text: /* SPDX-License-Identifier: GPL-2.0 */
  /*
   * System Control and Management Interface (SCMI) Message Protocol
   * driver common header file containing some definitions, structures
   * and function prototypes used in all the different SCMI protocols.
   *
   * Copyright (C) 2018 ARM Ltd.
   */
  
  #include <linux/bitfield.h>
  #include <linux/completion.h>
  #include <linux/device.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/scmi_protocol.h>
  #include <linux/types.h>
  
  #define PROTOCOL_REV_MINOR_MASK	GENMASK(15, 0)
  #define PROTOCOL_REV_MAJOR_MASK	GENMASK(31, 16)
  #define PROTOCOL_REV_MAJOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))
  #define PROTOCOL_REV_MINOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))
  #define MAX_PROTOCOLS_IMP	16
  #define MAX_OPPS		16
  
  enum scmi_common_cmd {
  	PROTOCOL_VERSION = 0x0,
  	PROTOCOL_ATTRIBUTES = 0x1,
  	PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
  };
  
  /**
   * struct scmi_msg_resp_prot_version - Response for a message
   *
   * @major_version: Major version of the ABI that firmware supports
   * @minor_version: 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 SCMI_MSG_VERSION
   */
  struct scmi_msg_resp_prot_version {
  	__le16 minor_version;
  	__le16 major_version;
  };
  
  /**
   * struct scmi_msg_hdr - Message(Tx/Rx) header
   *
   * @id: The identifier of the command being sent
   * @protocol_id: The identifier of the protocol used to send @id command
   * @seq: The token to identify the message. when a message/command returns,
   *	the platform returns the whole message header unmodified including
   *	the token
   * @status: Status of the transfer once it's complete
   * @poll_completion: Indicate if the transfer needs to be polled for
   *	completion or interrupt mode is used
   */
  struct scmi_msg_hdr {
  	u8 id;
  	u8 protocol_id;
  	u16 seq;
  	u32 status;
  	bool poll_completion;
  };
  
  /**
   * struct scmi_msg - Message(Tx/Rx) structure
   *
   * @buf: Buffer pointer
   * @len: Length of data in the Buffer
   */
  struct scmi_msg {
  	void *buf;
  	size_t len;
  };
  
  /**
   * struct scmi_xfer - Structure representing a message flow
   *
   * @hdr: Transmit message header
   * @tx: Transmit message
   * @rx: Receive message, the buffer should be pre-allocated to store
   *	message. If request-ACK protocol is used, we can reuse the same
   *	buffer for the rx path as we use for the tx path.
   * @done: completion event
   */
  struct scmi_xfer {
  	struct scmi_msg_hdr hdr;
  	struct scmi_msg tx;
  	struct scmi_msg rx;
  	struct completion done;
  };
  
  void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
  int scmi_do_xfer(const struct scmi_handle *h, struct scmi_xfer *xfer);
  int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
  		       size_t tx_size, size_t rx_size, struct scmi_xfer **p);
  int scmi_handle_put(const struct scmi_handle *handle);
  struct scmi_handle *scmi_handle_get(struct device *dev);
  void scmi_set_handle(struct scmi_device *scmi_dev);
  int scmi_version_get(const struct scmi_handle *h, u8 protocol, u32 *version);
  void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
  				     u8 *prot_imp);
  
  int scmi_base_protocol_init(struct scmi_handle *h);
  