Client Driver API Documentation

Serial Hub Communication

enum ssh_frame_type

Frame types for SSH frames.

Constants

SSH_FRAME_TYPE_DATA_SEQ

Indicates a data frame, followed by a payload with the length specified in the struct ssh_frame.len field. This frame is sequenced, meaning that an ACK is required.

SSH_FRAME_TYPE_DATA_NSQ

Same as SSH_FRAME_TYPE_DATA_SEQ, but unsequenced, meaning that the message does not have to be ACKed.

SSH_FRAME_TYPE_ACK

Indicates an ACK message.

SSH_FRAME_TYPE_NAK

Indicates an error response for previously sent frame. In general, this means that the frame and/or payload is malformed, e.g. a CRC is wrong. For command-type payloads, this can also mean that the command is invalid.
struct ssh_frame

SSH communication frame.

Definition

struct ssh_frame {
  u8 type;
  __le16 len;
  u8 seq;
};

Members

type
The type of the frame. See enum ssh_frame_type.
len
The length of the frame payload directly following the CRC for this frame. Does not include the final CRC for that payload.
seq
The sequence number for this message/exchange.
enum ssh_payload_type

Type indicator for the SSH payload.

Constants

SSH_PLD_TYPE_CMD
The payload is a command structure with optional command payload.
struct ssh_command

Payload of a command-type frame.

Definition

struct ssh_command {
  u8 type;
  u8 tc;
  u8 tid_out;
  u8 tid_in;
  u8 iid;
  __le16 rqid;
  u8 cid;
};

Members

type
The type of the payload. See enum ssh_payload_type. Should be SSH_PLD_TYPE_CMD for this struct.
tc
Command target category.
tid_out
Output target ID. Should be zero if this an incoming (EC to host) message.
tid_in
Input target ID. Should be zero if this is an outgoing (host to EC) message.
iid
Instance ID.
rqid
Request ID. Used to match requests with responses and differentiate between responses and events.
cid
Command ID.
SSH_MESSAGE_LENGTH(payload_size)

Compute length of SSH message.

Parameters

payload_size
Length of the payload inside the SSH frame.

Return

Returns the length of a SSH message with payload of specified size.

SSH_COMMAND_MESSAGE_LENGTH(payload_size)

Compute length of SSH command message.

Parameters

payload_size
Length of the command payload.

Return

Returns the length of a SSH command message with command payload of specified size.

SSH_MSGOFFSET_FRAME(field)

Compute offset in SSH message to specified field in frame.

Parameters

field
The field for which the offset should be computed.

Return

Returns the offset of the specified struct ssh_frame field in the raw SSH message data as. Takes SYN bytes (u16) preceding the frame into account.

SSH_MSGOFFSET_COMMAND(field)

Compute offset in SSH message to specified field in command.

Parameters

field
The field for which the offset should be computed.

Return

Returns the offset of the specified struct ssh_command field in the raw SSH message data. Takes SYN bytes (u16) preceding the frame and the frame CRC (u16) between frame and command into account.

u16 ssh_crc(const u8 *buf, size_t len)

Compute CRC for SSH messages.

Parameters

const u8 *buf
The pointer pointing to the data for which the CRC should be computed.
size_t len
The length of the data for which the CRC should be computed.

Return

Returns the CRC computed on the provided data, as used for SSH messages.

u16 ssh_rqid_next_valid(u16 rqid)

Return the next valid request ID.

Parameters

u16 rqid
The current request ID.

Return

Returns the next valid request ID, following the current request ID provided to this function. This function skips any request IDs reserved for events.

u16 ssh_rqid_to_event(u16 rqid)

Convert request ID to its corresponding event ID.

Parameters

u16 rqid
The request ID to convert.
bool ssh_rqid_is_event(u16 rqid)

Check if given request ID is a valid event ID.

Parameters

u16 rqid
The request ID to check.
u16 ssh_tc_to_rqid(u8 tc)

Convert target category to its corresponding request ID.

Parameters

u8 tc
The target category to convert.
u8 ssh_tid_to_index(u8 tid)

Convert target ID to its corresponding target index.

Parameters

u8 tid
The target ID to convert.
bool ssh_tid_is_valid(u8 tid)

Check if target ID is valid/supported.

Parameters

u8 tid
The target ID to check.
struct ssam_span

Reference to a buffer region.

Definition

struct ssam_span {
  u8 *ptr;
  size_t len;
};

Members

ptr
Pointer to the buffer region.
len
Length of the buffer region.

Description

A reference to a (non-owned) buffer segment, consisting of pointer and length. Use of this struct indicates non-owned data, i.e. data of which the life-time is managed (i.e. it is allocated/freed) via another pointer.

enum ssh_packet_base_priority

Base priorities for struct ssh_packet.

Constants

SSH_PACKET_PRIORITY_FLUSH
Base priority for flush packets.
SSH_PACKET_PRIORITY_DATA
Base priority for normal data packets.
SSH_PACKET_PRIORITY_NAK
Base priority for NAK packets.
SSH_PACKET_PRIORITY_ACK
Base priority for ACK packets.
SSH_PACKET_PRIORITY(base, try)

Compute packet priority from base priority and number of tries.

Parameters

base
The base priority as suffix of enum ssh_packet_base_priority, e.g. FLUSH, DATA, ACK, or NAK.
try
The number of tries (must be less than 16).

Description

Compute the combined packet priority. The combined priority is dominated by the base priority, whereas the number of (re-)tries decides the precedence of packets with the same base priority, giving higher priority to packets that already have more tries.

Return

Returns the computed priority as value fitting inside a u8. A higher number means a higher priority.

u8 ssh_packet_priority_get_try(u8 priority)

Get number of tries from packet priority.

Parameters

u8 priority
The packet priority.

Return

Returns the number of tries encoded in the specified packet priority.

u8 ssh_packet_priority_get_base(u8 priority)

Get base priority from packet priority.

Parameters

u8 priority
The packet priority.

Return

Returns the base priority encoded in the given packet priority.

struct ssh_packet_ops

Callback operations for a SSH packet.

Definition

struct ssh_packet_ops {
  void (*release)(struct ssh_packet *p);
  void (*complete)(struct ssh_packet *p, int status);
};

Members

release
Function called when the packet reference count reaches zero. This callback must be relied upon to ensure that the packet has left the transport system(s).
complete
Function called when the packet is completed, either with success or failure. In case of failure, the reason for the failure is indicated by the value of the provided status code argument. This value will be zero in case of success. Note that a call to this callback does not guarantee that the packet is not in use by the transport system any more.
struct ssh_packet

SSH transport packet.

