1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2012-2022, Intel Corporation. All rights reserved.
4 * Intel Management Engine Interface (Intel MEI) Linux driver
5 */
6
7 #include <linux/export.h>
8 #include <linux/sched.h>
9 #include <linux/wait.h>
10 #include <linux/delay.h>
11
12 #include <linux/mei.h>
13
14 #include "mei_dev.h"
15 #include "hbm.h"
16 #include "client.h"
17
mei_dev_state_str(int state)18 const char *mei_dev_state_str(int state)
19 {
20 #define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
21 switch (state) {
22 MEI_DEV_STATE(INITIALIZING);
23 MEI_DEV_STATE(INIT_CLIENTS);
24 MEI_DEV_STATE(ENABLED);
25 MEI_DEV_STATE(RESETTING);
26 MEI_DEV_STATE(DISABLED);
27 MEI_DEV_STATE(POWERING_DOWN);
28 MEI_DEV_STATE(POWER_DOWN);
29 MEI_DEV_STATE(POWER_UP);
30 default:
31 return "unknown";
32 }
33 #undef MEI_DEV_STATE
34 }
35
mei_pg_state_str(enum mei_pg_state state)36 const char *mei_pg_state_str(enum mei_pg_state state)
37 {
38 #define MEI_PG_STATE(state) case MEI_PG_##state: return #state
39 switch (state) {
40 MEI_PG_STATE(OFF);
41 MEI_PG_STATE(ON);
42 default:
43 return "unknown";
44 }
45 #undef MEI_PG_STATE
46 }
47
48 /**
49 * mei_fw_status2str - convert fw status registers to printable string
50 *
51 * @fw_status: firmware status
52 * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
53 * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
54 *
55 * Return: number of bytes written or -EINVAL if buffer is to small
56 */
mei_fw_status2str(struct mei_fw_status * fw_status,char * buf,size_t len)57 ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
58 char *buf, size_t len)
59 {
60 ssize_t cnt = 0;
61 int i;
62
63 buf[0] = '\0';
64
65 if (len < MEI_FW_STATUS_STR_SZ)
66 return -EINVAL;
67
68 for (i = 0; i < fw_status->count; i++)
69 cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
70 fw_status->status[i]);
71
72 /* drop last space */
73 buf[cnt] = '\0';
74 return cnt;
75 }
76 EXPORT_SYMBOL_GPL(mei_fw_status2str);
77
78 /**
79 * mei_cancel_work - Cancel mei background jobs
80 *
81 * @dev: the device structure
82 */
mei_cancel_work(struct mei_device * dev)83 void mei_cancel_work(struct mei_device *dev)
84 {
85 cancel_work_sync(&dev->reset_work);
86 cancel_work_sync(&dev->bus_rescan_work);
87
88 cancel_delayed_work_sync(&dev->timer_work);
89 }
90 EXPORT_SYMBOL_GPL(mei_cancel_work);
91
92 /**
93 * mei_reset - resets host and fw.
94 *
95 * @dev: the device structure
96 *
97 * Return: 0 on success or < 0 if the reset hasn't succeeded
98 */
mei_reset(struct mei_device * dev)99 int mei_reset(struct mei_device *dev)
100 {
101 enum mei_dev_state state = dev->dev_state;
102 bool interrupts_enabled;
103 int ret;
104
105 if (state != MEI_DEV_INITIALIZING &&
106 state != MEI_DEV_DISABLED &&
107 state != MEI_DEV_POWER_DOWN &&
108 state != MEI_DEV_POWER_UP) {
109 char fw_sts_str[MEI_FW_STATUS_STR_SZ];
110
111 mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
112 dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
113 mei_dev_state_str(state), fw_sts_str);
114 }
115
116 mei_clear_interrupts(dev);
117
118 /* we're already in reset, cancel the init timer
119 * if the reset was called due the hbm protocol error
120 * we need to call it before hw start
121 * so the hbm watchdog won't kick in
122 */
123 mei_hbm_idle(dev);
124
125 /* enter reset flow */
126 interrupts_enabled = state != MEI_DEV_POWER_DOWN;
127 mei_set_devstate(dev, MEI_DEV_RESETTING);
128
129 dev->reset_count++;
130 if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
131 dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
132 mei_set_devstate(dev, MEI_DEV_DISABLED);
133 return -ENODEV;
134 }
135
136 ret = mei_hw_reset(dev, interrupts_enabled);
137 /* fall through and remove the sw state even if hw reset has failed */
138
139 /* no need to clean up software state in case of power up */
140 if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
141 mei_cl_all_disconnect(dev);
142
143 mei_hbm_reset(dev);
144
145 memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
146
147 if (ret) {
148 dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
149 return ret;
150 }
151
152 if (state == MEI_DEV_POWER_DOWN) {
153 dev_dbg(dev->dev, "powering down: end of reset\n");
154 mei_set_devstate(dev, MEI_DEV_DISABLED);
155 return 0;
156 }
157
158 ret = mei_hw_start(dev);
159 if (ret) {
160 dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
161 return ret;
162 }
163
164 if (dev->dev_state != MEI_DEV_RESETTING) {
165 dev_dbg(dev->dev, "wrong state = %d on link start\n", dev->dev_state);
166 return 0;
167 }
168
169 dev_dbg(dev->dev, "link is established start sending messages.\n");
170
171 mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
172 ret = mei_hbm_start_req(dev);
173 if (ret) {
174 dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
175 mei_set_devstate(dev, MEI_DEV_RESETTING);
176 return ret;
177 }
178
179 return 0;
180 }
181 EXPORT_SYMBOL_GPL(mei_reset);
182
183 /**
184 * mei_start - initializes host and fw to start work.
