[PATCH V3 19/21] pci, acpi: Support for ACPI based generic PCI host controller init

[Tomasz Nowicki]

Because of two patch series:
1. Jiang Liu's common interface to support PCI host controller init
2. MMCONFIG refactoring (part of this patch set)
now we can think about generic ACPI based PCI host controller init
implementation out of arch/ directory.

These calls use information from MCFG table (PCI config space regions)
and _CRS method (IO/irq resources) to initialize PCI hostbridge.

TBD: We are still not sure whether we should reassign resources
after PCI bus enumeration or trust firmware to do all that work for
us properly.

Signed-off-by: Tomasz Nowicki <tn at semihalf.com>
Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com>
CC: Arnd Bergmann <arnd at arndb.de>
CC: Catalin Marinas <catalin.marinas at arm.com>
CC: Liviu Dudau <Liviu.Dudau at arm.com>
CC: Lorenzo Pieralisi <Lorenzo.Pieralisi at arm.com>
CC: Will Deacon <will.deacon at arm.com>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com>
Tested-by: Jeremy Linton <jeremy.linton at arm.com>
---
 drivers/acpi/Kconfig    |   5 ++
 drivers/acpi/pci_root.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 136 insertions(+)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index c3664be..e315061 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -335,6 +335,11 @@ config ACPI_PCI_SLOT
 	  i.e., segment/bus/device/function tuples, with physical slots in
 	  the system.  If you are unsure, say N.
 
+config ACPI_PCI_HOST_GENERIC
+	bool "Generic ACPI PCI host controller"
+	help
+	  Say Y here if you want to support generic ACPI PCI host controller.
+
 config X86_PM_TIMER
 	bool "Power Management Timer Support" if EXPERT
 	depends on X86
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index a65c8c2..d483e2a 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/mutex.h>
+#include <linux/of_address.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/pci.h>
@@ -514,6 +515,136 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
 	}
 }
 
+#ifdef CONFIG_ACPI_PCI_HOST_GENERIC
+static int pcibios_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
+{
+	if (pci_dev_msi_enabled(dev))
+		return 0;
+
+	acpi_pci_irq_enable(dev);
+	return dev->irq;
+}
+
+static void pci_mcfg_release_info(struct acpi_pci_root_info *ci)
+{
+	pci_mmcfg_teardown_map(ci);
+	kfree(ci);
+}
+
+static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
+{
+	struct list_head *list = &ci->resources;
+	struct acpi_device *device = ci->bridge;
+	struct resource_entry *entry, *tmp;
+	unsigned long flags;
+	int ret;
+
+	flags = IORESOURCE_IO | IORESOURCE_MEM;
+	ret = acpi_dev_get_resources(device, list,
+				     acpi_dev_filter_resource_type_cb,
+				     (void *)flags);
+	if (ret < 0) {
+		dev_warn(&device->dev,
+			 "failed to parse _CRS method, error code %d\n", ret);
+		return ret;
+	} else if (ret == 0)
+		dev_dbg(&device->dev,
+			"no IO and memory resources present in _CRS\n");
+
+	resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
+		resource_size_t cpu_addr, length;
+		struct resource *res = entry->res;
+
+		if (entry->res->flags & IORESOURCE_DISABLED)
+			resource_list_destroy_entry(entry);
+		else
+			res->name = ci->name;
+
+		/* PCI -> CPU space translation */
+		cpu_addr = res->start + entry->offset;
+		length = res->end - res->start + 1;
+
+		if (res->flags & IORESOURCE_MEM) {
+			res->start = cpu_addr;
+			res->end = cpu_addr + length - 1;
+		} else if (res->flags & IORESOURCE_IO) {
+			resource_size_t pci_addr = res->start;
+			unsigned long port;
+
+			if (pci_register_io_range(cpu_addr, length)) {
+				resource_list_destroy_entry(entry);
+				continue;
+			}
+
+			port = pci_address_to_pio(cpu_addr);
+			if (port == (unsigned long)-1) {
+				resource_list_destroy_entry(entry);
+				continue;
+			}
+
+			res->start = port;
+			res->end = port + length - 1;
+			entry->offset = port - pci_addr;
+
+			if (pci_remap_iospace(res, cpu_addr) < 0)
+				resource_list_destroy_entry(entry);
+		}
+	}
+	return ret;
+}
+
+static struct acpi_pci_root_ops acpi_pci_root_ops = {
+	.init_info = pci_mmcfg_setup_map,
+	.release_info = pci_mcfg_release_info,
+	.prepare_resources = pci_acpi_root_prepare_resources,
+};
+
+/* Root bridge scanning */
+struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
+{
+	int node = acpi_get_node(root->device->handle);
+	int domain = root->segment;
+	int busnum = root->secondary.start;
+	struct acpi_pci_root_info *info;
+	struct pci_host_bridge *bridge;
+	struct pci_bus *bus, *child;
+
+	if (domain && !pci_domains_supported) {
+		pr_warn("PCI %04x:%02x: multiple domains not supported.\n",
+			domain, busnum);
+		return NULL;
+	}
+
+	info = kzalloc_node(sizeof(*info), GFP_KERNEL, node);
+	if (!info) {
+		dev_err(&root->device->dev,
+			"pci_bus %04x:%02x: ignored (out of memory)\n",
+			domain, busnum);
+		return NULL;
+	}
+
+	acpi_pci_root_ops.pci_ops = pci_mcfg_get_ops(root);
+	bus = acpi_pci_root_create(root, &acpi_pci_root_ops, info, root);
+	if (!bus)
+		return NULL;
+
+	bridge = pci_find_host_bridge(bus);
+	bridge->map_irq = pcibios_map_irq;
+
+	pci_bus_size_bridges(bus);
+	pci_bus_assign_resources(bus);
+
+	/*
+	 * After the PCI-E bus has been walked and all devices discovered,
+	 * configure any settings of the fabric that might be necessary.
+	 */
+	list_for_each_entry(child, &bus->children, node)
+		pcie_bus_configure_settings(child);
+
+	return bus;
+}
+#endif /* CONFIG_ARCH_PCI_HOST_GENERIC_ACPI */
+
 static int acpi_pci_root_add(struct acpi_device *device,
 			     const struct acpi_device_id *not_used)
 {
-- 
1.9.1