Definition

struct ssh_packet {
  struct ssh_ptl *ptl;
  struct kref refcnt;
  u8 priority;
  struct {
    size_t len;
    u8 *ptr;
  } data;
  unsigned long state;
  ktime_t timestamp;
  struct list_head queue_node;
  struct list_head pending_node;
  const struct ssh_packet_ops *ops;
};

Members

ptl
Pointer to the packet transport layer. May be NULL if the packet (or enclosing request) has not been submitted yet.
refcnt
Reference count of the packet.
priority
Priority of the packet. Must be computed via SSH_PACKET_PRIORITY(). Must only be accessed while holding the queue lock after first submission.
data
Raw message data.
data.len
Length of the raw message data.
data.ptr
Pointer to the raw message data buffer.
state
State and type flags describing current packet state (dynamic) and type (static). See enum ssh_packet_flags for possible options.
timestamp
Timestamp specifying when the latest transmission of a currently pending packet has been started. May be KTIME_MAX before or in-between transmission attempts. Used for the packet timeout implementation. Must only be accessed while holding the pending lock after first submission.
queue_node
The list node for the packet queue.
pending_node
The list node for the set of pending packets.
ops
Packet operations.
void ssh_packet_set_data(struct ssh_packet *p, u8 *ptr, size_t len)

Set raw message data of packet.

Parameters

struct ssh_packet *p
The packet for which the message data should be set.
u8 *ptr
Pointer to the memory holding the message data.
size_t len
Length of the message data.

Description

Sets the raw message data buffer of the packet to the provided memory. The memory is not copied. Instead, the caller is responsible for management (i.e. allocation and deallocation) of the memory. The caller must ensure that the provided memory is valid and contains a valid SSH message, starting from the time of submission of the packet until the release callback has been called. During this time, the memory may not be altered in any way.

struct ssh_request_ops

Callback operations for a SSH request.

Definition

struct ssh_request_ops {
  void (*release)(struct ssh_request *rqst);
  void (*complete)(struct ssh_request *rqst,const struct ssh_command *cmd, const struct ssam_span *data, int status);
};

Members

release
Function called when the request’s reference count reaches zero. This callback must be relied upon to ensure that the request has left the transport systems (both, packet an request systems).
complete

Function called when the request is completed, either with success or failure. The command data for the request response is provided via the struct ssh_command parameter (cmd), the command payload of the request response via the struct ssh_span parameter (data).

If the request does not have any response or has not been completed with success, both cmd and data parameters will be NULL. If the request response does not have any command payload, the data span will be an empty (zero-length) span.

In case of failure, the reason for the failure is indicated by the value of the provided status code argument (status). This value will be zero in case of success and a regular errno otherwise.

Note that a call to this callback does not guarantee that the request is not in use by the transport systems any more.

struct ssh_request

SSH transport request.

Definition

struct ssh_request {
  struct ssh_packet packet;
  struct list_head node;
  unsigned long state;
  ktime_t timestamp;
  const struct ssh_request_ops *ops;
};

Members

packet
The underlying SSH transport packet.
node
List node for the request queue and pending set.
state
State and type flags describing current request state (dynamic) and type (static). See enum ssh_request_flags for possible options.
timestamp
Timestamp specifying when we start waiting on the response of the request. This is set once the underlying packet has been completed and may be KTIME_MAX before that, or when the request does not expect a response. Used for the request timeout implementation.
ops
Request Operations.
struct ssh_request * to_ssh_request(struct ssh_packet *p)

Cast a SSH packet to its enclosing SSH request.

Parameters

struct ssh_packet *p
The packet to cast.

Description

Casts the given struct ssh_packet to its enclosing struct ssh_request. The caller is responsible for making sure that the packet is actually wrapped in a struct ssh_request.

Return

Returns the struct ssh_request wrapping the provided packet.

struct ssh_request * ssh_request_get(struct ssh_request *r)

Increment reference count of request.

Parameters

struct ssh_request *r
The request to increment the reference count of.

Description

Increments the reference count of the given request by incrementing the reference count of the underlying struct ssh_packet, enclosed in it.

See also ssh_request_put(), ssh_packet_get().

Return

Returns the request provided as input.

void ssh_request_put(struct ssh_request *r)

Decrement reference count of request.

Parameters

struct ssh_request *r
The request to decrement the reference count of.

Description

Decrements the reference count of the given request by decrementing the reference count of the underlying struct ssh_packet, enclosed in it. If the reference count reaches zero, the release callback specified in the request’s struct ssh_request_ops, i.e. r->ops->release, will be called.

See also ssh_request_get(), ssh_packet_put().

void ssh_request_set_data(struct ssh_request *r, u8 *ptr, size_t len)

Set raw message data of request.

Parameters

struct ssh_request *r
The request for which the message data should be set.
u8 *ptr
Pointer to the memory holding the message data.
size_t len
Length of the message data.

Description

Sets the raw message data buffer of the underlying packet to the specified buffer. Does not copy the actual message data, just sets the buffer pointer and length. Refer to ssh_packet_set_data() for more details.

struct ssh_packet * ssh_packet_get(struct ssh_packet *packet)

Increment reference count of packet.

Parameters

struct ssh_packet *packet
The packet to increment the reference count of.

Description

Increments the reference count of the given packet. See ssh_packet_put() for the counter-part of this function.

Return

Returns the packet provided as input.

void ssh_packet_put(struct ssh_packet *packet)

Decrement reference count of packet.

Parameters

struct ssh_packet *packet
The packet to decrement the reference count of.

Description

If the reference count reaches zero, the release callback specified in the packet’s struct ssh_packet_ops, i.e. packet->ops->release, will be called.

See ssh_packet_get() for the counter-part of this function.

Controller and Core Interface

enum ssam_event_flags

Flags for enabling/disabling SAM events

Constants

SSAM_EVENT_SEQUENCED
The event will be sent via a sequenced data frame.
struct ssam_event

SAM event sent from the EC to the host.

Definition

struct ssam_event {
  u8 target_category;
  u8 target_id;
  u8 command_id;
  u8 instance_id;
  u16 length;
  u8 data[];
};

Members

target_category
Target category of the event source. See enum ssam_ssh_tc.
target_id
Target ID of the event source.
command_id
Command ID of the event.
instance_id
Instance ID of the event source.
length
Length of the event payload in bytes.
data
Event payload data.
enum ssam_request_flags

Flags for SAM requests.