185 *
186 * @dev: the device structure
187 *
188 * Return: 0 on success, <0 on failure.
189 */
mei_start(struct mei_device * dev)190 int mei_start(struct mei_device *dev)
191 {
192 int ret;
193
194 mutex_lock(&dev->device_lock);
195
196 /* acknowledge interrupt and stop interrupts */
197 mei_clear_interrupts(dev);
198
199 ret = mei_hw_config(dev);
200 if (ret)
201 goto err;
202
203 dev_dbg(dev->dev, "reset in start the mei device.\n");
204
205 dev->reset_count = 0;
206 do {
207 mei_set_devstate(dev, MEI_DEV_INITIALIZING);
208 ret = mei_reset(dev);
209
210 if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
211 dev_err(dev->dev, "reset failed ret = %d", ret);
212 goto err;
213 }
214 } while (ret);
215
216 if (mei_hbm_start_wait(dev)) {
217 dev_err(dev->dev, "HBM haven't started");
218 goto err;
219 }
220
221 if (!mei_hbm_version_is_supported(dev)) {
222 dev_dbg(dev->dev, "MEI start failed.\n");
223 goto err;
224 }
225
226 dev_dbg(dev->dev, "link layer has been established.\n");
227
228 mutex_unlock(&dev->device_lock);
229 return 0;
230 err:
231 dev_err(dev->dev, "link layer initialization failed.\n");
232 mei_set_devstate(dev, MEI_DEV_DISABLED);
233 mutex_unlock(&dev->device_lock);
234 return -ENODEV;
235 }
236 EXPORT_SYMBOL_GPL(mei_start);
237
238 /**
239 * mei_restart - restart device after suspend
240 *
241 * @dev: the device structure
242 *
243 * Return: 0 on success or -ENODEV if the restart hasn't succeeded
244 */
mei_restart(struct mei_device * dev)245 int mei_restart(struct mei_device *dev)
246 {
247 int err;
248
249 mutex_lock(&dev->device_lock);
250
251 mei_set_devstate(dev, MEI_DEV_POWER_UP);
252 dev->reset_count = 0;
253
254 err = mei_reset(dev);
255
256 mutex_unlock(&dev->device_lock);
257
258 if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
259 dev_err(dev->dev, "device disabled = %d\n", err);
260 return -ENODEV;
261 }
262
263 /* try to start again */
264 if (err)
265 schedule_work(&dev->reset_work);
266
267
268 return 0;
269 }
270 EXPORT_SYMBOL_GPL(mei_restart);
271
mei_reset_work(struct work_struct * work)272 static void mei_reset_work(struct work_struct *work)
273 {
274 struct mei_device *dev =
275 container_of(work, struct mei_device, reset_work);
276 int ret;
277
278 mei_clear_interrupts(dev);
279 mei_synchronize_irq(dev);
280
281 mutex_lock(&dev->device_lock);
282
283 ret = mei_reset(dev);
284
285 mutex_unlock(&dev->device_lock);
286
287 if (dev->dev_state == MEI_DEV_DISABLED) {
288 dev_err(dev->dev, "device disabled = %d\n", ret);
289 return;
290 }
291
292 /* retry reset in case of failure */
293 if (ret)
294 schedule_work(&dev->reset_work);
295 }
296
mei_stop(struct mei_device * dev)297 void mei_stop(struct mei_device *dev)
298 {
299 dev_dbg(dev->dev, "stopping the device.\n");
300
301 mutex_lock(&dev->device_lock);
302 mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
303 mutex_unlock(&dev->device_lock);
304 mei_cl_bus_remove_devices(dev);
305 mutex_lock(&dev->device_lock);
306 mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
307 mutex_unlock(&dev->device_lock);
308
309 mei_cancel_work(dev);
310
311 mei_clear_interrupts(dev);
312 mei_synchronize_irq(dev);
313 /* to catch HW-initiated reset */
314 mei_cancel_work(dev);
315
316 mutex_lock(&dev->device_lock);
317
318 mei_reset(dev);
319 /* move device to disabled state unconditionally */
320 mei_set_devstate(dev, MEI_DEV_DISABLED);
