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>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index bf26bd5..f32f0fc 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -80,6 +80,16 @@ extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
 extern void early_init_dt_add_memory_arch(u64 base, u64 size);
 extern u64 dt_mem_next_cell(int s, u32 **cellp);
 
+/*
+ * If BLK_DEV_INITRD, the fdt early init code will call this function,
+ * to be provided by the arch code. start and end are specified as
+ * physical addresses.
+ */
+#ifdef CONFIG_BLK_DEV_INITRD
+extern void early_init_dt_setup_initrd_arch(unsigned long start,
+					    unsigned long end);
+#endif
+
 /* Early flat tree scan hooks */
 extern int early_init_dt_scan_root(unsigned long node, const char *uname,
 				   int depth, void *data);