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1 /*
2  *
3  * Intel Management Engine Interface (Intel MEI) Linux driver
4  * Copyright (c) 2003-2012, Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  */
16 
17 #include <linux/pci.h>
18 
19 #include <linux/kthread.h>
20 #include <linux/interrupt.h>
21 
22 #include "mei_dev.h"
23 #include "hw-me.h"
24 
25 #include "hbm.h"
26 
27 
28 /**
29  * mei_me_reg_read - Reads 32bit data from the mei device
30  *
31  * @dev: the device structure
32  * @offset: offset from which to read the data
33  *
34  * returns register value (u32)
35  */
mei_me_reg_read(const struct mei_me_hw * hw,unsigned long offset)36 static inline u32 mei_me_reg_read(const struct mei_me_hw *hw,
37 			       unsigned long offset)
38 {
39 	return ioread32(hw->mem_addr + offset);
40 }
41 
42 
43 /**
44  * mei_me_reg_write - Writes 32bit data to the mei device
45  *
46  * @dev: the device structure
47  * @offset: offset from which to write the data
48  * @value: register value to write (u32)
49  */
mei_me_reg_write(const struct mei_me_hw * hw,unsigned long offset,u32 value)50 static inline void mei_me_reg_write(const struct mei_me_hw *hw,
51 				 unsigned long offset, u32 value)
52 {
53 	iowrite32(value, hw->mem_addr + offset);
54 }
55 
56 /**
57  * mei_me_mecbrw_read - Reads 32bit data from ME circular buffer
58  *  read window register
59  *
60  * @dev: the device structure
61  *
62  * returns ME_CB_RW register value (u32)
63  */
mei_me_mecbrw_read(const struct mei_device * dev)64 static u32 mei_me_mecbrw_read(const struct mei_device *dev)
65 {
66 	return mei_me_reg_read(to_me_hw(dev), ME_CB_RW);
67 }
68 /**
69  * mei_me_mecsr_read - Reads 32bit data from the ME CSR
70  *
71  * @dev: the device structure
72  *
73  * returns ME_CSR_HA register value (u32)
74  */
mei_me_mecsr_read(const struct mei_me_hw * hw)75 static inline u32 mei_me_mecsr_read(const struct mei_me_hw *hw)
76 {
77 	return mei_me_reg_read(hw, ME_CSR_HA);
78 }
79 
80 /**
81  * mei_hcsr_read - Reads 32bit data from the host CSR
82  *
83  * @dev: the device structure
84  *
85  * returns H_CSR register value (u32)
86  */
mei_hcsr_read(const struct mei_me_hw * hw)87 static inline u32 mei_hcsr_read(const struct mei_me_hw *hw)
88 {
89 	return mei_me_reg_read(hw, H_CSR);
90 }
91 
92 /**
93  * mei_hcsr_set - writes H_CSR register to the mei device,
94  * and ignores the H_IS bit for it is write-one-to-zero.
95  *
96  * @dev: the device structure
97  */
mei_hcsr_set(struct mei_me_hw * hw,u32 hcsr)98 static inline void mei_hcsr_set(struct mei_me_hw *hw, u32 hcsr)
99 {
100 	hcsr &= ~H_IS;
101 	mei_me_reg_write(hw, H_CSR, hcsr);
102 }
103 
104 
105 /**
106  * mei_me_hw_config - configure hw dependent settings
107  *
108  * @dev: mei device
109  */
mei_me_hw_config(struct mei_device * dev)110 static void mei_me_hw_config(struct mei_device *dev)
111 {
112 	u32 hcsr = mei_hcsr_read(to_me_hw(dev));
113 	/* Doesn't change in runtime */
114 	dev->hbuf_depth = (hcsr & H_CBD) >> 24;
115 }
116 /**
117  * mei_clear_interrupts - clear and stop interrupts
118  *
119  * @dev: the device structure
120  */
mei_me_intr_clear(struct mei_device * dev)121 static void mei_me_intr_clear(struct mei_device *dev)
122 {
123 	struct mei_me_hw *hw = to_me_hw(dev);
124 	u32 hcsr = mei_hcsr_read(hw);
125 	if ((hcsr & H_IS) == H_IS)
126 		mei_me_reg_write(hw, H_CSR, hcsr);
127 }
128 /**
129  * mei_me_intr_enable - enables mei device interrupts
130  *
131  * @dev: the device structure
132  */
mei_me_intr_enable(struct mei_device * dev)133 static void mei_me_intr_enable(struct mei_device *dev)
