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>

1 files changed, 51 insertions, 0 deletions

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
new file mode 100644
index 000000000000..0b8f0daef933
--- /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));
+}