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1// SPDX-License-Identifier: GPL-2.02/*3 * For transports using message passing.4 *5 * Derived from shm.c.6 *7 * Copyright (C) 2019-2024 ARM Ltd.8 * Copyright (C) 2020-2021 OpenSynergy GmbH9 */10 11#include <linux/types.h>12 13#include "common.h"14 15/*16 * struct scmi_msg_payld - Transport SDU layout17 *18 * The SCMI specification requires all parameters, message headers, return19 * arguments or any protocol data to be expressed in little endian format only.20 */21struct scmi_msg_payld {22 __le32 msg_header;23 __le32 msg_payload[];24};25 26/**27 * msg_command_size() - Actual size of transport SDU for command.28 *29 * @xfer: message which core has prepared for sending30 *31 * Return: transport SDU size.32 */33static size_t msg_command_size(struct scmi_xfer *xfer)34{35 return sizeof(struct scmi_msg_payld) + xfer->tx.len;36}37 38/**39 * msg_response_size() - Maximum size of transport SDU for response.40 *41 * @xfer: message which core has prepared for sending42 *43 * Return: transport SDU size.44 */45static size_t msg_response_size(struct scmi_xfer *xfer)46{47 return sizeof(struct scmi_msg_payld) + sizeof(__le32) + xfer->rx.len;48}49 50/**51 * msg_tx_prepare() - Set up transport SDU for command.52 *53 * @msg: transport SDU for command54 * @xfer: message which is being sent55 */56static void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer)57{58 msg->msg_header = cpu_to_le32(pack_scmi_header(&xfer->hdr));59 if (xfer->tx.buf)60 memcpy(msg->msg_payload, xfer->tx.buf, xfer->tx.len);61}62 63/**64 * msg_read_header() - Read SCMI header from transport SDU.65 *66 * @msg: transport SDU67 *68 * Return: SCMI header69 */70static u32 msg_read_header(struct scmi_msg_payld *msg)71{72 return le32_to_cpu(msg->msg_header);73}74 75/**76 * msg_fetch_response() - Fetch response SCMI payload from transport SDU.77 *78 * @msg: transport SDU with response79 * @len: transport SDU size80 * @xfer: message being responded to81 */82static void msg_fetch_response(struct scmi_msg_payld *msg,83 size_t len, struct scmi_xfer *xfer)84{85 size_t prefix_len = sizeof(*msg) + sizeof(msg->msg_payload[0]);86 87 xfer->hdr.status = le32_to_cpu(msg->msg_payload[0]);88 xfer->rx.len = min_t(size_t, xfer->rx.len,89 len >= prefix_len ? len - prefix_len : 0);90 91 /* Take a copy to the rx buffer.. */92 memcpy(xfer->rx.buf, &msg->msg_payload[1], xfer->rx.len);93}94 95/**96 * msg_fetch_notification() - Fetch notification payload from transport SDU.97 *98 * @msg: transport SDU with notification99 * @len: transport SDU size100 * @max_len: maximum SCMI payload size to fetch101 * @xfer: notification message102 */103static void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,104 size_t max_len, struct scmi_xfer *xfer)105{106 xfer->rx.len = min_t(size_t, max_len,107 len >= sizeof(*msg) ? len - sizeof(*msg) : 0);108 109 /* Take a copy to the rx buffer.. */110 memcpy(xfer->rx.buf, msg->msg_payload, xfer->rx.len);111}112 113static const struct scmi_message_operations scmi_msg_ops = {114 .tx_prepare = msg_tx_prepare,115 .command_size = msg_command_size,116 .response_size = msg_response_size,117 .read_header = msg_read_header,118 .fetch_response = msg_fetch_response,119 .fetch_notification = msg_fetch_notification,120};121 122const struct scmi_message_operations *scmi_message_operations_get(void)123{124 return &scmi_msg_ops;125}126