134 {
135 	struct mei_me_hw *hw = to_me_hw(dev);
136 	u32 hcsr = mei_hcsr_read(hw);
137 	hcsr |= H_IE;
138 	mei_hcsr_set(hw, hcsr);
139 }
140 
141 /**
142  * mei_disable_interrupts - disables mei device interrupts
143  *
144  * @dev: the device structure
145  */
mei_me_intr_disable(struct mei_device * dev)146 static void mei_me_intr_disable(struct mei_device *dev)
147 {
148 	struct mei_me_hw *hw = to_me_hw(dev);
149 	u32 hcsr = mei_hcsr_read(hw);
150 	hcsr  &= ~H_IE;
151 	mei_hcsr_set(hw, hcsr);
152 }
153 
154 /**
155  * mei_me_hw_reset_release - release device from the reset
156  *
157  * @dev: the device structure
158  */
mei_me_hw_reset_release(struct mei_device * dev)159 static void mei_me_hw_reset_release(struct mei_device *dev)
160 {
161 	struct mei_me_hw *hw = to_me_hw(dev);
162 	u32 hcsr = mei_hcsr_read(hw);
163 
164 	hcsr |= H_IG;
165 	hcsr &= ~H_RST;
166 	mei_hcsr_set(hw, hcsr);
167 }
168 /**
169  * mei_me_hw_reset - resets fw via mei csr register.
170  *
171  * @dev: the device structure
172  * @intr_enable: if interrupt should be enabled after reset.
173  */
mei_me_hw_reset(struct mei_device * dev,bool intr_enable)174 static void mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
175 {
176 	struct mei_me_hw *hw = to_me_hw(dev);
177 	u32 hcsr = mei_hcsr_read(hw);
178 
179 	dev_dbg(&dev->pdev->dev, "before reset HCSR = 0x%08x.\n", hcsr);
180 
181 	hcsr |= (H_RST | H_IG);
182 
183 	if (intr_enable)
184 		hcsr |= H_IE;
185 	else
186 		hcsr |= ~H_IE;
187 
188 	mei_hcsr_set(hw, hcsr);
189 
190 	if (dev->dev_state == MEI_DEV_POWER_DOWN)
191 		mei_me_hw_reset_release(dev);
192 
193 	dev_dbg(&dev->pdev->dev, "current HCSR = 0x%08x.\n", mei_hcsr_read(hw));
194 }
195 
196 /**
197  * mei_me_host_set_ready - enable device
198  *
199  * @dev - mei device
200  * returns bool
201  */
202 
mei_me_host_set_ready(struct mei_device * dev)203 static void mei_me_host_set_ready(struct mei_device *dev)
204 {
205 	struct mei_me_hw *hw = to_me_hw(dev);
206 	hw->host_hw_state |= H_IE | H_IG | H_RDY;
207 	mei_hcsr_set(hw, hw->host_hw_state);
208 }
209 /**
210  * mei_me_host_is_ready - check whether the host has turned ready
211  *
212  * @dev - mei device
213  * returns bool
214  */
mei_me_host_is_ready(struct mei_device * dev)215 static bool mei_me_host_is_ready(struct mei_device *dev)
216 {
217 	struct mei_me_hw *hw = to_me_hw(dev);
218 	hw->host_hw_state = mei_hcsr_read(hw);
219 	return (hw->host_hw_state & H_RDY) == H_RDY;
220 }
221 
222 /**
223  * mei_me_hw_is_ready - check whether the me(hw) has turned ready
224  *
225  * @dev - mei device
226  * returns bool
227  */
mei_me_hw_is_ready(struct mei_device * dev)228 static bool mei_me_hw_is_ready(struct mei_device *dev)
229 {
230 	struct mei_me_hw *hw = to_me_hw(dev);
231 	hw->me_hw_state = mei_me_mecsr_read(hw);
232 	return (hw->me_hw_state & ME_RDY_HRA) == ME_RDY_HRA;
233 }
234 
mei_me_hw_ready_wait(struct mei_device * dev)235 static int mei_me_hw_ready_wait(struct mei_device *dev)
236 {
237 	int err;
238 	if (mei_me_hw_is_ready(dev))
239 		return 0;
240 
241 	mutex_unlock(&dev->device_lock);
242 	err = wait_event_interruptible_timeout(dev->wait_hw_ready,
243 			dev->recvd_hw_ready, MEI_INTEROP_TIMEOUT);
244 	mutex_lock(&dev->device_lock);
245 	if (!err && !dev->recvd_hw_ready) {
246 		dev_err(&dev->pdev->dev,
247 			"wait hw ready failed. status = 0x%x\n", err);
248 		return -ETIMEDOUT;
249 	}
250 
251 	dev->recvd_hw_ready = false;
252 	return 0;
253 }
254 