Constants

SSAM_REQUEST_HAS_RESPONSE

Specifies that the request expects a response. If not set, the request will be directly completed after its underlying packet has been transmitted. If set, the request transport system waits for a response of the request.

SSAM_REQUEST_UNSEQUENCED

Specifies that the request should be transmitted via an unsequenced packet. If set, the request must not have a response, meaning that this flag and the SSAM_REQUEST_HAS_RESPONSE flag are mutually exclusive.
struct ssam_request

SAM request description.

Definition

struct ssam_request {
  u8 target_category;
  u8 target_id;
  u8 command_id;
  u8 instance_id;
  u16 flags;
  u16 length;
  const u8 *payload;
};

Members

target_category
Category of the request’s target. See enum ssam_ssh_tc.
target_id
ID of the request’s target.
command_id
Command ID of the request.
instance_id
Instance ID of the request’s target.
flags
Flags for the request. See enum ssam_request_flags.
length
Length of the request payload in bytes.
payload
Request payload data.

Description

This struct fully describes a SAM request with payload. It is intended to help set up the actual transport struct, e.g. struct ssam_request_sync, and specifically its raw message data via ssam_request_write_data().

struct ssam_response

Response buffer for SAM request.

Definition

struct ssam_response {
  size_t capacity;
  size_t length;
  u8 *pointer;
};

Members

capacity
Capacity of the buffer, in bytes.
length
Length of the actual data stored in the memory pointed to by pointer, in bytes. Set by the transport system.
pointer
Pointer to the buffer’s memory, storing the response payload data.
struct ssam_request_sync

Synchronous SAM request struct.

Definition

struct ssam_request_sync {
  struct ssh_request base;
  struct completion comp;
  struct ssam_response *resp;
  int status;
};

Members

base
Underlying SSH request.
comp
Completion used to signal full completion of the request. After the request has been submitted, this struct may only be modified or deallocated after the completion has been signaled. request has been submitted,
resp
Buffer to store the response.
status
Status of the request, set after the base request has been completed or has failed.
void ssam_request_sync_set_data(struct ssam_request_sync *rqst, u8 *ptr, size_t len)

Set message data of a synchronous request.

Parameters

struct ssam_request_sync *rqst
The request.
u8 *ptr
Pointer to the request message data.
size_t len
Length of the request message data.

Description

Set the request message data of a synchronous request. The provided buffer needs to live until the request has been completed.

void ssam_request_sync_set_resp(struct ssam_request_sync *rqst, struct ssam_response *resp)

Set response buffer of a synchronous request.

Parameters

struct ssam_request_sync *rqst
The request.
struct ssam_response *resp
The response buffer.

Description

Sets the response buffer of a synchronous request. This buffer will store the response of the request after it has been completed. May be NULL if no response is expected.

int ssam_request_sync_wait(struct ssam_request_sync *rqst)

Wait for completion of a synchronous request.

Parameters

struct ssam_request_sync *rqst
The request to wait for.

Description

Wait for completion and release of a synchronous request. After this function terminates, the request is guaranteed to have left the transport system. After successful submission of a request, this function must be called before accessing the response of the request, freeing the request, or freeing any of the buffers associated with the request.

This function must not be called if the request has not been submitted yet and may lead to a deadlock/infinite wait if a subsequent request submission fails in that case, due to the completion never triggering.

Return

Returns the status of the given request, which is set on completion of the packet. This value is zero on success and negative on failure.

ssam_request_sync_onstack(ctrl, rqst, rsp, payload_len)

Execute a synchronous request on the stack.

Parameters

ctrl
The controller via which the request is submitted.
rqst
The request specification.
rsp
The response buffer.
payload_len
The (maximum) request payload length.

Description

Allocates a synchronous request with specified payload length on the stack, fully initializes it via the provided request specification, submits it, and finally waits for its completion before returning its status. This helper macro essentially allocates the request message buffer on the stack and then calls ssam_request_sync_with_buffer().

Note

The payload_len parameter specifies the maximum payload length, used for buffer allocation. The actual payload length may be smaller.

Return

Returns the status of the request or any failure during setup, i.e. zero on success and a negative value on failure.

__ssam_retry(request, n, args…)

Retry request in case of I/O errors or timeouts.

Parameters

request
The request function to execute. Must return an integer.
n
Number of tries.
args...
Arguments for the request function.

Description

Executes the given request function, i.e. calls request. In case the request returns -EREMOTEIO (indicates I/O error) or -ETIMEDOUT (request or underlying packet timed out), request will be re-executed again, up to n times in total.

Return

Returns the return value of the last execution of request.

ssam_retry(request, args…)

Retry request in case of I/O errors or timeouts up to three times in total.

Parameters

request
The request function to execute. Must return an integer.
args...
Arguments for the request function.

Description

Executes the given request function, i.e. calls request. In case the request returns -EREMOTEIO (indicates I/O error) or -ETIMEDOUT (request or underlying packet timed out), request will be re-executed again, up to three times in total.

See __ssam_retry() for a more generic macro for this purpose.

Return

Returns the return value of the last execution of request.

struct ssam_request_spec

Blue-print specification of SAM request.

Definition

struct ssam_request_spec {
  u8 target_category;
  u8 target_id;
  u8 command_id;
  u8 instance_id;
  u8 flags;
};

Members

target_category
Category of the request’s target. See enum ssam_ssh_tc.
target_id
ID of the request’s target.
command_id
Command ID of the request.
instance_id
Instance ID of the request’s target.
flags
Flags for the request. See enum ssam_request_flags.

Description

Blue-print specification for a SAM request. This struct describes the unique static parameters of a request (i.e. type) without specifying any of its instance-specific data (e.g. payload). It is intended to be used as base for defining simple request functions via the SSAM_DEFINE_SYNC_REQUEST_x() family of macros.

struct ssam_request_spec_md

Blue-print specification for multi-device SAM request.

Definition

struct ssam_request_spec_md {
  u8 target_category;
  u8 command_id;
  u8 flags;
};

Members

target_category
Category of the request’s target. See enum ssam_ssh_tc.
command_id
Command ID of the request.
flags
Flags for the request. See enum ssam_request_flags.

Description

Blue-print specification for a multi-device SAM request, i.e. a request that is applicable to multiple device instances, described by their individual target and instance IDs. This struct describes the unique static parameters of a request (i.e. type) without specifying any of its instance-specific data (e.g. payload) and without specifying any of its device specific IDs (i.e. target and instance ID). It is intended to be used as base for defining simple multi-device request functions via the SSAM_DEFINE_SYNC_REQUEST_MD_x() and SSAM_DEFINE_SYNC_REQUEST_CL_x() families of macros.

