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https://github.com/AsahiLinux/u-boot
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8e96801aa6
Adds resources for SCMI protocols to possibly use a dedicated SCMI channel instead of the default channel allocated by the SCMI agent during initialization. As per DT binding documentation, some SCMI transports can define a specific SCMI communication channel for given SCMI protocols. It allows SCMI protocols to pass messages concurrently each other. This change introduces new scmi agent uclass API function devm_scmi_of_get_channel() for SCMI drivers probe sequences to get a reference to the SCMI channel assigned to its related SCMI protocol. The function queries the channel reference to its SCMI transport driver through new scmi agent uclass operator .of_get_channel that uses Device Tree information from related SCMI agent node. Operator .of_get_channel returns a reference to the SCMI channel assigned to SCMI protocol used by the caller device. SCMI transport drivers that do not support multi-channel are not mandated to register this operator. When so, API function devm_scmi_of_get_channel() returns NULL and SCMI transport driver are expected to retrieve by their own means the reference to the unique SCMI channel, for example using platform data as these drivers currently do in U-Boot source tree. Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
80 lines
2.5 KiB
C
80 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
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/*
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* Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
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* Copyright (C) 2019-2020, Linaro Limited
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*
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* An SCMI agent device represent on communication path from a
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* device driver to the remote SCMI server which driver sends
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* messages to and receives response messages from.
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*/
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#ifndef SCMI_AGENT_H
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#define SCMI_AGENT_H
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#include <asm/types.h>
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struct udevice;
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struct scmi_channel;
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/*
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* struct scmi_msg - Context of a SCMI message sent and the response received
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*
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* @protocol_id: SCMI protocol ID
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* @message_id: SCMI message ID for a defined protocol ID
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* @in_msg: Pointer to the message payload sent by the driver
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* @in_msg_sz: Byte size of the message payload sent
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* @out_msg: Pointer to buffer to store response message payload
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* @out_msg_sz: Byte size of the response buffer and response payload
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*/
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struct scmi_msg {
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unsigned int protocol_id;
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unsigned int message_id;
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u8 *in_msg;
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size_t in_msg_sz;
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u8 *out_msg;
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size_t out_msg_sz;
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};
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/* Helper macro to match a message on input/output array references */
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#define SCMI_MSG_IN(_protocol, _message, _in_array, _out_array) \
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(struct scmi_msg){ \
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.protocol_id = (_protocol), \
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.message_id = (_message), \
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.in_msg = (uint8_t *)&(_in_array), \
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.in_msg_sz = sizeof(_in_array), \
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.out_msg = (uint8_t *)&(_out_array), \
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.out_msg_sz = sizeof(_out_array), \
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}
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/**
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* devm_scmi_of_get_channel() - Get SCMI channel handle from SCMI agent DT node
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*
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* @dev: Device requesting a channel
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* @channel: Output reference to the SCMI channel upon success
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* @return 0 on success and a negative errno on failure
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*/
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int devm_scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel);
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/**
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* devm_scmi_process_msg() - Send and process an SCMI message
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*
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* Send a message to an SCMI server through a target SCMI agent device.
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* Caller sets scmi_msg::out_msg_sz to the output message buffer size.
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* On return, scmi_msg::out_msg_sz stores the response payload size.
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*
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* @dev: SCMI device
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* @channel: Communication channel for the device
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* @msg: Message structure reference
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* Return: 0 on success and a negative errno on failure
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*/
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int devm_scmi_process_msg(struct udevice *dev, struct scmi_channel *channel,
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struct scmi_msg *msg);
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/**
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* scmi_to_linux_errno() - Convert an SCMI error code into a Linux errno code
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*
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* @scmi_errno: SCMI error code value
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* Return: 0 for successful status and a negative errno otherwise
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*/
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int scmi_to_linux_errno(s32 scmi_errno);
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#endif /* SCMI_H */
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