/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef _SPCOM_H_
#define _SPCOM_H_

#include <linux/types.h>	/* uint32_t ,bool */

/**
 * @brief - Secure Processor Communication API
 *
 * This API should be used by Linux Kernel drivers,
 * similar API is provided to user space applications
 * via spcomlib.h API file.
 * Sending Request and receiving Response is synchronous, only one at a time.
 * The API is based on Client/Server model.
 * The API resemble the trustzone QSEECOM API.
 * In most cases, the Secure Processor side has servers and the HLOS
 * side has clients. Request is initiated by the client and responded by the
 * server.
 */

/*===========================================================================*/
/*                           defines, enums , types                          */
/*===========================================================================*/

/* Maximum size (including null) for channel names - match glink */
#define SPCOM_CHANNEL_NAME_SIZE		32

/**
 * Request buffer size.
 * Any large data (multiply of 4KB) is provided by temp buffer in DDR.
 * Request shall provide the temp buffer physical address (align to 4KB).
 * Maximum request/response size of 268 is used to accommodate APDU size.
 * From kernel spcom driver perspective a PAGE_SIZE of 4K
 * is the actual maximum size for a single read/write file operation.
 */
#define SPCOM_MAX_REQUEST_SIZE		268
#define SPCOM_MAX_RESPONSE_SIZE		268

/**
 * Abstract spcom handle.
 * The actual struct definition is internal to the spcom driver.
 */
struct spcom_client; /* Forward declaration */
struct spcom_server; /* Forward declaration */

/**
 * Client registration info
 *
 * @ch_name:	glink logical channel name
 * @notify_ssr_cb: callback when the remote SP side reset (power down).
 *      This is likely to happen due to remote subsystem restart (SSR).
 *      NULL callback means no notification required.
 *      Upon ssr callback, the user should unregister,
 *      Poll for link up and then register again.
 */
struct spcom_client_info {
	const char *ch_name;
	void (*notify_ssr_cb)(void);
};

/**
 * Server registration info
 *
 * @ch_name:	glink logical channel name
 * @notify_ssr_cb: callback when the remote SP side reset (power down).
 *      This is likely to happen due to remote subsystem restart (SSR).
 *      NULL callback means no notification required.
 *      Upon ssr callback, the user should unregister,
 *      Poll for link up and then register again.
 */
struct spcom_service_info {
	const char *ch_name;
	void (*notify_ssr_cb)(void);
};

/*===========================================================================*/
/*                           RESET                                           */
/*===========================================================================*/


/**
 * spcom_reset_sp_subsystem() - send reset command to secure processor.
 *
 * Gracefully ask the remote SP to reset itself.
 * SP will probably initiate a Watch-Dog-Bite.
 *
 * return: 0 on success, negative error code on failure.
 */
int spcom_reset_sp_subsystem(void);

/**
 * spcom_is_sp_subsystem_link_up() - check if SPSS link is up.
 *
 * return: true if link is up, false if link is down.
 */
bool spcom_is_sp_subsystem_link_up(void);

/*===========================================================================*/
/*                           Client LOAD SP Application                      */
/*===========================================================================*/

/**
 * spcom_is_app_loaded() - check if the SP App is already loaded.
 *
 * This shall be useful when the HLOS app restarts.
 * This API will check if logical channel node has been created.
 *
 * @ch_name:	glink logical channel name
 *
 * @note: This API is available only on HLOS.
 *
 * return: true if loaded,false otherwise.
 */
bool spcom_is_app_loaded(const char *ch_name);

/**
 * spcom_load_app() - Load Secure Processor Application.
 *
 * @ch_name:	glink logical channel name
 *      spcom shall open channel file node after application is loaded.
 *
 * @file_path:	Path to the encrypted file containing the application.
 *
 * @note: This API is available only on HLOS.
 *
 * return: 0 on success, negative error code on failure.
 */
int spcom_load_app(const char *ch_name, const char *file_path);