SSAM_DEFINE_SYNC_REQUEST_N(name, spec…)

Define synchronous SAM request function with neither argument nor return value.

Parameters

name
Name of the generated function.
spec...
Specification (struct ssam_request_spec) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request having neither argument nor return value. The generated function takes care of setting up the request struct and buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is being sent.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_W(name, atype, spec…)

Define synchronous SAM request function with argument.

Parameters

name
Name of the generated function.
atype
Type of the request’s argument.
spec...
Specification (struct ssam_request_spec) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking an argument of type atype and having no return value. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl, const atype *arg), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is sent. The request argument is specified via the arg pointer.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_R(name, rtype, spec…)

Define synchronous SAM request function with return value.

Parameters

name
Name of the generated function.
rtype
Type of the request’s return value.
spec...
Specification (struct ssam_request_spec) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking no argument but having a return value of type rtype. The generated function takes care of setting up the request and response structs, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl, rtype *ret), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is sent. The request’s return value is written to the memory pointed to by the ret parameter.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_MD_N(name, spec…)

Define synchronous multi-device SAM request function with neither argument nor return value.

Parameters

name
Name of the generated function.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request having neither argument nor return value. Device specifying parameters are not hard-coded, but instead must be provided to the function. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl, u8 tid, u8 iid), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is sent, tid the target ID for the request, and iid the instance ID.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_MD_W(name, atype, spec…)

Define synchronous multi-device SAM request function with argument.

Parameters

name
Name of the generated function.
atype
Type of the request’s argument.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking an argument of type atype and having no return value. Device specifying parameters are not hard-coded, but instead must be provided to the function. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl, u8 tid, u8 iid, const atype *arg), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is sent, tid the target ID for the request, and iid the instance ID. The request argument is specified via the arg pointer.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_MD_R(name, rtype, spec…)

Define synchronous multi-device SAM request function with return value.

Parameters

name
Name of the generated function.
rtype
Type of the request’s return value.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking no argument but having a return value of type rtype. Device specifying parameters are not hard-coded, but instead must be provided to the function. The generated function takes care of setting up the request and response structs, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_controller *ctrl, u8 tid, u8 iid, rtype *ret), returning the status of the request, which is zero on success and negative on failure. The ctrl parameter is the controller via which the request is sent, tid the target ID for the request, and iid the instance ID. The request’s return value is written to the memory pointed to by the ret parameter.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

enum ssam_notif_flags

Flags used in return values from SSAM notifier callback functions.

Constants

SSAM_NOTIF_HANDLED

Indicates that the notification has been handled. This flag should be set by the handler if the handler can act/has acted upon the event provided to it. This flag should not be set if the handler is not a primary handler intended for the provided event.

If this flag has not been set by any handler after the notifier chain has been traversed, a warning will be emitted, stating that the event has not been handled.

SSAM_NOTIF_STOP

Indicates that the notifier traversal should stop. If this flag is returned from a notifier callback, notifier chain traversal will immediately stop and any remaining notifiers will not be called. This flag is automatically set when ssam_notifier_from_errno() is called with a negative error value.
struct ssam_notifier_block

Base notifier block for SSAM event notifications.

Definition

struct ssam_notifier_block {
  struct list_head node;
  ssam_notifier_fn_t fn;
  int priority;
};

Members

node
The node for the list of notifiers.
fn
The callback function of this notifier. This function takes the respective notifier block and event as input and should return a notifier value, which can either be obtained from the flags provided in enum ssam_notif_flags, converted from a standard error value via ssam_notifier_from_errno(), or a combination of both (e.g. ssam_notifier_from_errno(e) | SSAM_NOTIF_HANDLED).
priority
Priority value determining the order in which notifier callbacks will be called. A higher value means higher priority, i.e. the associated callback will be executed earlier than other (lower priority) callbacks.
u32 ssam_notifier_from_errno(int err)

Convert standard error value to notifier return code.

Parameters

int err
The error code to convert, must be negative (in case of failure) or zero (in case of success).

Return

Returns the notifier return value obtained by converting the specified err value. In case err is negative, the SSAM_NOTIF_STOP flag will be set, causing notifier call chain traversal to abort.

int ssam_notifier_to_errno(u32 ret)

Convert notifier return code to standard error value.

Parameters

u32 ret
The notifier return value to convert.

Return

Returns the negative error value encoded in ret or zero if ret indicates success.

struct ssam_event_registry

Registry specification used for enabling events.

Definition

struct ssam_event_registry {
  u8 target_category;
  u8 target_id;
  u8 cid_enable;
  u8 cid_disable;
};

Members

target_category
Target category for the event registry requests.
target_id
Target ID for the event registry requests.
cid_enable
Command ID for the event-enable request.
cid_disable
Command ID for the event-disable request.

Description

This struct describes a SAM event registry via the minimal collection of SAM IDs specifying the requests to use for enabling and disabling an event. The individual event to be enabled/disabled itself is specified via struct ssam_event_id.

struct ssam_event_id

Unique event ID used for enabling events.

Definition

struct ssam_event_id {
  u8 target_category;
  u8 instance;
};

Members

target_category
Target category of the event source.
instance
Instance ID of the event source.

Description

This struct specifies the event to be enabled/disabled via an externally provided registry. It does not specify the registry to be used itself, this is done via struct ssam_event_registry.

enum ssam_event_mask

Flags specifying how events are matched to notifiers.

Constants

SSAM_EVENT_MASK_TARGET

In addition to filtering by target category, only execute the notifier callback for events with a target ID matching to the one of the registry used for enabling/disabling the event.

SSAM_EVENT_MASK_INSTANCE

In addition to filtering by target category, only execute the notifier callback for events with an instance ID matching to the instance ID used when enabling the event.

SSAM_EVENT_MASK_NONE

Run the callback for any event with matching target category. Do not do any additional filtering.

SSAM_EVENT_MASK_STRICT

Do all the filtering above.
SSAM_EVENT_REGISTRY(tc, tid, cid_en, cid_dis)

Define a new event registry.

Parameters

tc
Target category for the event registry requests.
tid
Target ID for the event registry requests.
cid_en
Command ID for the event-enable request.
cid_dis
Command ID for the event-disable request.

Return

Returns the struct ssam_event_registry specified by the given parameters.

enum ssam_event_notifier_flags

Flags for event notifiers.

