Re: [PATCH 10/18] iommu/msm: Add IOMMU_DOMAIN_DMA support

[Robin Murphy]

On 2020-08-20 16:55, Rob Clark wrote:
> Side note, I suspect we'll end up needing something like
> 0e764a01015dfebff8a8ffd297d74663772e248a .. if someone can dig a 32b
> device out of the closet and dust it off, the fix is easy enough.
> Just wanted to mention that here so anyone with a 32b device could
> find what is needed.

FWIW there shouldn't be any material change here - the generic default 
domain is installed under the same circumstances as the Arm 
dma_iommu_mapping was, so if any platform does have an issue, then it 
should already have started 4 years with f78ebca8ff3d ("iommu/msm: Add 
support for generic master bindings").

Robin.

> BR,
> -R
>
> On Thu, Aug 20, 2020 at 8:09 AM Robin Murphy <robin.murphy@xxxxxxx> wrote:
> > Now that arch/arm is wired up for default domains and iommu-dma,
> > implement the corresponding driver-side support for DMA domains.
> >
> > Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
> > ---
> >   drivers/iommu/msm_iommu.c | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
> > index 3615cd6241c4..f34efcbb0b2b 100644
> > --- a/drivers/iommu/msm_iommu.c
> > +++ b/drivers/iommu/msm_iommu.c
> > @@ -8,6 +8,7 @@
> >   #include <linux/kernel.h>
> >   #include <linux/init.h>
> >   #include <linux/platform_device.h>
> > +#include <linux/dma-iommu.h>
> >   #include <linux/errno.h>
> >   #include <linux/io.h>
> >   #include <linux/io-pgtable.h>
> > @@ -314,13 +315,16 @@ static struct iommu_domain *msm_iommu_domain_alloc(unsigned type)
> >   {
> >          struct msm_priv *priv;
> >
> > -       if (type != IOMMU_DOMAIN_UNMANAGED)
> > +       if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
> >                  return NULL;
> >
> >          priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> >          if (!priv)
> >                  goto fail_nomem;
> >
> > +       if (type == IOMMU_DOMAIN_DMA && iommu_get_dma_cookie(&priv->domain))
> > +               goto fail_nomem;
> > +
> >          INIT_LIST_HEAD(&priv->list_attached);
> >
> >          priv->domain.geometry.aperture_start = 0;
> > @@ -339,6 +343,7 @@ static void msm_iommu_domain_free(struct iommu_domain *domain)
> >          struct msm_priv *priv;
> >          unsigned long flags;
> >
> > +       iommu_put_dma_cookie(domain);
> >          spin_lock_irqsave(&msm_iommu_lock, flags);
> >          priv = to_msm_priv(domain);
> >          kfree(priv);
> > --
> > 2.28.0.dirty
> >
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