From 37f6b42e9c2966b08c7df5cfddc0d73c39cead4a Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Mon, 2 Oct 2017 18:28:44 +0100 Subject: [PATCH] ACPI/IORT: Fix PCI ACS enablement 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 workarounds") Reviewed-by: Robin Murphy Tested-by: Nate Watterson Signed-off-by: Lorenzo Pieralisi Cc: Will Deacon Cc: Hanjun Guo Cc: Sudeep Holla Cc: Zhou Wang Cc: Alex Williamson Signed-off-by: Catalin Marinas --- 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 9565d572f8dd..de56394dd161 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -1178,12 +1178,44 @@ dev_put: 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)) { + 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)) { -- 2.20.1