diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/surface_aggregator/controller.h | 824 | ||||
| -rw-r--r-- | include/linux/surface_aggregator/serial_hub.h | 672 |
2 files changed, 1496 insertions, 0 deletions
diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h new file mode 100644 index 000000000000..f4b1ba887384 --- /dev/null +++ b/include/linux/surface_aggregator/controller.h @@ -0,0 +1,824 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Surface System Aggregator Module (SSAM) controller interface. + * + * Main communication interface for the SSAM EC. Provides a controller + * managing access and communication to and from the SSAM EC, as well as main + * communication structures and definitions. + * + * Copyright (C) 2019-2020 Maximilian Luz <luzmaximilian@gmail.com> + */ + +#ifndef _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H +#define _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H + +#include <linux/completion.h> +#include <linux/device.h> +#include <linux/types.h> + +#include <linux/surface_aggregator/serial_hub.h> + + +/* -- Main data types and definitions --------------------------------------- */ + +/** + * enum ssam_event_flags - Flags for enabling/disabling SAM events + * @SSAM_EVENT_SEQUENCED: The event will be sent via a sequenced data frame. + */ +enum ssam_event_flags { + SSAM_EVENT_SEQUENCED = BIT(0), +}; + +/** + * struct ssam_event - SAM event sent from the EC to the host. + * @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. + */ +struct ssam_event { + u8 target_category; + u8 target_id; + u8 command_id; + u8 instance_id; + u16 length; + u8 data[]; +}; + +/** + * enum ssam_request_flags - Flags for SAM requests. + * + * @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. + */ +enum ssam_request_flags { + SSAM_REQUEST_HAS_RESPONSE = BIT(0), + SSAM_REQUEST_UNSEQUENCED = BIT(1), +}; + +/** + * struct ssam_request - SAM request description. + * @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. + * + * 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_request { + u8 target_category; + u8 target_id; + u8 command_id; + u8 instance_id; + u16 flags; + u16 length; + const u8 *payload; +}; + +/** + * struct ssam_response - Response buffer for SAM request. + * @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_response { + size_t capacity; + size_t length; + u8 *pointer; +}; + +struct ssam_controller; + +struct ssam_controller *ssam_get_controller(void); +struct ssam_controller *ssam_client_bind(struct device *client); +int ssam_client_link(struct ssam_controller *ctrl, struct device *client); + +struct device *ssam_controller_device(struct ssam_controller *c); + +struct ssam_controller *ssam_controller_get(struct ssam_controller *c); +void ssam_controller_put(struct ssam_controller *c); + +void ssam_controller_statelock(struct ssam_controller *c); +void ssam_controller_stateunlock(struct ssam_controller *c); + +ssize_t ssam_request_write_data(struct ssam_span *buf, + struct ssam_controller *ctrl, + const struct ssam_request *spec); + + +/* -- Synchronous request interface. ---------------------------------------- */ + +/** + * struct ssam_request_sync - Synchronous SAM request struct. + * @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. + */ +struct ssam_request_sync { + struct ssh_request base; + struct completion comp; + struct ssam_response *resp; + int status; +}; + +int ssam_request_sync_alloc(size_t payload_len, gfp_t flags, + struct ssam_request_sync **rqst, + struct ssam_span *buffer); + +void ssam_request_sync_free(struct ssam_request_sync *rqst); + +int ssam_request_sync_init(struct ssam_request_sync *rqst, + enum ssam_request_flags flags); + +/** + * ssam_request_sync_set_data - Set message data of a synchronous request. + * @rqst: The request. + * @ptr: Pointer to the request message data. + * @len: Length of the request message data. + * + * Set the request message data of a synchronous request. The provided buffer + * needs to live until the request has been completed. + */ +static inline void ssam_request_sync_set_data(struct ssam_request_sync *rqst, + u8 *ptr, size_t len) +{ + ssh_request_set_data(&rqst->base, ptr, len); +} + +/** + * ssam_request_sync_set_resp - Set response buffer of a synchronous request. + * @rqst: The request. + * @resp: The response buffer. + * + * 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. + */ +static inline void ssam_request_sync_set_resp(struct ssam_request_sync *rqst, + struct ssam_response *resp) +{ + rqst->resp = resp; +} + +int ssam_request_sync_submit(struct ssam_controller *ctrl, + struct ssam_request_sync *rqst); + +/** + * ssam_request_sync_wait - Wait for completion of a synchronous request. + * @rqst: The request to wait for. + * + * 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. + */ +static inline int ssam_request_sync_wait(struct ssam_request_sync *rqst) +{ + wait_for_completion(&rqst->comp); + return rqst->status; +} + +int ssam_request_sync(struct ssam_controller *ctrl, + const struct ssam_request *spec, + struct ssam_response *rsp); + +int ssam_request_sync_with_buffer(struct ssam_controller *ctrl, + const struct ssam_request *spec, + struct ssam_response *rsp, + struct ssam_span *buf); + +/** + * ssam_request_sync_onstack - Execute a synchronous request on the stack. + * @ctrl: The controller via which the request is submitted. + * @rqst: The request specification. + * @rsp: The response buffer. + * @payload_len: The (maximum) request payload length. + * + * 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. + */ +#define ssam_request_sync_onstack(ctrl, rqst, rsp, payload_len) \ + ({ \ + u8 __data[SSH_COMMAND_MESSAGE_LENGTH(payload_len)]; \ + struct ssam_span __buf = { &__data[0], ARRAY_SIZE(__data) }; \ + \ + ssam_request_sync_with_buffer(ctrl, rqst, rsp, &__buf); \ + }) + +/** + * __ssam_retry - Retry request in case of I/O errors or timeouts. + * @request: The request function to execute. Must return an integer. + * @n: Number of tries. + * @args: Arguments for the request function. + * + * 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. + */ +#define __ssam_retry(request, n, args...) \ + ({ \ + int __i, __s = 0; \ + \ + for (__i = (n); __i > 0; __i--) { \ + __s = request(args); \ + if (__s != -ETIMEDOUT && __s != -EREMOTEIO) \ + break; \ + } \ + __s; \ + }) + +/** + * ssam_retry - Retry request in case of I/O errors or timeouts up to three + * times in total. + * @request: The request function to execute. Must return an integer. + * @args: Arguments for the request function. + * + * 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. + */ +#define ssam_retry(request, args...) \ + __ssam_retry(request, 3, args) + +/** + * struct ssam_request_spec - Blue-print specification of SAM request. + * @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. + * + * 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 { + u8 target_category; + u8 target_id; + u8 command_id; + u8 instance_id; + u8 flags; +}; + +/** + * struct ssam_request_spec_md - Blue-print specification for multi-device SAM + * request. + * @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. + * + * 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. + */ +struct ssam_request_spec_md { + u8 target_category; + u8 command_id; + u8 flags; +}; + +/** + * SSAM_DEFINE_SYNC_REQUEST_N() - Define synchronous SAM request function + * with neither argument nor return value. + * @name: Name of the generated function. + * @spec: Specification (&struct ssam_request_spec) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_N(name, spec...) \ + int name(struct ssam_controller *ctrl) \ + { \ + struct ssam_request_spec s = (struct ssam_request_spec)spec; \ + struct ssam_request rqst; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = s.target_id; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = s.instance_id; \ + rqst.flags = s.flags; \ + rqst.length = 0; \ + rqst.payload = NULL; \ + \ + return ssam_request_sync_onstack(ctrl, &rqst, NULL, 0); \ + } + +/** + * SSAM_DEFINE_SYNC_REQUEST_W() - Define synchronous SAM request function with + * argument. + * @name: Name of the generated function. + * @atype: Type of the request's argument. + * @spec: Specification (&struct