Constants

SSAM_EVENT_NOTIFIER_OBSERVER

The corresponding notifier acts as observer. Registering a notifier with this flag set will not attempt to enable any event. Equally, unregistering will not attempt to disable any event. Note that a notifier with this flag may not even correspond to a certain event at all, only to a specific event target category. Event matching will not be influenced by this flag.
struct ssam_event_notifier

Notifier block for SSAM events.

Definition

struct ssam_event_notifier {
  struct ssam_notifier_block base;
  struct {
    struct ssam_event_registry reg;
    struct ssam_event_id id;
    enum ssam_event_mask mask;
    u8 flags;
  } event;
  unsigned long flags;
};

Members

base
The base notifier block with callback function and priority.
event
The event for which this block will receive notifications.
event.reg
Registry via which the event will be enabled/disabled.
event.id
ID specifying the event.
event.mask
Flags determining how events are matched to the notifier.
event.flags
Flags used for enabling the event.
flags
Notifier flags (see enum ssam_event_notifier_flags).
struct device * ssam_controller_device(struct ssam_controller *c)

Get the struct device associated with this controller.

Parameters

struct ssam_controller *c
The controller for which to get the device.

Return

Returns the struct device associated with this controller, providing its lower-level transport.

struct ssam_controller * ssam_controller_get(struct ssam_controller *c)

Increment reference count of controller.

Parameters

struct ssam_controller *c
The controller.

Return

Returns the controller provided as input.

void ssam_controller_put(struct ssam_controller *c)

Decrement reference count of controller.

Parameters

struct ssam_controller *c
The controller.
void ssam_controller_statelock(struct ssam_controller *c)

Lock the controller against state transitions.

Parameters

struct ssam_controller *c
The controller to lock.

Description

Lock the controller against state transitions. Holding this lock guarantees that the controller will not transition between states, i.e. if the controller is in state “started”, when this lock has been acquired, it will remain in this state at least until the lock has been released.

Multiple clients may concurrently hold this lock. In other words: The statelock functions represent the read-lock part of a r/w-semaphore. Actions causing state transitions of the controller must be executed while holding the write-part of this r/w-semaphore (see ssam_controller_lock() and ssam_controller_unlock() for that).

See ssam_controller_stateunlock() for the corresponding unlock function.

void ssam_controller_stateunlock(struct ssam_controller *c)

Unlock controller state transitions.

Parameters

struct ssam_controller *c
The controller to unlock.

Description

See ssam_controller_statelock() for the corresponding lock function.

ssize_t ssam_request_write_data(struct ssam_span *buf, struct ssam_controller *ctrl, const struct ssam_request *spec)

Construct and write SAM request message to buffer.

Parameters

struct ssam_span *buf
The buffer to write the data to.
struct ssam_controller *ctrl
The controller via which the request will be sent.
const struct ssam_request *spec
The request data and specification.

Description

Constructs a SAM/SSH request message and writes it to the provided buffer. The request and transport counters, specifically RQID and SEQ, will be set in this call. These counters are obtained from the controller. It is thus only valid to send the resulting message via the controller specified here.

For calculation of the required buffer size, refer to the SSH_COMMAND_MESSAGE_LENGTH() macro.

Return

Returns the number of bytes used in the buffer on success. Returns -EINVAL if the payload length provided in the request specification is too large (larger than SSH_COMMAND_MAX_PAYLOAD_SIZE) or if the provided buffer is too small.

int ssam_request_sync_alloc(size_t payload_len, gfp_t flags, struct ssam_request_sync **rqst, struct ssam_span *buffer)

Allocate a synchronous request.

Parameters

size_t payload_len
The length of the request payload.
gfp_t flags
Flags used for allocation.
struct ssam_request_sync **rqst
Where to store the pointer to the allocated request.
struct ssam_span *buffer
Where to store the buffer descriptor for the message buffer of the request.

Description

Allocates a synchronous request with corresponding message buffer. The request still needs to be initialized ssam_request_sync_init() before it can be submitted, and the message buffer data must still be set to the returned buffer via ssam_request_sync_set_data() after it has been filled, if need be with adjusted message length.

After use, the request and its corresponding message buffer should be freed via ssam_request_sync_free(). The buffer must not be freed separately.

Return

Returns zero on success, -ENOMEM if the request could not be allocated.

void ssam_request_sync_free(struct ssam_request_sync *rqst)

Free a synchronous request.

Parameters

struct ssam_request_sync *rqst
The request to be freed.

Description

Free a synchronous request and its corresponding buffer allocated with ssam_request_sync_alloc(). Do not use for requests allocated on the stack or via any other function.

Warning: The caller must ensure that the request is not in use any more. I.e. the caller must ensure that it has the only reference to the request and the request is not currently pending. This means that the caller has either never submitted the request, request submission has failed, or the caller has waited until the submitted request has been completed via ssam_request_sync_wait().

int ssam_request_sync_init(struct ssam_request_sync *rqst, enum ssam_request_flags flags)

Initialize a synchronous request struct.

Parameters

struct ssam_request_sync *rqst
The request to initialize.
enum ssam_request_flags flags
The request flags.

Description

Initializes the given request struct. Does not initialize the request message data. This has to be done explicitly after this call via ssam_request_sync_set_data() and the actual message data has to be written via ssam_request_write_data().

Return

Returns zero on success or -EINVAL if the given flags are invalid.

int ssam_request_sync_submit(struct ssam_controller *ctrl, struct ssam_request_sync *rqst)

Submit a synchronous request.

Parameters

struct ssam_controller *ctrl
The controller with which to submit the request.
struct ssam_request_sync *rqst
The request to submit.

Description

Submit a synchronous request. The request has to be initialized and properly set up, including response buffer (may be NULL if no response is expected) and command message data. This function does not wait for the request to be completed.

If this function succeeds, ssam_request_sync_wait() must be used to ensure that the request has been completed before the response data can be accessed and/or the request can be freed. On failure, the request may immediately be freed.

This function may only be used if the controller is active, i.e. has been initialized and not suspended.

int ssam_request_sync(struct ssam_controller *ctrl, const struct ssam_request *spec, struct ssam_response *rsp)

Execute a synchronous request.

Parameters

struct ssam_controller *ctrl
The controller via which the request will be submitted.
const struct ssam_request *spec
The request specification and payload.
struct ssam_response *rsp
The response buffer.

Description

Allocates a synchronous request with its message data buffer on the heap via ssam_request_sync_alloc(), fully initializes it via the provided request specification, submits it, and finally waits for its completion before freeing it and returning its status.

