/*
 * Texas Instruments System Control Interface (TISCI) Protocol
 *
 * Communication protocol with TI SCI hardware
 * The system works in a message response protocol
 * See: http://processors.wiki.ti.com/index.php/TISCI for details
 *
 * Copyright (C)  2015-2016 Texas Instruments Incorporated - http://www.ti.com/
 *
 * 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 Texas Instruments Incorporated 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
 * OWNER 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.
 *
 */

#ifndef __TI_SCI_H
#define __TI_SCI_H

/* Generic Messages */
#define TI_SCI_MSG_ENABLE_WDT	0x0000
#define TI_SCI_MSG_WAKE_RESET	0x0001
#define TI_SCI_MSG_VERSION	0x0002
#define TI_SCI_MSG_WAKE_REASON	0x0003
#define TI_SCI_MSG_GOODBYE	0x0004

/* Device requests */
#define TI_SCI_MSG_SET_DEVICE_STATE	0x0200
#define TI_SCI_MSG_GET_DEVICE_STATE	0x0201
#define TI_SCI_MSG_SET_DEVICE_RESETS	0x0202

/**
 * struct ti_sci_msg_hdr - Generic Message Header for All messages and responses
 * @type:	Type of messages: One of TI_SCI_MSG* values
 * @host:	Host of the message
 * @seq:	Message identifier indicating a transfer sequence
 * @flags:	Flag for the message
 */
struct ti_sci_msg_hdr {
	u16 type;
	u8 host;
	u8 seq;
#define TI_SCI_MSG_FLAG(val)			(1 << (val))
#define TI_SCI_FLAG_REQ_GENERIC_NORESPONSE	0x0
#define TI_SCI_FLAG_REQ_ACK_ON_RECEIVED		TI_SCI_MSG_FLAG(0)
#define TI_SCI_FLAG_REQ_ACK_ON_PROCESSED	TI_SCI_MSG_FLAG(1)
#define TI_SCI_FLAG_RESP_GENERIC_NACK		0x0
#define TI_SCI_FLAG_RESP_GENERIC_ACK		TI_SCI_MSG_FLAG(1)
	/* Additional Flags */
	u32 flags;
} __packed;

/**
 * struct ti_sci_msg_resp_version - Response for a message
 * @hdr:		Generic header
 * @firmware_description: String describing the firmware
 * @firmware_revision:	Firmware revision
 * @abi_major:		Major version of the ABI that firmware supports
 * @abi_minor:		Minor version of the ABI that firmware supports
 *
 * In general, ABI version changes follow the rule that minor version increments
 * are backward compatible. Major revision changes in ABI may not be
 * backward compatible.
 *
 * Response to a generic message with message type TI_SCI_MSG_VERSION
 */
struct ti_sci_msg_resp_version {
	struct ti_sci_msg_hdr hdr;
	char firmware_description[32];
	u16 firmware_revision;
	u8 abi_major;
	u8 abi_minor;
} __packed;

/**
 * struct ti_sci_msg_req_set_device_state - Set the desired state of the device
 * @hdr:		Generic header
 * @id:	Indicates which device to modify
 * @reserved: Reserved space in message, must be 0 for backward compatibility
 * @state: The desired state of the device.
 *
 * Certain flags can also be set to alter the device state:
 * + MSG_FLAG_DEVICE_WAKE_ENABLED - Configure the device to be a wake source.
 * The meaning of this flag will vary slightly from device to device and from
 * SoC to SoC but it generally allows the device to wake the SoC out of deep
 * suspend states.
 * + MSG_FLAG_DEVICE_RESET_ISO - Enable reset isolation for this device.
 * + MSG_FLAG_DEVICE_EXCLUSIVE - Claim this device exclusively. When passed
 * with STATE_RETENTION or STATE_ON, it will claim the device exclusively.
 * If another host already has this device set to STATE_RETENTION or STATE_ON,
 * the message will fail. Once successful, other hosts attempting to set
 * STATE_RETENTION or STATE_ON will fail.
 *
 * Request type is TI_SCI_MSG_SET_DEVICE_STATE, responded with a generic
 * ACK/NACK message.
 */
struct ti_sci_msg_req_set_device_state {
	/* Additional hdr->flags options */
#define MSG_FLAG_DEVICE_WAKE_ENABLED	TI_SCI_MSG_FLAG(8)
#define MSG_FLAG_DEVICE_RESET_ISO	TI_SCI_MSG_FLAG(9)
#define MSG_FLAG_DEVICE_EXCLUSIVE	TI_SCI_MSG_FLAG(10)
	struct ti_sci_msg_hdr hdr;
	u32 id;
	u32 reserved;

#define MSG_DEVICE_SW_STATE_AUTO_OFF	0
#define MSG_DEVICE_SW_STATE_RETENTION	1
#define MSG_DEVICE_SW_STATE_ON		2
	u8 state;
} __packed;

/**
 * struct ti_sci_msg_req_get_device_state - Request to get device.
 * @hdr:		Generic header
 * @id:		Device Identifier
 *
 * Request type is TI_SCI_MSG_GET_DEVICE_STATE, responded device state
 * information
 */
struct ti_sci_msg_req_get_device_state {
	struct ti_sci_msg_hdr hdr;
	u32 id;
} __packed;

/**
 * struct ti_sci_msg_resp_get_device_state - Response to get device request.
 * @hdr:		Generic header
 * @context_loss_count: Indicates how many times the device has lost context. A
 *	driver can use this monotonic counter to determine if the device has
 *	lost context since the last time this message was exchanged.
 * @resets: Programmed state of the reset lines.
 * @programmed_state:	The state as programmed by set_device.
 *			- Uses the MSG_DEVICE_SW_* macros
 * @current_state:	The actual state of the hardware.
 *
 * Response to request TI_SCI_MSG_GET_DEVICE_STATE.
 */
struct ti_sci_msg_resp_get_device_state {
	struct ti_sci_msg_hdr hdr;
	u32 context_loss_count;
	u32 resets;
	u8 programmed_state;
#define MSG_DEVICE_HW_STATE_OFF		0
#define MSG_DEVICE_HW_STATE_ON		1
#define MSG_DEVICE_HW_STATE_TRANS	2
	u8 current_state;
} __packed;

/**
 * struct ti_sci_msg_req_set_device_resets - Set the desired resets
 *				configuration of the device
 * @hdr:		Generic header
 * @id:	Indicates which device to modify
 * @resets: A bit field of resets for the device. The meaning, behavior,
 *	and usage of the reset flags are device specific. 0 for a bit
 *	indicates releasing the reset represented by that bit while 1
 *	indicates keeping it held.
 *
 * Request type is TI_SCI_MSG_SET_DEVICE_RESETS, responded with a generic
 * ACK/NACK message.
 */
struct ti_sci_msg_req_set_device_resets {
	struct ti_sci_msg_hdr hdr;
	u32 id;
	u32 resets;
} __packed;

#endif /* __TI_SCI_H */