diff --git a/drivers/arm/css/scmi/scmi_ap_core_proto.c b/drivers/arm/css/scmi/scmi_ap_core_proto.c
new file mode 100644
index 0000000..2caccc2
--- /dev/null
+++ b/drivers/arm/css/scmi/scmi_ap_core_proto.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
+
+#include "scmi_private.h"
+
+/*
+ * API to set the SCMI AP core reset address and attributes
+ */
+int scmi_ap_core_set_reset_addr(void *p, uint64_t reset_addr, uint32_t attr)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_AP_CORE_PROTO_ID,
+			SCMI_AP_CORE_RESET_ADDR_SET_MSG, token);
+	mbx_mem->len = SCMI_AP_CORE_RESET_ADDR_SET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+	SCMI_PAYLOAD_ARG3(mbx_mem->payload, reset_addr & 0xffffffff,
+		reset_addr >> 32, attr);
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
+	assert(mbx_mem->len == SCMI_AP_CORE_RESET_ADDR_SET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
+
+/*
+ * API to get the SCMI AP core reset address and attributes
+ */
+int scmi_ap_core_get_reset_addr(void *p, uint64_t *reset_addr, uint32_t *attr)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+	uint32_t lo_addr, hi_addr;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_AP_CORE_PROTO_ID,
+			SCMI_AP_CORE_RESET_ADDR_GET_MSG, token);
+	mbx_mem->len = SCMI_AP_CORE_RESET_ADDR_GET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL4(mbx_mem->payload, ret, lo_addr, hi_addr, *attr);
+	*reset_addr = lo_addr | (uint64_t)hi_addr << 32;
+	assert(mbx_mem->len == SCMI_AP_CORE_RESET_ADDR_GET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
diff --git a/drivers/arm/css/scmi/scmi_common.c b/drivers/arm/css/scmi/scmi_common.c
new file mode 100644
index 0000000..e2c353d
--- /dev/null
+++ b/drivers/arm/css/scmi/scmi_common.c
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
+
+#include "scmi_private.h"
+
+#if HW_ASSISTED_COHERENCY
+#define scmi_lock_init(lock)
+#define scmi_lock_get(lock)		spin_lock(lock)
+#define scmi_lock_release(lock)		spin_unlock(lock)
+#else
+#define scmi_lock_init(lock)		bakery_lock_init(lock)
+#define scmi_lock_get(lock)		bakery_lock_get(lock)
+#define scmi_lock_release(lock)		bakery_lock_release(lock)
+#endif
+
+
+/*
+ * Private helper function to get exclusive access to SCMI channel.
+ */
+void scmi_get_channel(scmi_channel_t *ch)
+{
+	assert(ch->lock);
+	scmi_lock_get(ch->lock);
+
+	/* Make sure any previous command has finished */
+	assert(SCMI_IS_CHANNEL_FREE(
+			((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
+}
+
+/*
+ * Private helper function to transfer ownership of channel from AP to SCP.
+ */
+void scmi_send_sync_command(scmi_channel_t *ch)
+{
+	mailbox_mem_t *mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+
+	SCMI_MARK_CHANNEL_BUSY(mbx_mem->status);
+
+	/*
+	 * Ensure that any write to the SCMI payload area is seen by SCP before
+	 * we write to the doorbell register. If these 2 writes were reordered
+	 * by the CPU then SCP would read stale payload data
+	 */
+	dmbst();
+
+	ch->info->ring_doorbell(ch->info);
+	/*
+	 * Ensure that the write to the doorbell register is ordered prior to
+	 * checking whether the channel is free.
+	 */
+	dmbsy();
+
+	/* Wait for channel to be free */
+	while (!SCMI_IS_CHANNEL_FREE(mbx_mem->status))
+		;
+
+	/*
+	 * Ensure that any read to the SCMI payload area is done after reading
+	 * mailbox status. If these 2 reads were reordered then the CPU would
+	 * read invalid payload data
+	 */
+	dmbld();
+}
+
+/*
+ * Private helper function to release exclusive access to SCMI channel.
+ */
+void scmi_put_channel(scmi_channel_t *ch)
+{
+	/* Make sure any previous command has finished */
+	assert(SCMI_IS_CHANNEL_FREE(
+			((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
+
+	assert(ch->lock);
+	scmi_lock_release(ch->lock);
+}
+
+/*
+ * API to query the SCMI protocol version.
+ */
+int scmi_proto_version(void *p, uint32_t proto_id, uint32_t *version)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id, SCMI_PROTO_VERSION_MSG,
+							token);
+	mbx_mem->len = SCMI_PROTO_VERSION_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *version);
+	assert(mbx_mem->len == SCMI_PROTO_VERSION_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
+
+/*
+ * API to query the protocol message attributes for a SCMI protocol.
+ */
+int scmi_proto_msg_attr(void *p, uint32_t proto_id,
+		uint32_t command_id, uint32_t *attr)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id,
+				SCMI_PROTO_MSG_ATTR_MSG, token);
+	mbx_mem->len = SCMI_PROTO_MSG_ATTR_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+	SCMI_PAYLOAD_ARG1(mbx_mem->payload, command_id);
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *attr);
+	assert(mbx_mem->len == SCMI_PROTO_MSG_ATTR_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
+
+/*
+ * SCMI Driver initialization API. Returns initialized channel on success
+ * or NULL on error. The return type is an opaque void pointer.
+ */
+void *scmi_init(scmi_channel_t *ch)
+{
+	uint32_t version;
+	int ret;
+
+	assert(ch && ch->info);
+	assert(ch->info->db_reg_addr);
+	assert(ch->info->db_modify_mask);
+	assert(ch->info->db_preserve_mask);
+	assert(ch->info->ring_doorbell != NULL);
+
+	assert(ch->lock);
+
+	scmi_lock_init(ch->lock);
+
+	ch->is_initialized = 1;
+
+	ret = scmi_proto_version(ch, SCMI_PWR_DMN_PROTO_ID, &version);
+	if (ret != SCMI_E_SUCCESS) {
+		WARN("SCMI power domain protocol version message failed");
+		goto error;
+	}
+
+	if (!is_scmi_version_compatible(SCMI_PWR_DMN_PROTO_VER, version)) {
+		WARN("SCMI power domain protocol version 0x%x incompatible with driver version 0x%x",
+			version, SCMI_PWR_DMN_PROTO_VER);
+		goto error;
+	}
+
+	VERBOSE("SCMI power domain protocol version 0x%x detected\n", version);
+
+	ret = scmi_proto_version(ch, SCMI_SYS_PWR_PROTO_ID, &version);
+	if ((ret != SCMI_E_SUCCESS)) {
+		WARN("SCMI system power protocol version message failed");
+		goto error;
+	}
+
+	if (!is_scmi_version_compatible(SCMI_SYS_PWR_PROTO_VER, version)) {
+		WARN("SCMI system power management protocol version 0x%x incompatible with driver version 0x%x",
+			version, SCMI_SYS_PWR_PROTO_VER);
+		goto error;
+	}
+
+	VERBOSE("SCMI system power management protocol version 0x%x detected\n",
+						version);
+
+	INFO("SCMI driver initialized\n");
+
+	return (void *)ch;
+
+error:
+	ch->is_initialized = 0;
+	return NULL;
+}
diff --git a/drivers/arm/css/scmi/scmi_private.h b/drivers/arm/css/scmi/scmi_private.h
new file mode 100644
index 0000000..6530573
--- /dev/null
+++ b/drivers/arm/css/scmi/scmi_private.h
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SCMI_PRIVATE_H
+#define SCMI_PRIVATE_H
+
+#include <lib/mmio.h>
+
+/*
+ * SCMI power domain management protocol message and response lengths. It is
+ * calculated as sum of length in bytes of the message header (4) and payload
+ * area (the number of bytes of parameters or return values in the payload).
+ */
+#define SCMI_PROTO_VERSION_MSG_LEN		4
+#define SCMI_PROTO_VERSION_RESP_LEN		12
+
+#define SCMI_PROTO_MSG_ATTR_MSG_LEN		8
+#define SCMI_PROTO_MSG_ATTR_RESP_LEN		12
+
+#define SCMI_AP_CORE_RESET_ADDR_SET_MSG_LEN	16
+#define SCMI_AP_CORE_RESET_ADDR_SET_RESP_LEN	8
+
