ARM64: PCI: Support ACPI-based PCI host controller

Implement pci_acpi_scan_root() and other arch-specific calls so ARM64 can
use ACPI to setup and enumerate PCI buses.

Use memory-mapped configuration space information from either the ACPI
_CBA method or the MCFG table and the ECAM library and generic ECAM config
accessor ops.

Implement acpi_pci_bus_find_domain_nr() to retrieve the domain number from
the acpi_pci_root structure.

Implement pcibios_add_bus() and pcibios_remove_bus() to call
acpi_pci_add_bus() and acpi_pci_remove_bus() for ACPI slot management and
other configuration.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5a0a691..4806cde 100644 (file)
--- 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 (file)
--- 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