321
322 mutex_unlock(&dev->device_lock);
323 }
324 EXPORT_SYMBOL_GPL(mei_stop);
325
326 /**
327 * mei_write_is_idle - check if the write queues are idle
328 *
329 * @dev: the device structure
330 *
331 * Return: true of there is no pending write
332 */
mei_write_is_idle(struct mei_device * dev)333 bool mei_write_is_idle(struct mei_device *dev)
334 {
335 bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
336 list_empty(&dev->ctrl_wr_list) &&
337 list_empty(&dev->write_list) &&
338 list_empty(&dev->write_waiting_list));
339
340 dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
341 idle,
342 mei_dev_state_str(dev->dev_state),
343 list_empty(&dev->ctrl_wr_list),
344 list_empty(&dev->write_list),
345 list_empty(&dev->write_waiting_list));
346
347 return idle;
348 }
349 EXPORT_SYMBOL_GPL(mei_write_is_idle);
350
351 /**
352 * mei_device_init - initialize mei_device structure
353 *
354 * @dev: the mei device
355 * @device: the device structure
356 * @slow_fw: configure longer timeouts as FW is slow
357 * @hw_ops: hw operations
358 */
mei_device_init(struct mei_device * dev,struct device * device,bool slow_fw,const struct mei_hw_ops * hw_ops)359 void mei_device_init(struct mei_device *dev,
360 struct device *device,
361 bool slow_fw,
362 const struct mei_hw_ops *hw_ops)
363 {
364 /* setup our list array */
365 INIT_LIST_HEAD(&dev->file_list);
366 INIT_LIST_HEAD(&dev->device_list);
367 INIT_LIST_HEAD(&dev->me_clients);
368 mutex_init(&dev->device_lock);
369 init_rwsem(&dev->me_clients_rwsem);
370 mutex_init(&dev->cl_bus_lock);
371 init_waitqueue_head(&dev->wait_hw_ready);
372 init_waitqueue_head(&dev->wait_pg);
373 init_waitqueue_head(&dev->wait_hbm_start);
374 dev->dev_state = MEI_DEV_INITIALIZING;
375 dev->reset_count = 0;
376
377 INIT_LIST_HEAD(&dev->write_list);
378 INIT_LIST_HEAD(&dev->write_waiting_list);
379 INIT_LIST_HEAD(&dev->ctrl_wr_list);
380 INIT_LIST_HEAD(&dev->ctrl_rd_list);
381 dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
382
383 INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
384 INIT_WORK(&dev->reset_work, mei_reset_work);
385 INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
386
387 bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
388 dev->open_handle_count = 0;
389
390 dev->pxp_mode = MEI_DEV_PXP_DEFAULT;
391
392 /*
393 * Reserving the first client ID
394 * 0: Reserved for MEI Bus Message communications
395 */
396 bitmap_set(dev->host_clients_map, 0, 1);
397
398 dev->pg_event = MEI_PG_EVENT_IDLE;
399 dev->ops = hw_ops;
400 dev->dev = device;
401
402 dev->timeouts.hw_ready = mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT);
403 dev->timeouts.connect = MEI_CONNECT_TIMEOUT;
404 dev->timeouts.client_init = MEI_CLIENTS_INIT_TIMEOUT;
405 dev->timeouts.pgi = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
406 dev->timeouts.d0i3 = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
407 if (slow_fw) {
408 dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT_SLOW);
409 dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT_SLOW);
410 dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT_SLOW);
411 } else {
412 dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
413 dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT);
414 dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT);
415 }
416 }
417 EXPORT_SYMBOL_GPL(mei_device_init);
418
419