+#define SCMI_AP_CORE_RESET_ADDR_GET_MSG_LEN	4
+#define SCMI_AP_CORE_RESET_ADDR_GET_RESP_LEN	20
+
+#define SCMI_PWR_STATE_SET_MSG_LEN		16
+#define SCMI_PWR_STATE_SET_RESP_LEN		8
+
+#define SCMI_PWR_STATE_GET_MSG_LEN		8
+#define SCMI_PWR_STATE_GET_RESP_LEN		12
+
+#define SCMI_SYS_PWR_STATE_SET_MSG_LEN		12
+#define SCMI_SYS_PWR_STATE_SET_RESP_LEN		8
+
+#define SCMI_SYS_PWR_STATE_GET_MSG_LEN		4
+#define SCMI_SYS_PWR_STATE_GET_RESP_LEN		12
+
+/* SCMI message header format bit field */
+#define SCMI_MSG_ID_SHIFT		0
+#define SCMI_MSG_ID_WIDTH		8
+#define SCMI_MSG_ID_MASK		((1 << SCMI_MSG_ID_WIDTH) - 1)
+
+#define SCMI_MSG_TYPE_SHIFT		8
+#define SCMI_MSG_TYPE_WIDTH		2
+#define SCMI_MSG_TYPE_MASK		((1 << SCMI_MSG_TYPE_WIDTH) - 1)
+
+#define SCMI_MSG_PROTO_ID_SHIFT		10
+#define SCMI_MSG_PROTO_ID_WIDTH		8
+#define SCMI_MSG_PROTO_ID_MASK		((1 << SCMI_MSG_PROTO_ID_WIDTH) - 1)
+
+#define SCMI_MSG_TOKEN_SHIFT		18
+#define SCMI_MSG_TOKEN_WIDTH		10
+#define SCMI_MSG_TOKEN_MASK		((1 << SCMI_MSG_TOKEN_WIDTH) - 1)
+
+
+/* SCMI mailbox flags */
+#define SCMI_FLAG_RESP_POLL	0
+#define SCMI_FLAG_RESP_INT	1
+
+/* SCMI power domain protocol `POWER_STATE_SET` message flags */
+#define SCMI_PWR_STATE_SET_FLAG_SYNC	0
+#define SCMI_PWR_STATE_SET_FLAG_ASYNC	1
+
+/*
+ * Helper macro to create an SCMI message header given protocol, message id
+ * and token.
+ */
+#define SCMI_MSG_CREATE(_protocol, _msg_id, _token)				\
+	((((_protocol) & SCMI_MSG_PROTO_ID_MASK) << SCMI_MSG_PROTO_ID_SHIFT) |	\
+	(((_msg_id) & SCMI_MSG_ID_MASK) << SCMI_MSG_ID_SHIFT) |			\
+	(((_token) & SCMI_MSG_TOKEN_MASK) << SCMI_MSG_TOKEN_SHIFT))
+
+/* Helper macro to get the token from a SCMI message header */
+#define SCMI_MSG_GET_TOKEN(_msg)				\
+	(((_msg) >> SCMI_MSG_TOKEN_SHIFT) & SCMI_MSG_TOKEN_MASK)
+
+/* SCMI Channel Status bit fields */
+#define SCMI_CH_STATUS_RES0_MASK	0xFFFFFFFE
+#define SCMI_CH_STATUS_FREE_SHIFT	0
+#define SCMI_CH_STATUS_FREE_WIDTH	1
+#define SCMI_CH_STATUS_FREE_MASK	((1 << SCMI_CH_STATUS_FREE_WIDTH) - 1)
+
+/* Helper macros to check and write the channel status */
+#define SCMI_IS_CHANNEL_FREE(status)					\
+	(!!(((status) >> SCMI_CH_STATUS_FREE_SHIFT) & SCMI_CH_STATUS_FREE_MASK))
+
+#define SCMI_MARK_CHANNEL_BUSY(status)	do {				\
+		assert(SCMI_IS_CHANNEL_FREE(status));			\
+		(status) &= ~(SCMI_CH_STATUS_FREE_MASK <<		\
+				SCMI_CH_STATUS_FREE_SHIFT);		\
+	} while (0)
+
+/* Helper macros to copy arguments to the mailbox payload */
+#define SCMI_PAYLOAD_ARG1(payld_arr, arg1)				\
+		mmio_write_32((uintptr_t)&payld_arr[0], arg1)
+
+#define SCMI_PAYLOAD_ARG2(payld_arr, arg1, arg2)	do {		\
+		SCMI_PAYLOAD_ARG1(payld_arr, arg1);			\
+		mmio_write_32((uintptr_t)&payld_arr[1], arg2);		\
+	} while (0)
+
+#define SCMI_PAYLOAD_ARG3(payld_arr, arg1, arg2, arg3)	do {		\
+		SCMI_PAYLOAD_ARG2(payld_arr, arg1, arg2);		\
+		mmio_write_32((uintptr_t)&payld_arr[2], arg3);		\
+	} while (0)
+
+/* Helper macros to read return values from the mailbox payload */
+#define SCMI_PAYLOAD_RET_VAL1(payld_arr, val1)				\
+		(val1) = mmio_read_32((uintptr_t)&payld_arr[0])
+
+#define SCMI_PAYLOAD_RET_VAL2(payld_arr, val1, val2)	do {		\
+		SCMI_PAYLOAD_RET_VAL1(payld_arr, val1);			\
+		(val2) = mmio_read_32((uintptr_t)&payld_arr[1]);	\
+	} while (0)
+
+#define SCMI_PAYLOAD_RET_VAL3(payld_arr, val1, val2, val3)	do {	\
+		SCMI_PAYLOAD_RET_VAL2(payld_arr, val1, val2);		\
+		(val3) = mmio_read_32((uintptr_t)&payld_arr[2]);	\
+	} while (0)
+
+#define SCMI_PAYLOAD_RET_VAL4(payld_arr, val1, val2, val3, val4)	do {	\
+		SCMI_PAYLOAD_RET_VAL3(payld_arr, val1, val2, val3);		\
+		(val4) = mmio_read_32((uintptr_t)&payld_arr[3]);		\
+	} while (0)
+
+/*
+ * Private data structure for representing the mailbox memory layout. Refer
+ * the SCMI specification for more details.
+ */
+typedef struct mailbox_mem {
+	uint32_t res_a; /* Reserved */
+	volatile uint32_t status;
+	uint64_t res_b; /* Reserved */
+	uint32_t flags;
+	volatile uint32_t len;
+	uint32_t msg_header;
+	uint32_t payload[];
+} mailbox_mem_t;
+
+
+/* Private APIs for use within SCMI driver */
+void scmi_get_channel(scmi_channel_t *ch);
+void scmi_send_sync_command(scmi_channel_t *ch);
+void scmi_put_channel(scmi_channel_t *ch);
+
+static inline void validate_scmi_channel(scmi_channel_t *ch)
+{
+	assert(ch && ch->is_initialized);
+	assert(ch->info && ch->info->scmi_mbx_mem);
+}
+
+#endif /* SCMI_PRIVATE_H */
diff --git a/drivers/arm/css/scmi/scmi_pwr_dmn_proto.c b/drivers/arm/css/scmi/scmi_pwr_dmn_proto.c
new file mode 100644
index 0000000..70165de
--- /dev/null
+++ b/drivers/arm/css/scmi/scmi_pwr_dmn_proto.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
+
+#include "scmi_private.h"
+
+/*
+ * API to set the SCMI power domain power state.
+ */
+int scmi_pwr_state_set(void *p, uint32_t domain_id,
+					uint32_t scmi_pwr_state)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+
+	/*
+	 * Only asynchronous mode of `set power state` command is allowed on
+	 * application processors.
+	 */
+	uint32_t pwr_state_set_msg_flag = SCMI_PWR_STATE_SET_FLAG_ASYNC;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_PWR_DMN_PROTO_ID,
+			SCMI_PWR_STATE_SET_MSG, token);
+	mbx_mem->len = SCMI_PWR_STATE_SET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+	SCMI_PAYLOAD_ARG3(mbx_mem->payload, pwr_state_set_msg_flag,
+						domain_id, scmi_pwr_state);
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
+	assert(mbx_mem->len == SCMI_PWR_STATE_SET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
+
+/*
+ * API to get the SCMI power domain power state.
+ */
+int scmi_pwr_state_get(void *p, uint32_t domain_id,
+					uint32_t *scmi_pwr_state)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_PWR_DMN_PROTO_ID,
+			SCMI_PWR_STATE_GET_MSG, token);
+	mbx_mem->len = SCMI_PWR_STATE_GET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+	SCMI_PAYLOAD_ARG1(mbx_mem->payload, domain_id);
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *scmi_pwr_state);
+	assert(mbx_mem->len == SCMI_PWR_STATE_GET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
diff --git a/drivers/arm/css/scmi/scmi_sys_pwr_proto.c b/drivers/arm/css/scmi/scmi_sys_pwr_proto.c
new file mode 100644
index 0000000..a27c4a5
--- /dev/null
+++ b/drivers/arm/css/scmi/scmi_sys_pwr_proto.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
+
+#include "scmi_private.h"
+
+/*
+ * API to set the SCMI system power state
+ */
+int scmi_sys_pwr_state_set(void *p, uint32_t flags, uint32_t system_state)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_SYS_PWR_PROTO_ID,
+			SCMI_SYS_PWR_STATE_SET_MSG, token);
+	mbx_mem->len = SCMI_SYS_PWR_STATE_SET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+	SCMI_PAYLOAD_ARG2(mbx_mem->payload, flags, system_state);
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
+	assert(mbx_mem->len == SCMI_SYS_PWR_STATE_SET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
+
+/*
+ * API to get the SCMI system power state
+ */
+int scmi_sys_pwr_state_get(void *p, uint32_t *system_state)
+{
+	mailbox_mem_t *mbx_mem;
+	int token = 0, ret;
+	scmi_channel_t *ch = (scmi_channel_t *)p;
+
+	validate_scmi_channel(ch);
+
+	scmi_get_channel(ch);
