gxbb: Initial port of Amlogic Meson S905 (GXBB)

The Amlogic Meson S905 is a SoC with a quad core Arm Cortex-A53 running
at 1.5Ghz. It also contains a Cortex-M3 used as SCP.

This port is a minimal implementation of BL31 capable of booting
mainline U-Boot and Linux:

- Partial SCPI support.
- Basic PSCI support (CPU_ON, SYSTEM_RESET, SYSTEM_OFF).
- GICv2 driver set up.
- Basic SIP services (read efuse data, enable/disable JTAG).

This port has been tested in an ODROID-C2.

Change-Id: Ia4bc82d7aca42a69d6b118b947279f82b3f6c6da
Tested-by: Amit Singh Tomar <amittomer25@gmail.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/meson/gxbb/gxbb_scpi.c b/plat/meson/gxbb/gxbb_scpi.c
new file mode 100644
index 0000000..2390bca
--- /dev/null
+++ b/plat/meson/gxbb/gxbb_scpi.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <mmio.h>
+#include <platform.h>
+#include <platform_def.h>
+#include <string.h>
+
+#include "gxbb_private.h"
+
+#define SIZE_SHIFT	20
+#define SIZE_MASK	0x1FF
+
+/*
+ * Note: The Amlogic SCP firmware uses the legacy SCPI protocol.
+ */
+#define SCPI_CMD_SET_CSS_POWER_STATE	0x04
+#define SCPI_CMD_SET_SYS_POWER_STATE	0x08
+
+#define SCPI_CMD_JTAG_SET_STATE		0xC0
+#define SCPI_CMD_EFUSE_READ		0xC2
+
+static inline uint32_t scpi_cmd(uint32_t command, uint32_t size)
+{
+	return command | (size << SIZE_SHIFT);
+}
+
+void scpi_secure_message_send(uint32_t command, uint32_t size)
+{
+	mhu_secure_message_send(scpi_cmd(command, size));
+}
+
+uint32_t scpi_secure_message_receive(void **message_out, size_t *size_out)
+{
+	uint32_t response = mhu_secure_message_wait();
+
+	size_t size = (response >> SIZE_SHIFT) & SIZE_MASK;
+
+	response &= ~(SIZE_MASK << SIZE_SHIFT);
+
+	if (size_out != NULL)
+		*size_out = size;
+
+	if (message_out != NULL)
+		*message_out = (void *)GXBB_MHU_SECURE_SCP_TO_AP_PAYLOAD;
+
+	return response;
+}
+
+void scpi_set_css_power_state(u_register_t mpidr, uint32_t cpu_state,
+			      uint32_t cluster_state, uint32_t css_state)
+{
+	uint32_t state = (mpidr & 0x0F) | /* CPU ID */
+			 ((mpidr & 0xF00) >> 4) | /* Cluster ID */
+			 (cpu_state << 8) |
+			 (cluster_state << 12) |
+			 (css_state << 16);
+
+	mhu_secure_message_start();
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD, state);
+	mhu_secure_message_send(scpi_cmd(SCPI_CMD_SET_CSS_POWER_STATE, 4));
+	mhu_secure_message_wait();
+	mhu_secure_message_end();
+}
+
+uint32_t scpi_sys_power_state(uint64_t system_state)
+{
+	uint32_t *response;
+	size_t size;
+
+	mhu_secure_message_start();
+	mmio_write_8(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD, system_state);
+	mhu_secure_message_send(scpi_cmd(SCPI_CMD_SET_SYS_POWER_STATE, 1));
+	scpi_secure_message_receive((void *)&response, &size);
+	mhu_secure_message_end();
+
+	return *response;
+}
+
+void scpi_jtag_set_state(uint32_t state, uint8_t select)
+{
+	assert(state <= GXBB_JTAG_STATE_OFF);
+
+	if (select > GXBB_JTAG_A53_EE) {
+		WARN("BL31: Invalid JTAG select (0x%x).\n", select);
+		return;
+	}
+
+	mhu_secure_message_start();
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD,
+		      (state << 8) | (uint32_t)select);
+	mhu_secure_message_send(scpi_cmd(SCPI_CMD_JTAG_SET_STATE, 4));
+	mhu_secure_message_wait();
+	mhu_secure_message_end();
+}
+
+uint32_t scpi_efuse_read(void *dst, uint32_t base, uint32_t size)
+{
+	uint32_t *response;
+	size_t resp_size;
+
+	if (size > 0x1FC)
+		return 0;
+
+	mhu_secure_message_start();
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD, base);
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD + 4, size);
+	mhu_secure_message_send(scpi_cmd(SCPI_CMD_EFUSE_READ, 8));
+	scpi_secure_message_receive((void *)&response, &resp_size);
+	mhu_secure_message_end();
+
+	/*
+	 * response[0] is the size of the response message.
+	 * response[1 ... N] are the contents.
+	 */
+	if (*response != 0)
+		memcpy(dst, response + 1, *response);
+
+	return *response;
+}
+
+void scpi_unknown_thermal(uint32_t arg0, uint32_t arg1,
+			  uint32_t arg2, uint32_t arg3)
+{
+	mhu_secure_message_start();
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD + 0x0, arg0);
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD + 0x4, arg1);
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD + 0x8, arg2);
+	mmio_write_32(GXBB_MHU_SECURE_AP_TO_SCP_PAYLOAD + 0xC, arg3);
+	mhu_secure_message_send(scpi_cmd(0xC3, 16));
+	mhu_secure_message_wait();
+	mhu_secure_message_end();
+}