synquacer: Add SCPI driver

Add System Control and Power Interface (SCPI) driver which provides APIs
for PSCI framework to work. SCPI driver uses MHU driver APIs to communicate
with SCP firmware for various system control and power operations.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>

3 files changed, 255 insertions, 0 deletions

diff --git a/plat/socionext/synquacer/drivers/scpi/sq_scpi.c b/plat/socionext/synquacer/drivers/scpi/sq_scpi.c
new file mode 100644
index 00000000..a6924e2e
--- /dev/null
+++ b/plat/socionext/synquacer/drivers/scpi/sq_scpi.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <platform_def.h>
+#include <sq_common.h>
+#include <debug.h>
+#include <string.h>
+#include "sq_mhu.h"
+#include "sq_scpi.h"
+
+#define SCPI_SHARED_MEM_SCP_TO_AP	PLAT_SQ_SCP_COM_SHARED_MEM_BASE
+#define SCPI_SHARED_MEM_AP_TO_SCP	(PLAT_SQ_SCP_COM_SHARED_MEM_BASE \
+								 + 0x100)
+
+#define SCPI_CMD_HEADER_AP_TO_SCP		\
+	((scpi_cmd_t *) SCPI_SHARED_MEM_AP_TO_SCP)
+#define SCPI_CMD_PAYLOAD_AP_TO_SCP		\
+	((void *) (SCPI_SHARED_MEM_AP_TO_SCP + sizeof(scpi_cmd_t)))
+
+/* ID of the MHU slot used for the SCPI protocol */
+#define SCPI_MHU_SLOT_ID		0
+
+static void scpi_secure_message_start(void)
+{
+	mhu_secure_message_start(SCPI_MHU_SLOT_ID);
+}
+
+static void scpi_secure_message_send(size_t payload_size)
+{
+	/*
+	 * Ensure that any write to the SCPI payload area is seen by SCP before
+	 * we write to the MHU register. If these 2 writes were reordered by
+	 * the CPU then SCP would read stale payload data
+	 */
+	dmbst();
+
+	mhu_secure_message_send(SCPI_MHU_SLOT_ID);
+}
+
+static void scpi_secure_message_receive(scpi_cmd_t *cmd)
+{
+	uint32_t mhu_status;
+
+	assert(cmd != NULL);
+
+	mhu_status = mhu_secure_message_wait();
+
+	/* Expect an SCPI message, reject any other protocol */
+	if (mhu_status != (1 << SCPI_MHU_SLOT_ID)) {
+		ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
+			mhu_status);
+		panic();
+	}
+
+	/*
+	 * Ensure that any read to the SCPI payload area is done after reading
+	 * the MHU register. If these 2 reads were reordered then the CPU would
+	 * read invalid payload data
+	 */
+	dmbld();
+
+	memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
+}
+
+static void scpi_secure_message_end(void)
+{
+	mhu_secure_message_end(SCPI_MHU_SLOT_ID);
+}
+
+int scpi_wait_ready(void)
+{
+	scpi_cmd_t scpi_cmd;
+	scpi_status_t status = SCP_OK;
+
+	VERBOSE("Waiting for SCP_READY command...\n");
+
+	/* Get a message from the SCP */
+	scpi_secure_message_start();
+	scpi_secure_message_receive(&scpi_cmd);
+	scpi_secure_message_end();
+
+	/* We are expecting 'SCP Ready', produce correct error if it's not */
+	if (scpi_cmd.id != SCPI_CMD_SCP_READY) {
+		ERROR("Unexpected SCP command: expected command #%u,"
+		      "got command #%u\n", SCPI_CMD_SCP_READY, scpi_cmd.id);
+		status = SCP_E_SUPPORT;
+	} else if (scpi_cmd.size != 0) {
+		ERROR("SCP_READY command has incorrect size: expected 0,"
+		      "got %u\n", scpi_cmd.size);
+		status = SCP_E_SIZE;
+	}
+
+	VERBOSE("Sending response for SCP_READY command\n");
+
+	/*
+	 * Send our response back to SCP.
+	 * We are using the same SCPI header, just update the status field.
+	 */
+	scpi_cmd.status = status;
+	scpi_secure_message_start();
+	memcpy((void *) SCPI_SHARED_MEM_AP_TO_SCP, &scpi_cmd, sizeof(scpi_cmd));
+	scpi_secure_message_send(0);
+	scpi_secure_message_end();
+
+	return status == SCP_OK ? 0 : -1;
+}
+
+void scpi_set_sq_power_state(unsigned int mpidr, scpi_power_state_t cpu_state,
+		scpi_power_state_t cluster_state, scpi_power_state_t sq_state)
+{
+	scpi_cmd_t *cmd;
+	uint32_t state = 0;
+	uint32_t *payload_addr;
+
+	state |= mpidr & 0x0f;	/* CPU ID */
+	state |= (mpidr & 0xf00) >> 4;	/* Cluster ID */
+	state |= cpu_state << 8;
+	state |= cluster_state << 12;
+	state |= sq_state << 16;
+
+	scpi_secure_message_start();
+
+	/* Populate the command header */
+	cmd = SCPI_CMD_HEADER_AP_TO_SCP;
+	cmd->id = SCPI_CMD_SET_POWER_STATE;