+
+	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_SYS_PWR_PROTO_ID,
+			SCMI_SYS_PWR_STATE_GET_MSG, token);
+	mbx_mem->len = SCMI_SYS_PWR_STATE_GET_MSG_LEN;
+	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+
+	scmi_send_sync_command(ch);
+
+	/* Get the return values */
+	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *system_state);
+	assert(mbx_mem->len == SCMI_SYS_PWR_STATE_GET_RESP_LEN);
+	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+	scmi_put_channel(ch);
+
+	return ret;
+}
diff --git a/include/drivers/arm/css/scmi.h b/include/drivers/arm/css/scmi.h
new file mode 100644
index 0000000..df259f7
--- /dev/null
+++ b/include/drivers/arm/css/scmi.h
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SCMI_H
+#define SCMI_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <lib/bakery_lock.h>
+#include <lib/psci/psci.h>
+#include <lib/spinlock.h>
+
+/* Supported SCMI Protocol Versions */
+#define SCMI_AP_CORE_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
+#define SCMI_PWR_DMN_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
+#define SCMI_SYS_PWR_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
+
+#define GET_SCMI_MAJOR_VER(ver)			(((ver) >> 16) & 0xffff)
+#define GET_SCMI_MINOR_VER(ver)			((ver) & 0xffff)
+
+#define MAKE_SCMI_VERSION(maj, min)	\
+			((((maj) & 0xffff) << 16) | ((min) & 0xffff))
+
+/* Macro to check if the driver is compatible with the SCMI version reported */
+#define is_scmi_version_compatible(drv, scmi)				\
+	((GET_SCMI_MAJOR_VER(drv) == GET_SCMI_MAJOR_VER(scmi)) &&	\
+	(GET_SCMI_MINOR_VER(drv) <= GET_SCMI_MINOR_VER(scmi)))
+
+/* SCMI Protocol identifiers */
+#define SCMI_PWR_DMN_PROTO_ID			0x11
+#define SCMI_SYS_PWR_PROTO_ID			0x12
+/* The AP core protocol is a CSS platform-specific extension */
+#define SCMI_AP_CORE_PROTO_ID			0x90
+
+/* Mandatory messages IDs for all SCMI protocols */
+#define SCMI_PROTO_VERSION_MSG			0x0
+#define SCMI_PROTO_ATTR_MSG			0x1
+#define SCMI_PROTO_MSG_ATTR_MSG			0x2
+
+/* SCMI power domain management protocol message IDs */
+#define SCMI_PWR_STATE_SET_MSG			0x4
+#define SCMI_PWR_STATE_GET_MSG			0x5
+
+/* SCMI system power management protocol message IDs */
+#define SCMI_SYS_PWR_STATE_SET_MSG		0x3
+#define SCMI_SYS_PWR_STATE_GET_MSG		0x4
+
+/* SCMI AP core protocol message IDs */
+#define SCMI_AP_CORE_RESET_ADDR_SET_MSG		0x3
+#define SCMI_AP_CORE_RESET_ADDR_GET_MSG		0x4
+
+/* Helper macros for system power management protocol commands */
+
+/*
+ * Macros to describe the bit-fields of the `attribute` of system power domain
+ * protocol PROTOCOL_MSG_ATTRIBUTE message.
+ */
+#define SYS_PWR_ATTR_WARM_RESET_SHIFT		31
+#define SCMI_SYS_PWR_WARM_RESET_SUPPORTED	(1U << SYS_PWR_ATTR_WARM_RESET_SHIFT)
+
+#define SYS_PWR_ATTR_SUSPEND_SHIFT		30
+#define SCMI_SYS_PWR_SUSPEND_SUPPORTED		(1 << SYS_PWR_ATTR_SUSPEND_SHIFT)
+
+/*
+ * Macros to describe the bit-fields of the `flags` parameter of system power
+ * domain protocol SYSTEM_POWER_STATE_SET message.
+ */
+#define SYS_PWR_SET_GRACEFUL_REQ_SHIFT		0
+#define SCMI_SYS_PWR_GRACEFUL_REQ		(1 << SYS_PWR_SET_GRACEFUL_REQ_SHIFT)
+#define SCMI_SYS_PWR_FORCEFUL_REQ		(0 << SYS_PWR_SET_GRACEFUL_REQ_SHIFT)
+
+/*
+ * Macros to describe the `system_state` parameter of system power
+ * domain protocol SYSTEM_POWER_STATE_SET message.
+ */
+#define SCMI_SYS_PWR_SHUTDOWN			0x0
+#define SCMI_SYS_PWR_COLD_RESET			0x1
+#define SCMI_SYS_PWR_WARM_RESET			0x2
+#define SCMI_SYS_PWR_POWER_UP			0x3
+#define SCMI_SYS_PWR_SUSPEND			0x4
+
+/*
+ * Macros to describe the bit-fields of the `attribute` of AP core protocol
+ * AP_CORE_RESET_ADDR set/get messages.
+ */
+#define SCMI_AP_CORE_LOCK_ATTR_SHIFT		0x0
+#define SCMI_AP_CORE_LOCK_ATTR			(1U << SCMI_AP_CORE_LOCK_ATTR_SHIFT)
+
+/* SCMI Error code definitions */
+#define SCMI_E_QUEUED			1
+#define SCMI_E_SUCCESS			0
+#define SCMI_E_NOT_SUPPORTED		-1
+#define SCMI_E_INVALID_PARAM		-2
+#define SCMI_E_DENIED			-3
+#define SCMI_E_NOT_FOUND		-4
+#define SCMI_E_OUT_OF_RANGE		-5
+#define SCMI_E_BUSY			-6
+
+/*
+ * SCMI driver platform information. The details of the doorbell mechanism
+ * can be found in the SCMI specification.
+ */
+typedef struct scmi_channel_plat_info {
+	/* SCMI mailbox memory */
+	uintptr_t scmi_mbx_mem;
+	/* The door bell register address */
+	uintptr_t db_reg_addr;
+	/* The bit mask that need to be preserved when ringing doorbell */
+	uint32_t db_preserve_mask;
+	/* The bit mask that need to be set to ring doorbell */
+	uint32_t db_modify_mask;
+	/* The handler for ringing doorbell */
+	void (*ring_doorbell)(struct scmi_channel_plat_info *plat_info);
+	/* cookie is unused now. But added for future enhancements. */
+	void *cookie;
+} scmi_channel_plat_info_t;
+
+
+#if HW_ASSISTED_COHERENCY
+typedef spinlock_t scmi_lock_t;
+#else
+typedef bakery_lock_t scmi_lock_t;
+#endif
+
+/*
+ * Structure to represent an SCMI channel.
+ */
+typedef struct scmi_channel {
+	scmi_channel_plat_info_t *info;
+	 /* The lock for channel access */
+	scmi_lock_t *lock;
+	/* Indicate whether the channel is initialized */
+	int is_initialized;
+} scmi_channel_t;
+
+/* External Common API */
+void *scmi_init(scmi_channel_t *ch);
+int scmi_proto_msg_attr(void *p, uint32_t proto_id, uint32_t command_id,
+						uint32_t *attr);
+int scmi_proto_version(void *p, uint32_t proto_id, uint32_t *version);
+
+/*
+ * Power domain protocol commands. Refer to the SCMI specification for more
+ * details on these commands.
+ */
+int scmi_pwr_state_set(void *p, uint32_t domain_id, uint32_t scmi_pwr_state);
+int scmi_pwr_state_get(void *p, uint32_t domain_id, uint32_t *scmi_pwr_state);
+
+/*
+ * System power management protocol commands. Refer SCMI specification for more
+ * details on these commands.
+ */
+int scmi_sys_pwr_state_set(void *p, uint32_t flags, uint32_t system_state);
+int scmi_sys_pwr_state_get(void *p, uint32_t *system_state);
+
+/* SCMI AP core configuration protocol commands. */
+int scmi_ap_core_set_reset_addr(void *p, uint64_t reset_addr, uint32_t attr);
+int scmi_ap_core_get_reset_addr(void *p, uint64_t *reset_addr, uint32_t *attr);
+
+/* API to get the platform specific SCMI channel information. */
+scmi_channel_plat_info_t *plat_css_get_scmi_info();
+
+/* API to override default PSCI callbacks for platforms that support SCMI. */
+const plat_psci_ops_t *css_scmi_override_pm_ops(plat_psci_ops_t *ops);
+
+#endif /* SCMI_H */
diff --git a/plat/arm/board/juno/juno_pm.c b/plat/arm/board/juno/juno_pm.c
index 4864f48..cc80651 100644
--- a/plat/arm/board/juno/juno_pm.c
+++ b/plat/arm/board/juno/juno_pm.c
@@ -4,10 +4,9 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 
-#include <scmi.h>
-
 const plat_psci_ops_t *plat_arm_psci_override_pm_ops(plat_psci_ops_t *ops)
 {
 #if CSS_USE_SCMI_SDS_DRIVER
diff --git a/plat/arm/board/juno/juno_topology.c b/plat/arm/board/juno/juno_topology.c
index 1402bbd..d83bd9a 100644
--- a/plat/arm/board/juno/juno_topology.c
+++ b/plat/arm/board/juno/juno_topology.c
@@ -4,12 +4,12 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 #include <plat/arm/css/common/css_pm.h>
 #include <plat/common/platform.h>
 #include <platform_def.h>
 
