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// SPDX-License-Identifier: GPL-2.0
/*
* For transports using message passing.
*
* Derived from shm.c.
*
* Copyright (C) 2019-2024 ARM Ltd.
* Copyright (C) 2020-2021 OpenSynergy GmbH
*/
#include <linux/types.h>
#include "common.h"
/*
* struct scmi_msg_payld - Transport SDU layout
*
* The SCMI specification requires all parameters, message headers, return
* arguments or any protocol data to be expressed in little endian format only.
*/
struct scmi_msg_payld {
__le32 msg_header;
__le32 msg_payload[];
};
/**
* msg_command_size() - Actual size of transport SDU for command.
*
* @xfer: message which core has prepared for sending
*
* Return: transport SDU size.
*/
static size_t msg_command_size(struct scmi_xfer *xfer)
{
return sizeof(struct scmi_msg_payld) + xfer->tx.len;
}
/**
* msg_response_size() - Maximum size of transport SDU for response.
*
* @xfer: message which core has prepared for sending
*
* Return: transport SDU size.
*/
static size_t msg_response_size(struct scmi_xfer *xfer)
{
return sizeof(struct scmi_msg_payld) + sizeof(__le32) + xfer->rx.len;
}
/**
* msg_tx_prepare() - Set up transport SDU for command.
*
* @msg: transport SDU for command
* @xfer: message which is being sent
*/
static void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer)
{
msg->msg_header = cpu_to_le32(pack_scmi_header(&xfer->hdr));
if (xfer->tx.buf)
memcpy(msg->msg_payload, xfer->tx.buf, xfer->tx.len);
}
/**
* msg_read_header() - Read SCMI header from transport SDU.
*
* @msg: transport SDU
*
* Return: SCMI header
*/
static u32 msg_read_header(struct scmi_msg_payld *msg)
{
return le32_to_cpu(msg->msg_header);
}
/**
* msg_fetch_response() - Fetch response SCMI payload from transport SDU.
*
* @msg: transport SDU with response
* @len: transport SDU size
* @xfer: message being responded to
*/
static void msg_fetch_response(struct scmi_msg_payld *msg,
size_t len, struct scmi_xfer *xfer)
{
size_t prefix_len = sizeof(*msg) + sizeof(msg->msg_payload[0]);
xfer->hdr.status = le32_to_cpu(msg->msg_payload[0]);
xfer->rx.len = min_t(size_t, xfer->rx.len,
len >= prefix_len ? len - prefix_len : 0);
/* Take a copy to the rx buffer.. */
memcpy(xfer->rx.buf, &msg->msg_payload[1], xfer->rx.len);
}
/**
* msg_fetch_notification() - Fetch notification payload from transport SDU.
*
* @msg: transport SDU with notification
* @len: transport SDU size
* @max_len: maximum SCMI payload size to fetch
* @xfer: notification message
*/
static void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
size_t max_len, struct scmi_xfer *xfer)
{
xfer->rx.len = min_t(size_t, max_len,
len >= sizeof(*msg) ? len - sizeof(*msg) : 0);
/* Take a copy to the rx buffer.. */
memcpy(xfer->rx.buf, msg->msg_payload, xfer->rx.len);
}
static const struct scmi_message_operations scmi_msg_ops = {
.tx_prepare = msg_tx_prepare,
.command_size = msg_command_size,
.response_size = msg_response_size,
.read_header = msg_read_header,
.fetch_response = msg_fetch_response,
.fetch_notification = msg_fetch_notification,
};
const struct scmi_message_operations *scmi_message_operations_get(void)
{
return &scmi_msg_ops;
}
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