mei_me_hw_start(struct mei_device * dev)255 static int mei_me_hw_start(struct mei_device *dev)
256 {
257 	int ret = mei_me_hw_ready_wait(dev);
258 	if (ret)
259 		return ret;
260 	dev_dbg(&dev->pdev->dev, "hw is ready\n");
261 
262 	mei_me_host_set_ready(dev);
263 	return ret;
264 }
265 
266 
267 /**
268  * mei_hbuf_filled_slots - gets number of device filled buffer slots
269  *
270  * @dev: the device structure
271  *
272  * returns number of filled slots
273  */
mei_hbuf_filled_slots(struct mei_device * dev)274 static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
275 {
276 	struct mei_me_hw *hw = to_me_hw(dev);
277 	char read_ptr, write_ptr;
278 
279 	hw->host_hw_state = mei_hcsr_read(hw);
280 
281 	read_ptr = (char) ((hw->host_hw_state & H_CBRP) >> 8);
282 	write_ptr = (char) ((hw->host_hw_state & H_CBWP) >> 16);
283 
284 	return (unsigned char) (write_ptr - read_ptr);
285 }
286 
287 /**
288  * mei_me_hbuf_is_empty - checks if host buffer is empty.
289  *
290  * @dev: the device structure
291  *
292  * returns true if empty, false - otherwise.
293  */
mei_me_hbuf_is_empty(struct mei_device * dev)294 static bool mei_me_hbuf_is_empty(struct mei_device *dev)
295 {
296 	return mei_hbuf_filled_slots(dev) == 0;
297 }
298 
299 /**
300  * mei_me_hbuf_empty_slots - counts write empty slots.
301  *
302  * @dev: the device structure
303  *
304  * returns -1(ESLOTS_OVERFLOW) if overflow, otherwise empty slots count
305  */
mei_me_hbuf_empty_slots(struct mei_device * dev)306 static int mei_me_hbuf_empty_slots(struct mei_device *dev)
307 {
308 	unsigned char filled_slots, empty_slots;
309 
310 	filled_slots = mei_hbuf_filled_slots(dev);
311 	empty_slots = dev->hbuf_depth - filled_slots;
312 
313 	/* check for overflow */
314 	if (filled_slots > dev->hbuf_depth)
315 		return -EOVERFLOW;
316 
317 	return empty_slots;
318 }
319 
mei_me_hbuf_max_len(const struct mei_device * dev)320 static size_t mei_me_hbuf_max_len(const struct mei_device *dev)
321 {
322 	return dev->hbuf_depth * sizeof(u32) - sizeof(struct mei_msg_hdr);
323 }
324 
325 
326 /**
327  * mei_write_message - writes a message to mei device.
328  *
329  * @dev: the device structure
330  * @header: mei HECI header of message
331  * @buf: message payload will be written
332  *
333  * This function returns -EIO if write has failed
334  */
mei_me_write_message(struct mei_device * dev,struct mei_msg_hdr * header,unsigned char * buf)335 static int mei_me_write_message(struct mei_device *dev,
336 			struct mei_msg_hdr *header,
337 			unsigned char *buf)
338 {
339 	struct mei_me_hw *hw = to_me_hw(dev);
340 	unsigned long rem;
341 	unsigned long length = header->length;
342 	u32 *reg_buf = (u32 *)buf;
343 	u32 hcsr;
344 	u32 dw_cnt;
345 	int i;
346 	int empty_slots;
347 
348 	dev_dbg(&dev->pdev->dev, MEI_HDR_FMT, MEI_HDR_PRM(header));
349 
350 	empty_slots = mei_hbuf_empty_slots(dev);
351 	dev_dbg(&dev->pdev->dev, "empty slots = %hu.\n", empty_slots);
352 
353 	dw_cnt = mei_data2slots(length);
354 	if (empty_slots < 0 || dw_cnt > empty_slots)
355 		return -EIO;
356 
357 	mei_me_reg_write(hw, H_CB_WW, *((u32 *) header));
358 
359 	for (i = 0; i < length / 4; i++)
360 		mei_me_reg_write(hw, H_CB_WW, reg_buf[i]);
361 
362 	rem = length & 0x3;
363 	if (rem > 0) {
364 		u32 reg = 0;
365 		memcpy(&reg, &buf[length - rem], rem);
366 		mei_me_reg_write(hw, H_CB_WW, reg);
367 	}
368 
369 	hcsr = mei_hcsr_read(hw) | H_IG;
370 	mei_hcsr_set(hw, hcsr);
371 	if (!mei_me_hw_is_ready(dev))
372 		return -EIO;
373 
374 	return 0;
375 }
376 
377 /**
378  * mei_me_count_full_read_slots - counts read full slots.
