Re: [PATCH] powerpc: Add sync_*_for_* to dma_ops
dma_addr_t dma_address, size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs);
+ void(*sync_single_for_cpu)(struct device *hwdev,
+ dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_for_device)(struct device *hwdev,
+ dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_range_for_cpu)(struct device *hwdev,
+ dma_addr_t dma_handle, unsigned long offset,
+ size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_range_for_device)(struct device *hwdev,
+ dma_addr_t dma_handle, unsigned long offset,
+ size_t size,
+ enum dma_data_direction direction);
Can't we implement the first 2 using the next 2 and passing a 0 offset ?
I mean, we're going to go through a function pointer, it's not like
handling the offset was going to cost us something :-)
+ void(*sync_sg_for_cpu)(struct device *hwdev,
+ struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction);
+ void(*sync_sg_for_device)(struct device *hwdev,
+ struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction);
};
/*
@@ -286,42 +306,75 @@ static inline void dma_sync_single_for_cpu(struct
device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
- BUG_ON(direction == DMA_NONE);
- __dma_sync(bus_to_virt(dma_handle), size, direction);
+ struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
+
+ BUG_ON(!dma_ops);
+ if (dma_ops-sync_single_for_cpu != NULL)
+ dma_ops-sync_single_for_cpu(dev, dma_handle, size,
+ direction);
}
.../...
The only objection that comes to mind here is that generally, you know
that your platform is going to be coherent or not at compile time, and
you don't want the above at all when it is (or won't need swiotlb).
So maybe we could have a Kconfig trickery so that
CONFIG_PPC_DMA_NEED_SYNC_OPS is set when either non coherent DMA is
select'ed or swiotlb support is select'ed by one of the enabled
platform. So if I enable only powermac, I get neither and don't get the
bloody inlines :-)
Cheers,
Ben.
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Re: [PATCH] powerpc: Add sync_*_for_* to dma_ops
On Nov 18, 2008, at 6:22 AM, Benjamin Herrenschmidt wrote:
dma_addr_t dma_address, size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs);
+ void(*sync_single_for_cpu)(struct device *hwdev,
+ dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_for_device)(struct device *hwdev,
+ dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_range_for_cpu)(struct device *hwdev,
+ dma_addr_t dma_handle, unsigned long offset,
+ size_t size,
+ enum dma_data_direction direction);
+ void(*sync_single_range_for_device)(struct device
*hwdev,
+ dma_addr_t dma_handle, unsigned long offset,
+ size_t size,
+ enum dma_data_direction direction);
Can't we implement the first 2 using the next 2 and passing a 0
offset ?
I mean, we're going to go through a function pointer, it's not like
handling the offset was going to cost us something :-)
Looking at the swiotlb code; I think that's a reasonable thing to do.
Will respin.
+ void(*sync_sg_for_cpu)(struct device *hwdev,
+ struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction);
+ void(*sync_sg_for_device)(struct device *hwdev,
+ struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction);
};
/*
@@ -286,42 +306,75 @@ static inline void
dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
- BUG_ON(direction == DMA_NONE);
- __dma_sync(bus_to_virt(dma_handle), size, direction);
+ struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
+
+ BUG_ON(!dma_ops);
+ if (dma_ops-sync_single_for_cpu != NULL)
+ dma_ops-sync_single_for_cpu(dev, dma_handle, size,
+direction);
}
.../...
The only objection that comes to mind here is that generally, you know
that your platform is going to be coherent or not at compile time, and
you don't want the above at all when it is (or won't need swiotlb).
So maybe we could have a Kconfig trickery so that
CONFIG_PPC_DMA_NEED_SYNC_OPS is set when either non coherent DMA is
select'ed or swiotlb support is select'ed by one of the enabled
platform. So if I enable only powermac, I get neither and don't get
the
bloody inlines :-)
I thought about doing something like this, but didn't know if it was
worth the ifdeffing/CONFIG foo that would ensue; I guess your response
answers that question :)
Thanks!
B
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Re: [PATCH] powerpc: Add sync_*_for_* to dma_ops
@@ -286,42 +306,75 @@ static inline void dma_sync_single_for_cpu
(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
- BUG_ON(direction == DMA_NONE);
Did you intend to remove this here? It would be nice to test for it
even on platforms where the op is a nop; if there is an equivalent
test in every implementation of the ops, remove it there instead
(that's more source + binary code to remove, always a good thing ;-) )
Segher
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Re: [PATCH] powerpc: Add sync_*_for_* to dma_ops
On Nov 18, 2008, at 10:57 AM, Segher Boessenkool wrote:
@@ -286,42 +306,75 @@ static inline void
dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
- BUG_ON(direction == DMA_NONE);
Did you intend to remove this here? It would be nice to test for it
even on platforms where the op is a nop; if there is an equivalent
test in every implementation of the ops, remove it there instead
(that's more source + binary code to remove, always a good thing ;-) )
You're right that we have lost this test in platforms which do not
implement the sync ops, and if the test is useful, I can certainly
move it. However, it will actually result in more code on the current
ppc kernel, as there are 3x more dma_sync_* instances than there are
actual dma_direct_* instances (and nobody else implements
dma_sync_* :) Not that we're talking about a lot of code here, but it
definitely won't make the kernel smaller since we just don't need a
sync unless we're noncoherent which, thank insert deity here, is rare.
With the swiotlb case, the check needs to be in the swiotlb code
because there are other architectures that use the swiotlb code that
do not use a structure to get to their dma_ops like we do. IA64, for
example, sets up its dma_ops using config options and #defines the
names of the various dma_ functions. They don't go through a dma_ops
dereference, so the (possibly redundant for us) check in the swiotlb
code would need to remain.
So, the reason for moving it would be that we think it's still a
useful check to have. I'm happy to move it in that case.
Thanks,
-Becky
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