Re: [PATCH 1/7] iommu: Add DMA mapping operations

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> From: Simon Glass <sjg@chromium.org>
> Date: Wed, 18 Jan 2023 12:42:19 -0700
> 
> Hi Mark,
> 
> On Tue, 17 Jan 2023 at 15:04, Mark Kettenis <kettenis@openbsd.org> wrote:
> >
> > In order to support IOMMUs in non-bypass mode we need device ops
> > to map and unmap DMA memory.  The map operation enters a mapping
> > for a region specified by CPU address and size into the translation
> > table of the IOMMU and returns a DMA address suitable for
> > programming the device to do DMA.  The unmap operation removes
> > this mapping from the translation table of the IOMMU.
> >
> > Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
> > ---
> >  drivers/iommu/iommu-uclass.c | 28 ++++++++++++++++++++++++++++
> >  include/dm/device.h          |  3 +++
> >  include/iommu.h              | 24 ++++++++++++++++++++++++
> >  3 files changed, 55 insertions(+)
> >
> > diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
> > index ed917b3c3e..f6b1457736 100644
> > --- a/drivers/iommu/iommu-uclass.c
> > +++ b/drivers/iommu/iommu-uclass.c
> > @@ -7,6 +7,9 @@
> >
> >  #include <common.h>
> >  #include <dm.h>
> > +#include <iommu.h>
> > +#include <phys2bus.h>
> > +#include <asm/io.h>
> >
> >  #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
> >  int dev_iommu_enable(struct udevice *dev)
> > @@ -33,12 +36,37 @@ int dev_iommu_enable(struct udevice *dev)
> >                               __func__, ret);
> >                         return ret;
> >                 }
> > +               dev->iommu = dev_iommu;
> >         }
> >
> >         return 0;
> >  }
> >  #endif
> >
> > +dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size)
> > +{
> > +       const struct iommu_ops *ops;
> > +
> > +       if (dev->iommu) {
> > +               ops = device_get_ops(dev->iommu);
> > +               if (ops && ops->map)
> > +                       return ops->map(dev->iommu, addr, size);
> > +       }
> > +
> > +       return dev_phys_to_bus(dev, virt_to_phys(addr));
> > +}
> > +
> > +void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size)
> > +{
> > +       const struct iommu_ops *ops;
> > +
> > +       if (dev->iommu) {
> > +               ops = device_get_ops(dev->iommu);
> > +               if (ops && ops->unmap)
> > +                       ops->unmap(dev->iommu, addr, size);
> > +       }
> > +}
> > +
> >  UCLASS_DRIVER(iommu) = {
> >         .id             = UCLASS_IOMMU,
> >         .name           = "iommu",
> > diff --git a/include/dm/device.h b/include/dm/device.h
> > index f3f953c9af..abe1927ecd 100644
> > --- a/include/dm/device.h
> > +++ b/include/dm/device.h
> > @@ -194,6 +194,9 @@ struct udevice {
> >  #if CONFIG_IS_ENABLED(DM_DMA)
> >         ulong dma_offset;
> >  #endif
> > +#if CONFIG_IS_ENABLED(IOMMU)
> > +       struct udevice *iommu;
> > +#endif
> >  };
> >
> >  static inline int dm_udevice_size(void)
> > diff --git a/include/iommu.h b/include/iommu.h
> > index 6c46adf449..cf9719c5e9 100644
> > --- a/include/iommu.h
> > +++ b/include/iommu.h
> > @@ -3,6 +3,27 @@
> >
> >  struct udevice;
> >
> > +struct iommu_ops {
> > +       /**
> > +        * map() - map DMA memory
> > +        *
> > +        * @dev:        device for which to map DMA memory
> > +        * @addr:       CPU address of the memory
> > +        * @size:       size of the memory
> > +        * @return DMA address for the device
> > +        */
> > +       dma_addr_t (*map)(struct udevice *dev, void *addr, size_t size);
> > +
> > +       /**
> > +        * unmap() - unmap DMA memory
> > +        *
> > +        * @dev:        device for which to unmap DMA memory
> > +        * @addr:       DMA address of the memory
> > +        * @size:       size of the memory
> > +        */
> > +       void (*unmap)(struct udevice *dev, dma_addr_t addr, size_t size);
> > +};
> > +
> >  #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
> >         CONFIG_IS_ENABLED(IOMMU)
> >  int dev_iommu_enable(struct udevice *dev);
> > @@ -13,4 +34,7 @@ static inline int dev_iommu_enable(struct udevice *dev)
> >  }
> >  #endif
> >
> > +dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size);
> > +void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size);
> > +
> >  #endif
> 
> Please add some tests for these operations to test/dm/iommc.c

Sure; just sent v2 with some tests added.