379  *
380  * @dev: the device structure
381  *
382  * returns -1(ESLOTS_OVERFLOW) if overflow, otherwise filled slots count
383  */
mei_me_count_full_read_slots(struct mei_device * dev)384 static int mei_me_count_full_read_slots(struct mei_device *dev)
385 {
386 	struct mei_me_hw *hw = to_me_hw(dev);
387 	char read_ptr, write_ptr;
388 	unsigned char buffer_depth, filled_slots;
389 
390 	hw->me_hw_state = mei_me_mecsr_read(hw);
391 	buffer_depth = (unsigned char)((hw->me_hw_state & ME_CBD_HRA) >> 24);
392 	read_ptr = (char) ((hw->me_hw_state & ME_CBRP_HRA) >> 8);
393 	write_ptr = (char) ((hw->me_hw_state & ME_CBWP_HRA) >> 16);
394 	filled_slots = (unsigned char) (write_ptr - read_ptr);
395 
396 	/* check for overflow */
397 	if (filled_slots > buffer_depth)
398 		return -EOVERFLOW;
399 
400 	dev_dbg(&dev->pdev->dev, "filled_slots =%08x\n", filled_slots);
401 	return (int)filled_slots;
402 }
403 
404 /**
405  * mei_me_read_slots - reads a message from mei device.
406  *
407  * @dev: the device structure
408  * @buffer: message buffer will be written
409  * @buffer_length: message size will be read
410  */
mei_me_read_slots(struct mei_device * dev,unsigned char * buffer,unsigned long buffer_length)411 static int mei_me_read_slots(struct mei_device *dev, unsigned char *buffer,
412 		    unsigned long buffer_length)
413 {
414 	struct mei_me_hw *hw = to_me_hw(dev);
415 	u32 *reg_buf = (u32 *)buffer;
416 	u32 hcsr;
417 
418 	for (; buffer_length >= sizeof(u32); buffer_length -= sizeof(u32))
419 		*reg_buf++ = mei_me_mecbrw_read(dev);
420 
421 	if (buffer_length > 0) {
422 		u32 reg = mei_me_mecbrw_read(dev);
423 		memcpy(reg_buf, &reg, buffer_length);
424 	}
425 
426 	hcsr = mei_hcsr_read(hw) | H_IG;
427 	mei_hcsr_set(hw, hcsr);
428 	return 0;
429 }
430 
431 /**
432  * mei_me_irq_quick_handler - The ISR of the MEI device
433  *
434  * @irq: The irq number
435  * @dev_id: pointer to the device structure
436  *
437  * returns irqreturn_t
438  */
439 
mei_me_irq_quick_handler(int irq,void * dev_id)440 irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id)
441 {
442 	struct mei_device *dev = (struct mei_device *) dev_id;
443 	struct mei_me_hw *hw = to_me_hw(dev);
444 	u32 csr_reg = mei_hcsr_read(hw);
445 
446 	if ((csr_reg & H_IS) != H_IS)
447 		return IRQ_NONE;
448 
449 	/* clear H_IS bit in H_CSR */
450 	mei_me_reg_write(hw, H_CSR, csr_reg);
451 
452 	return IRQ_WAKE_THREAD;
453 }
454 
455 /**
456  * mei_me_irq_thread_handler - function called after ISR to handle the interrupt
457  * processing.
