1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Main SSAM/SSH controller structure and functionality.
4  *
5  * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
6  */
7 
8 #ifndef _SURFACE_AGGREGATOR_CONTROLLER_H
9 #define _SURFACE_AGGREGATOR_CONTROLLER_H
10 
11 #include <linux/kref.h>
12 #include <linux/list.h>
13 #include <linux/mutex.h>
14 #include <linux/rbtree.h>
15 #include <linux/rwsem.h>
16 #include <linux/serdev.h>
17 #include <linux/spinlock.h>
18 #include <linux/srcu.h>
19 #include <linux/types.h>
20 #include <linux/workqueue.h>
21 
22 #include <linux/surface_aggregator/controller.h>
23 #include <linux/surface_aggregator/serial_hub.h>
24 
25 #include "ssh_request_layer.h"
26 
27 
28 /* -- Safe counters. -------------------------------------------------------- */
29 
30 /**
31  * struct ssh_seq_counter - Safe counter for SSH sequence IDs.
32  * @value: The current counter value.
33  */
34 struct ssh_seq_counter {
35 	u8 value;
36 };
37 
38 /**
39  * struct ssh_rqid_counter - Safe counter for SSH request IDs.
40  * @value: The current counter value.
41  */
42 struct ssh_rqid_counter {
43 	u16 value;
44 };
45 
46 
47 /* -- Event/notification system. -------------------------------------------- */
48 
49 /**
50  * struct ssam_nf_head - Notifier head for SSAM events.
51  * @srcu: The SRCU struct for synchronization.
52  * @head: List-head for notifier blocks registered under this head.
53  */
54 struct ssam_nf_head {
55 	struct srcu_struct srcu;
56 	struct list_head head;
57 };
58 
59 /**
60  * struct ssam_nf - Notifier callback- and activation-registry for SSAM events.
61  * @lock:     Lock guarding (de-)registration of notifier blocks. Note: This
62  *            lock does not need to be held for notifier calls, only
63  *            registration and deregistration.
64  * @refcount: The root of the RB-tree used for reference-counting enabled
65  *            events/notifications.
66  * @head:     The list of notifier heads for event/notification callbacks.
67  */
68 struct ssam_nf {
69 	struct mutex lock;
70 	struct rb_root refcount;
71 	struct ssam_nf_head head[SSH_NUM_EVENTS];
72 };
73 
74 
75 /* -- Event/async request completion system. -------------------------------- */
76 
77 struct ssam_cplt;
78 
79 /**
80  * struct ssam_event_item - Struct for event queuing and completion.
81  * @node:     The node in the queue.
82  * @rqid:     The request ID of the event.
83  * @ops:      Instance specific functions.
84  * @ops.free: Callback for freeing this event item.
85  * @event:    Actual event data.
86  */
87 struct ssam_event_item {
88 	struct list_head node;
89 	u16 rqid;
90 
91 	struct {
92 		void (*free)(struct ssam_event_item *event);
93 	} ops;
94 
95 	struct ssam_event event;	/* must be last */
96 };
97 
98 /**
99  * struct ssam_event_queue - Queue for completing received events.
100  * @cplt: Reference to the completion system on which this queue is active.
101  * @lock: The lock for any operation on the queue.
102  * @head: The list-head of the queue.
103  * @work: The &struct work_struct performing completion work for this queue.
104  */
105 struct ssam_event_queue {
106 	struct ssam_cplt *cplt;
107 
108 	spinlock_t lock;
109 	struct list_head head;
110 	struct work_struct work;
111 };
112 
113 /**
114  * struct ssam_event_target - Set of queues for a single SSH target ID.
115  * @queue: The array of queues, one queue per event ID.
116  */
117 struct ssam_event_target {
118 	struct ssam_event_queue queue[SSH_NUM_EVENTS];
119 };
120 
121 /**
122  * struct ssam_cplt - SSAM event/async request completion system.
123  * @dev:          The device with which this system is associated. Only used
124  *                for logging.
125  * @wq:           The &struct workqueue_struct on which all completion work
126  *                items are queued.
127  * @event:        Event completion management.
128  * @event.target: Array of &struct ssam_event_target, one for each target.
129  * @event.notif:  Notifier callbacks and event activation reference counting.
130  */
131 struct ssam_cplt {
132 	struct device *dev;
133 	struct workqueue_struct *wq;
134 
135 	struct {
136 		struct ssam_event_target target[SSH_NUM_TARGETS];
137 		struct ssam_nf notif;
138 	} event;
139 };
140 
141 
142 /* -- Main SSAM device structures. ------------------------------------------ */
143 
144 /**
145  * enum ssam_controller_state - State values for &struct ssam_controller.
146  * @SSAM_CONTROLLER_UNINITIALIZED:
147  *	The controller has not been initialized yet or has been deinitialized.
148  * @SSAM_CONTROLLER_INITIALIZED:
149  *	The controller is initialized, but has not been started yet.
150  * @SSAM_CONTROLLER_STARTED:
151  *	The controller has been started and is ready to use.
152  * @SSAM_CONTROLLER_STOPPED:
153  *	The controller has been stopped.
154  * @SSAM_CONTROLLER_SUSPENDED:
155  *	The controller has been suspended.
156  */
157 enum ssam_controller_state {
158 	SSAM_CONTROLLER_UNINITIALIZED,
159 	SSAM_CONTROLLER_INITIALIZED,
160 	SSAM_CONTROLLER_STARTED,
161 	SSAM_CONTROLLER_STOPPED,
162 	SSAM_CONTROLLER_SUSPENDED,
163 };
164 
165 /**
166  * struct ssam_controller_caps - Controller device capabilities.
