Introduce arch_phys_memset which works like memset but on physical memory

The default implementation of this function is just memset, but other
implementations will be needed when physical memory isn't accessible by
U-Boot using normal addressing mechanisms.

Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

README

@@ -2200,6 +2200,14 @@ CBFS (Coreboot Filesystem) support
 			HERMES, IP860, RPXlite, LWMON,
 			FLAGADM, TQM8260
 
+- Access to physical memory region (> 4GB)
+		Some basic support is provided for operations on memory not
+		normally accessible to U-Boot - e.g. some architectures
+		support access to more than 4GB of memory on 32-bit
+		machines using physical address extension or similar.
+		Define CONFIG_PHYSMEM to access this basic support, which
+		currently only supports clearing the memory.
+
 - Error Recovery:
 		CONFIG_PANIC_HANG
 

include/physmem.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+/*
+ * These functions work like memset but operate on physical memory which may
+ * not be accessible directly.
+ *
+ * @param s	The physical address to start setting memory at.
+ * @param c	The character to set each byte of the region to.
+ * @param n	The number of bytes to set.
+ *
+ * @return	The physical address of the memory which was set.
+ */
+phys_addr_t arch_phys_memset(phys_addr_t s, int c, phys_size_t n);

lib/Makefile

@@ -48,6 +48,7 @@ COBJS-$(CONFIG_LMB) += lmb.o
 COBJS-y += ldiv.o
 COBJS-$(CONFIG_MD5) += md5.o
 COBJS-y += net_utils.o
+COBJS-$(CONFIG_PHYSMEM) += physmem.o
 COBJS-y += qsort.o
 COBJS-$(CONFIG_SHA1) += sha1.o
 COBJS-$(CONFIG_SHA256) += sha256.o

lib/physmem.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+#include <common.h>
+#include <physmem.h>
+
+static phys_addr_t __arch_phys_memset(phys_addr_t s, int c, phys_size_t n)
+{
+	void *s_ptr = (void *)(uintptr_t)s;
+
+	assert(((phys_addr_t)(uintptr_t)s) == s);
+	assert(((phys_addr_t)(uintptr_t)(s + n)) == s + n);
+	return (phys_addr_t)(uintptr_t)memset(s_ptr, c, n);
+}
+
+phys_addr_t arch_phys_memset(phys_addr_t s, int c, phys_size_t n)
+	__attribute__((weak, alias("__arch_phys_memset")));