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/css_mhu.c b/plat/arm/css/common/css_mhu.c
new file mode 100644
index 0000000..fa4a81d
--- /dev/null
+++ b/plat/arm/css/common/css_mhu.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2014-2015, 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_helpers.h>
+#include <bakery_lock.h>
+#include <css_def.h>
+#include <mmio.h>
+#include <plat_arm.h>
+#include "css_mhu.h"
+
+/* SCP MHU secure channel registers */
+#define SCP_INTR_S_STAT		0x200
+#define SCP_INTR_S_SET		0x208
+#define SCP_INTR_S_CLEAR	0x210
+
+/* CPU MHU secure channel registers */
+#define CPU_INTR_S_STAT		0x300
+#define CPU_INTR_S_SET		0x308
+#define CPU_INTR_S_CLEAR	0x310
+
+ARM_INSTANTIATE_LOCK
+
+/* Weak definition may be overridden in specific CSS based platform */
+#pragma weak plat_arm_pwrc_setup
+
+
+void mhu_secure_message_start(void)
+{
+	arm_lock_get();
+
+	/* Make sure any previous command has finished */
+	while (mmio_read_32(MHU_BASE + CPU_INTR_S_STAT) != 0)
+		;
+}
+
+void mhu_secure_message_send(uint32_t command)
+{
+	/* Send command to SCP and wait for it to pick it up */
+	mmio_write_32(MHU_BASE + CPU_INTR_S_SET, command);
+	while (mmio_read_32(MHU_BASE + CPU_INTR_S_STAT) != 0)
+		;
+}
+
+uint32_t mhu_secure_message_wait(void)
+{
+	/* Wait for response from SCP */
+	uint32_t response;
+	while (!(response = mmio_read_32(MHU_BASE + SCP_INTR_S_STAT)))
+		;
+
+	return response;
+}
+
+void mhu_secure_message_end(void)
+{
+	/*
+	 * Clear any response we got by writing all ones to the CLEAR
+	 * register
+	 */
+	mmio_write_32(MHU_BASE + SCP_INTR_S_CLEAR, 0xffffffffu);
+
+	arm_lock_release();
+}
+
+void mhu_secure_init(void)
+{
+	arm_lock_init();
+
+	/*
+	 * Clear the CPU's INTR register to make sure we don't see a stale
+	 * or garbage value and think it's a message we've already sent.
+	 */
+	mmio_write_32(MHU_BASE + CPU_INTR_S_CLEAR, 0xffffffffu);
+}
+
+void plat_arm_pwrc_setup(void)
+{
+	mhu_secure_init();
+}