Return

Returns the status of the request or any failure during setup.

int ssam_request_sync_with_buffer(struct ssam_controller *ctrl, const struct ssam_request *spec, struct ssam_response *rsp, struct ssam_span *buf)

Execute a synchronous request with the provided buffer as back-end for the message buffer.

Parameters

struct ssam_controller *ctrl
The controller via which the request will be submitted.
const struct ssam_request *spec
The request specification and payload.
struct ssam_response *rsp
The response buffer.
struct ssam_span *buf
The buffer for the request message data.

Description

Allocates a synchronous request struct on the stack, fully initializes it using the provided buffer as message data buffer, submits it, and then waits for its completion before returning its status. The SSH_COMMAND_MESSAGE_LENGTH() macro can be used to compute the required message buffer size.

This function does essentially the same as ssam_request_sync(), but instead of dynamically allocating the request and message data buffer, it uses the provided message data buffer and stores the (small) request struct on the heap.

Return

Returns the status of the request or any failure during setup.

int ssam_notifier_register(struct ssam_controller *ctrl, struct ssam_event_notifier *n)

Register an event notifier.

Parameters

struct ssam_controller *ctrl
The controller to register the notifier on.
struct ssam_event_notifier *n
The event notifier to register.

Description

Register an event notifier. Increment the usage counter of the associated SAM event if the notifier is not marked as an observer. If the event is not marked as an observer and is currently not enabled, it will be enabled during this call. If the notifier is marked as an observer, no attempt will be made at enabling any event and no reference count will be modified.

Notifiers marked as observers do not need to be associated with one specific event, i.e. as long as no event matching is performed, only the event target category needs to be set.

Return

Returns zero on success, -ENOSPC if there have already been INT_MAX notifiers for the event ID/type associated with the notifier block registered, -ENOMEM if the corresponding event entry could not be allocated. If this is the first time that a notifier block is registered for the specific associated event, returns the status of the event-enable EC-command.

int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n)

Unregister an event notifier.

Parameters

struct ssam_controller *ctrl
The controller the notifier has been registered on.
struct ssam_event_notifier *n
The event notifier to unregister.

Description

Unregister an event notifier. Decrement the usage counter of the associated SAM event if the notifier is not marked as an observer. If the usage counter reaches zero, the event will be disabled.

Return

Returns zero on success, -ENOENT if the given notifier block has not been registered on the controller. If the given notifier block was the last one associated with its specific event, returns the status of the event-disable EC-command.

int ssam_controller_event_enable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags)

Enable the specified event.

Parameters

struct ssam_controller *ctrl
The controller to enable the event for.
struct ssam_event_registry reg
The event registry to use for enabling the event.
struct ssam_event_id id
The event ID specifying the event to be enabled.
u8 flags
The SAM event flags used for enabling the event.

Description

Increment the event reference count of the specified event. If the event has not been enabled previously, it will be enabled by this call.

Note

In general, ssam_notifier_register() with a non-observer notifier should be preferred for enabling/disabling events, as this will guarantee proper ordering and event forwarding in case of errors during event enabling/disabling.

Return

Returns zero on success, -ENOSPC if the reference count for the specified event has reached its maximum, -ENOMEM if the corresponding event entry could not be allocated. If this is the first time that this event has been enabled (i.e. the reference count was incremented from zero to one by this call), returns the status of the event-enable EC-command.

int ssam_controller_event_disable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags)

Disable the specified event.

Parameters

struct ssam_controller *ctrl
The controller to disable the event for.
struct ssam_event_registry reg
The event registry to use for disabling the event.
struct ssam_event_id id
The event ID specifying the event to be disabled.
u8 flags
The flags used when enabling the event.

Description

Decrement the reference count of the specified event. If the reference count reaches zero, the event will be disabled.

Note

In general, ssam_notifier_register()/ssam_notifier_unregister() with a non-observer notifier should be preferred for enabling/disabling events, as this will guarantee proper ordering and event forwarding in case of errors during event enabling/disabling.

Return

Returns zero on success, -ENOENT if the given event has not been enabled on the controller. If the reference count of the event reaches zero during this call, returns the status of the event-disable EC-command.

struct ssam_controller * ssam_get_controller(void)

Get reference to SSAM controller.

Parameters

void
no arguments

Description

Returns a reference to the SSAM controller of the system or NULL if there is none, it hasn’t been set up yet, or it has already been unregistered. This function automatically increments the reference count of the controller, thus the calling party must ensure that ssam_controller_put() is called when it doesn’t need the controller any more.

Link an arbitrary client device to the controller.

Parameters

struct ssam_controller *c
The controller to link to.
struct device *client
The client device.

Description

Link an arbitrary client device to the controller by creating a device link between it as consumer and the controller device as provider. This function can be used for non-SSAM devices (or SSAM devices not registered as child under the controller) to guarantee that the controller is valid for as long as the driver of the client device is bound, and that proper suspend and resume ordering is guaranteed.

The device link does not have to be destructed manually. It is removed automatically once the driver of the client device unbinds.

Return

Returns zero on success, -ENODEV if the controller is not ready or going to be removed soon, or -ENOMEM if the device link could not be created for other reasons.

struct ssam_controller * ssam_client_bind(struct device *client)

Bind an arbitrary client device to the controller.

Parameters

struct device *client
The client device.

Description

Link an arbitrary client device to the controller by creating a device link between it as consumer and the main controller device as provider. This function can be used for non-SSAM devices to guarantee that the controller returned by this function is valid for as long as the driver of the client device is bound, and that proper suspend and resume ordering is guaranteed.

This function does essentially the same as ssam_client_link(), except that it first fetches the main controller reference, then creates the link, and finally returns this reference. Note that this function does not increment the reference counter of the controller, as, due to the link, the controller lifetime is assured as long as the driver of the client device is bound.

It is not valid to use the controller reference obtained by this method outside of the driver bound to the client device at the time of calling this function, without first incrementing the reference count of the controller via ssam_controller_get(). Even after doing this, care must be taken that requests are only submitted and notifiers are only (un-)registered when the controller is active and not suspended. In other words: The device link only lives as long as the client driver is bound and any guarantees enforced by this link (e.g. active controller state) can only be relied upon as long as this link exists and may need to be enforced in other ways afterwards.

The created device link does not have to be destructed manually. It is removed automatically once the driver of the client device unbinds.

