1 files changed, 98 insertions, 0 deletions
diff --git a/include/linux/mtd/xip.h b/include/linux/mtd/xip.h
new file mode 100644
index 000000000..3cac93605
--- /dev/null
+++ b/include/linux/mtd/xip.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * MTD primitives for XIP support
+ *
+ * Author:	Nicolas Pitre
+ * Created:	Nov 2, 2004
+ * Copyright:	(C) 2004 MontaVista Software, Inc.
+ *
+ * This XIP support for MTD has been loosely inspired
+ * by an earlier patch authored by David Woodhouse.
+ */
+
+#ifndef __LINUX_MTD_XIP_H__
+#define __LINUX_MTD_XIP_H__
+
+
+#ifdef CONFIG_MTD_XIP
+
+/*
+ * We really don't want gcc to guess anything.
+ * We absolutely _need_ proper inlining.
+ */
+#include <linux/compiler.h>
+
+/*
+ * Function that are modifying the flash state away from array mode must
+ * obviously not be running from flash.  The __xipram is therefore marking
+ * those functions so they get relocated to ram.
+ */
+#ifdef CONFIG_XIP_KERNEL
+#define __xipram noinline __section(".xiptext")
+#endif
+
+/*
+ * Each architecture has to provide the following macros.  They must access
+ * the hardware directly and not rely on any other (XIP) functions since they
+ * won't be available when used (flash not in array mode).
+ *
+ * xip_irqpending()
+ *
+ * 	return non zero when any hardware interrupt is pending.
+ *
+ * xip_currtime()
+ *
+ * 	return a platform specific time reference to be used with
+ * 	xip_elapsed_since().
+ *
+ * xip_elapsed_since(x)
+ *
+ * 	return in usecs the elapsed timebetween now and the reference x as
+ * 	returned by xip_currtime().
+ *
+ * 	note 1: conversion to usec can be approximated, as long as the
+ * 		returned value is <= the real elapsed time.
+ * 	note 2: this should be able to cope with a few seconds without
+ * 		overflowing.
+ *
+ * xip_iprefetch()
+ *
+ *      Macro to fill instruction prefetch
+ *	e.g. a series of nops:  asm volatile (".rep 8; nop; .endr");
+ */
+
+#include <asm/mtd-xip.h>
+
+#ifndef xip_irqpending
+
+#warning "missing IRQ and timer primitives for XIP MTD support"
+#warning "some of the XIP MTD support code will be disabled"
+#warning "your system will therefore be unresponsive when writing or erasing flash"
+
+#define xip_irqpending()	(0)
+#define xip_currtime()		(0)
+#define xip_elapsed_since(x)	(0)
+
+#endif
+
+#ifndef xip_iprefetch
+#define xip_iprefetch()		do { } while (0)
+#endif
+
+/*
+ * xip_cpu_idle() is used when waiting for a delay equal or larger than
+ * the system timer tick period.  This should put the CPU into idle mode
+ * to save power and to be woken up only when some interrupts are pending.
+ * This should not rely upon standard kernel code.
+ */
+#ifndef xip_cpu_idle
+#define xip_cpu_idle()  do { } while (0)
+#endif
+
+#endif /* CONFIG_MTD_XIP */
+
+#ifndef __xipram
+#define __xipram
+#endif
+
+#endif /* __LINUX_MTD_XIP_H__ */