-#include "../../css/drivers/scmi/scmi.h"
 #include "../../css/drivers/mhu/css_mhu_doorbell.h"
 
 #if CSS_USE_SCMI_SDS_DRIVER
diff --git a/plat/arm/board/juno/platform.mk b/plat/arm/board/juno/platform.mk
index 96c7e6c..a0281af 100644
--- a/plat/arm/board/juno/platform.mk
+++ b/plat/arm/board/juno/platform.mk
@@ -27,7 +27,6 @@
 CSS_USE_SCMI_SDS_DRIVER		:=	1
 
 PLAT_INCLUDES		:=	-Iplat/arm/board/juno/include		\
-				-Iplat/arm/css/drivers/scmi		\
 				-Iplat/arm/css/drivers/sds
 
 PLAT_BL_COMMON_SOURCES	:=	plat/arm/board/juno/${ARCH}/juno_helpers.S \
diff --git a/plat/arm/board/n1sdp/n1sdp_bl31_setup.c b/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
index 93f2803..a1669b9 100644
--- a/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
+++ b/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
@@ -6,9 +6,9 @@
 
 #include <platform_def.h>
 
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 
-#include "../../css/drivers/scmi/scmi.h"
 #include "../../css/drivers/mhu/css_mhu_doorbell.h"
 
 static scmi_channel_plat_info_t n1sdp_scmi_plat_info = {
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
index 0795306..b8e974f 100644
--- a/plat/arm/css/common/css_common.mk
+++ b/plat/arm/css/common/css_common.mk
@@ -30,11 +30,11 @@
 				plat/arm/css/drivers/mhu/css_mhu.c		\
 				plat/arm/css/drivers/scpi/css_scpi.c
 else
-BL31_SOURCES		+=	plat/arm/css/drivers/scp/css_pm_scmi.c		\
-				plat/arm/css/drivers/scmi/scmi_ap_core_proto.c	\
-				plat/arm/css/drivers/scmi/scmi_common.c		\
-				plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c	\
-				plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c	\
+BL31_SOURCES		+=	drivers/arm/css/scmi/scmi_ap_core_proto.c	\
+				drivers/arm/css/scmi/scmi_common.c		\
+				drivers/arm/css/scmi/scmi_pwr_dmn_proto.c	\
+				drivers/arm/css/scmi/scmi_sys_pwr_proto.c	\
+				plat/arm/css/drivers/scp/css_pm_scmi.c		\
 				plat/arm/css/drivers/mhu/css_mhu_doorbell.c
 endif
 
diff --git a/plat/arm/css/common/sp_min/css_sp_min.mk b/plat/arm/css/common/sp_min/css_sp_min.mk
index 9fb280c..7c2dcf5 100644
--- a/plat/arm/css/common/sp_min/css_sp_min.mk
+++ b/plat/arm/css/common/sp_min/css_sp_min.mk
@@ -13,9 +13,9 @@
 				plat/arm/css/drivers/mhu/css_mhu.c		\
 				plat/arm/css/drivers/scpi/css_scpi.c
 else
-BL32_SOURCES		+=	plat/arm/css/drivers/scp/css_pm_scmi.c		\
-				plat/arm/css/drivers/scmi/scmi_common.c		\
-				plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c	\
-				plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c	\
+BL32_SOURCES		+=	drivers/arm/css/scmi/scmi_common.c		\
+				drivers/arm/css/scmi/scmi_pwr_dmn_proto.c	\
+				drivers/arm/css/scmi/scmi_sys_pwr_proto.c	\
+				plat/arm/css/drivers/scp/css_pm_scmi.c		\
 				plat/arm/css/drivers/mhu/css_mhu_doorbell.c
 endif
diff --git a/plat/arm/css/drivers/mhu/css_mhu_doorbell.c b/plat/arm/css/drivers/mhu/css_mhu_doorbell.c
index 964428b..c031efa 100644
--- a/plat/arm/css/drivers/mhu/css_mhu_doorbell.c
+++ b/plat/arm/css/drivers/mhu/css_mhu_doorbell.c
@@ -7,9 +7,9 @@
 #include <platform_def.h>
 