Return

Returns the controller on success, an error pointer with -ENODEV if the controller is not present, not ready or going to be removed soon, or -ENOMEM if the device link could not be created for other reasons.

Client Bus and Client Device API

enum ssam_device_domain

SAM device domain.

Constants

SSAM_DOMAIN_VIRTUAL
Virtual device.
SSAM_DOMAIN_SERIALHUB
Physical device connected via Surface Serial Hub.
enum ssam_virtual_tc

Target categories for the virtual SAM domain.

Constants

SSAM_VIRTUAL_TC_HUB
Device hub category.
struct ssam_device_uid

Unique identifier for SSAM device.

Definition

struct ssam_device_uid {
  u8 domain;
  u8 category;
  u8 target;
  u8 instance;
  u8 function;
};

Members

domain
Domain of the device.
category
Target category of the device.
target
Target ID of the device.
instance
Instance ID of the device.
function
Sub-function of the device. This field can be used to split a single SAM device into multiple virtual subdevices to separate different functionality of that device and allow one driver per such functionality.
SSAM_DEVICE(d, cat, tid, iid, fun)

Initialize a struct ssam_device_id with the given parameters.

Parameters

d
Domain of the device.
cat
Target category of the device.
tid
Target ID of the device.
iid
Instance ID of the device.
fun
Sub-function of the device.

Description

Initializes a struct ssam_device_id with the given parameters. See struct ssam_device_uid for details regarding the parameters. The special values SSAM_ANY_TID, SSAM_ANY_IID, and SSAM_ANY_FUN can be used to specify that matching should ignore target ID, instance ID, and/or sub-function, respectively. This macro initializes the match_flags field based on the given parameters.

Note

The parameters d and cat must be valid u8 values, the parameters tid, iid, and fun must be either valid u8 values or SSAM_ANY_TID, SSAM_ANY_IID, or SSAM_ANY_FUN, respectively. Other non-u8 values are not allowed.

SSAM_VDEV(cat, tid, iid, fun)

Initialize a struct ssam_device_id as virtual device with the given parameters.

Parameters

cat
Target category of the device.
tid
Target ID of the device.
iid
Instance ID of the device.
fun
Sub-function of the device.

Description

Initializes a struct ssam_device_id with the given parameters in the virtual domain. See struct ssam_device_uid for details regarding the parameters. The special values SSAM_ANY_TID, SSAM_ANY_IID, and SSAM_ANY_FUN can be used to specify that matching should ignore target ID, instance ID, and/or sub-function, respectively. This macro initializes the match_flags field based on the given parameters.

Note

The parameter cat must be a valid u8 value, the parameters tid, iid, and fun must be either valid u8 values or SSAM_ANY_TID, SSAM_ANY_IID, or SSAM_ANY_FUN, respectively. Other non-u8 values are not allowed.

SSAM_SDEV(cat, tid, iid, fun)

Initialize a struct ssam_device_id as physical SSH device with the given parameters.

Parameters

cat
Target category of the device.
tid
Target ID of the device.
iid
Instance ID of the device.
fun
Sub-function of the device.

Description

Initializes a struct ssam_device_id with the given parameters in the SSH domain. See struct ssam_device_uid for details regarding the parameters. The special values SSAM_ANY_TID, SSAM_ANY_IID, and SSAM_ANY_FUN can be used to specify that matching should ignore target ID, instance ID, and/or sub-function, respectively. This macro initializes the match_flags field based on the given parameters.

Note

The parameter cat must be a valid u8 value, the parameters tid, iid, and fun must be either valid u8 values or SSAM_ANY_TID, SSAM_ANY_IID, or SSAM_ANY_FUN, respectively. Other non-u8 values are not allowed.

struct ssam_device

SSAM client device.

Definition

struct ssam_device {
  struct device dev;
  struct ssam_controller *ctrl;
  struct ssam_device_uid uid;
};

Members

dev
Driver model representation of the device.
ctrl
SSAM controller managing this device.
uid
UID identifying the device.
struct ssam_device_driver

SSAM client device driver.

Definition

struct ssam_device_driver {
  struct device_driver driver;
  const struct ssam_device_id *match_table;
  int (*probe)(struct ssam_device *sdev);
  void (*remove)(struct ssam_device *sdev);
};

Members

driver
Base driver model structure.
match_table
Match table specifying which devices the driver should bind to.
probe
Called when the driver is being bound to a device.
remove
Called when the driver is being unbound from the device.
bool is_ssam_device(struct device *d)

Check if the given device is a SSAM client device.

Parameters

struct device *d
The device to test the type of.

Return

Returns true if the specified device is of type struct ssam_device, i.e. the device type points to ssam_device_type, and false otherwise.

struct ssam_device * to_ssam_device(struct device *d)

Casts the given device to a SSAM client device.

Parameters

struct device *d
The device to cast.

Description

Casts the given struct device to a struct ssam_device. The caller has to ensure that the given device is actually enclosed in a struct ssam_device, e.g. by calling is_ssam_device().

Return

Returns a pointer to the struct ssam_device wrapping the given device d.

struct ssam_device_driver * to_ssam_device_driver(struct device_driver *d)

Casts the given device driver to a SSAM client device driver.

Parameters

struct device_driver *d
The driver to cast.

Description

Casts the given struct device_driver to a struct ssam_device_driver. The caller has to ensure that the given driver is actually enclosed in a struct ssam_device_driver.

Return

Returns the pointer to the struct ssam_device_driver wrapping the given device driver d.

struct ssam_device * ssam_device_get(struct ssam_device *sdev)

Increment reference count of SSAM client device.

Parameters

struct ssam_device *sdev
The device to increment the reference count of.

Description

Increments the reference count of the given SSAM client device by incrementing the reference count of the enclosed struct device via get_device().

See ssam_device_put() for the counter-part of this function.

Return

Returns the device provided as input.

void ssam_device_put(struct ssam_device *sdev)

Decrement reference count of SSAM client device.

Parameters

struct ssam_device *sdev
The device to decrement the reference count of.

Description

Decrements the reference count of the given SSAM client device by decrementing the reference count of the enclosed struct device via put_device().

See ssam_device_get() for the counter-part of this function.

void * ssam_device_get_drvdata(struct ssam_device *sdev)

Get driver-data of SSAM client device.

Parameters

struct ssam_device *sdev
The device to get the driver-data from.

Return

Returns the driver-data of the given device, previously set via ssam_device_set_drvdata().

void ssam_device_set_drvdata(struct ssam_device *sdev, void *data)

Set driver-data of SSAM client device.

