Re: [PATCH v4] iommu/of: Fix pci_request_acs() before enumerating PCI devices

[Xingang Wang]

Hi everyone,

On 2021/5/22 3:03, Rob Herring wrote:
> On Thu, May 20, 2021 at 10:03 PM Wang Xingang <wangxingang5@xxxxxxxxxx> wrote:
> > From: Xingang Wang <wangxingang5@xxxxxxxxxx>
> >
> > When booting with devicetree, the pci_request_acs() is called after the
> > enumeration and initialization of PCI devices, thus the ACS is not
> > enabled. And ACS should be enabled when IOMMU is detected for the
> > PCI host bridge, so add check for IOMMU before probe of PCI host and call
> > pci_request_acs() to make sure ACS will be enabled when enumerating PCI
> > devices.
> >
> > Fixes: 6bf6c24720d33 ("iommu/of: Request ACS from the PCI core when
> > configuring IOMMU linkage")
> > Signed-off-by: Xingang Wang <wangxingang5@xxxxxxxxxx>
> > ---
> >   drivers/iommu/of_iommu.c | 1 -
> >   drivers/pci/of.c         | 8 +++++++-
> >   2 files changed, 7 insertions(+), 2 deletions(-)
>
> Reviewed-by: Rob Herring <robh@xxxxxxxxxx>

Ping, is this patch appropriate for mainline?

> > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> > index a9d2df001149..54a14da242cc 100644
> > --- a/drivers/iommu/of_iommu.c
> > +++ b/drivers/iommu/of_iommu.c
> > @@ -205,7 +205,6 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
> >                          .np = master_np,
> >                  };
> >
> > -               pci_request_acs();
> >                  err = pci_for_each_dma_alias(to_pci_dev(dev),
> >                                               of_pci_iommu_init, &info);
> >          } else {
> > diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> > index da5b414d585a..2313c3f848b0 100644
> > --- a/drivers/pci/of.c
> > +++ b/drivers/pci/of.c
> > @@ -581,9 +581,15 @@ static int pci_parse_request_of_pci_ranges(struct device *dev,
> >
> >   int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
> >   {
> > -       if (!dev->of_node)
> > +       struct device_node *node = dev->of_node;
> > +
> > +       if (!node)
> >                  return 0;
> >
> > +       /* Detect IOMMU and make sure ACS will be enabled */
> > +       if (of_property_read_bool(node, "iommu-map"))
> > +               pci_request_acs();
> > +
> >          bridge->swizzle_irq = pci_common_swizzle;
> >          bridge->map_irq = of_irq_parse_and_map_pci;
> >
> > --
> > 2.19.1
> .