[POWERPC] Setup RTAS values earlier, to enable rtas_call() earlier

Althought RTAS is instantiated when we enter the kernel, we can't actually
call into it until we know its entry point address. Currently we grab that
in rtas_initialize(), however that's quite late in the boot sequence.

To enable rtas_call() earlier, we can grab the RTAS entry etc. values while
we're scanning the flattened device tree. There's existing code to retrieve
the values from /chosen, however we don't store them there anymore, so remove
that code.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index b6aed765966a..061d8afd246e 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -801,3 +801,25 @@ void __init rtas_initialize(void)
         rtas_last_error_token = rtas_token("rtas-last-error");
 #endif
 }
+
+int __init early_init_dt_scan_rtas(unsigned long node,
+                const char *uname, int depth, void *data)
+{
+        u32 *basep, *entryp, *sizep;
+
+        if (depth != 1 || strcmp(uname, "rtas") != 0)
+                return 0;
+
+        basep  = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
+        entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
+        sizep  = of_get_flat_dt_prop(node, "rtas-size", NULL);
+
+        if (basep && entryp && sizep) {
+                rtas.base = *basep;
+                rtas.entry = *entryp;
+                rtas.size = *sizep;
+        }
+
+        /* break now */
+        return 1;
+}