On Tue, Oct 03, 2017 at 03:45:38PM +0100, John Garry wrote:
> On 02/10/2017 18:28, Lorenzo Pieralisi wrote:
> >commit f6810c15cf97 ("iommu/arm-smmu: Clean up early-probing
> >workarounds") removed kernel code that was allowing to initialize
> >and probe the SMMU devices early (ie earlier than PCI devices, through
> >linker script callback entries) in the boot process because it was not
> >needed any longer in that the SMMU devices/drivers now support deferred
> >probing.
> >
> >Since the SMMUs probe routines are also in charge of requesting global
> >PCI ACS kernel enablement, commit f6810c15cf97 ("iommu/arm-smmu: Clean
> >up early-probing workarounds") also postponed PCI ACS enablement to
> >SMMUs devices probe time, which is too late given that PCI devices needs
> >to detect if PCI ACS is enabled to init the respective capability
> >through the following call path:
> >
> >pci_device_add()
> > -> pci_init_capabilities()
> > -> pci_enable_acs()
> >
> >Add code in the ACPI IORT SMMU platform devices initialization path
> >(that is called before ACPI PCI enumeration) to detect if there
> >exists firmware mappings to map root complexes ids to SMMU ids
> >and if so enable ACS for the system.
> >
> >Fixes: f6810c15cf97 ("iommu/arm-smmu: Clean up early-probing
> >Signed-workarounds")
> >Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> >Cc: Will Deacon <will.deacon@xxxxxxx>
> >Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> >Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
> >Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> >Cc: Robin Murphy <robin.murphy@xxxxxxx>
> >Cc: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
> >Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> >---
> >v1 -> v2:
> >
> >- Reworked ACS enablement logic and based on root complex to SMMU
> > ids firmware mapping detection
> >- Rebased against v4.14-rc3
> >
> >v1: https://marc.info/?l=linux-acpi&m=150584059818925&w=2
> >
> > drivers/acpi/arm64/iort.c | 35 +++++++++++++++++++++++++++++++++++
> > 1 file changed, 35 insertions(+)
> >
> >diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> >index 9565d57..de56394 100644
> >--- a/drivers/acpi/arm64/iort.c
> >+++ b/drivers/acpi/arm64/iort.c
> >@@ -1178,12 +1178,44 @@ static int __init iort_add_smmu_platform_device(struct acpi_iort_node *node)
> > return ret;
> > }
> >
> >+static bool __init iort_enable_acs(struct acpi_iort_node *iort_node)
> >+{
> >+ if (iort_node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
> >+ struct acpi_iort_node *parent;
> >+ struct acpi_iort_id_mapping *map;
> >+ int i;
> >+
> >+ map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, iort_node,
> >+ iort_node->mapping_offset);
> >+
> >+ for (i = 0; i < iort_node->mapping_count; i++, map++) {
> >+ if (!map->output_reference)
> >+ continue;
> >+
> >+ parent = ACPI_ADD_PTR(struct acpi_iort_node,
> >+ iort_table, map->output_reference);
> >+ /*
> >+ * If we detect a RC->SMMU mapping, make sure
> >+ * we enable ACS on the system.
> >+ */
> >+ if ((parent->type == ACPI_IORT_NODE_SMMU) ||
> >+ (parent->type == ACPI_IORT_NODE_SMMU_V3)) {
>
> Hi Lorenzo,
>
> There are a couple of places now which check for any SMMU type.
> Should we have a helper function/macro to condense, like this:
> IORT_TYPE_MASK(type) & IORT_IOMMU_TYPE
>
> Personal taste, I guess.
I agree, I will add that macro for 4.15, I would like to merge this
as a fix now.
> BTW, unfortunately we can't re-test this week due to Chinese holiday.
Understood, I just would like to get some coverage before asking Will
and Catalin to queue it as a fix.
Cheers,
Lorenzo
> Cheers,
> John
>
> >+ pci_request_acs();
> >+ return true;
> >+ }
> >+ }
> >+ }
> >+
> >+ return false;
> >+}
> >+
> > static void __init iort_init_platform_devices(void)
> > {
> > struct acpi_iort_node *iort_node, *iort_end;
> > struct acpi_table_iort *iort;
> > struct fwnode_handle *fwnode;
> > int i, ret;
> >+ bool acs_enabled = false;
> >
> > /*
> > * iort_table and iort both point to the start of IORT table, but
> >@@ -1203,6 +1235,9 @@ static void __init iort_init_platform_devices(void)
> > return;
> > }
> >
> >+ if (!acs_enabled)
> >+ acs_enabled = iort_enable_acs(iort_node);
> >+
> > if ((iort_node->type == ACPI_IORT_NODE_SMMU) ||
> > (iort_node->type == ACPI_IORT_NODE_SMMU_V3)) {
> >
> >
>
>
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