[PATCH V5 12/15] pci, acpi: Support for ACPI based generic PCI host controller initialization

[Tomasz Nowicki]

This patch is going to implement generic PCI host controller for
ACPI world, similar to what pci-host-generic.c driver does for DT world.

All such drivers, which we have seen so far, were implemented within
arch/ directory since they had some arch assumptions (x86 and ia64).
However, they all are doing similar thing, so it makes sense to find
some common code and abstract it into the generic driver.

This driver aims to initialize PCI host controller without architecture
assumptions. It uses MCFG library to manage PCI config space regions properly.
Also, it parses _CRS content to find out host bridge's resources (i.e. MEM/IO).
As mentioned in Kconfig help section, ACPI_PCI_HOST_GENERIC choice should be
made on a per-architecture basis.

Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Signed-off-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@xxxxxxx>
TO: Bjorn Helgaas <helgaas@xxxxxxxxxx>
TO: Rafael J. Wysocki <rafael@xxxxxxxxxx>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Tested-by: Jeremy Linton <jeremy.linton@xxxxxxx>
Tested-by: Duc Dang <dhdang@xxxxxxx>
Tested-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Tested-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
Tested-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
 drivers/acpi/Kconfig     |   7 +++
 drivers/acpi/pci_root.c  | 128 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pci-acpi.h |  10 ++--
 3 files changed, 141 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 183ffa3..1c7f57bd 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -346,6 +346,13 @@ 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
+	help
+	  Select this config option from the architecture Kconfig,
+	  if it is preferred to enable ACPI PCI host controller driver which
+	  has no arch-specific assumptions.
+
 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 3b284dc..02fd690 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -532,6 +532,134 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
 	}
 }
 
+#ifdef CONFIG_ACPI_PCI_HOST_GENERIC
+static int pci_acpi_setup_mcfg_map(struct acpi_pci_root_info *ci)
+{
+	struct acpi_pci_root *root = ci->root;
+	int ret;
+
+	ret = pci_mmconfig_insert(&ci->bridge->dev, root->segment,
+				   root->secondary.start, root->secondary.end,
+				   root->mcfg_addr);
+	if (ret == -EEXIST)
+		ret = 0;
+
+	return ret;
+}
+
+static void pci_acpi_teardown_mcfg_map(struct acpi_pci_root_info *ci)
+{
+	struct acpi_pci_root *root = ci->root;
+
+	pci_mmconfig_delete(root->segment, root->secondary.start,
+			    root->secondary.end);
+	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) {
+		struct resource *res = entry->res;
+
+		if (entry->res->flags & IORESOURCE_DISABLED)
+			resource_list_destroy_entry(entry);
+		else
+			res->name = ci->name;
+
+		if (res->flags & IORESOURCE_IO) {
+			resource_size_t cpu_addr = res->start;
+			resource_size_t pci_addr = cpu_addr - entry->offset;
+			resource_size_t length = resource_size(res);
+			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_acpi_setup_mcfg_map,
+	.release_info = pci_acpi_teardown_mcfg_map,
+	.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_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;
+
+	pci_bus_claim_resources(bus);
+	pci_assign_unassigned_bus_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_ACPI_PCI_HOST_GENERIC */
+
 static int acpi_pci_root_add(struct acpi_device *device,
 			     const struct acpi_device_id *not_used)
 {
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 3dc6a8c..93feb04 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -123,10 +123,6 @@ struct pci_mmcfg_region {
 	bool hot_added;
 };
 
-extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
-			       phys_addr_t addr);
-extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
-
 extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
 extern struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
 							int end, u64 addr);
@@ -142,10 +138,16 @@ extern struct list_head pci_mmcfg_list;
 #define PCI_MMCFG_OFFSET(bus, devfn)   ((bus) << 20 | (devfn) << 12)
 
 #ifdef	CONFIG_PCI_MMCONFIG
+extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
+			       phys_addr_t addr);
+extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
 extern struct pci_ops *pci_mcfg_get_ops(struct acpi_pci_root *root);
 extern void __iomem *pci_mcfg_dev_base(struct pci_bus *bus, unsigned int devfn,
 				       int offset);
 #else
+static inline int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start,
+				      u8 end, phys_addr_t addr) { return 0; }
+static inline int pci_mmconfig_delete(u16 seg, u8 start, u8 end) { return 0; }
 static inline struct pci_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
 { return NULL; }
 static inline void __iomem *pci_mcfg_dev_base(struct pci_bus *bus,
-- 
1.9.1