Implement pci_acpi_scan_root and other arch-specific call so that ARM64 can start using ACPI to setup and enumerate PCI buses.
Prior to buses enumeration the pci_acpi_scan_root() implementation looks for configuration space start address (obtained through ACPI _CBA method or MCFG interface). If succeed, it uses ECAM library to create new mapping. Then it attaches generic ECAM ops (pci_generic_ecam_ops) which are used for accessing configuration space later on.
On ARM64, we need to use generic domains (CONFIG_PCI_DOMAINS_GENERIC). In order to achieve that for ACPI case implement acpi_pci_bus_find_domain_nr() body so that it retrieves pci_config_window structure from bus sysdata and eventually gets domain number from acpi_pci_root structure.
ACPI requires to run acpi_pci_{add|remove}_bus while new PCI bus is created. This allows to do some ACPI-specific additional configuration, like PCI hotplug slot enumeration. In order to fulfill these requirements, we implement arch-specific pcibios_{add|remove}_bus calls and call acpi_pci_{add|remove}_bus from there.
Signed-off-by: Tomasz Nowicki tn@semihalf.com Signed-off-by: Jayachandran C jchandra@broadcom.com Reviewed-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com --- arch/arm64/Kconfig | 2 + arch/arm64/kernel/pci.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 115 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5a0a691..4806cde 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -3,6 +3,7 @@ config ARM64 select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI select ACPI_REDUCED_HARDWARE_ONLY if ACPI + select ACPI_MCFG if ACPI select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_ELF_RANDOMIZE @@ -96,6 +97,7 @@ config ARM64 select OF_EARLY_FLATTREE select OF_NUMA if NUMA && OF select OF_RESERVED_MEM + select PCI_ECAM if ACPI select PERF_USE_VMALLOC select POWER_RESET select POWER_SUPPLY diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 328f857..94cd43c 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -18,6 +18,8 @@ #include <linux/of_pci.h> #include <linux/of_platform.h> #include <linux/pci.h> +#include <linux/pci-acpi.h> +#include <linux/pci-ecam.h> #include <linux/slab.h>
/* @@ -100,15 +102,123 @@ EXPORT_SYMBOL(pcibus_to_node);
#ifdef CONFIG_ACPI
+struct acpi_pci_generic_root_info { + struct acpi_pci_root_info common; + struct pci_config_window *cfg; /* config space mapping */ +}; + int acpi_pci_bus_find_domain_nr(struct pci_bus *bus) { + struct pci_config_window *cfg = bus->sysdata; + struct acpi_device *adev = to_acpi_device(cfg->parent); + struct acpi_pci_root *root = acpi_driver_data(adev); + + return root->segment; +} + +int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) +{ + if (!acpi_disabled) { + struct pci_config_window *cfg = bridge->bus->sysdata; + struct acpi_device *adev = to_acpi_device(cfg->parent); + ACPI_COMPANION_SET(&bridge->dev, adev); + } + return 0; }
-/* Root bridge scanning */ +/* + * Lookup the bus range for the domain in MCFG, and set up config space + * mapping. + */ +static struct pci_config_window * +pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root) +{ + struct resource *bus_res = &root->secondary; + u16 seg = root->segment; + struct pci_config_window *cfg; + struct resource cfgres; + unsigned int bsz; + + /* Use address from _CBA if present, otherwise lookup MCFG */ + if (!root->mcfg_addr) + root->mcfg_addr = pci_mcfg_lookup(seg, bus_res); + + if (!root->mcfg_addr) { + dev_err(&root->device->dev, "%04x:%pR ECAM region not found\n", + seg, bus_res); + return NULL; + } + + bsz = 1 << pci_generic_ecam_ops.bus_shift; + cfgres.start = root->mcfg_addr + bus_res->start * bsz; + cfgres.end = cfgres.start + resource_size(bus_res) * bsz - 1; + cfgres.flags = IORESOURCE_MEM; + cfg = pci_ecam_create(&root->device->dev, &cfgres, bus_res, + &pci_generic_ecam_ops); + if (IS_ERR(cfg)) { + dev_err(&root->device->dev, "%04x:%pR error %ld mapping ECAM\n", + seg, bus_res, PTR_ERR(cfg)); + return NULL; + } + + return cfg; +} + +/* release_info: free resources allocated by init_info */ +static void pci_acpi_generic_release_info(struct acpi_pci_root_info *ci) +{ + struct acpi_pci_generic_root_info *ri; + + ri = container_of(ci, struct acpi_pci_generic_root_info, common); + pci_ecam_free(ri->cfg); + kfree(ri); +} + +static struct acpi_pci_root_ops acpi_pci_root_ops = { + .release_info = pci_acpi_generic_release_info, +}; + +/* Interface called from ACPI code to setup PCI host controller */ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) { - /* TODO: Should be revisited when implementing PCI on ACPI */ - return NULL; + int node = acpi_get_node(root->device->handle); + struct acpi_pci_generic_root_info *ri; + struct pci_bus *bus, *child; + + ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node); + if (!ri) + return NULL; + + ri->cfg = pci_acpi_setup_ecam_mapping(root); + if (!ri->cfg) { + kfree(ri); + return NULL; + } + + acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops; + bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &ri->common, + ri->cfg); + if (!bus) + return NULL; + + pci_bus_size_bridges(bus); + pci_bus_assign_resources(bus); + + list_for_each_entry(child, &bus->children, node) + pcie_bus_configure_settings(child); + + return bus; +} + +void pcibios_add_bus(struct pci_bus *bus) +{ + acpi_pci_add_bus(bus); } + +void pcibios_remove_bus(struct pci_bus *bus) +{ + acpi_pci_remove_bus(bus); +} + #endif