blob: dea1bfbe10527c593caff1934c903475ead6ecd1 [file] [log] [blame]
/* 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) 2018-2021 ARM Ltd.
#ifndef _SCMI_COMMON_H
#define _SCMI_COMMON_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>
#include "notify.h"
#define MAX_OPPS 16
enum scmi_common_cmd {
* 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;
#define MSG_ID_MASK GENMASK(7, 0)
#define MSG_XTRACT_ID(hdr) FIELD_GET(MSG_ID_MASK, (hdr))
* Size of @pending_xfers hashtable included in @scmi_xfers_info; ideally, in
* order to minimize space and collisions, this should equal max_msg, i.e. the
* maximum number of in-flight messages on a specific platform, but such value
* is only available at runtime while kernel hashtables are statically sized:
* pick instead as a fixed static size the maximum number of entries that can
* fit the whole table into one 4k page.
* 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;
* pack_scmi_header() - packs and returns 32-bit header
* @hdr: pointer to header containing all the information on message id,
* protocol id, sequence id and type.
* Return: 32-bit packed message header to be sent to the platform.
static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
return FIELD_PREP(MSG_ID_MASK, hdr->id) |
* unpack_scmi_header() - unpacks and records message and protocol id
* @msg_hdr: 32-bit packed message header sent from the platform
* @hdr: pointer to header to fetch message and protocol id.
static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
hdr->id = MSG_XTRACT_ID(msg_hdr);
hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
hdr->type = MSG_XTRACT_TYPE(msg_hdr);
* 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
* @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:
* (Missing synchronous response is assumed OK and ignored)
* @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;
int state;
/* A lock to protect state and busy fields */
spinlock_t lock;
void *priv;
* An helper macro to lookup an xfer from the @pending_xfers hashtable
* using the message sequence number token as a key.
#define XFER_FIND(__ht, __k) \
({ \
typeof(__k) k_ = __k; \
struct scmi_xfer *xfer_ = NULL; \
hash_for_each_possible((__ht), xfer_, node, k_) \
if (xfer_->hdr.seq == k_) \
break; \
xfer_; \
struct scmi_xfer_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;
int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
void *(*get_priv)(const struct scmi_protocol_handle *ph);
* 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);
struct scmi_revision_info *
scmi_revision_area_get(const struct scmi_protocol_handle *ph);
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);
void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
u8 *prot_imp);
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;
int __init scmi_bus_init(void);
void __exit scmi_bus_exit(void);
int __init scmi_##func##_register(void); \
void __exit scmi_##func##_unregister(void)
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); \
const struct scmi_protocol *scmi_protocol_get(int protocol_id);
void scmi_protocol_put(int protocol_id);
int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
/* SCMI Transport */
* struct scmi_chan_info - Structure representing a SCMI channel information
* @dev: Reference to device in the SCMI hierarchy corresponding to this
* channel
* @handle: Pointer to SCMI entity handle
* @transport_info: Transport layer related information
struct scmi_chan_info {
struct device *dev;
struct scmi_handle *handle;
void *transport_info;
* struct scmi_transport_ops - Structure representing a SCMI transport ops
* @link_supplier: Optional callback to add link to a supplier device
* @chan_available: Callback to check if channel is available or not
* @chan_setup: Callback to allocate and setup a channel
* @chan_free: Callback to free a channel
* @get_max_msg: Optional callback to provide max_msg dynamically
* Returns the maximum number of messages for the channel type
* (tx or rx) that can be pending simultaneously in the system
* @send_message: Callback to send a message
* @mark_txdone: Callback to mark tx as done
* @fetch_response: Callback to fetch response
* @fetch_notification: Callback to fetch notification
* @clear_channel: Callback to clear a channel
* @poll_done: Callback to poll transfer status
struct scmi_transport_ops {
int (*link_supplier)(struct device *dev);
bool (*chan_available)(struct device *dev, int idx);
int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
bool tx);
int (*chan_free)(int id, void *p, void *data);
unsigned int (*get_max_msg)(struct scmi_chan_info *base_cinfo);
int (*send_message)(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer);
void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret);
void (*fetch_response)(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer);
void (*fetch_notification)(struct scmi_chan_info *cinfo,
size_t max_len, struct scmi_xfer *xfer);
void (*clear_channel)(struct scmi_chan_info *cinfo);
bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
int scmi_protocol_device_request(const struct scmi_device_id *id_table);
void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table);
struct scmi_device *scmi_child_dev_find(struct device *parent,
int prot_id, const char *name);
* struct scmi_desc - Description of SoC integration
* @transport_init: An optional function that a transport can provide to
* initialize some transport-specific setup during SCMI core
* initialization, so ahead of SCMI core probing.
* @transport_exit: An optional function that a transport can provide to
* de-initialize some transport-specific setup during SCMI core
* de-initialization, so after SCMI core removal.
* @ops: Pointer to the transport specific ops structure
* @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
* @max_msg: Maximum number of messages for a channel type (tx or rx) that can
* be pending simultaneously in the system. May be overridden by the
* get_max_msg op.
* @max_msg_size: Maximum size of data per message that can be handled.
struct scmi_desc {
int (*transport_init)(void);
void (*transport_exit)(void);
const struct scmi_transport_ops *ops;
int max_rx_timeout_ms;
int max_msg;
int max_msg_size;
extern const struct scmi_desc scmi_mailbox_desc;
extern const struct scmi_desc scmi_smc_desc;
extern const struct scmi_desc scmi_virtio_desc;
void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv);
void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
/* shmem related declarations */
struct scmi_shared_mem;
void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer);
u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer);
void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
size_t max_len, struct scmi_xfer *xfer);
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);
#endif /* _SCMI_COMMON_H */