593eac9805
Changes implementation when using TEE dynamically allocated shared memory to synchronize with the Linux implementation where the legacy SMT protocol cannot be used with such memory since it is expected from device mapped memory whereas OP-TEE shared memory is cached and hence should not be accessed using memcpy_toio()/memcpy_fromio(). This change implements the MSG shared memory protocol introduced in Linux [1]. The protocol uses a simplified SMT header of 32bit named MSG_SMT to carry SCMI protocol information and uses side channel means to carry exchanged buffer size information, as TEE invocation API parameters when used in the SCMI OP-TEE transport. Link: [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f301bba0ca7392d16a6ea4f1d264a91f1fadea1a Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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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) 2019-2022 Linaro Limited.
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*/
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#ifndef SCMI_SMT_H
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#define SCMI_SMT_H
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#include <asm/types.h>
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/**
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* struct scmi_smt_header - Description of the shared memory message buffer
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*
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* SMT stands for Shared Memory based Transport.
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* SMT uses 28 byte header prior message payload to handle the state of
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* the communication channel realized by the shared memory area and
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* to define SCMI protocol information the payload relates to.
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*/
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struct scmi_smt_header {
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__le32 reserved;
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__le32 channel_status;
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#define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR BIT(1)
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#define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE BIT(0)
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__le32 reserved1[2];
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__le32 flags;
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#define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0)
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__le32 length;
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__le32 msg_header;
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u8 msg_payload[0];
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};
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/**
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* struct scmi_msg_header - Description of a MSG shared memory message buffer
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*
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* MSG communication protocol uses a 32bit header memory cell to store SCMI
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* protocol data followed by the exchange SCMI message payload.
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*/
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struct scmi_smt_msg_header {
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__le32 msg_header;
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u8 msg_payload[0];
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};
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#define SMT_HEADER_TOKEN(token) (((token) << 18) & GENMASK(31, 18))
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#define SMT_HEADER_PROTOCOL_ID(proto) (((proto) << 10) & GENMASK(17, 10))
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#define SMT_HEADER_MESSAGE_TYPE(type) (((type) << 18) & GENMASK(9, 8))
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#define SMT_HEADER_MESSAGE_ID(id) ((id) & GENMASK(7, 0))
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/**
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* struct scmi_smt - Description of a SMT memory buffer
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* @buf: Shared memory base address
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* @size: Shared memory byte size
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*/
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struct scmi_smt {
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u8 *buf;
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size_t size;
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};
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static inline bool scmi_smt_channel_is_free(struct scmi_smt *smt)
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{
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struct scmi_smt_header *hdr = (void *)smt->buf;
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return hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
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}
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static inline bool scmi_smt_channel_reports_error(struct scmi_smt *smt)
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{
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struct scmi_smt_header *hdr = (void *)smt->buf;
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return hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR;
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}
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static inline void scmi_smt_get_channel(struct scmi_smt *smt)
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{
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struct scmi_smt_header *hdr = (void *)smt->buf;
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hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
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}
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static inline void scmi_smt_put_channel(struct scmi_smt *smt)
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{
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struct scmi_smt_header *hdr = (void *)smt->buf;
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hdr->channel_status |= SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
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hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR;
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}
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int scmi_dt_get_smt_buffer(struct udevice *dev, struct scmi_smt *smt);
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/*
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* Write SCMI message to a SMT shared memory
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* @dev: SCMI device
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* @smt: Reference to shared memory using SMT header
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* @msg: Input SCMI message transmitted
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*/
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int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt,
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struct scmi_msg *msg);
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/*
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* Read SCMI message from a SMT shared memory
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* @dev: SCMI device
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* @smt: Reference to shared memory using SMT header
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* @msg: Output SCMI message received
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*/
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int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt,
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struct scmi_msg *msg);
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void scmi_clear_smt_channel(struct scmi_smt *smt);
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/*
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* Write SCMI message to SMT_MSG shared memory
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* @dev: SCMI device
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* @smt: Reference to shared memory using SMT_MSG header
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* @msg: Input SCMI message transmitted
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* @buf_size: Size of the full SMT_MSG buffer transmitted
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*/
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int scmi_msg_to_smt_msg(struct udevice *dev, struct scmi_smt *smt,
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struct scmi_msg *msg, size_t *buf_size);
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/*
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* Read SCMI message from SMT_MSG shared memory
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* @dev: SCMI device
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* @smt: Reference to shared memory using SMT_MSG header
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* @msg: Output SCMI message received
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* @buf_size: Size of the full SMT_MSG buffer received
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*/
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int scmi_msg_from_smt_msg(struct udevice *dev, struct scmi_smt *smt,
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struct scmi_msg *msg, size_t buf_size);
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#endif /* SCMI_SMT_H */
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