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 buss(es) in the device tree and adds its children
 (devices) 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.

Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
Tested-by: Dirk Brandewie <redacted>
Signed-off-by: Sebastian Andrzej Siewior <redacted>
---
 arch/x86/include/asm/prom.h |   17 +++++++++
 arch/x86/kernel/prom.c      |   82 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
index bd67ab2..3ed0bd6 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>
 #include <asm/setup.h>

@@ -28,8 +29,24 @@ 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->dev.of_node;
+}
+
+static inline struct device_node *pci_bus_to_OF_node(struct pci_bus *bus)
+{
+       if (bus->self)
+               return pci_device_to_OF_node(bus->self);
+       else
+               return NULL;
+}

+
 #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/prom.c b/arch/x86/kernel/prom.c
index 16c124e..8525ca0 100644
--- a/arch/x86/kernel/prom.c
+++ b/arch/x86/kernel/prom.c

@@ -9,10 +9,13 @@

 #include <linux/of_address.h>
 #include <linux/of_platform.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/io_apic.h>
+#include <asm/pci_x86.h>

 __initdata u64 initial_dtb;
 char __initdata cmd_line[COMMAND_LINE_SIZE];

@@ -99,6 +102,85 @@ 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;
--
1.7.3.2

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