 #include <arch_helpers.h>
+#include <drivers/arm/css/scmi.h>
 
 #include "css_mhu_doorbell.h"
-#include "../scmi/scmi.h"
 
 void mhu_ring_doorbell(struct scmi_channel_plat_info *plat_info)
 {
diff --git a/plat/arm/css/drivers/scmi/scmi.h b/plat/arm/css/drivers/scmi/scmi.h
deleted file mode 100644
index df259f7..0000000
--- a/plat/arm/css/drivers/scmi/scmi.h
+++ /dev/null
@@ -1,170 +0,0 @@
-/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#ifndef SCMI_H
-#define SCMI_H
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <lib/bakery_lock.h>
-#include <lib/psci/psci.h>
-#include <lib/spinlock.h>
-
-/* Supported SCMI Protocol Versions */
-#define SCMI_AP_CORE_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
-#define SCMI_PWR_DMN_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
-#define SCMI_SYS_PWR_PROTO_VER			MAKE_SCMI_VERSION(1, 0)
-
-#define GET_SCMI_MAJOR_VER(ver)			(((ver) >> 16) & 0xffff)
-#define GET_SCMI_MINOR_VER(ver)			((ver) & 0xffff)
-
-#define MAKE_SCMI_VERSION(maj, min)	\
-			((((maj) & 0xffff) << 16) | ((min) & 0xffff))
-
-/* Macro to check if the driver is compatible with the SCMI version reported */
-#define is_scmi_version_compatible(drv, scmi)				\
-	((GET_SCMI_MAJOR_VER(drv) == GET_SCMI_MAJOR_VER(scmi)) &&	\
-	(GET_SCMI_MINOR_VER(drv) <= GET_SCMI_MINOR_VER(scmi)))
-
-/* SCMI Protocol identifiers */
-#define SCMI_PWR_DMN_PROTO_ID			0x11
-#define SCMI_SYS_PWR_PROTO_ID			0x12
-/* The AP core protocol is a CSS platform-specific extension */
-#define SCMI_AP_CORE_PROTO_ID			0x90
-
-/* Mandatory messages IDs for all SCMI protocols */
-#define SCMI_PROTO_VERSION_MSG			0x0
-#define SCMI_PROTO_ATTR_MSG			0x1
-#define SCMI_PROTO_MSG_ATTR_MSG			0x2
-
-/* SCMI power domain management protocol message IDs */
-#define SCMI_PWR_STATE_SET_MSG			0x4
-#define SCMI_PWR_STATE_GET_MSG			0x5
-
-/* SCMI system power management protocol message IDs */
-#define SCMI_SYS_PWR_STATE_SET_MSG		0x3
-#define SCMI_SYS_PWR_STATE_GET_MSG		0x4
-
-/* SCMI AP core protocol message IDs */
-#define SCMI_AP_CORE_RESET_ADDR_SET_MSG		0x3
-#define SCMI_AP_CORE_RESET_ADDR_GET_MSG		0x4
-
-/* Helper macros for system power management protocol commands */
-
-/*
- * Macros to describe the bit-fields of the `attribute` of system power domain
- * protocol PROTOCOL_MSG_ATTRIBUTE message.
- */
-#define SYS_PWR_ATTR_WARM_RESET_SHIFT		31
-#define SCMI_SYS_PWR_WARM_RESET_SUPPORTED	(1U << SYS_PWR_ATTR_WARM_RESET_SHIFT)
-
-#define SYS_PWR_ATTR_SUSPEND_SHIFT		30
-#define SCMI_SYS_PWR_SUSPEND_SUPPORTED		(1 << SYS_PWR_ATTR_SUSPEND_SHIFT)
-
-/*
- * Macros to describe the bit-fields of the `flags` parameter of system power
- * domain protocol SYSTEM_POWER_STATE_SET message.
- */
-#define SYS_PWR_SET_GRACEFUL_REQ_SHIFT		0
-#define SCMI_SYS_PWR_GRACEFUL_REQ		(1 << SYS_PWR_SET_GRACEFUL_REQ_SHIFT)
-#define SCMI_SYS_PWR_FORCEFUL_REQ		(0 << SYS_PWR_SET_GRACEFUL_REQ_SHIFT)
-
-/*
- * Macros to describe the `system_state` parameter of system power
- * domain protocol SYSTEM_POWER_STATE_SET message.
- */
-#define SCMI_SYS_PWR_SHUTDOWN			0x0
-#define SCMI_SYS_PWR_COLD_RESET			0x1
-#define SCMI_SYS_PWR_WARM_RESET			0x2
-#define SCMI_SYS_PWR_POWER_UP			0x3
-#define SCMI_SYS_PWR_SUSPEND			0x4
-
-/*
- * Macros to describe the bit-fields of the `attribute` of AP core protocol
- * AP_CORE_RESET_ADDR set/get messages.
- */
-#define SCMI_AP_CORE_LOCK_ATTR_SHIFT		0x0
-#define SCMI_AP_CORE_LOCK_ATTR			(1U << SCMI_AP_CORE_LOCK_ATTR_SHIFT)
-
-/* SCMI Error code definitions */
-#define SCMI_E_QUEUED			1
-#define SCMI_E_SUCCESS			0
-#define SCMI_E_NOT_SUPPORTED		-1
-#define SCMI_E_INVALID_PARAM		-2
-#define SCMI_E_DENIED			-3
-#define SCMI_E_NOT_FOUND		-4
-#define SCMI_E_OUT_OF_RANGE		-5
-#define SCMI_E_BUSY			-6
-
-/*
- * SCMI driver platform information. The details of the doorbell mechanism
- * can be found in the SCMI specification.
- */
-typedef struct scmi_channel_plat_info {
-	/* SCMI mailbox memory */
-	uintptr_t scmi_mbx_mem;
-	/* The door bell register address */
-	uintptr_t db_reg_addr;
-	/* The bit mask that need to be preserved when ringing doorbell */
-	uint32_t db_preserve_mask;
-	/* The bit mask that need to be set to ring doorbell */
-	uint32_t db_modify_mask;
-	/* The handler for ringing doorbell */
-	void (*ring_doorbell)(struct scmi_channel_plat_info *plat_info);
-	/* cookie is unused now. But added for future enhancements. */
-	void *cookie;
-} scmi_channel_plat_info_t;
-
-
-#if HW_ASSISTED_COHERENCY
-typedef spinlock_t scmi_lock_t;
-#else
-typedef bakery_lock_t scmi_lock_t;
-#endif
-
-/*
- * Structure to represent an SCMI channel.
- */
-typedef struct scmi_channel {
-	scmi_channel_plat_info_t *info;
-	 /* The lock for channel access */
-	scmi_lock_t *lock;
-	/* Indicate whether the channel is initialized */
-	int is_initialized;
-} scmi_channel_t;
-
-/* External Common API */
-void *scmi_init(scmi_channel_t *ch);
-int scmi_proto_msg_attr(void *p, uint32_t proto_id, uint32_t command_id,
-						uint32_t *attr);
-int scmi_proto_version(void *p, uint32_t proto_id, uint32_t *version);
-
-/*
- * Power domain protocol commands. Refer to the SCMI specification for more
- * details on these commands.
- */
-int scmi_pwr_state_set(void *p, uint32_t domain_id, uint32_t scmi_pwr_state);
-int scmi_pwr_state_get(void *p, uint32_t domain_id, uint32_t *scmi_pwr_state);
-
-/*
- * System power management protocol commands. Refer SCMI specification for more
- * details on these commands.
- */
-int scmi_sys_pwr_state_set(void *p, uint32_t flags, uint32_t system_state);
-int scmi_sys_pwr_state_get(void *p, uint32_t *system_state);
-
-/* SCMI AP core configuration protocol commands. */
-int scmi_ap_core_set_reset_addr(void *p, uint64_t reset_addr, uint32_t attr);
-int scmi_ap_core_get_reset_addr(void *p, uint64_t *reset_addr, uint32_t *attr);
-
-/* API to get the platform specific SCMI channel information. */
-scmi_channel_plat_info_t *plat_css_get_scmi_info();
-
-/* API to override default PSCI callbacks for platforms that support SCMI. */
-const plat_psci_ops_t *css_scmi_override_pm_ops(plat_psci_ops_t *ops);
-
-#endif /* SCMI_H */
diff --git a/plat/arm/css/drivers/scmi/scmi_ap_core_proto.c b/plat/arm/css/drivers/scmi/scmi_ap_core_proto.c
deleted file mode 100644
index e495dcc..0000000
--- a/plat/arm/css/drivers/scmi/scmi_ap_core_proto.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#include <assert.h>
-
-#include <arch_helpers.h>
-#include <common/debug.h>
-
-#include "scmi.h"
-#include "scmi_private.h"
-
-/*
- * API to set the SCMI AP core reset address and attributes
- */
-int scmi_ap_core_set_reset_addr(void *p, uint64_t reset_addr, uint32_t attr)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_AP_CORE_PROTO_ID,
-			SCMI_AP_CORE_RESET_ADDR_SET_MSG, token);
-	mbx_mem->len = SCMI_AP_CORE_RESET_ADDR_SET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-	SCMI_PAYLOAD_ARG3(mbx_mem->payload, reset_addr & 0xffffffff,
-		reset_addr >> 32, attr);
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
-	assert(mbx_mem->len == SCMI_AP_CORE_RESET_ADDR_SET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
-
-/*
- * API to get the SCMI AP core reset address and attributes
- */
