include/scmi_agent.h

   1 /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
   2 /*
   3  * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
   4  * Copyright (C) 2019-2020, Linaro Limited
   5  *
   6  * An SCMI agent device represent on communication path from a
   7  * device driver to the remote SCMI server which driver sends
   8  * messages to and receives response messages from.
   9  */
  10 #ifndef SCMI_AGENT_H
  11 #define SCMI_AGENT_H
  12
  13 #include <scmi_protocols.h>
  14 #include <asm/types.h>
  15
  16 struct udevice;
  17 struct scmi_channel;
  18
  19 /**
  20  * struct scmi_agent_proto_priv - Private data in device for SCMI agent
  21  * @channel: Reference to the SCMI channel to use
  22  */
  23 struct scmi_agent_proto_priv {
  24         struct scmi_channel *channel;
  25 };
  26
  27 /*
  28  * struct scmi_msg - Context of a SCMI message sent and the response received
  29  *
  30  * @protocol_id:        SCMI protocol ID
  31  * @message_id:         SCMI message ID for a defined protocol ID
  32  * @in_msg:             Pointer to the message payload sent by the driver
  33  * @in_msg_sz:          Byte size of the message payload sent
  34  * @out_msg:            Pointer to buffer to store response message payload
  35  * @out_msg_sz:         Byte size of the response buffer and response payload
  36  */
  37 struct scmi_msg {
  38         unsigned int protocol_id;
  39         unsigned int message_id;
  40         u8 *in_msg;
  41         size_t in_msg_sz;
  42         u8 *out_msg;
  43         size_t out_msg_sz;
  44 };
  45
  46 /* Helper macro to match a message on input/output array references */
  47 #define SCMI_MSG_IN(_protocol, _message, _in_array, _out_array) \
  48         (struct scmi_msg){                      \
  49                 .protocol_id = (_protocol),     \
  50                 .message_id = (_message),       \
  51                 .in_msg = (uint8_t *)&(_in_array),      \
  52                 .in_msg_sz = sizeof(_in_array), \
  53                 .out_msg = (uint8_t *)&(_out_array),    \
  54                 .out_msg_sz = sizeof(_out_array),       \
  55         }
  56
  57 /**
  58  * devm_scmi_of_get_channel() - Get SCMI channel handle from SCMI agent DT node
  59  *
  60  * @dev:        Device requesting a channel
  61  * @return 0 on success and a negative errno on failure
  62  */
  63 int devm_scmi_of_get_channel(struct udevice *dev);
  64
  65 /**
  66  * devm_scmi_process_msg() - Send and process an SCMI message
  67  *
  68  * Send a message to an SCMI server through a target SCMI agent device.
  69  * Caller sets scmi_msg::out_msg_sz to the output message buffer size.
  70  * On return, scmi_msg::out_msg_sz stores the response payload size.
  71  *
  72  * @dev:        SCMI device
  73  * @msg:        Message structure reference
  74  * Return: 0 on success and a negative errno on failure
  75  */
  76 int devm_scmi_process_msg(struct udevice *dev, struct scmi_msg *msg);
  77
  78 /**
  79  * scmi_get_protocol() - get protocol instance
  80  *
  81  * @dev:        SCMI agent device
  82  * @id:         SCMI protocol ID
  83  *
  84  * Obtain the device instance for given protocol ID, @id.
  85  *
  86  * Return:      Pointer to the device if found, null otherwise
  87  */
  88 struct udevice *scmi_get_protocol(struct udevice *dev,
  89                                   enum scmi_std_protocol id);
  90
  91 /**
  92  * scmi_to_linux_errno() - Convert an SCMI error code into a Linux errno code
  93  *
  94  * @scmi_errno: SCMI error code value
  95  * Return: 0 for successful status and a negative errno otherwise
  96  */
  97 int scmi_to_linux_errno(s32 scmi_errno);
  98
  99 #endif /* SCMI_H */