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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2012-2019, 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
18const 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(POWER_DOWN);
28 MEI_DEV_STATE(POWER_UP);
29 default:
30 return "unknown";
31 }
32#undef MEI_DEV_STATE
33}
34
35const char *mei_pg_state_str(enum mei_pg_state state)
36{
37#define MEI_PG_STATE(state) case MEI_PG_##state: return #state
38 switch (state) {
39 MEI_PG_STATE(OFF);
40 MEI_PG_STATE(ON);
41 default:
42 return "unknown";
43 }
44#undef MEI_PG_STATE
45}
46
47/**
48 * mei_fw_status2str - convert fw status registers to printable string
49 *
50 * @fw_status: firmware status
51 * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
52 * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
53 *
54 * Return: number of bytes written or -EINVAL if buffer is to small
55 */
56ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
57 char *buf, size_t len)
58{
59 ssize_t cnt = 0;
60 int i;
61
62 buf[0] = '\0';
63
64 if (len < MEI_FW_STATUS_STR_SZ)
65 return -EINVAL;
66
67 for (i = 0; i < fw_status->count; i++)
68 cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
69 fw_status->status[i]);
70
71 /* drop last space */
72 buf[cnt] = '\0';
73 return cnt;
74}
75EXPORT_SYMBOL_GPL(mei_fw_status2str);
76
77/**
78 * mei_cancel_work - Cancel mei background jobs
79 *
80 * @dev: the device structure
81 */
82void mei_cancel_work(struct mei_device *dev)
83{
84 cancel_work_sync(&dev->reset_work);
85 cancel_work_sync(&dev->bus_rescan_work);
86
87 cancel_delayed_work_sync(&dev->timer_work);
88}
89EXPORT_SYMBOL_GPL(mei_cancel_work);
90
91/**
92 * mei_reset - resets host and fw.
93 *
94 * @dev: the device structure
95 *
96 * Return: 0 on success or < 0 if the reset hasn't succeeded
97 */
98int mei_reset(struct mei_device *dev)
99{
100 enum mei_dev_state state = dev->dev_state;
101 bool interrupts_enabled;
102 int ret;
103
104 if (state != MEI_DEV_INITIALIZING &&
105 state != MEI_DEV_DISABLED &&
106 state != MEI_DEV_POWER_DOWN &&
107 state != MEI_DEV_POWER_UP) {
108 char fw_sts_str[MEI_FW_STATUS_STR_SZ];
109
110 mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
111 dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
112 mei_dev_state_str(state), fw_sts_str);
113 }
114
115 mei_clear_interrupts(dev);
116
117 /* we're already in reset, cancel the init timer
118 * if the reset was called due the hbm protocol error
119 * we need to call it before hw start
120 * so the hbm watchdog won't kick in
121 */
122 mei_hbm_idle(dev);
123
124 /* enter reset flow */
125 interrupts_enabled = state != MEI_DEV_POWER_DOWN;
126 mei_set_devstate(dev, MEI_DEV_RESETTING);
127
128 dev->reset_count++;
129 if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
130 dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
131 mei_set_devstate(dev, MEI_DEV_DISABLED);
132 return -ENODEV;
133 }
134
135 ret = mei_hw_reset(dev, interrupts_enabled);
136 /* fall through and remove the sw state even if hw reset has failed */
137
138 /* no need to clean up software state in case of power up */
139 if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
140 mei_cl_all_disconnect(dev);
141
142 mei_hbm_reset(dev);
143
144 memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
145
146 if (ret) {
147 dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
148 return ret;
149 }
150
151 if (state == MEI_DEV_POWER_DOWN) {
152 dev_dbg(dev->dev, "powering down: end of reset\n");
153 mei_set_devstate(dev, MEI_DEV_DISABLED);
154 return 0;
155 }
156
157 ret = mei_hw_start(dev);
158 if (ret) {
159 dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
160 return ret;
161 }
162
163 dev_dbg(dev->dev, "link is established start sending messages.\n");
164
165 mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
166 ret = mei_hbm_start_req(dev);
167 if (ret) {
168 dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
169 mei_set_devstate(dev, MEI_DEV_RESETTING);
170 return ret;
171 }
172
173 return 0;
174}
175EXPORT_SYMBOL_GPL(mei_reset);
176
177/**
178 * mei_start - initializes host and fw to start work.
179 *
180 * @dev: the device structure
181 *
182 * Return: 0 on success, <0 on failure.
