x86: Add device tree support

This patch adds minimal support for device tree on x86. The device
tree blob is passed to the kernel via setup_data which requires at
least boot protocol 2.09.

Memory size, restricted memory regions, boot arguments are gathered
the traditional way so things like cmd_line are just here to let the
code compile.

The current plan is use the device tree as an extension and to gather
information which can not be enumerated and would have to be hardcoded
otherwise. This includes things like 
   - which devices are on this I2C/SPI bus?
   - how are the interrupts wired to IO APIC?
   - where could my hpet be?

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-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: <1298405266-1624-3-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 56 insertions, 9 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 34244b2cd88..6ac5036adf4 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -109,6 +109,7 @@ obj-$(CONFIG_MICROCODE)			+= microcode.o
 obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 
 obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb.o
+obj-$(CONFIG_OF)			+= devicetree.o
 
 ###
 # 64 bit specific files
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
new file mode 100644
index 00000000000..0b8f0daef93
--- /dev/null
+++ b/arch/x86/kernel/devicetree.c
@@ -0,0 +1,51 @@
+/*
+ * Architecture specific OF callbacks.
+ */
+#include <linux/bootmem.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+
+char __initdata cmd_line[COMMAND_LINE_SIZE];
+
+unsigned int irq_create_of_mapping(struct device_node *controller,
+				   const u32 *intspec, unsigned int intsize)
+{
+	return intspec[0];
+
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+unsigned long pci_address_to_pio(phys_addr_t address)
+{
+	/*
+	 * The ioport address can be directly used by inX / outX
+	 */
+	BUG_ON(address >= (1 << 16));
+	return (unsigned long)address;
+}
+EXPORT_SYMBOL_GPL(pci_address_to_pio);
+
+void __init early_init_dt_scan_chosen_arch(unsigned long node)
+{
+	BUG();
+}
+
+void __init early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	BUG();
+}
+
+void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+{
+	return __alloc_bootmem(size, align, __pa(MAX_DMA_ADDRESS));
+}
+
+void __init add_dtb(u64 data)
+{
+	initial_boot_params = phys_to_virt((u64) (u32) data +
+				offsetof(struct setup_data, data));
+}
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 387b6a0c9e8..753136003af 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -276,15 +276,6 @@ void smp_x86_platform_ipi(struct pt_regs *regs)
 
 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
 
-#ifdef CONFIG_OF
-unsigned int irq_create_of_mapping(struct device_node *controller,
-		const u32 *intspec, unsigned int intsize)
-{
-	return intspec[0];
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);
-#endif
-
 #ifdef CONFIG_HOTPLUG_CPU
 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 void fixup_irqs(void)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9521483ce58..33dcbce1ab0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -113,6 +113,7 @@
 #endif
 #include <asm/mce.h>
 #include <asm/alternative.h>
+#include <asm/prom.h>
 
 /*
  * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
@@ -445,6 +446,9 @@ static void __init parse_setup_data(void)
 		case SETUP_E820_EXT:
 			parse_e820_ext(data);
 			break;
+		case SETUP_DTB:
+			add_dtb(pa_data);
+			break;
 		default:
 			break;
 		}