-int scmi_ap_core_get_reset_addr(void *p, uint64_t *reset_addr, uint32_t *attr)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-	uint32_t lo_addr, hi_addr;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_AP_CORE_PROTO_ID,
-			SCMI_AP_CORE_RESET_ADDR_GET_MSG, token);
-	mbx_mem->len = SCMI_AP_CORE_RESET_ADDR_GET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL4(mbx_mem->payload, ret, lo_addr, hi_addr, *attr);
-	*reset_addr = lo_addr | (uint64_t)hi_addr << 32;
-	assert(mbx_mem->len == SCMI_AP_CORE_RESET_ADDR_GET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
diff --git a/plat/arm/css/drivers/scmi/scmi_common.c b/plat/arm/css/drivers/scmi/scmi_common.c
deleted file mode 100644
index 1b4ecb2..0000000
--- a/plat/arm/css/drivers/scmi/scmi_common.c
+++ /dev/null
@@ -1,208 +0,0 @@
-/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#include <assert.h>
-
-#include <arch_helpers.h>
-#include <common/debug.h>
-
-#include "scmi.h"
-#include "scmi_private.h"
-
-#if HW_ASSISTED_COHERENCY
-#define scmi_lock_init(lock)
-#define scmi_lock_get(lock)		spin_lock(lock)
-#define scmi_lock_release(lock)		spin_unlock(lock)
-#else
-#define scmi_lock_init(lock)		bakery_lock_init(lock)
-#define scmi_lock_get(lock)		bakery_lock_get(lock)
-#define scmi_lock_release(lock)		bakery_lock_release(lock)
-#endif
-
-
-/*
- * Private helper function to get exclusive access to SCMI channel.
- */
-void scmi_get_channel(scmi_channel_t *ch)
-{
-	assert(ch->lock);
-	scmi_lock_get(ch->lock);
-
-	/* Make sure any previous command has finished */
-	assert(SCMI_IS_CHANNEL_FREE(
-			((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
-}
-
-/*
- * Private helper function to transfer ownership of channel from AP to SCP.
- */
-void scmi_send_sync_command(scmi_channel_t *ch)
-{
-	mailbox_mem_t *mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-
-	SCMI_MARK_CHANNEL_BUSY(mbx_mem->status);
-
-	/*
-	 * Ensure that any write to the SCMI payload area is seen by SCP before
-	 * we write to the doorbell register. If these 2 writes were reordered
-	 * by the CPU then SCP would read stale payload data
-	 */
-	dmbst();
-
-	ch->info->ring_doorbell(ch->info);
-	/*
-	 * Ensure that the write to the doorbell register is ordered prior to
-	 * checking whether the channel is free.
-	 */
-	dmbsy();
-
-	/* Wait for channel to be free */
-	while (!SCMI_IS_CHANNEL_FREE(mbx_mem->status))
-		;
-
-	/*
-	 * Ensure that any read to the SCMI payload area is done after reading
-	 * mailbox status. If these 2 reads were reordered then the CPU would
-	 * read invalid payload data
-	 */
-	dmbld();
-}
-
-/*
- * Private helper function to release exclusive access to SCMI channel.
- */
-void scmi_put_channel(scmi_channel_t *ch)
-{
-	/* Make sure any previous command has finished */
-	assert(SCMI_IS_CHANNEL_FREE(
-			((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
-
-	assert(ch->lock);
-	scmi_lock_release(ch->lock);
-}
-
-/*
- * API to query the SCMI protocol version.
- */
-int scmi_proto_version(void *p, uint32_t proto_id, uint32_t *version)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id, SCMI_PROTO_VERSION_MSG,
-							token);
-	mbx_mem->len = SCMI_PROTO_VERSION_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *version);
-	assert(mbx_mem->len == SCMI_PROTO_VERSION_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
-
-/*
- * API to query the protocol message attributes for a SCMI protocol.
- */
-int scmi_proto_msg_attr(void *p, uint32_t proto_id,
-		uint32_t command_id, uint32_t *attr)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id,
-				SCMI_PROTO_MSG_ATTR_MSG, token);
-	mbx_mem->len = SCMI_PROTO_MSG_ATTR_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-	SCMI_PAYLOAD_ARG1(mbx_mem->payload, command_id);
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *attr);
-	assert(mbx_mem->len == SCMI_PROTO_MSG_ATTR_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
-
-/*
- * SCMI Driver initialization API. Returns initialized channel on success
- * or NULL on error. The return type is an opaque void pointer.
- */
-void *scmi_init(scmi_channel_t *ch)
-{
-	uint32_t version;
-	int ret;
-
-	assert(ch && ch->info);
-	assert(ch->info->db_reg_addr);
-	assert(ch->info->db_modify_mask);
-	assert(ch->info->db_preserve_mask);
-	assert(ch->info->ring_doorbell != NULL);
-
-	assert(ch->lock);
-
-	scmi_lock_init(ch->lock);
-
-	ch->is_initialized = 1;
-
-	ret = scmi_proto_version(ch, SCMI_PWR_DMN_PROTO_ID, &version);
-	if (ret != SCMI_E_SUCCESS) {
-		WARN("SCMI power domain protocol version message failed");
-		goto error;
-	}
-
-	if (!is_scmi_version_compatible(SCMI_PWR_DMN_PROTO_VER, version)) {
-		WARN("SCMI power domain protocol version 0x%x incompatible with driver version 0x%x",
-			version, SCMI_PWR_DMN_PROTO_VER);
-		goto error;
-	}
-
-	VERBOSE("SCMI power domain protocol version 0x%x detected\n", version);
-
-	ret = scmi_proto_version(ch, SCMI_SYS_PWR_PROTO_ID, &version);
-	if ((ret != SCMI_E_SUCCESS)) {
-		WARN("SCMI system power protocol version message failed");
-		goto error;
-	}
-
-	if (!is_scmi_version_compatible(SCMI_SYS_PWR_PROTO_VER, version)) {
-		WARN("SCMI system power management protocol version 0x%x incompatible with driver version 0x%x",
-			version, SCMI_SYS_PWR_PROTO_VER);
-		goto error;
-	}
-
-	VERBOSE("SCMI system power management protocol version 0x%x detected\n",
-						version);
-
-	INFO("SCMI driver initialized\n");
-
-	return (void *)ch;
-
-error:
-	ch->is_initialized = 0;
-	return NULL;
-}
diff --git a/plat/arm/css/drivers/scmi/scmi_private.h b/plat/arm/css/drivers/scmi/scmi_private.h
deleted file mode 100644
index 6530573..0000000
--- a/plat/arm/css/drivers/scmi/scmi_private.h
+++ /dev/null
@@ -1,155 +0,0 @@
-/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#ifndef SCMI_PRIVATE_H
-#define SCMI_PRIVATE_H
-
-#include <lib/mmio.h>
-
-/*
- * SCMI power domain management protocol message and response lengths. It is
- * calculated as sum of length in bytes of the message header (4) and payload
- * area (the number of bytes of parameters or return values in the payload).
- */
-#define SCMI_PROTO_VERSION_MSG_LEN		4
-#define SCMI_PROTO_VERSION_RESP_LEN		12
-
-#define SCMI_PROTO_MSG_ATTR_MSG_LEN		8
-#define SCMI_PROTO_MSG_ATTR_RESP_LEN		12
-
-#define SCMI_AP_CORE_RESET_ADDR_SET_MSG_LEN	16
-#define SCMI_AP_CORE_RESET_ADDR_SET_RESP_LEN	8
-
-#define SCMI_AP_CORE_RESET_ADDR_GET_MSG_LEN	4
-#define SCMI_AP_CORE_RESET_ADDR_GET_RESP_LEN	20
-
-#define SCMI_PWR_STATE_SET_MSG_LEN		16
-#define SCMI_PWR_STATE_SET_RESP_LEN		8
-
-#define SCMI_PWR_STATE_GET_MSG_LEN		8
-#define SCMI_PWR_STATE_GET_RESP_LEN		12
-
-#define SCMI_SYS_PWR_STATE_SET_MSG_LEN		12
-#define SCMI_SYS_PWR_STATE_SET_RESP_LEN		8
-
-#define SCMI_SYS_PWR_STATE_GET_MSG_LEN		4
-#define SCMI_SYS_PWR_STATE_GET_RESP_LEN		12
-
-/* SCMI message header format bit field */
-#define SCMI_MSG_ID_SHIFT		0
-#define SCMI_MSG_ID_WIDTH		8
-#define SCMI_MSG_ID_MASK		((1 << SCMI_MSG_ID_WIDTH) - 1)
-
-#define SCMI_MSG_TYPE_SHIFT		8
-#define SCMI_MSG_TYPE_WIDTH		2
-#define SCMI_MSG_TYPE_MASK		((1 << SCMI_MSG_TYPE_WIDTH) - 1)
-
-#define SCMI_MSG_PROTO_ID_SHIFT		10
-#define SCMI_MSG_PROTO_ID_WIDTH		8
-#define SCMI_MSG_PROTO_ID_MASK		((1 << SCMI_MSG_PROTO_ID_WIDTH) - 1)
-
