x86: dtb: Add early parsing of IO_APIC

APIC and IO_APIC have to be added to the system early because
native_init_IRQ() requires it.

In order to obtain the address of the ioapic the device tree has to be
unflattened so of_address_to_resource() works.

The device tree is relocated to ensure it is always covered by the
kernel mapping. That way the boot loader does not have to make
any assumptions about kernel's memory layout.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Dirk Brandewie <dirk.brandewie@gmail.com>
LKML-Reference: <1298405266-1624-6-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 110 insertions, 3 deletions

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index ef98e4edada1..2739d5613a38 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -7,15 +7,20 @@
 #include <linux/list.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
 
 #include <asm/irq_controller.h>
+#include <asm/apic.h>
 
+__initdata u64 initial_dtb;
 char __initdata cmd_line[COMMAND_LINE_SIZE];
 static LIST_HEAD(irq_domains);
 static DEFINE_RAW_SPINLOCK(big_irq_lock);
 
+int __initdata of_ioapic;
+
 void add_interrupt_host(struct irq_domain *ih)
 {
         unsigned long flags;
@@ -90,6 +95,107 @@ void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
 
 void __init add_dtb(u64 data)
 {
-        initial_boot_params = phys_to_virt((u64) (u32) data +
-                                offsetof(struct setup_data, data));
+        initial_dtb = data + offsetof(struct setup_data, data);
+}
+
+static void __init dtb_lapic_setup(void)
+{
+#ifdef CONFIG_X86_LOCAL_APIC
+        if (apic_force_enable())
+                return;
+
+        smp_found_config = 1;
+        pic_mode = 1;
+        /* Required for ioapic registration */
+        set_fixmap_nocache(FIX_APIC_BASE, mp_lapic_addr);
+        if (boot_cpu_physical_apicid == -1U)
+                boot_cpu_physical_apicid = read_apic_id();
+
+        generic_processor_info(boot_cpu_physical_apicid,
+                        GET_APIC_VERSION(apic_read(APIC_LVR)));
+#endif
+}
+
+#ifdef CONFIG_X86_IO_APIC
+static unsigned int ioapic_id;
+
+static void __init dtb_add_ioapic(struct device_node *dn)
+{
+        struct resource r;
+        int ret;
+
+        ret = of_address_to_resource(dn, 0, &r);
+        if (ret) {
+                printk(KERN_ERR "Can't obtain address from node %s.\n",
+                                dn->full_name);
+                return;
+        }
+        mp_register_ioapic(++ioapic_id, r.start, gsi_top);
+}
+
+static void __init dtb_ioapic_setup(void)
+{
+        struct device_node *dn;
+
+        if (!smp_found_config)
+                return;
+
+        for_each_compatible_node(dn, NULL, "intel,ce4100-ioapic")
+                dtb_add_ioapic(dn);
+
+        if (nr_ioapics) {
+                of_ioapic = 1;
+                return;
+        }
+        printk(KERN_ERR "Error: No information about IO-APIC in OF.\n");
+        smp_found_config = 0;
+}
+#else
+static void __init dtb_ioapic_setup(void) {}
+#endif
+
+static void __init dtb_apic_setup(void)
+{
+        dtb_lapic_setup();
+        dtb_ioapic_setup();
+}
+
+void __init x86_dtb_find_config(void)
+{
+        if (initial_dtb)
+                smp_found_config = 1;
+        else
+                printk(KERN_ERR "Missing device tree!.\n");
+}
+
+void __init x86_dtb_get_config(unsigned int unused)
+{
+        u32 size, map_len;
+        void *new_dtb;
+
+        if (!initial_dtb)
+                return;
+
+        map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK),
+                        (u64)sizeof(struct boot_param_header));
+
+        initial_boot_params = early_memremap(initial_dtb, map_len);
+        size = be32_to_cpu(initial_boot_params->totalsize);
+        if (map_len < size) {
+                early_iounmap(initial_boot_params, map_len);
+                initial_boot_params = early_memremap(initial_dtb, size);
+                map_len = size;
+        }
+
+        new_dtb = alloc_bootmem(size);
+        memcpy(new_dtb, initial_boot_params, size);
+        early_iounmap(initial_boot_params, map_len);
+
+        initial_boot_params = new_dtb;
+
+        /* root level address cells */
+        of_scan_flat_dt(early_init_dt_scan_root, NULL);
+
+        unflatten_device_tree();
+        dtb_apic_setup();
 }
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index c752e973958d..4cadf8688dbd 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -25,6 +25,7 @@
 #include <asm/setup.h>
 #include <asm/i8259.h>
 #include <asm/traps.h>
+#include <asm/prom.h>
 
 /*
  * ISA PIC or low IO-APIC triggered (INTA-cycle or APIC) interrupts:
@@ -243,7 +244,7 @@ void __init native_init_IRQ(void)
                         set_intr_gate(i, interrupt[i-FIRST_EXTERNAL_VECTOR]);
         }
 
-        if (!acpi_ioapic)
+        if (!acpi_ioapic && !of_ioapic)
                 setup_irq(2, &irq2);
 
 #ifdef CONFIG_X86_32