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@xxxxxxxxxxxx>
Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
---
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
--
1.9.1
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