Factor out translation table setup in ARM FVP port

This patch factors out the ARM FVP specific code to create MMU
translation tables so that it is possible for a boot loader stage to
create a different set of tables instead of using the default ones.
The default translation tables are created with the assumption that
the calling boot loader stage executes out of secure SRAM. This might
not be true for the BL3_2 stage in the future.

A boot loader stage can define the `fill_xlation_tables()` function as
per its requirements. It returns a reference to the level 1
translation table which is used by the common platform code to setup
the TTBR_EL3.

This patch is a temporary solution before a larger rework of
translation table creation logic is introduced.

Change-Id: I09a075d5da16822ee32a411a9dbe284718fb4ff6
diff --git a/lib/arch/aarch64/xlat_helpers.c b/lib/arch/aarch64/xlat_helpers.c
new file mode 100644
index 0000000..87d24ec
--- /dev/null
+++ b/lib/arch/aarch64/xlat_helpers.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <string.h>
+#include <assert.h>
+#include <arch.h>
+
+/*******************************************************************************
+ * Helper to create a level 1/2 table descriptor which points to a level 2/3
+ * table.
+ ******************************************************************************/
+unsigned long create_table_desc(unsigned long *next_table_ptr)
+{
+	unsigned long desc = (unsigned long) next_table_ptr;
+
+	/* Clear the last 12 bits */
+	desc >>= FOUR_KB_SHIFT;
+	desc <<= FOUR_KB_SHIFT;
+
+	desc |= TABLE_DESC;
+
+	return desc;
+}
+
+/*******************************************************************************
+ * Helper to create a level 1/2/3 block descriptor which maps the va to addr
+ ******************************************************************************/
+unsigned long create_block_desc(unsigned long desc,
+				unsigned long addr,
+				unsigned int level)
+{
+	switch (level) {
+	case LEVEL1:
+		desc |= (addr << FIRST_LEVEL_DESC_N) | BLOCK_DESC;
+		break;
+	case LEVEL2:
+		desc |= (addr << SECOND_LEVEL_DESC_N) | BLOCK_DESC;
+		break;
+	case LEVEL3:
+		desc |= (addr << THIRD_LEVEL_DESC_N) | TABLE_DESC;
+		break;
+	default:
+		assert(0);
+	}
+
+	return desc;
+}
+
+/*******************************************************************************
+ * Helper to create a level 1/2/3 block descriptor which maps the va to output_
+ * addr with Device nGnRE attributes.
+ ******************************************************************************/
+unsigned long create_device_block(unsigned long output_addr,
+				  unsigned int level,
+				  unsigned int ns)
+{
+	unsigned long upper_attrs, lower_attrs, desc;
+
+	lower_attrs = LOWER_ATTRS(ACCESS_FLAG | OSH | AP_RW);
+	lower_attrs |= LOWER_ATTRS(ns | ATTR_DEVICE_INDEX);
+	upper_attrs = UPPER_ATTRS(XN);
+	desc = upper_attrs | lower_attrs;
+
+	return create_block_desc(desc, output_addr, level);
+}
+
+/*******************************************************************************
+ * Helper to create a level 1/2/3 block descriptor which maps the va to output_
+ * addr with inner-shareable normal wbwa read-only memory attributes.
+ ******************************************************************************/
+unsigned long create_romem_block(unsigned long output_addr,
+				 unsigned int level,
+				 unsigned int ns)
+{
+	unsigned long upper_attrs, lower_attrs, desc;
+
+	lower_attrs = LOWER_ATTRS(ACCESS_FLAG | ISH | AP_RO);
+	lower_attrs |= LOWER_ATTRS(ns | ATTR_IWBWA_OWBWA_NTR_INDEX);
+	upper_attrs = UPPER_ATTRS(0ull);
+	desc = upper_attrs | lower_attrs;
+
+	return create_block_desc(desc, output_addr, level);
+}
+
+/*******************************************************************************
+ * Helper to create a level 1/2/3 block descriptor which maps the va to output_
+ * addr with inner-shareable normal wbwa read-write memory attributes.
+ ******************************************************************************/
+unsigned long create_rwmem_block(unsigned long output_addr,
+				 unsigned int level,
+				 unsigned int ns)
+{
+	unsigned long upper_attrs, lower_attrs, desc;
+
+	lower_attrs = LOWER_ATTRS(ACCESS_FLAG | ISH | AP_RW);
+	lower_attrs |= LOWER_ATTRS(ns | ATTR_IWBWA_OWBWA_NTR_INDEX);
+	upper_attrs = UPPER_ATTRS(XN);
+	desc = upper_attrs | lower_attrs;
+
+	return create_block_desc(desc, output_addr, level);
+}