167  * @ssh_power_profile:             SSH power profile.
168  * @ssh_buffer_size:               SSH driver UART buffer size.
169  * @screen_on_sleep_idle_timeout:  SAM UART screen-on sleep idle timeout.
170  * @screen_off_sleep_idle_timeout: SAM UART screen-off sleep idle timeout.
171  * @d3_closes_handle:              SAM closes UART handle in D3.
172  *
173  * Controller and SSH device capabilities found in ACPI.
174  */
175 struct ssam_controller_caps {
176 	u32 ssh_power_profile;
177 	u32 ssh_buffer_size;
178 	u32 screen_on_sleep_idle_timeout;
179 	u32 screen_off_sleep_idle_timeout;
180 	u32 d3_closes_handle:1;
181 };
182 
183 /**
184  * struct ssam_controller - SSAM controller device.
185  * @kref:  Reference count of the controller.
186  * @lock:  Main lock for the controller, used to guard state changes.
187  * @state: Controller state.
188  * @rtl:   Request transport layer for SSH I/O.
189  * @cplt:  Completion system for SSH/SSAM events and asynchronous requests.
190  * @counter:      Safe SSH message ID counters.
191  * @counter.seq:  Sequence ID counter.
192  * @counter.rqid: Request ID counter.
193  * @irq:          Wakeup IRQ resources.
194  * @irq.num:      The wakeup IRQ number.
195  * @irq.wakeup_enabled: Whether wakeup by IRQ is enabled during suspend.
196  * @caps: The controller device capabilities.
197  */
198 struct ssam_controller {
199 	struct kref kref;
200 
201 	struct rw_semaphore lock;
202 	enum ssam_controller_state state;
203 
204 	struct ssh_rtl rtl;
205 	struct ssam_cplt cplt;
206 
207 	struct {
208 		struct ssh_seq_counter seq;
209 		struct ssh_rqid_counter rqid;
210 	} counter;
211 
212 	struct {
213 		int num;
214 		bool wakeup_enabled;
215 	} irq;
216 
217 	struct ssam_controller_caps caps;
218 };
219 
220 #define to_ssam_controller(ptr, member) \
221 	container_of(ptr, struct ssam_controller, member)
222 
223 #define ssam_dbg(ctrl, fmt, ...)  rtl_dbg(&(ctrl)->rtl, fmt, ##__VA_ARGS__)
224 #define ssam_info(ctrl, fmt, ...) rtl_info(&(ctrl)->rtl, fmt, ##__VA_ARGS__)
225 #define ssam_warn(ctrl, fmt, ...) rtl_warn(&(ctrl)->rtl, fmt, ##__VA_ARGS__)
226 #define ssam_err(ctrl, fmt, ...)  rtl_err(&(ctrl)->rtl, fmt, ##__VA_ARGS__)
227 
228 /**
229  * ssam_controller_receive_buf() - Provide input-data to the controller.
230  * @ctrl: The controller.
231  * @buf:  The input buffer.
232  * @n:    The number of bytes in the input buffer.
233  *
234  * Provide input data to be evaluated by the controller, which has been
235  * received via the lower-level transport.
236  *
237  * Return: Returns the number of bytes consumed, or, if the packet transport
238  * layer of the controller has been shut down, %-ESHUTDOWN.
239  */
240 static inline
241 int ssam_controller_receive_buf(struct ssam_controller *ctrl,
242 				const unsigned char *buf, size_t n)
243 {
244 	return ssh_ptl_rx_rcvbuf(&ctrl->rtl.ptl, buf, n);
245 }
246 
247 /**
248  * ssam_controller_write_wakeup() - Notify the controller that the underlying
249  * device has space available for data to be written.
250  * @ctrl: The controller.
251  */
252 static inline void ssam_controller_write_wakeup(struct ssam_controller *ctrl)
253 {
254 	ssh_ptl_tx_wakeup_transfer(&ctrl->rtl.ptl);
255 }
256 
257 int ssam_controller_init(struct ssam_controller *ctrl, struct serdev_device *s);
258 int ssam_controller_start(struct ssam_controller *ctrl);
259 void ssam_controller_shutdown(struct ssam_controller *ctrl);
260 void ssam_controller_destroy(struct ssam_controller *ctrl);
261 
262 int ssam_notifier_disable_registered(struct ssam_controller *ctrl);
263 void ssam_notifier_restore_registered(struct ssam_controller *ctrl);
264 
265 int ssam_irq_setup(struct ssam_controller *ctrl);
266 void ssam_irq_free(struct ssam_controller *ctrl);
267 int ssam_irq_arm_for_wakeup(struct ssam_controller *ctrl);
268 void ssam_irq_disarm_wakeup(struct ssam_controller *ctrl);
269 
270 void ssam_controller_lock(struct ssam_controller *c);
271 void ssam_controller_unlock(struct ssam_controller *c);
272 
273 int ssam_get_firmware_version(struct ssam_controller *ctrl, u32 *version);
274 int ssam_ctrl_notif_display_off(struct ssam_controller *ctrl);
275 int ssam_ctrl_notif_display_on(struct ssam_controller *ctrl);
276 int ssam_ctrl_notif_d0_exit(struct ssam_controller *ctrl);
277 int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl);
278 
279 int ssam_controller_suspend(struct ssam_controller *ctrl);
280 int ssam_controller_resume(struct ssam_controller *ctrl);
281 
282 int ssam_event_item_cache_init(void);
283 void ssam_event_item_cache_destroy(void);
284 
285 #endif /* _SURFACE_AGGREGATOR_CONTROLLER_H */
286