Parameters

struct ssam_device *sdev
The device to set the driver-data of.
void *data
The data to set the device’s driver-data pointer to.
ssam_device_driver_register(drv)

Register a SSAM client device driver.

Parameters

drv
The driver to register.
module_ssam_device_driver(drv)

Helper macro for SSAM device driver registration.

Parameters

drv
The driver managed by this module.

Description

Helper macro to register a SSAM device driver via module_init() and module_exit(). This macro may only be used once per module and replaces the aforementioned definitions.

SSAM_DEFINE_SYNC_REQUEST_CL_N(name, spec…)

Define synchronous client-device SAM request function with neither argument nor return value.

Parameters

name
Name of the generated function.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request having neither argument nor return value. Device specifying parameters are not hard-coded, but instead are provided via the client device, specifically its UID, supplied when calling this function. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_device *sdev), returning the status of the request, which is zero on success and negative on failure. The sdev parameter specifies both the target device of the request and by association the controller via which the request is sent.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_CL_W(name, atype, spec…)

Define synchronous client-device SAM request function with argument.

Parameters

name
Name of the generated function.
atype
Type of the request’s argument.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking an argument of type atype and having no return value. Device specifying parameters are not hard-coded, but instead are provided via the client device, specifically its UID, supplied when calling this function. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_device *sdev, const atype *arg), returning the status of the request, which is zero on success and negative on failure. The sdev parameter specifies both the target device of the request and by association the controller via which the request is sent. The request’s argument is specified via the arg pointer.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

SSAM_DEFINE_SYNC_REQUEST_CL_R(name, rtype, spec…)

Define synchronous client-device SAM request function with return value.

Parameters

name
Name of the generated function.
rtype
Type of the request’s return value.
spec...
Specification (struct ssam_request_spec_md) defining the request.

Description

Defines a function executing the synchronous SAM request specified by spec, with the request taking no argument but having a return value of type rtype. Device specifying parameters are not hard-coded, but instead are provided via the client device, specifically its UID, supplied when calling this function. The generated function takes care of setting up the request struct, buffer allocation, as well as execution of the request itself, returning once the request has been fully completed. The required transport buffer will be allocated on the stack.

The generated function is defined as static int name(struct ssam_device *sdev, rtype *ret), returning the status of the request, which is zero on success and negative on failure. The sdev parameter specifies both the target device of the request and by association the controller via which the request is sent. The request’s return value is written to the memory pointed to by the ret parameter.

Refer to ssam_request_sync_onstack() for more details on the behavior of the generated function.

struct ssam_device * ssam_device_alloc(struct ssam_controller *ctrl, struct ssam_device_uid uid)

Allocate and initialize a SSAM client device.

Parameters

struct ssam_controller *ctrl
The controller under which the device should be added.
struct ssam_device_uid uid
The UID of the device to be added.

Description

Allocates and initializes a new client device. The parent of the device will be set to the controller device and the name will be set based on the UID. Note that the device still has to be added via ssam_device_add(). Refer to that function for more details.

Return

Returns the newly allocated and initialized SSAM client device, or NULL if it could not be allocated.

int ssam_device_add(struct ssam_device *sdev)

Add a SSAM client device.

Parameters

struct ssam_device *sdev
The SSAM client device to be added.

Description

Added client devices must be guaranteed to always have a valid and active controller. Thus, this function will fail with -ENODEV if the controller of the device has not been initialized yet, has been suspended, or has been shut down.

The caller of this function should ensure that the corresponding call to ssam_device_remove() is issued before the controller is shut down. If the added device is a direct child of the controller device (default), it will be automatically removed when the controller is shut down.

By default, the controller device will become the parent of the newly created client device. The parent may be changed before ssam_device_add is called, but care must be taken that a) the correct suspend/resume ordering is guaranteed and b) the client device does not outlive the controller, i.e. that the device is removed before the controller is being shut down. In case these guarantees have to be manually enforced, please refer to the ssam_client_link() and ssam_client_bind() functions, which are intended to set up device-links for this purpose.

Return

Returns zero on success, a negative error code on failure.

void ssam_device_remove(struct ssam_device *sdev)

Remove a SSAM client device.

Parameters

struct ssam_device *sdev
The device to remove.

Description

Removes and unregisters the provided SSAM client device.

const struct ssam_device_id * ssam_device_id_match(const struct ssam_device_id *table, const struct ssam_device_uid uid)

Find the matching ID table entry for the given UID.

Parameters

const struct ssam_device_id *table
The table to search in.
const struct ssam_device_uid uid
The UID to matched against the individual table entries.

Description

Find the first match for the provided device UID in the provided ID table and return it. Returns NULL if no match could be found.

const struct ssam_device_id * ssam_device_get_match(const struct ssam_device *dev)

Find and return the ID matching the device in the ID table of the bound driver.

Parameters

const struct ssam_device *dev
The device for which to get the matching ID table entry.

Description

Find the fist match for the UID of the device in the ID table of the currently bound driver and return it. Returns NULL if the device does not have a driver bound to it, the driver does not have match_table (i.e. it is NULL), or there is no match in the driver’s match_table.

This function essentially calls ssam_device_id_match() with the ID table of the bound device driver and the UID of the device.

Return

Returns the first match for the UID of the device in the device driver’s match table, or NULL if no such match could be found.

const void * ssam_device_get_match_data(const struct ssam_device *dev)

Find the ID matching the device in the ID table of the bound driver and return its driver_data member.

Parameters

const struct ssam_device *dev
The device for which to get the match data.

Description

Find the fist match for the UID of the device in the ID table of the corresponding driver and return its driver_data. Returns NULL if the device does not have a driver bound to it, the driver does not have match_table (i.e. it is NULL), there is no match in the driver’s match_table, or the match does not have any driver_data.

This function essentially calls ssam_device_get_match() and, if any match could be found, returns its struct ssam_device_id.driver_data member.

Return

Returns the driver data associated with the first match for the UID of the device in the device driver’s match table, or NULL if no such match could be found.

int __ssam_device_driver_register(struct ssam_device_driver *sdrv, struct module *owner)

Register a SSAM client device driver.

Parameters

struct ssam_device_driver *sdrv
The driver to register.
struct module *owner
The module owning the provided driver.

Description

Please refer to the ssam_device_driver_register() macro for the normal way to register a driver from inside its owning module.

void ssam_device_driver_unregister(struct ssam_device_driver *sdrv)

Unregister a SSAM device driver.

Parameters

struct ssam_device_driver *sdrv
The driver to unregister.