-#define SCMI_MSG_TOKEN_SHIFT		18
-#define SCMI_MSG_TOKEN_WIDTH		10
-#define SCMI_MSG_TOKEN_MASK		((1 << SCMI_MSG_TOKEN_WIDTH) - 1)
-
-
-/* SCMI mailbox flags */
-#define SCMI_FLAG_RESP_POLL	0
-#define SCMI_FLAG_RESP_INT	1
-
-/* SCMI power domain protocol `POWER_STATE_SET` message flags */
-#define SCMI_PWR_STATE_SET_FLAG_SYNC	0
-#define SCMI_PWR_STATE_SET_FLAG_ASYNC	1
-
-/*
- * Helper macro to create an SCMI message header given protocol, message id
- * and token.
- */
-#define SCMI_MSG_CREATE(_protocol, _msg_id, _token)				\
-	((((_protocol) & SCMI_MSG_PROTO_ID_MASK) << SCMI_MSG_PROTO_ID_SHIFT) |	\
-	(((_msg_id) & SCMI_MSG_ID_MASK) << SCMI_MSG_ID_SHIFT) |			\
-	(((_token) & SCMI_MSG_TOKEN_MASK) << SCMI_MSG_TOKEN_SHIFT))
-
-/* Helper macro to get the token from a SCMI message header */
-#define SCMI_MSG_GET_TOKEN(_msg)				\
-	(((_msg) >> SCMI_MSG_TOKEN_SHIFT) & SCMI_MSG_TOKEN_MASK)
-
-/* SCMI Channel Status bit fields */
-#define SCMI_CH_STATUS_RES0_MASK	0xFFFFFFFE
-#define SCMI_CH_STATUS_FREE_SHIFT	0
-#define SCMI_CH_STATUS_FREE_WIDTH	1
-#define SCMI_CH_STATUS_FREE_MASK	((1 << SCMI_CH_STATUS_FREE_WIDTH) - 1)
-
-/* Helper macros to check and write the channel status */
-#define SCMI_IS_CHANNEL_FREE(status)					\
-	(!!(((status) >> SCMI_CH_STATUS_FREE_SHIFT) & SCMI_CH_STATUS_FREE_MASK))
-
-#define SCMI_MARK_CHANNEL_BUSY(status)	do {				\
-		assert(SCMI_IS_CHANNEL_FREE(status));			\
-		(status) &= ~(SCMI_CH_STATUS_FREE_MASK <<		\
-				SCMI_CH_STATUS_FREE_SHIFT);		\
-	} while (0)
-
-/* Helper macros to copy arguments to the mailbox payload */
-#define SCMI_PAYLOAD_ARG1(payld_arr, arg1)				\
-		mmio_write_32((uintptr_t)&payld_arr[0], arg1)
-
-#define SCMI_PAYLOAD_ARG2(payld_arr, arg1, arg2)	do {		\
-		SCMI_PAYLOAD_ARG1(payld_arr, arg1);			\
-		mmio_write_32((uintptr_t)&payld_arr[1], arg2);		\
-	} while (0)
-
-#define SCMI_PAYLOAD_ARG3(payld_arr, arg1, arg2, arg3)	do {		\
-		SCMI_PAYLOAD_ARG2(payld_arr, arg1, arg2);		\
-		mmio_write_32((uintptr_t)&payld_arr[2], arg3);		\
-	} while (0)
-
-/* Helper macros to read return values from the mailbox payload */
-#define SCMI_PAYLOAD_RET_VAL1(payld_arr, val1)				\
-		(val1) = mmio_read_32((uintptr_t)&payld_arr[0])
-
-#define SCMI_PAYLOAD_RET_VAL2(payld_arr, val1, val2)	do {		\
-		SCMI_PAYLOAD_RET_VAL1(payld_arr, val1);			\
-		(val2) = mmio_read_32((uintptr_t)&payld_arr[1]);	\
-	} while (0)
-
-#define SCMI_PAYLOAD_RET_VAL3(payld_arr, val1, val2, val3)	do {	\
-		SCMI_PAYLOAD_RET_VAL2(payld_arr, val1, val2);		\
-		(val3) = mmio_read_32((uintptr_t)&payld_arr[2]);	\
-	} while (0)
-
-#define SCMI_PAYLOAD_RET_VAL4(payld_arr, val1, val2, val3, val4)	do {	\
-		SCMI_PAYLOAD_RET_VAL3(payld_arr, val1, val2, val3);		\
-		(val4) = mmio_read_32((uintptr_t)&payld_arr[3]);		\
-	} while (0)
-
-/*
- * Private data structure for representing the mailbox memory layout. Refer
- * the SCMI specification for more details.
- */
-typedef struct mailbox_mem {
-	uint32_t res_a; /* Reserved */
-	volatile uint32_t status;
-	uint64_t res_b; /* Reserved */
-	uint32_t flags;
-	volatile uint32_t len;
-	uint32_t msg_header;
-	uint32_t payload[];
-} mailbox_mem_t;
-
-
-/* Private APIs for use within SCMI driver */
-void scmi_get_channel(scmi_channel_t *ch);
-void scmi_send_sync_command(scmi_channel_t *ch);
-void scmi_put_channel(scmi_channel_t *ch);
-
-static inline void validate_scmi_channel(scmi_channel_t *ch)
-{
-	assert(ch && ch->is_initialized);
-	assert(ch->info && ch->info->scmi_mbx_mem);
-}
-
-#endif /* SCMI_PRIVATE_H */
diff --git a/plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c b/plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c
deleted file mode 100644
index f315621..0000000
--- a/plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#include <assert.h>
-
-#include <arch_helpers.h>
-#include <common/debug.h>
-
-#include "scmi.h"
-#include "scmi_private.h"
-
-/*
- * API to set the SCMI power domain power state.
- */
-int scmi_pwr_state_set(void *p, uint32_t domain_id,
-					uint32_t scmi_pwr_state)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-
-	/*
-	 * Only asynchronous mode of `set power state` command is allowed on
-	 * application processors.
-	 */
-	uint32_t pwr_state_set_msg_flag = SCMI_PWR_STATE_SET_FLAG_ASYNC;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_PWR_DMN_PROTO_ID,
-			SCMI_PWR_STATE_SET_MSG, token);
-	mbx_mem->len = SCMI_PWR_STATE_SET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-	SCMI_PAYLOAD_ARG3(mbx_mem->payload, pwr_state_set_msg_flag,
-						domain_id, scmi_pwr_state);
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
-	assert(mbx_mem->len == SCMI_PWR_STATE_SET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
-
-/*
- * API to get the SCMI power domain power state.
- */
-int scmi_pwr_state_get(void *p, uint32_t domain_id,
-					uint32_t *scmi_pwr_state)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_PWR_DMN_PROTO_ID,
-			SCMI_PWR_STATE_GET_MSG, token);
-	mbx_mem->len = SCMI_PWR_STATE_GET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-	SCMI_PAYLOAD_ARG1(mbx_mem->payload, domain_id);
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *scmi_pwr_state);
-	assert(mbx_mem->len == SCMI_PWR_STATE_GET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
diff --git a/plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c b/plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c
deleted file mode 100644
index 03c3c06..0000000
--- a/plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#include <assert.h>
-
-#include <arch_helpers.h>
-#include <common/debug.h>
-
-#include "scmi.h"
-#include "scmi_private.h"
-
-/*
- * API to set the SCMI system power state
- */
-int scmi_sys_pwr_state_set(void *p, uint32_t flags, uint32_t system_state)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_SYS_PWR_PROTO_ID,
-			SCMI_SYS_PWR_STATE_SET_MSG, token);
-	mbx_mem->len = SCMI_SYS_PWR_STATE_SET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-	SCMI_PAYLOAD_ARG2(mbx_mem->payload, flags, system_state);
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL1(mbx_mem->payload, ret);
-	assert(mbx_mem->len == SCMI_SYS_PWR_STATE_SET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
-
-/*
- * API to get the SCMI system power state
- */
-int scmi_sys_pwr_state_get(void *p, uint32_t *system_state)
-{
-	mailbox_mem_t *mbx_mem;
-	int token = 0, ret;
-	scmi_channel_t *ch = (scmi_channel_t *)p;
-
-	validate_scmi_channel(ch);
-
-	scmi_get_channel(ch);
-
-	mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
-	mbx_mem->msg_header = SCMI_MSG_CREATE(SCMI_SYS_PWR_PROTO_ID,
-			SCMI_SYS_PWR_STATE_GET_MSG, token);
-	mbx_mem->len = SCMI_SYS_PWR_STATE_GET_MSG_LEN;
-	mbx_mem->flags = SCMI_FLAG_RESP_POLL;
-
-	scmi_send_sync_command(ch);
-
-	/* Get the return values */
-	SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *system_state);
-	assert(mbx_mem->len == SCMI_SYS_PWR_STATE_GET_RESP_LEN);
-	assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
-
-	scmi_put_channel(ch);
-
-	return ret;
-}
diff --git a/plat/arm/css/drivers/scp/css_pm_scmi.c b/plat/arm/css/drivers/scp/css_pm_scmi.c
index ab9f5f5..2980d9a 100644
--- a/plat/arm/css/drivers/scp/css_pm_scmi.c
+++ b/plat/arm/css/drivers/scp/css_pm_scmi.c
@@ -9,12 +9,12 @@
 
