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f301bba0ca
Add abstractions for future transports using message passing, such as virtio. Derive the abstractions from the shared memory abstractions. Abstract the transport SDU through the opaque struct scmi_msg_payld. Also enable the transport to determine all other required information about the transport SDU. Link: https://lore.kernel.org/r/20210803131024.40280-12-cristian.marussi@arm.com Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com> [ Cristian: Adapted to new SCMI Kconfig layout, updated Copyrights ] Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
111 lines
2.7 KiB
C
111 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* For transports using message passing.
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*
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* Derived from shm.c.
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*
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* Copyright (C) 2019-2021 ARM Ltd.
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* Copyright (C) 2020-2021 OpenSynergy GmbH
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*/
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#include <linux/types.h>
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#include "common.h"
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/*
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* struct scmi_msg_payld - Transport SDU layout
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*
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* The SCMI specification requires all parameters, message headers, return
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* arguments or any protocol data to be expressed in little endian format only.
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*/
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struct scmi_msg_payld {
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__le32 msg_header;
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__le32 msg_payload[];
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};
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/**
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* msg_command_size() - Actual size of transport SDU for command.
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*
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* @xfer: message which core has prepared for sending
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*
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* Return: transport SDU size.
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*/
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size_t msg_command_size(struct scmi_xfer *xfer)
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{
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return sizeof(struct scmi_msg_payld) + xfer->tx.len;
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}
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/**
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* msg_response_size() - Maximum size of transport SDU for response.
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*
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* @xfer: message which core has prepared for sending
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*
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* Return: transport SDU size.
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*/
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size_t msg_response_size(struct scmi_xfer *xfer)
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{
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return sizeof(struct scmi_msg_payld) + sizeof(__le32) + xfer->rx.len;
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}
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/**
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* msg_tx_prepare() - Set up transport SDU for command.
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*
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* @msg: transport SDU for command
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* @xfer: message which is being sent
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*/
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void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer)
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{
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msg->msg_header = cpu_to_le32(pack_scmi_header(&xfer->hdr));
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if (xfer->tx.buf)
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memcpy(msg->msg_payload, xfer->tx.buf, xfer->tx.len);
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}
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/**
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* msg_read_header() - Read SCMI header from transport SDU.
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*
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* @msg: transport SDU
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*
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* Return: SCMI header
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*/
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u32 msg_read_header(struct scmi_msg_payld *msg)
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{
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return le32_to_cpu(msg->msg_header);
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}
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/**
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* msg_fetch_response() - Fetch response SCMI payload from transport SDU.
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*
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* @msg: transport SDU with response
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* @len: transport SDU size
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* @xfer: message being responded to
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*/
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void msg_fetch_response(struct scmi_msg_payld *msg, size_t len,
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struct scmi_xfer *xfer)
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{
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size_t prefix_len = sizeof(*msg) + sizeof(msg->msg_payload[0]);
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xfer->hdr.status = le32_to_cpu(msg->msg_payload[0]);
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xfer->rx.len = min_t(size_t, xfer->rx.len,
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len >= prefix_len ? len - prefix_len : 0);
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/* Take a copy to the rx buffer.. */
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memcpy(xfer->rx.buf, &msg->msg_payload[1], xfer->rx.len);
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}
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/**
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* msg_fetch_notification() - Fetch notification payload from transport SDU.
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*
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* @msg: transport SDU with notification
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* @len: transport SDU size
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* @max_len: maximum SCMI payload size to fetch
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* @xfer: notification message
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*/
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void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
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size_t max_len, struct scmi_xfer *xfer)
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{
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xfer->rx.len = min_t(size_t, max_len,
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len >= sizeof(*msg) ? len - sizeof(*msg) : 0);
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/* Take a copy to the rx buffer.. */
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memcpy(xfer->rx.buf, msg->msg_payload, xfer->rx.len);
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}
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