x86: dtb: Add support for PCI devices backed by dtb nodes

x86_of_pci_init() does two things:

- it provides a generic irq enable and disable function. enable queries
  the device tree for the interrupt information, calls ->xlate on the
  irq host and updates the pci->irq information for the device.

- it walks through PCI bus(es) in the device tree and adds its children
  (device) nodes to appropriate pci_dev nodes in kernel. So the dtb
  node information is available at probe time of the PCI device.

Adding a PCI bus based on the information in the device tree is
currently not supported. Right now direct access via ioports is used.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
LKML-Reference: <1298405266-1624-8-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 97 insertions, 0 deletions

diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
index 35ec32b47500..8fcd519a44dc 100644
--- a/arch/x86/include/asm/prom.h
+++ b/arch/x86/include/asm/prom.h
@@ -16,6 +16,7 @@
 
 #include <linux/of.h>
 #include <linux/types.h>
+#include <linux/pci.h>
 
 #include <asm/irq.h>
 #include <asm/atomic.h>
@@ -29,8 +30,21 @@ extern void add_dtb(u64 data);
 void x86_dtb_find_config(void);
 void x86_dtb_get_config(unsigned int unused);
 void add_interrupt_host(struct irq_domain *ih);
+void __cpuinit x86_of_pci_init(void);
+
+static inline struct device_node *pci_device_to_OF_node(struct pci_dev *pdev)
+{
+        return pdev ? pdev->dev.of_node : NULL;
+}
+
+static inline struct device_node *pci_bus_to_OF_node(struct pci_bus *bus)
+{
+        return pci_device_to_OF_node(bus->self);
+}
+
 #else
 static inline void add_dtb(u64 data) { }
+static inline void x86_of_pci_init(void) { }
 #define x86_dtb_find_config x86_init_noop
 #define x86_dtb_get_config x86_init_uint_noop
 #define of_ioapic 0
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index dbb3bda40af9..7b574226e0a8 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -9,11 +9,15 @@
 #include <linux/of_fdt.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
+#include <linux/of_irq.h>
 #include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/of_pci.h>
 
 #include <asm/hpet.h>
 #include <asm/irq_controller.h>
 #include <asm/apic.h>
+#include <asm/pci_x86.h>
 
 __initdata u64 initial_dtb;
 char __initdata cmd_line[COMMAND_LINE_SIZE];
@@ -99,6 +103,85 @@ void __init add_dtb(u64 data)
         initial_dtb = data + offsetof(struct setup_data, data);
 }
 
+#ifdef CONFIG_PCI
+static int x86_of_pci_irq_enable(struct pci_dev *dev)
+{
+        struct of_irq oirq;
+        u32 virq;
+        int ret;
+        u8 pin;
+
+        ret = pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
+        if (ret)
+                return ret;
+        if (!pin)
+                return 0;
+
+        ret = of_irq_map_pci(dev, &oirq);
+        if (ret)
+                return ret;
+
+        virq = irq_create_of_mapping(oirq.controller, oirq.specifier,
+                        oirq.size);
+        if (virq == 0)
+                return -EINVAL;
+        dev->irq = virq;
+        return 0;
+}
+
+static void x86_of_pci_irq_disable(struct pci_dev *dev)
+{
+}
+
+void __cpuinit x86_of_pci_init(void)
+{
+        struct device_node *np;
+
+        pcibios_enable_irq = x86_of_pci_irq_enable;
+        pcibios_disable_irq = x86_of_pci_irq_disable;
+
+        for_each_node_by_type(np, "pci") {
+                const void *prop;
+                struct pci_bus *bus;
+                unsigned int bus_min;
+                struct device_node *child;
+
+                prop = of_get_property(np, "bus-range", NULL);
+                if (!prop)
+                        continue;
+                bus_min = be32_to_cpup(prop);
+
+                bus = pci_find_bus(0, bus_min);
+                if (!bus) {
+                        printk(KERN_ERR "Can't find a node for bus %s.\n",
+                                        np->full_name);
+                        continue;
+                }
+
+                if (bus->self)
+                        bus->self->dev.of_node = np;
+                else
+                        bus->dev.of_node = np;
+
+                for_each_child_of_node(np, child) {
+                        struct pci_dev *dev;
+                        u32 devfn;
+
+                        prop = of_get_property(child, "reg", NULL);
+                        if (!prop)
+                                continue;
+
+                        devfn = (be32_to_cpup(prop) >> 8) & 0xff;
+                        dev = pci_get_slot(bus, devfn);
+                        if (!dev)
+                                continue;
+                        dev->dev.of_node = child;
+                        pci_dev_put(dev);
+                }
+        }
+}
+#endif
+
 static void __init dtb_setup_hpet(void)
 {
         struct device_node *dn;