of/flattree: use callback to setup initrd from /chosen

At present, the fdt code sets the kernel-wide initrd_start and
initrd_end variables when parsing /chosen. On ARM, we only set these
once the bootmem has been reserved.

This change adds an arch hook to setup the initrd from the device
tree:

 void early_init_dt_setup_initrd_arch(unsigned long start,
				      unsigned long end);

The arch-specific code can then setup the initrd however it likes.

Compiled on powerpc, with CONFIG_BLK_DEV_INITRD=y and =n.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 20 insertions, 0 deletions

diff --git a/arch/microblaze/kernel/prom.c b/arch/microblaze/kernel/prom.c
index 459c32e4a5fe..050b7993c51c 100644
--- a/arch/microblaze/kernel/prom.c
+++ b/arch/microblaze/kernel/prom.c
@@ -118,6 +118,16 @@ void __init early_init_devtree(void *params)
         pr_debug(" <- early_init_devtree()\n");
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init early_init_dt_setup_initrd_arch(unsigned long start,
+                unsigned long end)
+{
+        initrd_start = (unsigned long)__va(start);
+        initrd_end = (unsigned long)__va(end);
+        initrd_below_start_ok = 1;
+}
+#endif
+
 /*******
  *
  * New implementation of the OF "find" APIs, return a refcounted
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index e0f368ff8d12..40fce1c2f33b 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -510,6 +510,16 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size)
         memstart_addr = min((u64)memstart_addr, base);
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init early_init_dt_setup_initrd_arch(unsigned long start,
+                unsigned long end)
+{
+        initrd_start = (unsigned long)__va(start);
+        initrd_end = (unsigned long)__va(end);
+        initrd_below_start_ok = 1;
+}
+#endif
+
 static void __init early_reserve_mem(void)
 {
         u64 base, size;