Add common ARM and CSS platform code

This major change pulls out the common functionality from the
FVP and Juno platform ports into the following categories:

*   (include/)plat/common. Common platform porting functionality that
typically may be used by all platforms.

*   (include/)plat/arm/common. Common platform porting functionality
that may be used by all ARM standard platforms. This includes all
ARM development platforms like FVP and Juno but may also include
non-ARM-owned platforms.

*   (include/)plat/arm/board/common. Common platform porting
functionality for ARM development platforms at the board
(off SoC) level.

*   (include/)plat/arm/css/common. Common platform porting
functionality at the ARM Compute SubSystem (CSS) level. Juno
is an example of a CSS-based platform.

*   (include/)plat/arm/soc/common. Common platform porting
functionality at the ARM SoC level, which is not already defined
at the ARM CSS level.

No guarantees are made about the backward compatibility of
functionality provided in (include/)plat/arm.

Also remove any unnecessary variation between the ARM development
platform ports, including:

*   Unify the way BL2 passes `bl31_params_t` to BL3-1. Use the
Juno implementation, which copies the information from BL2 memory
instead of expecting it to persist in shared memory.

*   Unify the TZC configuration. There is no need to add a region
for SCP in Juno; it's enough to simply not allow any access to
this reserved region. Also set region 0 to provide no access by
default instead of assuming this is the case.

*   Unify the number of memory map regions required for ARM
development platforms, although the actual ranges mapped for each
platform may be different. For the FVP port, this reduces the
mapped peripheral address space.

These latter changes will only be observed when the platform ports
are migrated to use the new common platform code in subsequent
patches.

Change-Id: Id9c269dd3dc6e74533d0e5116fdd826d53946dc8
diff --git a/plat/arm/css/common/aarch64/css_helpers.S b/plat/arm/css/common/aarch64/css_helpers.S
new file mode 100644
index 0000000..1eee762
--- /dev/null
+++ b/plat/arm/css/common/aarch64/css_helpers.S
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2013-2015, 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 <arch.h>
+#include <asm_macros.S>
+#include <cpu_macros.S>
+#include <css_def.h>
+
+	.weak	plat_secondary_cold_boot_setup
+	.weak	platform_get_entrypoint
+	.weak	platform_mem_init
+	.globl	platform_get_core_pos
+	.weak	platform_is_primary_cpu
+
+
+	/* -----------------------------------------------------
+	 * void plat_secondary_cold_boot_setup (void);
+	 *
+	 * This function performs any platform specific actions
+	 * needed for a secondary cpu after a cold reset e.g
+	 * mark the cpu's presence, mechanism to place it in a
+	 * holding pen etc.
+	 * -----------------------------------------------------
+	 */
+func plat_secondary_cold_boot_setup
+	/* todo: Implement secondary CPU cold boot setup on CSS platforms */
+cb_panic:
+	b	cb_panic
+endfunc plat_secondary_cold_boot_setup
+
+	/* -----------------------------------------------------
+	 * void platform_get_entrypoint (unsigned int mpid);
+	 *
+	 * Main job of this routine is to distinguish between
+	 * a cold and warm boot.
+	 * On a cold boot the secondaries first wait for the
+	 * platform to be initialized after which they are
+	 * hotplugged in. The primary proceeds to perform the
+	 * platform initialization.
+	 * On a warm boot, each cpu jumps to the address in its
+	 * mailbox.
+	 *
+	 * TODO: Not a good idea to save lr in a temp reg
+	 * -----------------------------------------------------
+	 */
+func platform_get_entrypoint
+	mov	x9, x30 // lr
+	bl	platform_get_core_pos
+	ldr	x1, =TRUSTED_MAILBOXES_BASE
+	lsl	x0, x0, #TRUSTED_MAILBOX_SHIFT
+	ldr	x0, [x1, x0]
+	ret	x9
+endfunc platform_get_entrypoint
+
+	/*
+	 * Override the default implementation to swap the cluster order.
+	 * This is necessary in order to match the format of the boot
+	 * information passed by the SCP and read in platform_is_primary_cpu
+	 * below.
+	 */
+func platform_get_core_pos
+	and	x1, x0, #MPIDR_CPU_MASK
+	and	x0, x0, #MPIDR_CLUSTER_MASK
+	eor	x0, x0, #(1 << MPIDR_AFFINITY_BITS)  // swap cluster order
+	add	x0, x1, x0, LSR #6
+	ret
+endfunc platform_get_core_pos
+
+	/* -----------------------------------------------------
+	 * void platform_mem_init(void);
+	 *
+	 * We don't need to carry out any memory initialization
+	 * on CSS platforms. The Secure RAM is accessible straight away.
+	 * -----------------------------------------------------
+	 */
+func platform_mem_init
+	ret
+endfunc platform_mem_init
+
+	/* -----------------------------------------------------
+	 * unsigned int platform_is_primary_cpu (unsigned int mpid);
+	 *
+	 * Given the mpidr say whether this cpu is the primary
+	 * cpu (applicable ony after a cold boot)
+	 * -----------------------------------------------------
+	 */
+func platform_is_primary_cpu
+	mov	x9, x30
+	bl	platform_get_core_pos
+	ldr	x1, =SCP_BOOT_CFG_ADDR
+	ldr	x1, [x1]
+	ubfx	x1, x1, #PRIMARY_CPU_SHIFT, #PRIMARY_CPU_MASK
+	cmp	x0, x1
+	cset	x0, eq
+	ret	x9
+endfunc platform_is_primary_cpu