protocols.h
/* SPDX-License-Identifier: GPL-2.0 */
/*
* System Control and Management Interface (SCMI) Message Protocol
* protocols common header file containing some definitions, structures
* and function prototypes used in all the different SCMI protocols.
*
* Copyright (C) 2022 ARM Ltd.
*/
#ifndef _SCMI_PROTOCOLS_H
#define _SCMI_PROTOCOLS_H
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/hashtable.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/refcount.h>
#include <linux/scmi_protocol.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/unaligned.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))))
enum scmi_common_cmd {
PROTOCOL_VERSION = 0x0,
PROTOCOL_ATTRIBUTES = 0x1,
PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
};
/**
* struct scmi_msg_resp_prot_version - Response for a message
*
* @minor_version: Minor version of the ABI that firmware supports
* @major_version: Major 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 - Message(Tx/Rx) structure
*
* @buf: Buffer pointer
* @len: Length of data in the Buffer
*/
struct scmi_msg {
void *buf;
size_t len;
};
/**
* 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
* @type: The SCMI type for this 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;
u8 type;
u16 seq;
u32 status;
bool poll_completion;
};
/**
* struct scmi_xfer - Structure representing a message flow
*
* @transfer_id: Unique ID for debug & profiling purpose
* @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_done: pointer to delayed response message received event completion
* @pending: True for xfers added to @pending_xfers hashtable
* @node: An hlist_node reference used to store this xfer, alternatively, on
* the free list @free_xfers or in the @pending_xfers hashtable
* @users: A refcount to track the active users for this xfer.
* This is meant to protect against the possibility that, when a command
* transaction times out concurrently with the reception of a valid
* response message, the xfer could be finally put on the TX path, and
* so vanish, while on the RX path scmi_rx_callback() is still
* processing it: in such a case this refcounting will ensure that, even
* though the timed-out transaction will anyway cause the command
* request to be reported as failed by time-out, the underlying xfer
* cannot be discarded and possibly reused until the last one user on
* the RX path has released it.
* @busy: An atomic flag to ensure exclusive write access to this xfer
* @state: The current state of this transfer, with states transitions deemed
* valid being:
* - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
* - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
* (Missing synchronous response is assumed OK and ignored)
* @flags: Optional flags associated to this xfer.
* @lock: A spinlock to protect state and busy fields.
* @priv: A pointer for transport private usage.
*/
struct scmi_xfer {
int transfer_id;
struct scmi_msg_hdr hdr;
struct scmi_msg tx;
struct scmi_msg rx;
struct completion done;
struct completion *async_done;
bool pending;
struct hlist_node node;
refcount_t users;
#define SCMI_XFER_FREE 0
#define SCMI_XFER_BUSY 1
atomic_t busy;
#define SCMI_XFER_SENT_OK 0
#define SCMI_XFER_RESP_OK 1
#define SCMI_XFER_DRESP_OK 2
int state;
#define SCMI_XFER_FLAG_IS_RAW BIT(0)
#define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW)
#define SCMI_XFER_FLAG_CHAN_SET BIT(1)
#define SCMI_XFER_IS_CHAN_SET(x) \
((x)->flags & SCMI_XFER_FLAG_CHAN_SET)
int flags;
/* A lock to protect state and busy fields */
spinlock_t lock;
void *priv;
};
struct scmi_xfer_ops;
struct scmi_proto_helpers_ops;
/**
* struct scmi_protocol_handle - Reference to an initialized protocol instance
*
* @dev: A reference to the associated SCMI instance device (handle->dev).
* @xops: A reference to a struct holding refs to the core xfer operations that
* can be used by the protocol implementation to generate SCMI messages.
* @set_priv: A method to set protocol private data for this instance.
* @get_priv: A method to get protocol private data previously set.
*
* This structure represents a protocol initialized against specific SCMI
* instance and it will be used as follows:
* - as a parameter fed from the core to the protocol initialization code so
* that it can access the core xfer operations to build and generate SCMI
* messages exclusively for the specific underlying protocol instance.
* - as an opaque handle fed by an SCMI driver user when it tries to access
* this protocol through its own protocol operations.
* In this case this handle will be returned as an opaque object together
* with the related protocol operations when the SCMI driver tries to access
* the protocol.
*/
struct scmi_protocol_handle {
struct device *dev;
const struct scmi_xfer_ops *xops;
const struct scmi_proto_helpers_ops *hops;
int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
void *(*get_priv)(const struct scmi_protocol_handle *ph);
};
/**
* struct scmi_iterator_state - Iterator current state descriptor
* @desc_index: Starting index for the current mulit-part request.
* @num_returned: Number of returned items in the last multi-part reply.
* @num_remaining: Number of remaining items in the multi-part message.
* @max_resources: Maximum acceptable number of items, configured by the caller
* depending on the underlying resources that it is querying.
* @loop_idx: The iterator loop index in the current multi-part reply.
* @rx_len: Size in bytes of the currenly processed message; it can be used by
* the user of the iterator to verify a reply size.
* @priv: Optional pointer to some additional state-related private data setup
* by the caller during the iterations.
