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Commit 0cb0786b authored by Tomasz Nowicki's avatar Tomasz Nowicki Committed by Bjorn Helgaas
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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: default avatarTomasz Nowicki <tn@semihalf.com>
Signed-off-by: default avatarJayachandran C <jchandra@broadcom.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
parent f058f4fb

arch/arm64/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/kernel/pci.c

+113 −3
Original line number Diff line number Diff line
@@ -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 */

	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