linux/drivers/firmware/arm_scmi/common.h
Sudeep Holla 58ecdf03db firmware: arm_scmi: Add support for asynchronous commands and delayed response
Messages that are sent to platform, also known as commands and can be:

1. Synchronous commands that block the channel until the requested work
has been completed. The platform responds to these commands over the
same channel and hence can't be used to send another command until the
previous command has completed.

2. Asynchronous commands on the other hand, the platform schedules the
requested work to complete later in time and returns almost immediately
freeing the channel for new commands. The response indicates the success
or failure in the ability to schedule the requested work. When the work
has completed, the platform sends an additional delayed response message.

Using the same transmit buffer used for sending the asynchronous command
even for the delayed response corresponding to it simplifies handling of
the delayed response. It's the caller of asynchronous command that is
responsible for allocating the completion flag that scmi driver can
complete to indicate the arrival of delayed response.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2019-08-12 12:23:00 +01:00

112 lines
3.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* System Control and Management Interface (SCMI) Message Protocol
* driver common header file containing some definitions, structures
* and function prototypes used in all the different SCMI protocols.
*
* Copyright (C) 2018 ARM Ltd.
*/
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/scmi_protocol.h>
#include <linux/types.h>
#define PROTOCOL_REV_MINOR_MASK GENMASK(15, 0)
#define PROTOCOL_REV_MAJOR_MASK GENMASK(31, 16)
#define PROTOCOL_REV_MAJOR(x) (u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))
#define PROTOCOL_REV_MINOR(x) (u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))
#define MAX_PROTOCOLS_IMP 16
#define MAX_OPPS 16
enum scmi_common_cmd {
PROTOCOL_VERSION = 0x0,
PROTOCOL_ATTRIBUTES = 0x1,
PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
};
/**
* struct scmi_msg_resp_prot_version - Response for a message
*
* @major_version: Major version of the ABI that firmware supports
* @minor_version: Minor version of the ABI that firmware supports
*
* In general, ABI version changes follow the rule that minor version increments
* are backward compatible. Major revision changes in ABI may not be
* backward compatible.
*
* Response to a generic message with message type SCMI_MSG_VERSION
*/
struct scmi_msg_resp_prot_version {
__le16 minor_version;
__le16 major_version;
};
/**
* struct scmi_msg_hdr - Message(Tx/Rx) header
*
* @id: The identifier of the message being sent
* @protocol_id: The identifier of the protocol used to send @id message
* @seq: The token to identify the message. When a message returns, the
* platform returns the whole message header unmodified including the
* token
* @status: Status of the transfer once it's complete
* @poll_completion: Indicate if the transfer needs to be polled for
* completion or interrupt mode is used
*/
struct scmi_msg_hdr {
u8 id;
u8 protocol_id;
u16 seq;
u32 status;
bool poll_completion;
};
/**
* struct scmi_msg - Message(Tx/Rx) structure
*
* @buf: Buffer pointer
* @len: Length of data in the Buffer
*/
struct scmi_msg {
void *buf;
size_t len;
};
/**
* struct scmi_xfer - Structure representing a message flow
*
* @hdr: Transmit message header
* @tx: Transmit message
* @rx: Receive message, the buffer should be pre-allocated to store
* message. If request-ACK protocol is used, we can reuse the same
* buffer for the rx path as we use for the tx path.
* @done: command message transmit completion event
* @async: pointer to delayed response message received event completion
*/
struct scmi_xfer {
struct scmi_msg_hdr hdr;
struct scmi_msg tx;
struct scmi_msg rx;
struct completion done;
struct completion *async_done;
};
void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
int scmi_do_xfer(const struct scmi_handle *h, struct scmi_xfer *xfer);
int scmi_do_xfer_with_response(const struct scmi_handle *h,
struct scmi_xfer *xfer);
int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
size_t tx_size, size_t rx_size, struct scmi_xfer **p);
int scmi_handle_put(const struct scmi_handle *handle);
struct scmi_handle *scmi_handle_get(struct device *dev);
void scmi_set_handle(struct scmi_device *scmi_dev);
int scmi_version_get(const struct scmi_handle *h, u8 protocol, u32 *version);
void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
u8 *prot_imp);
int scmi_base_protocol_init(struct scmi_handle *h);