/*===========================================================================*/
/*                           Client Send Message                             */
/*===========================================================================*/
/**
 * spcom_register_client() - register client for channel
 *
 * Only one client/Server can register on each side of a channel.
 * Server on remote side is expected to be running and connected,
 * therefore connection expected within the provided timeout.
 * Handle is returned even if timeout expired.
 * use spcom_client_is_server_connected() to check fully connected.
 *
 * @info:	Client configuration info (input).
 *
 * return: client handle on success, NULL on failure.
 */
struct spcom_client *spcom_register_client(struct spcom_client_info *info);

/**
 * spcom_unregister_client() - unregister client for channel
 *
 * @client:	Client Handle.
 *
 * return: 0 on success, negative error code on failure (see errno.h)
 */
int spcom_unregister_client(struct spcom_client *client);

/**
 * spcom_client_send_message_sync() - Send a synchronous request and response
 *
 * @client:	a pointer to spcom client
 * @req_ptr:	a pointer to the request C struct representation
 * @req_size:	size of the request C struct
 * @resp_ptr:	a pointer to the response C struct representation
 * @resp_size:  size of the response C struct
 * @timeout_msec: Timeout in msec between command and response, 0=no timeout.
 *
 * return: number of rx bytes on success, negative value on failure.
 */
int spcom_client_send_message_sync(struct spcom_client	*client,
				   void			*req_ptr,
				   uint32_t		req_size,
				   void			*resp_ptr,
				   uint32_t		resp_size,
				   uint32_t		timeout_msec);

/**
 * spcom_client_is_server_connected() - Check if remote server connected.
 *
 * This API checks that the logical channel is fully connected between
 * the client and the server.
 * Normally, the server should be up first and connect first.
 *
 * @client:	a pointer to spcom client
 *
 * return: true if server connected, false otherwise.
 */
bool spcom_client_is_server_connected(struct spcom_client *client);

/*===========================================================================*/
/*                           Service                                         */
/*===========================================================================*/

/**
 * spcom_register_service() - register server for channel
 *
 * Only one client/Server can register on each side of a channel.
 *
 * @info:	Server configuration info (input).
 *
 * return: server handle on success, NULL on failure.
 */
struct spcom_server *spcom_register_service(struct spcom_service_info *info);

/**
 * spcom_unregister_service() - unregister server for channel
 *
 * @server:	server Handle.
 *
 * return: 0 on success, negative error code on failure (see errno.h)
 */
int spcom_unregister_service(struct spcom_server *server);

/**
 * spcom_server_get_next_request_size() - get the size of the
 * next request
 *
 * This API MUST be called before calling spcom_server_wait_for_request().
 * The server should allocate the relevant buffer size.
 *
 * @server:	a pointer to spcom server
 *
 * return: size of request in bytes on success, negative value on failure.
 */
int spcom_server_get_next_request_size(struct spcom_server *server);

/**
 * spcom_server_wait_for_request() - server wait for request
 *
 * @server:     a pointer to spcom server
 * @req_ptr:	a pointer to the request buffer
 * @req_size:	size of the buffer provided.
 * The server should provide a buffer of at least the size
 * returned by spcom_server_get_next_request_size() and up to
 * SPCOM_MAX_REQUEST_SIZE.
 *
 * return: size of request on success, negative value on failure (see errno.h)
 */
int spcom_server_wait_for_request(struct spcom_server	*server,
				  void			*req_ptr,
				  uint32_t		req_size);

/**
 * spcom_server_send_response() - Send a the response to request
 *
 * @server:	a pointer to spcom server
 * @resp_ptr:	a pointer to the response C struct representation
 * @resp_size:  size of the response C struct
 *
 * return: sent data size on success, negative value on failure (see errno.h)
 */
int spcom_server_send_response(struct spcom_server	*server,
			       void			*resp_ptr,
			       uint32_t		resp_size);

#endif /* _SPCOM_H_ */