183 */
184int mei_start(struct mei_device *dev)
185{
186 int ret;
187
188 mutex_lock(&dev->device_lock);
189
190 /* acknowledge interrupt and stop interrupts */
191 mei_clear_interrupts(dev);
192
193 ret = mei_hw_config(dev);
194 if (ret)
195 goto err;
196
197 dev_dbg(dev->dev, "reset in start the mei device.\n");
198
199 dev->reset_count = 0;
200 do {
201 mei_set_devstate(dev, MEI_DEV_INITIALIZING);
202 ret = mei_reset(dev);
203
204 if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
205 dev_err(dev->dev, "reset failed ret = %d", ret);
206 goto err;
207 }
208 } while (ret);
209
210 if (mei_hbm_start_wait(dev)) {
211 dev_err(dev->dev, "HBM haven't started");
212 goto err;
213 }
214
215 if (!mei_host_is_ready(dev)) {
216 dev_err(dev->dev, "host is not ready.\n");
217 goto err;
218 }
219
220 if (!mei_hw_is_ready(dev)) {
221 dev_err(dev->dev, "ME is not ready.\n");
222 goto err;
223 }
224
225 if (!mei_hbm_version_is_supported(dev)) {
226 dev_dbg(dev->dev, "MEI start failed.\n");
227 goto err;
228 }
229
230 dev_dbg(dev->dev, "link layer has been established.\n");
231
232 mutex_unlock(&dev->device_lock);
233 return 0;
234err:
235 dev_err(dev->dev, "link layer initialization failed.\n");
236 mei_set_devstate(dev, MEI_DEV_DISABLED);
237 mutex_unlock(&dev->device_lock);
238 return -ENODEV;
239}
240EXPORT_SYMBOL_GPL(mei_start);
241
242/**
243 * mei_restart - restart device after suspend
244 *
245 * @dev: the device structure
246 *
247 * Return: 0 on success or -ENODEV if the restart hasn't succeeded
248 */
249int mei_restart(struct mei_device *dev)
250{
251 int err;
252
253 mutex_lock(&dev->device_lock);
254
255 mei_set_devstate(dev, MEI_DEV_POWER_UP);
256 dev->reset_count = 0;
257
258 err = mei_reset(dev);
259
260 mutex_unlock(&dev->device_lock);
261
262 if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
263 dev_err(dev->dev, "device disabled = %d\n", err);
264 return -ENODEV;
265 }
266
267 /* try to start again */
268 if (err)
269 schedule_work(&dev->reset_work);
270
271
272 return 0;
273}
274EXPORT_SYMBOL_GPL(mei_restart);
275
276static void mei_reset_work(struct work_struct *work)
277{
278 struct mei_device *dev =
279 container_of(work, struct mei_device, reset_work);
280 int ret;
281
282 mei_clear_interrupts(dev);
283 mei_synchronize_irq(dev);
284
285 mutex_lock(&dev->device_lock);
286
287 ret = mei_reset(dev);
288
289 mutex_unlock(&dev->device_lock);
290
291 if (dev->dev_state == MEI_DEV_DISABLED) {
292 dev_err(dev->dev, "device disabled = %d\n", ret);
293 return;
294 }
295
296 /* retry reset in case of failure */
297 if (ret)
298 schedule_work(&dev->reset_work);
299}
300
301void mei_stop(struct mei_device *dev)
302{
303 dev_dbg(dev->dev, "stopping the device.\n");
304
305 mutex_lock(&dev->device_lock);
306 mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
307 mutex_unlock(&dev->device_lock);
308 mei_cl_bus_remove_devices(dev);
309
310 mei_cancel_work(dev);
311
312 mei_clear_interrupts(dev);
313 mei_synchronize_irq(dev);
314
315 mutex_lock(&dev->device_lock);
316
317 mei_reset(dev);
318 /* move device to disabled state unconditionally */
319 mei_set_devstate(dev, MEI_DEV_DISABLED);
320
321 mutex_unlock(&dev->device_lock);
322}
323EXPORT_SYMBOL_GPL(mei_stop);
324
325/**
326 * mei_write_is_idle - check if the write queues are idle
327 *
328 * @dev: the device structure
329 *
330 * Return: true of there is no pending write
331 */
332bool mei_write_is_idle(struct mei_device *dev)
333{
334 bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
335 list_empty(&dev->ctrl_wr_list) &&
336 list_empty(&dev->write_list) &&
337 list_empty(&dev->write_waiting_list));
338
339 dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
340 idle,
341 mei_dev_state_str(dev->dev_state),
342 list_empty(&dev->ctrl_wr_list),
343 list_empty(&dev->write_list),
344 list_empty(&dev->write_waiting_list));
345
346 return idle;
347}
348EXPORT_SYMBOL_GPL(mei_write_is_idle);
349
350/**
351 * mei_device_init -- initialize mei_device structure
352 *
353 * @dev: the mei device
354 * @device: the device structure
355 * @hw_ops: hw operations
356 */
357void mei_device_init(struct mei_device *dev,
358 struct device *device,
359 const struct mei_hw_ops *hw_ops)
360{
361 /* setup our list array */
362 INIT_LIST_HEAD(&dev->file_list);
363 INIT_LIST_HEAD(&dev->device_list);
364 INIT_LIST_HEAD(&dev->me_clients);
365 mutex_init(&dev->device_lock);
366 init_rwsem(&dev->me_clients_rwsem);
367 mutex_init(&dev->cl_bus_lock);
368 init_waitqueue_head(&dev->wait_hw_ready);
369 init_waitqueue_head(&dev->wait_pg);
370 init_waitqueue_head(&dev->wait_hbm_start);
371 dev->dev_state = MEI_DEV_INITIALIZING;
372 dev->reset_count = 0;
373
374 INIT_LIST_HEAD(&dev->write_list);
375 INIT_LIST_HEAD(&dev->write_waiting_list);
376 INIT_LIST_HEAD(&dev->ctrl_wr_list);
377 INIT_LIST_HEAD(&dev->ctrl_rd_list);
378 dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
379
380 INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
381 INIT_WORK(&dev->reset_work, mei_reset_work);
382 INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
383
384 bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
385 dev->open_handle_count = 0;
386
387 /*
388 * Reserving the first client ID
389 * 0: Reserved for MEI Bus Message communications
390 */
391 bitmap_set(dev->host_clients_map, 0, 1);
392
393 dev->pg_event = MEI_PG_EVENT_IDLE;
394 dev->ops = hw_ops;
395 dev->dev = device;
396}
397EXPORT_SYMBOL_GPL(mei_device_init);
398