File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/sparc/prom/p1275.c b/arch/sparc/prom/p1275.c
new file mode 100644
index 0000000..545d8bb
--- /dev/null
+++ b/arch/sparc/prom/p1275.c
@@ -0,0 +1,54 @@
+/*
+ * p1275.c: Sun IEEE 1275 PROM low level interface routines
+ *
+ * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/irqflags.h>
+
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/spitfire.h>
+#include <asm/pstate.h>
+#include <asm/ldc.h>
+
+struct {
+	long prom_callback;			/* 0x00 */
+	void (*prom_cif_handler)(long *);	/* 0x08 */
+} p1275buf;
+
+extern void prom_world(int);
+
+extern void prom_cif_direct(unsigned long *args);
+extern void prom_cif_callback(void);
+
+/*
+ * This provides SMP safety on the p1275buf.
+ */
+DEFINE_RAW_SPINLOCK(prom_entry_lock);
+
+void p1275_cmd_direct(unsigned long *args)
+{
+	unsigned long flags;
+
+	local_save_flags(flags);
+	local_irq_restore((unsigned long)PIL_NMI);
+	raw_spin_lock(&prom_entry_lock);
+
+	prom_world(1);
+	prom_cif_direct(args);
+	prom_world(0);
+
+	raw_spin_unlock(&prom_entry_lock);
+	local_irq_restore(flags);
+}
+
+void prom_cif_init(void *cif_handler, void *cif_stack)
+{
+	p1275buf.prom_cif_handler = (void (*)(long *))cif_handler;
+}