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Subject: [PATCH v7 11/15] firmware: arm_scmi: Add message passing abstractions for transports
From: Peter Hilber <peter.hilber@opensynergy.com> 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. 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> --- v6 --> v7 - removed uneeded includes v4 --> v5 - adapted to new SCMI Kconfig - removed raw_payload msg helpers v3 --> v4 - added raw_payload msg helpers --- drivers/firmware/arm_scmi/Kconfig | 6 ++ drivers/firmware/arm_scmi/Makefile | 1 + drivers/firmware/arm_scmi/common.h | 15 ++++ drivers/firmware/arm_scmi/msg.c | 111 +++++++++++++++++++++++++++++ 4 files changed, 133 insertions(+) create mode 100644 drivers/firmware/arm_scmi/msg.c diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig index cd84e5f2ee02..24fed705b02c 100644 --- a/drivers/firmware/arm_scmi/Kconfig +++ b/drivers/firmware/arm_scmi/Kconfig @@ -36,6 +36,12 @@ config ARM_SCMI_HAVE_SHMEM This declares whether a shared memory based transport for SCMI is available. +config ARM_SCMI_HAVE_MSG + bool + help + This declares whether a message passing based transport for SCMI is + available. + config ARM_SCMI_TRANSPORT_MAILBOX bool "SCMI transport based on Mailbox" depends on MAILBOX diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile index e0e6bd3dba9e..aaad9f6589aa 100644 --- a/drivers/firmware/arm_scmi/Makefile +++ b/drivers/firmware/arm_scmi/Makefile @@ -4,6 +4,7 @@ scmi-driver-y = driver.o notify.o scmi-transport-$(CONFIG_ARM_SCMI_HAVE_SHMEM) = shmem.o scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_MAILBOX) += mailbox.o scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_SMC) += smc.o +scmi-transport-$(CONFIG_ARM_SCMI_HAVE_MSG) += msg.o scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o scmi-module-objs := $(scmi-bus-y) $(scmi-driver-y) $(scmi-protocols-y) \ $(scmi-transport-y) diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 6320345865e8..4da6cecc0a1c 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -432,6 +432,21 @@ void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem); bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer); +/* declarations for message passing transports */ +struct scmi_msg_payld; + +/* Maximum overhead of message w.r.t. struct scmi_desc.max_msg_size */ +#define SCMI_MSG_MAX_PROT_OVERHEAD (2 * sizeof(__le32)) + +size_t msg_response_size(struct scmi_xfer *xfer); +size_t msg_command_size(struct scmi_xfer *xfer); +void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer); +u32 msg_read_header(struct scmi_msg_payld *msg); +void msg_fetch_response(struct scmi_msg_payld *msg, size_t len, + struct scmi_xfer *xfer); +void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len, + size_t max_len, struct scmi_xfer *xfer); + void scmi_notification_instance_data_set(const struct scmi_handle *handle, void *priv); void *scmi_notification_instance_data_get(const struct scmi_handle *handle); diff --git a/drivers/firmware/arm_scmi/msg.c b/drivers/firmware/arm_scmi/msg.c new file mode 100644 index 000000000000..d33a704e5814 --- /dev/null +++ b/drivers/firmware/arm_scmi/msg.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * For transports using message passing. + * + * Derived from shm.c. + * + * Copyright (C) 2019-2021 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. + */ +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. + */ +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 + */ +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 + */ +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 + */ +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 + */ +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); +} -- 2.17.1
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