Re: [PATCH 17/20] powerpc/dma-swiotlb: use generic swiotlb_dma_ops

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Thu, 2018-08-09 at 10:54 +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-07-30 at 18:38 +0200, Christoph Hellwig wrote:
> > These are identical to the arch specific ones, so remove them.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Note: We will still need to implement some custom variant of this
for our secure VMs ... 

Basically we'll need to use the existing bounce bufferring as-is but
the condition will be different, it won't be whether the address is
below a certain limit, it will be *always*.

Cheers,
Ben.

> > ---
> >  arch/powerpc/include/asm/dma-direct.h |  4 ++++
> >  arch/powerpc/include/asm/swiotlb.h    |  2 --
> >  arch/powerpc/kernel/dma-swiotlb.c     | 28 ++-------------------------
> >  arch/powerpc/sysdev/fsl_pci.c         |  2 +-
> >  4 files changed, 7 insertions(+), 29 deletions(-)
> > 
> > diff --git a/arch/powerpc/include/asm/dma-direct.h b/arch/powerpc/include/asm/dma-direct.h
> > index 0fba19445ae8..657f84ddb20d 100644
> > --- a/arch/powerpc/include/asm/dma-direct.h
> > +++ b/arch/powerpc/include/asm/dma-direct.h
> > @@ -30,4 +30,8 @@ static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
> >  		return daddr - PCI_DRAM_OFFSET;
> >  	return daddr - dev->archdata.dma_offset;
> >  }
> > +
> > +u64 swiotlb_powerpc_get_required(struct device *dev);
> > +#define swiotlb_get_required_mask swiotlb_powerpc_get_required
> > +
> >  #endif /* ASM_POWERPC_DMA_DIRECT_H */
> > diff --git a/arch/powerpc/include/asm/swiotlb.h b/arch/powerpc/include/asm/swiotlb.h
> > index f65ecf57b66c..1d8c1da26ab3 100644
> > --- a/arch/powerpc/include/asm/swiotlb.h
> > +++ b/arch/powerpc/include/asm/swiotlb.h
> > @@ -13,8 +13,6 @@
> >  
> >  #include <linux/swiotlb.h>
> >  
> > -extern const struct dma_map_ops powerpc_swiotlb_dma_ops;
> > -
> >  extern unsigned int ppc_swiotlb_enable;
> >  int __init swiotlb_setup_bus_notifier(void);
> >  
> > diff --git a/arch/powerpc/kernel/dma-swiotlb.c b/arch/powerpc/kernel/dma-swiotlb.c
> > index 25986fcd1e5e..0c269de61f39 100644
> > --- a/arch/powerpc/kernel/dma-swiotlb.c
> > +++ b/arch/powerpc/kernel/dma-swiotlb.c
> > @@ -24,7 +24,7 @@
> >  
> >  unsigned int ppc_swiotlb_enable;
> >  
> > -static u64 swiotlb_powerpc_get_required(struct device *dev)
> > +u64 swiotlb_powerpc_get_required(struct device *dev)
> >  {
> >  	u64 end, mask, max_direct_dma_addr = dev->archdata.max_direct_dma_addr;
> >  
> > @@ -38,30 +38,6 @@ static u64 swiotlb_powerpc_get_required(struct device *dev)
> >  	return mask;
> >  }
> >  
> > -/*
> > - * At the moment, all platforms that use this code only require
> > - * swiotlb to be used if we're operating on HIGHMEM.  Since
> > - * we don't ever call anything other than map_sg, unmap_sg,
> > - * map_page, and unmap_page on highmem, use normal dma_ops
> > - * for everything else.
> > - */
> > -const struct dma_map_ops powerpc_swiotlb_dma_ops = {
> > -	.alloc = dma_direct_alloc,
> > -	.free = dma_direct_free,
> > -	.mmap = dma_nommu_mmap_coherent,
> > -	.map_sg = swiotlb_map_sg_attrs,
> > -	.unmap_sg = swiotlb_unmap_sg_attrs,
> > -	.dma_supported = swiotlb_dma_supported,
> > -	.map_page = swiotlb_map_page,
> > -	.unmap_page = swiotlb_unmap_page,
> > -	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
> > -	.sync_single_for_device = swiotlb_sync_single_for_device,
> > -	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
> > -	.sync_sg_for_device = swiotlb_sync_sg_for_device,
> > -	.mapping_error = swiotlb_dma_mapping_error,
> > -	.get_required_mask = swiotlb_powerpc_get_required,
> > -};
> > -
> >  void pci_dma_dev_setup_swiotlb(struct pci_dev *pdev)
> >  {
> >  	struct pci_controller *hose;
> > @@ -88,7 +64,7 @@ static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
> >  
> >  	/* May need to bounce if the device can't address all of DRAM */
> >  	if ((dma_get_mask(dev) + 1) < memblock_end_of_DRAM())
> > -		set_dma_ops(dev, &powerpc_swiotlb_dma_ops);
> > +		set_dma_ops(dev, &swiotlb_dma_ops);
> >  
> >  	return NOTIFY_DONE;
> >  }
> > diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
> > index 918be816b097..daf44bc0108d 100644
> > --- a/arch/powerpc/sysdev/fsl_pci.c
> > +++ b/arch/powerpc/sysdev/fsl_pci.c
> > @@ -118,7 +118,7 @@ static void setup_swiotlb_ops(struct pci_controller *hose)
> >  {
> >  	if (ppc_swiotlb_enable) {
> >  		hose->controller_ops.dma_dev_setup = pci_dma_dev_setup_swiotlb;
> > -		set_pci_dma_ops(&powerpc_swiotlb_dma_ops);
> > +		set_pci_dma_ops(&swiotlb_dma_ops);
> >  	}
> >  }
> >  #else