ssam_request_spec) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_W(name, atype, spec...) \ + int name(struct ssam_controller *ctrl, const atype *arg) \ + { \ + struct ssam_request_spec s = (struct ssam_request_spec)spec; \ + struct ssam_request rqst; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = s.target_id; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = s.instance_id; \ + rqst.flags = s.flags; \ + rqst.length = sizeof(atype); \ + rqst.payload = (u8 *)arg; \ + \ + return ssam_request_sync_onstack(ctrl, &rqst, NULL, \ + sizeof(atype)); \ + } + +/** + * SSAM_DEFINE_SYNC_REQUEST_R() - Define synchronous SAM request function with + * return value. + * @name: Name of the generated function. + * @rtype: Type of the request's return value. + * @spec: Specification (&struct ssam_request_spec) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_R(name, rtype, spec...) \ + int name(struct ssam_controller *ctrl, rtype *ret) \ + { \ + struct ssam_request_spec s = (struct ssam_request_spec)spec; \ + struct ssam_request rqst; \ + struct ssam_response rsp; \ + int status; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = s.target_id; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = s.instance_id; \ + rqst.flags = s.flags | SSAM_REQUEST_HAS_RESPONSE; \ + rqst.length = 0; \ + rqst.payload = NULL; \ + \ + rsp.capacity = sizeof(rtype); \ + rsp.length = 0; \ + rsp.pointer = (u8 *)ret; \ + \ + status = ssam_request_sync_onstack(ctrl, &rqst, &rsp, 0); \ + if (status) \ + return status; \ + \ + if (rsp.length != sizeof(rtype)) { \ + struct device *dev = ssam_controller_device(ctrl); \ + dev_err(dev, \ + "rqst: invalid response length, expected %zu, got %zu (tc: %#04x, cid: %#04x)", \ + sizeof(rtype), rsp.length, rqst.target_category,\ + rqst.command_id); \ + return -EIO; \ + } \ + \ + return 0; \ + } + +/** + * SSAM_DEFINE_SYNC_REQUEST_MD_N() - Define synchronous multi-device SAM + * request function with neither argument nor return value. + * @name: Name of the generated function. + * @spec: Specification (&struct ssam_request_spec_md) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_MD_N(name, spec...) \ + int name(struct ssam_controller *ctrl, u8 tid, u8 iid) \ + { \ + struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \ + struct ssam_request rqst; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = tid; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = iid; \ + rqst.flags = s.flags; \ + rqst.length = 0; \ + rqst.payload = NULL; \ + \ + return ssam_request_sync_onstack(ctrl, &rqst, NULL, 0); \ + } + +/** + * SSAM_DEFINE_SYNC_REQUEST_MD_W() - Define synchronous multi-device SAM + * request function with argument. + * @name: Name of the generated function. + * @atype: Type of the request's argument. + * @spec: Specification (&struct ssam_request_spec_md) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_MD_W(name, atype, spec...) \ + int name(struct ssam_controller *ctrl, u8 tid, u8 iid, const atype *arg)\ + { \ + struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \ + struct ssam_request rqst; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = tid; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = iid; \ + rqst.flags = s.flags; \ + rqst.length = sizeof(atype); \ + rqst.payload = (u8 *)arg; \ + \ + return ssam_request_sync_onstack(ctrl, &rqst, NULL, \ + sizeof(atype)); \ + } + +/** + * SSAM_DEFINE_SYNC_REQUEST_MD_R() - Define synchronous multi-device SAM + * request function with return value. + * @name: Name of the generated function. + * @rtype: Type of the request's return value. + * @spec: Specification (&struct ssam_request_spec_md) defining the request. + * + * 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 ``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. + */ +#define SSAM_DEFINE_SYNC_REQUEST_MD_R(name, rtype, spec...) \ + int name(struct ssam_controller *ctrl, u8 tid, u8 iid, rtype *ret) \ + { \ + struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \ + struct ssam_request rqst; \ + struct ssam_response rsp; \ + int status; \ + \ + rqst.target_category = s.target_category; \ + rqst.target_id = tid; \ + rqst.command_id = s.command_id; \ + rqst.instance_id = iid; \ + rqst.flags = s.flags | SSAM_REQUEST_HAS_RESPONSE; \ + rqst.length = 0; \ + rqst.payload = NULL; \ + \ + rsp.capacity = sizeof(rtype); \ + rsp.length = 0; \ + rsp.pointer = (u8 *)ret; \ + \ + status = ssam_request_sync_onstack(ctrl, &rqst, &rsp, 0); \ + if (status) \ + return status; \ + \ + if (rsp.length != sizeof(rtype)) { \ + struct device *dev = ssam_controller_device(ctrl); \ + dev_err(dev, \ + "rqst: invalid response length, expected %zu, got %zu (tc: %#04x, cid: %#04x)", \ + sizeof(rtype), rsp.length, rqst.target_category,\ + rqst.command_id); \ + return -EIO; \ + } \ + \ + return 0; \ + } + + +/* -- Event notifier/callbacks. --------------------------------------------- */ + +#define SSAM_NOTIF_STATE_SHIFT 2 +#define SSAM_NOTIF_STATE_MASK ((1 << SSAM_NOTIF_STATE_SHIFT) - 1) + +/** + * enum ssam_notif_flags - Flags used in return values from SSAM notifier + * callback functions. + * + * @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. + */ +enum ssam_notif_flags { + SSAM_NOTIF_HANDLED = BIT(0), + SSAM_NOTIF_STOP = BIT(1), +}; + +struct ssam_event_notifier; + +typedef u32 (*ssam_notifier_fn_t)(struct ssam_event_notifier *nf, + const struct ssam_event *event); + +/** + * struct ssam_notifier_block - Base notifier block for SSAM event + * notifications. + * @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. + */ +struct ssam_notifier_block { + struct list_head node; + ssam_notifier_fn_t fn; + int priority; +}; + +/** + * ssam_notifier_from_errno() - Convert standard error value to notifier + * return code. + * @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. + */ +static inline u32 ssam_notifier_from_errno(int err) +{ + if (WARN_ON(err > 0) || err == 0) + return 0; + else + return ((-err) << SSAM_NOTIF_STATE_SHIFT) | SSAM_NOTIF_STOP; +} + +/** + * ssam_notifier_to_errno() - Convert notifier return code to standard error + * value. + * @ret: The notifier return value to convert. + * + * Return: Returns the negative error value encoded in @ret or zero if @ret + * indicates success. + */ +static inline int ssam_notifier_to_errno(u32 ret) +{ + return -(ret >> SSAM_NOTIF_STATE_SHIFT); +} + + +/* -- Event/notification registry. ------------------------------------------ */ + +/** + * struct ssam_event_registry - Registry specification used for enabling events. + * @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. + * + * 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_registry { + u8 target_category; + u8 target_id; + u8 cid_enable; + u8 cid_disable; +}; + +/** + * struct ssam_event_id - Unique event ID used for enabling events. + * @target_category: Target category of the event source. + * @instance: Instance ID of the event source. + * + * 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. + */ +struct ssam_event_id { + u8 target_category; + u8 instance; +}; + +/** + * enum ssam_event_mask - Flags specifying how events are matched to notifiers. + * + * @SSAM_EVENT_MASK_NONE: + * Run the callback for any event with matching target category. Do not + * do any additional filtering. + * + * @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_STRICT: + * Do all the filtering above. + */ +enum ssam_event_mask { + SSAM_EVENT_MASK_TARGET = BIT(0), + SSAM_EVENT_MASK_INSTANCE = BIT(1), + + SSAM_EVENT_MASK_NONE = 0, + SSAM_EVENT_MASK_STRICT = + SSAM_EVENT_MASK_TARGET + | SSAM_EVENT_MASK_INSTANCE, +}; + +/** + * SSAM_EVENT_REGISTRY() - Define a new event registry. + * @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. + */ +#define SSAM_EVENT_REGISTRY(tc, tid, cid_en, cid_dis) \ + ((struct ssam_event_registry) { \ + .target_category = (tc), \ + .target_id = (tid), \ + .cid_enable = (cid_en), \ + .cid_disable = (cid_dis), \ + }) + +#define SSAM_EVENT_REGISTRY_SAM \ + SSAM_EVENT_REGISTRY(SSAM_SSH_TC_SAM, 0x01, 0x0b, 0x0c) + +#define SSAM_EVENT_REGISTRY_KIP \ + SSAM_EVENT_REGISTRY(SSAM_SSH_TC_KIP, 0x02, 0x27, 0x28) + +#define SSAM_EVENT_REGISTRY_REG \ + SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, 0x02, 0x01, 0x02) + +/** + * struct ssam_event_notifier - Notifier block for SSAM events. + * @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. + */ +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; +}; + +int ssam_notifier_register(struct ssam_controller *ctrl, + struct ssam_event_notifier *n); + +int ssam_notifier_unregister(struct ssam_controller *ctrl, + struct ssam_event_notifier *n); + +#endif /* _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H */ diff --git a/include/linux/surface_aggregator/serial_hub.h b/include/linux/surface_aggregator/serial_hub.h new file mode 100644 index 000000000000..64276fbfa1d5 --- /dev/null +++ b/include/linux/surface_aggregator/serial_hub.h @@ -0,0 +1,672 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Surface Serial Hub (SSH) protocol and communication interface. + * + * Lower-level communication layers and SSH protocol definitions for the + * Surface System Aggregator Module (SSAM). Provides the interface for basic + * packet- and request-based communication with the SSAM EC via SSH. + * + * Copyright (C) 2019-2020 Maximilian Luz <luzmaximilian@gmail.com> + */ + +#ifndef _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H +#define _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H + +#include <linux/crc-ccitt.h> +#include <linux/kref.h> +#include <linux/ktime.h> +#include <linux/list.h> +#include <linux/types.h> + + +/* -- Data structures for SAM-over-SSH communication. ----------------------- */ + +/** + * enum ssh_frame_type - Frame types for SSH frames. + * + * @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. + */ +enum ssh_frame_type { + SSH_FRAME_TYPE_DATA_SEQ = 0x80, + SSH_FRAME_TYPE_DATA_NSQ = 0x00, + SSH_FRAME_TYPE_ACK = 0x40, + SSH_FRAME_TYPE_NAK = 0x04, +}; + +/** + * struct ssh_frame - SSH communication frame. + * @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. + */ +struct ssh_frame { + u8 type; + __le16 len; + u8 seq; +} __packed; + +static_assert(sizeof(struct ssh_frame) == 4); + +/* + * SSH_FRAME_MAX_PAYLOAD_SIZE - Maximum SSH frame payload length in bytes. + * + * This is the physical maximum length of the protocol. Implementations may + * set a more constrained limit. + */ +#define SSH_FRAME_MAX_PAYLOAD_SIZE U16_MAX + +/** + * enum ssh_payload_type - Type indicator for the SSH payload. + * @SSH_PLD_TYPE_CMD: The payload is a command structure with optional command + * payload. + */ +enum ssh_payload_type { + SSH_PLD_TYPE_CMD = 0x80, +}; + +/** + * struct ssh_command - Payload of a command-type frame. + * @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. + */ +struct ssh_command { + u8 type; + u8 tc; + u8 tid_out; + u8 tid_in; + u8 iid; + __le16 rqid; + u8 cid; +} __packed; + +static_assert(sizeof(struct ssh_command) == 8); + +/* + * SSH_COMMAND_MAX_PAYLOAD_SIZE - Maximum SSH command payload length in bytes. + * + * This is the physical maximum length of the protocol. Implementations may + * set a more constrained limit. + */ +#define SSH_COMMAND_MAX_PAYLOAD_SIZE \ + (SSH_FRAME_MAX_PAYLOAD_SIZE - sizeof(struct ssh_command)) + +/* + * SSH_MSG_LEN_BASE - Base-length of a SSH message. + * + * This is the minimum number of bytes required to form a message. The actual + * message length is SSH_MSG_LEN_BASE plus the length of the frame payload. + */ +#define SSH_MSG_LEN_BASE (sizeof(struct ssh_frame) + 3ull * sizeof(u16)) + +/* + * SSH_MSG_LEN_CTRL - Length of a SSH control message. + * + * This is the length of a SSH control message, which is equal to a SSH + * message without any payload. + */ +#define SSH_MSG_LEN_CTRL SSH_MSG_LEN_BASE + +/** + * SSH_MESSAGE_LENGTH() - Compute length of SSH message. + * @payload_size: Length of the payload inside the SSH frame. + * + * Return: Returns the length of a SSH message with payload of specified size. + */ +#define SSH_MESSAGE_LENGTH(payload_size) (SSH_MSG_LEN_BASE + (payload_size)) + +/** + * SSH_COMMAND_MESSAGE_LENGTH() - Compute length of SSH command message. + * @payload_size: Length of the command payload. + * + * Return: Returns the length of a SSH command message with command payload of + * specified size. + */ +#define SSH_COMMAND_MESSAGE_LENGTH(payload_size) \ + SSH_MESSAGE_LENGTH(sizeof(struct ssh_command) + (payload_size)) + +/** + * S |