+	cmd->set = SCPI_SET_NORMAL;
+	cmd->sender = 0;
+	cmd->size = sizeof(state);
+	/* Populate the command payload */
+	payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
+	*payload_addr = state;
+	scpi_secure_message_send(sizeof(state));
+
+	/*
+	 * SCP does not reply to this command in order to avoid MHU interrupts
+	 * from the sender, which could interfere with its power state request.
+	 */
+	scpi_secure_message_end();
+}
+
+uint32_t scpi_sys_power_state(scpi_system_state_t system_state)
+{
+	scpi_cmd_t *cmd;
+	uint8_t *payload_addr;
+	scpi_cmd_t response;
+
+	scpi_secure_message_start();
+
+	/* Populate the command header */
+	cmd = SCPI_CMD_HEADER_AP_TO_SCP;
+	cmd->id = SCPI_CMD_SYS_POWER_STATE;
+	cmd->set = 0;
+	cmd->sender = 0;
+	cmd->size = sizeof(*payload_addr);
+	/* Populate the command payload */
+	payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
+	*payload_addr = system_state & 0xff;
+	scpi_secure_message_send(sizeof(*payload_addr));
+
+	scpi_secure_message_receive(&response);
+
+	scpi_secure_message_end();
+
+	return response.status;
+}
diff --git a/plat/socionext/synquacer/drivers/scpi/sq_scpi.h b/plat/socionext/synquacer/drivers/scpi/sq_scpi.h
new file mode 100644
index 00000000..30fa5c72
--- /dev/null
+++ b/plat/socionext/synquacer/drivers/scpi/sq_scpi.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __SQ_SCPI_H__
+#define __SQ_SCPI_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+/*
+ * An SCPI command consists of a header and a payload.
+ * The following structure describes the header. It is 64-bit long.
+ */
+typedef struct {
+	/* Command ID */
+	uint32_t id		: 7;
+	/* Set ID. Identifies whether this is a standard or extended command. */
+	uint32_t set		: 1;
+	/* Sender ID to match a reply. The value is sender specific. */
+	uint32_t sender		: 8;
+	/* Size of the payload in bytes (0 - 511) */
+	uint32_t size		: 9;
+	uint32_t reserved	: 7;
+	/*
+	 * Status indicating the success of a command.
+	 * See the enum below.
+	 */
+	uint32_t status;
+} scpi_cmd_t;
+
+typedef enum {
+	SCPI_SET_NORMAL = 0,	/* Normal SCPI commands */
+	SCPI_SET_EXTENDED	/* Extended SCPI commands */
+} scpi_set_t;
+
+enum {
+	SCP_OK = 0,	/* Success */
+	SCP_E_PARAM,	/* Invalid parameter(s) */
+	SCP_E_ALIGN,	/* Invalid alignment */
+	SCP_E_SIZE,	/* Invalid size */
+	SCP_E_HANDLER,	/* Invalid handler or callback */
+	SCP_E_ACCESS,	/* Invalid access or permission denied */
+	SCP_E_RANGE,	/* Value out of range */
+	SCP_E_TIMEOUT,	/* Time out has ocurred */
+	SCP_E_NOMEM,	/* Invalid memory area or pointer */
+	SCP_E_PWRSTATE,	/* Invalid power state */
+	SCP_E_SUPPORT,	/* Feature not supported or disabled */
+	SCPI_E_DEVICE,	/* Device error */
+	SCPI_E_BUSY,	/* Device is busy */
+};
+
+typedef uint32_t scpi_status_t;
+
+typedef enum {
+	SCPI_CMD_SCP_READY = 0x01,
+	SCPI_CMD_SET_POWER_STATE = 0x03,
+	SCPI_CMD_SYS_POWER_STATE = 0x05
+} scpi_command_t;
+
+typedef enum {
+	scpi_power_on = 0,
+	scpi_power_retention = 1,
+	scpi_power_off = 3,
+} scpi_power_state_t;
+
+typedef enum {
+	scpi_system_shutdown = 0,
+	scpi_system_reboot = 1,
+	scpi_system_reset = 2
+} scpi_system_state_t;
+
+extern int scpi_wait_ready(void);
+extern void scpi_set_sq_power_state(unsigned int mpidr,
+					scpi_power_state_t cpu_state,
+					scpi_power_state_t cluster_state,
+					scpi_power_state_t css_state);
+uint32_t scpi_sys_power_state(scpi_system_state_t system_state);
+
+#endif	/* __SQ_SCPI_H__ */
diff --git a/plat/socionext/synquacer/include/platform_def.h b/plat/socionext/synquacer/include/platform_def.h
index 07db2b6d..f9bc4022 100644
--- a/plat/socionext/synquacer/include/platform_def.h
+++ b/plat/socionext/synquacer/include/platform_def.h
@@ -56,6 +56,9 @@
 
 #define PLAT_SQ_MHU_BASE		0x45000000
 
+#define PLAT_SQ_SCP_COM_SHARED_MEM_BASE		0x45400000
+#define SCPI_CMD_GET_DRAMINFO			0x1
+
 #define SQ_BOOT_CFG_ADDR			0x45410000
 #define PLAT_SQ_PRIMARY_CPU_SHIFT		8
 #define PLAT_SQ_PRIMARY_CPU_BIT_WIDTH		6