On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote:
> Hi Sricharan,
>
> On 4/10/2017 7:21 AM, Sricharan R wrote:
> >This is an equivalent to the DT's handling of the iommu master's probe
> >with deferred probing when the corrsponding iommu is not probed yet.
> >The lack of a registered IOMMU can be caused by the lack of a driver for
> >the IOMMU, the IOMMU device probe not having been performed yet, having
> >been deferred, or having failed.
> >
> >The first case occurs when the firmware describes the bus master and
> >IOMMU topology correctly but no device driver exists for the IOMMU yet
> >or the device driver has not been compiled in. Return NULL, the caller
> >will configure the device without an IOMMU.
> >
> >The second and third cases are handled by deferring the probe of the bus
> >master device which will eventually get reprobed after the IOMMU.
> >
> >The last case is currently handled by deferring the probe of the bus
> >master device as well. A mechanism to either configure the bus master
> >device without an IOMMU or to fail the bus master device probe depending
> >on whether the IOMMU is optional or mandatory would be a good
> >enhancement.
> >
> >Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> >Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
> >[Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure
> > called multiple times for same device]
> >Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> >Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> >---
> > drivers/acpi/arm64/iort.c | 33 ++++++++++++++++++++++++++++++++-
> > drivers/acpi/scan.c | 11 ++++++++---
> > drivers/base/dma-mapping.c | 2 +-
> > include/acpi/acpi_bus.h | 2 +-
> > include/linux/acpi.h | 7 +++++--
> > 5 files changed, 47 insertions(+), 8 deletions(-)
> >
> >diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> >index 3dd9ec3..e323ece 100644
> >--- a/drivers/acpi/arm64/iort.c
> >+++ b/drivers/acpi/arm64/iort.c
> >@@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
> > const struct iommu_ops *ops = NULL;
> > int ret = -ENODEV;
> > struct fwnode_handle *iort_fwnode;
> >+ struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> >+
> >+ /*
> >+ * If we already translated the fwspec there
> >+ * is nothing left to do, return the iommu_ops.
> >+ */
> >+ if (fwspec && fwspec->ops)
> >+ return fwspec->ops;
>
> Is this logic strictly required? It breaks masters with multiple SIDs
> as only the first SID is actually added to the master's fwspec.
My bad, that's indeed a silly bug I introduced. Please let me know if the
patch below fixes it, we will send it upstream shortly.
Lorenzo
-- >8 --
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index c5fecf9..e326f2a 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -666,14 +666,6 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
int ret = -ENODEV;
struct fwnode_handle *iort_fwnode;
- /*
- * If we already translated the fwspec there
- * is nothing left to do, return the iommu_ops.
- */
- ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
- if (ops)
- return ops;
-
if (node) {
iort_fwnode = iort_get_fwnode(node);
if (!iort_fwnode)
@@ -735,6 +727,14 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
u32 streamid = 0;
int err;
+ /*
+ * If we already translated the fwspec there
+ * is nothing left to do, return the iommu_ops.
+ */
+ ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
+ if (ops)
+ return ops;
+
if (dev_is_pci(dev)) {
struct pci_bus *bus = to_pci_dev(dev)->bus;
u32 rid;