458  *
459  * @irq: The irq number
460  * @dev_id: pointer to the device structure
461  *
462  * returns irqreturn_t
463  *
464  */
mei_me_irq_thread_handler(int irq,void * dev_id)465 irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
466 {
467 	struct mei_device *dev = (struct mei_device *) dev_id;
468 	struct mei_cl_cb complete_list;
469 	s32 slots;
470 	int rets;
471 
472 	dev_dbg(&dev->pdev->dev, "function called after ISR to handle the interrupt processing.\n");
473 	/* initialize our complete list */
474 	mutex_lock(&dev->device_lock);
475 	mei_io_list_init(&complete_list);
476 
477 	/* Ack the interrupt here
478 	 * In case of MSI we don't go through the quick handler */
479 	if (pci_dev_msi_enabled(dev->pdev))
480 		mei_clear_interrupts(dev);
481 
482 	/* check if ME wants a reset */
483 	if (!mei_hw_is_ready(dev) &&
484 	    dev->dev_state != MEI_DEV_RESETTING &&
485 	    dev->dev_state != MEI_DEV_INITIALIZING) {
486 		dev_dbg(&dev->pdev->dev, "FW not ready.\n");
487 		mei_reset(dev, 1);
488 		mutex_unlock(&dev->device_lock);
489 		return IRQ_HANDLED;
490 	}
491 
492 	/*  check if we need to start the dev */
493 	if (!mei_host_is_ready(dev)) {
494 		if (mei_hw_is_ready(dev)) {
495 			dev_dbg(&dev->pdev->dev, "we need to start the dev.\n");
496 
497 			dev->recvd_hw_ready = true;
498 			wake_up_interruptible(&dev->wait_hw_ready);
499 
500 			mutex_unlock(&dev->device_lock);
501 			return IRQ_HANDLED;
502 		} else {
503 			dev_dbg(&dev->pdev->dev, "Reset Completed.\n");
504 			mei_me_hw_reset_release(dev);
505 			mutex_unlock(&dev->device_lock);
506 			return IRQ_HANDLED;
507 		}
508 	}
509 	/* check slots available for reading */
510 	slots = mei_count_full_read_slots(dev);
511 	while (slots > 0) {
512 		/* we have urgent data to send so break the read */
513 		if (dev->wr_ext_msg.hdr.length)
514 			break;
515 		dev_dbg(&dev->pdev->dev, "slots =%08x\n", slots);
516 		dev_dbg(&dev->pdev->dev, "call mei_irq_read_handler.\n");
517 		rets = mei_irq_read_handler(dev, &complete_list, &slots);
518 		if (rets)
519 			goto end;
520 	}
521 	rets = mei_irq_write_handler(dev, &complete_list);
522 end:
523 	dev_dbg(&dev->pdev->dev, "end of bottom half function.\n");
524 	dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
525 
526 	mutex_unlock(&dev->device_lock);
527 
528 	mei_irq_compl_handler(dev, &complete_list);
529 
530 	return IRQ_HANDLED;
531 }
532 static const struct mei_hw_ops mei_me_hw_ops = {
533 
534 	.host_is_ready = mei_me_host_is_ready,
535 
536 	.hw_is_ready = mei_me_hw_is_ready,
537 	.hw_reset = mei_me_hw_reset,
538 	.hw_config = mei_me_hw_config,
539 	.hw_start = mei_me_hw_start,
540 
541 	.intr_clear = mei_me_intr_clear,
542 	.intr_enable = mei_me_intr_enable,
543 	.intr_disable = mei_me_intr_disable,
544 
545 	.hbuf_free_slots = mei_me_hbuf_empty_slots,
546 	.hbuf_is_ready = mei_me_hbuf_is_empty,
547 	.hbuf_max_len = mei_me_hbuf_max_len,
548 
549 	.write = mei_me_write_message,
550 
551 	.rdbuf_full_slots = mei_me_count_full_read_slots,
552 	.read_hdr = mei_me_mecbrw_read,
553 	.read = mei_me_read_slots
554 };
555 
556 /**
557  * mei_me_dev_init - allocates and initializes the mei device structure
558  *
559  * @pdev: The pci device structure
560  *
561  * returns The mei_device_device pointer on success, NULL on failure.
562  */
mei_me_dev_init(struct pci_dev * pdev)563 struct mei_device *mei_me_dev_init(struct pci_dev *pdev)
564 {
565 	struct mei_device *dev;
566 
567 	dev = kzalloc(sizeof(struct mei_device) +
568 			 sizeof(struct mei_me_hw), GFP_KERNEL);
569 	if (!dev)
570 		return NULL;
571 
572 	mei_device_init(dev);
573 
574 	dev->ops = &mei_me_hw_ops;
575 
576 	dev->pdev = pdev;
577 	return dev;
578 }
579 
580