From: Alexander Duyck
> Sent: 05 December 2016 21:55
...
> > @@ -1010,6 +1018,11 @@ int i40e_setup_tx_descriptors(struct i40e_ring
> > *tx_ring)
> > */
> > tx_ring->size += sizeof(u32);
> > tx_ring->size = ALIGN(tx_ring->size, 4096);
> > +#ifdef CONFIG_SPARC
> > + tx_ring->dma_attrs = DMA_ATTR_WEAK_ORDERING;
> > +#else
> > + tx_ring->dma_attrs = 0;
> > +#endif
> > tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
> > &tx_ring->dma, GFP_KERNEL);
> > if (!tx_ring->desc) {
>
> Also not a fan of adding yet ring attribute. Is there any reason why
> you couldn't simply add a set of inline functions at the start of
> i40e_txrx.c that could replace the DMA map/unmap operations in this
> code but pass either 0 or DMA_ATTR_WEAK_ORDERING as needed for the
> drivers? Then the x86 code doesn't have to change while the SPARC
> code will be able to be passed the attribute.
Or use something like:
#ifdef CONFIG_SPARC
#define RING_DMA_ATTR DMA_ATTR_WEAK_ORDERING
#else
#define RING_DMA_ATTR 0
#endif
and pass the constant to the function calls.
Is there actually ever a problem passing DMA_ATTR_WEAK_ORDERING?
I'd guess that it will be ignored if it can't be implemented (or isn't needed).
David
