[+Nate]
Zhou, Nate,
On Mon, Oct 02, 2017 at 06:28:44PM +0100, 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(+)
I have reworked the enablement logic wrt v1, dou you mind testing it
please, I would like to get it merged since I have 4.15 patches depending
on it.
Thanks,
Lorenzo
> 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)) {
> + 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)) {
>
> --
> 2.4.12
>