 #include <arch_helpers.h>
 #include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 #include <plat/arm/css/common/css_pm.h>
 #include <plat/common/platform.h>
 #include <platform_def.h>
 
-#include "../scmi/scmi.h"
 #include "css_scp.h"
 
 /*
diff --git a/plat/arm/css/sgi/sgi_bl31_setup.c b/plat/arm/css/sgi/sgi_bl31_setup.c
index 5324482..82d8fed 100644
--- a/plat/arm/css/sgi/sgi_bl31_setup.c
+++ b/plat/arm/css/sgi/sgi_bl31_setup.c
@@ -10,12 +10,12 @@
 
 #include <common/bl_common.h>
 #include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 
 #include <sgi_ras.h>
 #include <sgi_variant.h>
 
-#include "../../css/drivers/scmi/scmi.h"
 #include "../../css/drivers/mhu/css_mhu_doorbell.h"
 
 sgi_platform_info_t sgi_plat_info;
diff --git a/plat/arm/css/sgm/sgm_bl31_setup.c b/plat/arm/css/sgm/sgm_bl31_setup.c
index 03d88e8..d9490b1 100644
--- a/plat/arm/css/sgm/sgm_bl31_setup.c
+++ b/plat/arm/css/sgm/sgm_bl31_setup.c
@@ -6,10 +6,10 @@
 
 #include <common/bl_common.h>
 #include <common/debug.h>
+#include <drivers/arm/css/scmi.h>
 #include <plat/arm/common/plat_arm.h>
 
 #include <sgm_plat_config.h>
-#include "../../css/drivers/scmi/scmi.h"
 #include "../../css/drivers/mhu/css_mhu_doorbell.h"
 
 static scmi_channel_plat_info_t sgm775_scmi_plat_info = {