*/
struct scmi_iterator_state {
unsigned int desc_index;
unsigned int num_returned;
unsigned int num_remaining;
unsigned int max_resources;
unsigned int loop_idx;
size_t rx_len;
void *priv;
};
/**
* struct scmi_iterator_ops - Custom iterator operations
* @prepare_message: An operation to provide the custom logic to fill in the
* SCMI command request pointed by @message. @desc_index is
* a reference to the next index to use in the multi-part
* request.
* @update_state: An operation to provide the custom logic to update the
* iterator state from the actual message response.
* @process_response: An operation to provide the custom logic needed to process
* each chunk of the multi-part message.
*/
struct scmi_iterator_ops {
void (*prepare_message)(void *message, unsigned int desc_index,
const void *priv);
int (*update_state)(struct scmi_iterator_state *st,
const void *response, void *priv);
int (*process_response)(const struct scmi_protocol_handle *ph,
const void *response,
struct scmi_iterator_state *st, void *priv);
};
struct scmi_fc_db_info {
int width;
u64 set;
u64 mask;
void __iomem *addr;
};
struct scmi_fc_info {
void __iomem *set_addr;
void __iomem *get_addr;
struct scmi_fc_db_info *set_db;
};
/**
* struct scmi_proto_helpers_ops - References to common protocol helpers
* @extended_name_get: A common helper function to retrieve extended naming
* for the specified resource using the specified command.
* Result is returned as a NULL terminated string in the
* pre-allocated area pointed to by @name with maximum
* capacity of @len bytes.
* @iter_response_init: A common helper to initialize a generic iterator to
* parse multi-message responses: when run the iterator
* will take care to send the initial command request as
* specified by @msg_id and @tx_size and then to parse the
* multi-part responses using the custom operations
* provided in @ops.
* @iter_response_run: A common helper to trigger the run of a previously
* initialized iterator.
* @fastchannel_init: A common helper used to initialize FC descriptors by
* gathering FC descriptions from the SCMI platform server.
* @fastchannel_db_ring: A common helper to ring a FC doorbell.
*/
struct scmi_proto_helpers_ops {
int (*extended_name_get)(const struct scmi_protocol_handle *ph,
u8 cmd_id, u32 res_id, char *name, size_t len);
void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
struct scmi_iterator_ops *ops,
unsigned int max_resources, u8 msg_id,
size_t tx_size, void *priv);
int (*iter_response_run)(void *iter);
void (*fastchannel_init)(const struct scmi_protocol_handle *ph,
u8 describe_id, u32 message_id,
u32 valid_size, u32 domain,
void __iomem **p_addr,
struct scmi_fc_db_info **p_db);
void (*fastchannel_db_ring)(struct scmi_fc_db_info *db);
};
/**
* struct scmi_xfer_ops - References to the core SCMI xfer operations.
* @version_get: Get this version protocol.
* @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
* @reset_rx_to_maxsz: Reset rx size to max transport size.
* @do_xfer: Do the SCMI transfer.
* @do_xfer_with_response: Do the SCMI transfer waiting for a response.
* @xfer_put: Free the xfer slot.
*
* Note that all this operations expect a protocol handle as first parameter;
* they then internally use it to infer the underlying protocol number: this
* way is not possible for a protocol implementation to forge messages for
* another protocol.
*/
struct scmi_xfer_ops {
int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version);
int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
size_t tx_size, size_t rx_size,
struct scmi_xfer **p);
void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer);
int (*do_xfer)(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer);
int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer);
void (*xfer_put)(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer);
};
typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
/**
* struct scmi_protocol - Protocol descriptor
* @id: Protocol ID.
* @owner: Module reference if any.
* @instance_init: Mandatory protocol initialization function.
* @instance_deinit: Optional protocol de-initialization function.
* @ops: Optional reference to the operations provided by the protocol and
* exposed in scmi_protocol.h.
* @events: An optional reference to the events supported by this protocol.
*/
struct scmi_protocol {
const u8 id;
struct module *owner;
const scmi_prot_init_ph_fn_t instance_init;
const scmi_prot_init_ph_fn_t instance_deinit;
const void *ops;
const struct scmi_protocol_events *events;
};
#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
static const struct scmi_protocol *__this_proto = &(proto); \
\
int __init scmi_##name##_register(void) \
{ \
return scmi_protocol_register(__this_proto); \
} \
\
void __exit scmi_##name##_unregister(void) \
{ \
scmi_protocol_unregister(__this_proto); \
}
#define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
int __init scmi_##func##_register(void); \
void __exit scmi_##func##_unregister(void)
DECLARE_SCMI_REGISTER_UNREGISTER(base);
DECLARE_SCMI_REGISTER_UNREGISTER(clock);
DECLARE_SCMI_REGISTER_UNREGISTER(perf);
DECLARE_SCMI_REGISTER_UNREGISTER(power);
DECLARE_SCMI_REGISTER_UNREGISTER(reset);
DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
DECLARE_SCMI_REGISTER_UNREGISTER(system);
DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
#endif /* _SCMI_PROTOCOLS_H */