dma address != bus address this is no longer
>> xen_bus_to_phys(). (And I guess the same is rue for xen_phys_to_bus()).
> Should I rename them to xen_dma_to_phys and xen_phys_to_dma?


Yes, please.


-boris
diff mbox series

Patch

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index c50448fd9b75..d011c4c7aa72 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -64,14 +64,16 @@  static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
 
 	dma |= paddr & ~XEN_PAGE_MASK;
 
-	return dma;
+	return phys_to_dma(dev, dma);
 }
 
-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,
+					  dma_addr_t dma_addr)
 {
+	phys_addr_t baddr = dma_to_phys(dev, dma_addr);
 	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;
+	phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
+			    (baddr & ~XEN_PAGE_MASK);
 
 	paddr |= baddr & ~XEN_PAGE_MASK;
 
@@ -99,7 +101,7 @@  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 = XEN_PFN_PHYS(xen_pfn);
 
@@ -304,11 +306,11 @@  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;
+	phys = dma_to_phys(hwdev, *dma_handle);
 	dev_addr = xen_phys_to_bus(hwdev, phys);
 	if (((dev_addr + size - 1 <= dma_mask)) &&
 	    !range_straddles_page_boundary(phys, size))
@@ -319,6 +321,7 @@  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);
@@ -351,7 +354,8 @@  xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
 	    TestClearPageXenRemapped(pg))
 		xen_destroy_contiguous_region(phys, order);
 
-	xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
+	xen_free_coherent_pages(hwdev, size, vaddr, phys_to_dma(hwdev, phys),
+				attrs);
 }
 
 /*