Re: [RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure

[Tomasz Nowicki]

On 17.05.2016 10:07, Tomasz Nowicki wrote:
> Hi Lorenzo,
>
> On 14.04.2016 19:25, Lorenzo Pieralisi wrote:
> > On DT based systems, the of_dma_configure() API implements DMA
> > configuration
> > for a given device. On ACPI systems an API equivalent to
> > of_dma_configure()
> > is missing which implies that it is currently not possible to set-up DMA
> > operations for devices through the ACPI generic kernel layer.
> >
> > This patch fills the gap by introducing acpi_dma_configure/deconfigure()
> > calls, that carry out IOMMU configuration through IORT (on systems where
> > it is present) and call arch_setup_dma_ops(...) with the retrieved
> > parameters.
> >
> > The DMA range size passed to arch_setup_dma_ops() is sized according
> > to the device coherent_dma_mask (starting at address 0x0), mirroring the
> > DT probing path behaviour when a dma-ranges property is not provided
> > for the device being probed; this changes the current
> > arch_setup_dma_ops()
> > call parameters in the ACPI probing case, but since arch_setup_dma_ops()
> > is a NOP on all architectures but ARM/ARM64 this patch does not change
> > the current kernel behaviour on them.
> >
> > This patch updates ACPI and PCI core code to use the newly introduced
> > acpi_dma_configure function, providing the same functionality
> > as of_dma_configure on ARM systems and leaving behaviour unchanged
> > for all other arches.
> >
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Cc: Robin Murphy <robin.murphy@xxxxxxx>
> > Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> > Cc: Joerg Roedel <joro@xxxxxxxxxx>
> > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> > ---
> >   drivers/acpi/glue.c     |  4 +--
> >   drivers/acpi/iort.c     | 85
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> >   drivers/acpi/scan.c     | 29 +++++++++++++++++
> >   drivers/pci/probe.c     |  3 +-
> >   include/acpi/acpi_bus.h |  2 ++
> >   include/linux/acpi.h    |  5 +++
> >   include/linux/iort.h    |  9 ++++++
> >   7 files changed, 133 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> > index 5ea5dc2..f8d6564 100644
> > --- a/drivers/acpi/glue.c
> > +++ b/drivers/acpi/glue.c
> > @@ -227,8 +227,7 @@ int acpi_bind_one(struct device *dev, struct
> > acpi_device *acpi_dev)
> >
> >       attr = acpi_get_dma_attr(acpi_dev);
> >       if (attr != DEV_DMA_NOT_SUPPORTED)
> > -        arch_setup_dma_ops(dev, 0, 0, NULL,
> > -                   attr == DEV_DMA_COHERENT);
> > +        acpi_dma_configure(dev, attr);
> >
> >       acpi_physnode_link_name(physical_node_name, node_id);
> >       retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
> > @@ -251,6 +250,7 @@ int acpi_bind_one(struct device *dev, struct
> > acpi_device *acpi_dev)
> >       return 0;
> >
> >    err:
> > +    acpi_dma_deconfigure(dev);
> >       ACPI_COMPANION_SET(dev, NULL);
> >       put_device(dev);
> >       put_device(&acpi_dev->dev);
> > diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
> > index 2b5ce65..b1bb8fb 100644
> > --- a/drivers/acpi/iort.c
> > +++ b/drivers/acpi/iort.c
> > @@ -72,6 +72,31 @@ int iort_iommu_set_node(struct iommu_ops *ops,
> > struct acpi_iort_node *node,
> >       return 0;
> >   }
> >
> > +/**
> > + * iort_iommu_get_node - Retrieve iort_iommu_node associated with an
> > IORT node.
> > + *
> > + * @node: IORT table node to be looked-up
> > + *
> > + * Returns: iort_iommu_node pointer on success
> > + *          NULL on failure
> > + */
> > +static struct iort_iommu_node *iort_iommu_get_node(struct
> > acpi_iort_node *node)
> > +{
> > +    struct iort_iommu_node *iommu_node;
> > +
> > +    spin_lock(&iort_iommu_lock);
> > +    list_for_each_entry(iommu_node, &iort_iommu_list, list) {
> > +        if (iommu_node->node == node)
> > +            goto found;
> > +    }
> > +
> > +    iommu_node = NULL;
> > +found:
> > +    spin_unlock(&iort_iommu_lock);
> > +
> > +    return iommu_node;
> > +}
> > +
> >   typedef acpi_status (*iort_find_node_callback)
> >       (struct acpi_iort_node *node, void *context);
> >
> > @@ -405,6 +430,66 @@ iort_pci_get_domain(struct pci_dev *pdev, u32
> > req_id)
> >       return domain_handle;
> >   }
> >
> > +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
> > +{
> > +    u32 *rid = data;
> > +
> > +    *rid = alias;
> > +    return 0;
> > +}
> > +
> > +/**
> > + * iort_iommu_configure - Set-up IOMMU configuration for a device.
> > + *
> > + * @dev: device that requires IOMMU set-up
> > + *
> > + * Returns: iommu_ops pointer on configuration success
> > + *          NULL on configuration failure
> > + */
> > +struct iommu_ops *iort_iommu_configure(struct device *dev)
> > +{
> > +    struct acpi_iort_node *node, *parent;
> > +    struct iommu_ops *ops = NULL;
> > +    struct iommu_fwspec fwspec;
> > +    struct iort_iommu_node *iommu_node;
> > +    u32 rid = 0, devid = 0;
> > +
> > +    if (dev_is_pci(dev)) {
> > +        struct pci_bus *bus = to_pci_dev(dev)->bus;
> > +
> > +        pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid,
> > +                       &rid);
> > +
> > +        node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
> > +                      iort_find_dev_callback, &bus->dev);
> > +    } else
> > +        node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
> > +                      iort_find_dev_callback, dev);
>
> I think this will not work for finding host bridge stream ID. We still
> need to use ACPI_IORT_NODE_PCI_ROOT_COMPLEX but 'dev' is not PCI device,
> right?

After private conversation, I think this part is OK.

Thanks,
Tomasz