1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PCI Express Downstream Port Containment services driver
4  * Author: Keith Busch <keith.busch@intel.com>
5  *
6  * Copyright (C) 2016 Intel Corp.
7  */
8 
9 #define dev_fmt(fmt) "DPC: " fmt
10 
11 #include <linux/aer.h>
12 #include <linux/bitfield.h>
13 #include <linux/delay.h>
14 #include <linux/interrupt.h>
15 #include <linux/init.h>
16 #include <linux/pci.h>
17 
18 #include "portdrv.h"
19 #include "../pci.h"
20 
21 #define PCI_EXP_DPC_CTL_EN_MASK	(PCI_EXP_DPC_CTL_EN_FATAL | \
22 				 PCI_EXP_DPC_CTL_EN_NONFATAL)
23 
24 static const char * const rp_pio_error_string[] = {
25 	"Configuration Request received UR Completion",	 /* Bit Position 0  */
26 	"Configuration Request received CA Completion",	 /* Bit Position 1  */
27 	"Configuration Request Completion Timeout",	 /* Bit Position 2  */
28 	NULL,
29 	NULL,
30 	NULL,
31 	NULL,
32 	NULL,
33 	"I/O Request received UR Completion",		 /* Bit Position 8  */
34 	"I/O Request received CA Completion",		 /* Bit Position 9  */
35 	"I/O Request Completion Timeout",		 /* Bit Position 10 */
36 	NULL,
37 	NULL,
38 	NULL,
39 	NULL,
40 	NULL,
41 	"Memory Request received UR Completion",	 /* Bit Position 16 */
42 	"Memory Request received CA Completion",	 /* Bit Position 17 */
43 	"Memory Request Completion Timeout",		 /* Bit Position 18 */
44 };
45 
pci_save_dpc_state(struct pci_dev * dev)46 void pci_save_dpc_state(struct pci_dev *dev)
47 {
48 	struct pci_cap_saved_state *save_state;
49 	u16 *cap;
50 
51 	if (!pci_is_pcie(dev))
52 		return;
53 
54 	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
55 	if (!save_state)
56 		return;
57 
58 	cap = (u16 *)&save_state->cap.data[0];
59 	pci_read_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, cap);
60 }
61 
pci_restore_dpc_state(struct pci_dev * dev)62 void pci_restore_dpc_state(struct pci_dev *dev)
63 {
64 	struct pci_cap_saved_state *save_state;
65 	u16 *cap;
66 
67 	if (!pci_is_pcie(dev))
68 		return;
69 
70 	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
71 	if (!save_state)
72 		return;
73 
74 	cap = (u16 *)&save_state->cap.data[0];
75 	pci_write_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, *cap);
76 }
77 
78 static DECLARE_WAIT_QUEUE_HEAD(dpc_completed_waitqueue);
79 
80 #ifdef CONFIG_HOTPLUG_PCI_PCIE
dpc_completed(struct pci_dev * pdev)81 static bool dpc_completed(struct pci_dev *pdev)
82 {
83 	u16 status;
84 
85 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
86 	if ((!PCI_POSSIBLE_ERROR(status)) && (status & PCI_EXP_DPC_STATUS_TRIGGER))
87 		return false;
88 
89 	if (test_bit(PCI_DPC_RECOVERING, &pdev->priv_flags))
90 		return false;
91 
92 	return true;
93 }
94 
95 /**
96  * pci_dpc_recovered - whether DPC triggered and has recovered successfully
97  * @pdev: PCI device
98  *
99  * Return true if DPC was triggered for @pdev and has recovered successfully.
100  * Wait for recovery if it hasn't completed yet.  Called from the PCIe hotplug
101  * driver to recognize and ignore Link Down/Up events caused by DPC.
102  */
pci_dpc_recovered(struct pci_dev * pdev)103 bool pci_dpc_recovered(struct pci_dev *pdev)
104 {
105 	struct pci_host_bridge *host;
106 
107 	if (!pdev->dpc_cap)
108 		return false;
109 
110 	/*
111 	 * Synchronization between hotplug and DPC is not supported
112 	 * if DPC is owned by firmware and EDR is not enabled.
113 	 */
114 	host = pci_find_host_bridge(pdev->bus);
115 	if (!host->native_dpc && !IS_ENABLED(CONFIG_PCIE_EDR))
116 		return false;
117 
118 	/*
119 	 * Need a timeout in case DPC never completes due to failure of
120 	 * dpc_wait_rp_inactive().  The spec doesn't mandate a time limit,
121 	 * but reports indicate that DPC completes within 4 seconds.
122 	 */
123 	wait_event_timeout(dpc_completed_waitqueue, dpc_completed(pdev),
124 			   msecs_to_jiffies(4000));
125 
126 	return test_and_clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
127 }
128 #endif /* CONFIG_HOTPLUG_PCI_PCIE */
129 
dpc_wait_rp_inactive(struct pci_dev * pdev)130 static int dpc_wait_rp_inactive(struct pci_dev *pdev)
131 {
132 	unsigned long timeout = jiffies + HZ;
133 	u16 cap = pdev->dpc_cap, status;
134 
135 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
136 	while (status & PCI_EXP_DPC_RP_BUSY &&
137 					!time_after(jiffies, timeout)) {
138 		msleep(10);
139 		pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
140 	}
141 	if (status & PCI_EXP_DPC_RP_BUSY) {
142 		pci_warn(pdev, "root port still busy\n");
143 		return -EBUSY;
144 	}
145 	return 0;
146 }
147 
dpc_reset_link(struct pci_dev * pdev)148 pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
149 {
150 	pci_ers_result_t ret;
151 	u16 cap;
152 
153 	set_bit(PCI_DPC_RECOVERING, &pdev->priv_flags);
154 
155 	/*
156 	 * DPC disables the Link automatically in hardware, so it has
157 	 * already been reset by the time we get here.
158 	 */
159 	cap = pdev->dpc_cap;
160 
161 	/*
162 	 * Wait until the Link is inactive, then clear DPC Trigger Status
163 	 * to allow the Port to leave DPC.
164 	 */
165 	if (!pcie_wait_for_link(pdev, false))
166 		pci_info(pdev, "Data Link Layer Link Active not cleared in 1000 msec\n");
167 
168 	if (pdev->dpc_rp_extensions && dpc_wait_rp_inactive(pdev)) {
169 		clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
170 		ret = PCI_ERS_RESULT_DISCONNECT;
171 		goto out;
172 	}
173 
174 	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
175 			      PCI_EXP_DPC_STATUS_TRIGGER);
176 
177 	if (pci_bridge_wait_for_secondary_bus(pdev, "DPC")) {
178 		clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
179 		ret = PCI_ERS_RESULT_DISCONNECT;
180 	} else {
181 		set_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
182 		ret = PCI_ERS_RESULT_RECOVERED;
183 	}
184 out:
185 	clear_bit(PCI_DPC_RECOVERING, &pdev->priv_flags);
186 	wake_up_all(&dpc_completed_waitqueue);
187 	return ret;
188 }
189 
dpc_process_rp_pio_error(struct pci_dev * pdev)190 static void dpc_process_rp_pio_error(struct pci_dev *pdev)
191 {
192 	u16 cap = pdev->dpc_cap, dpc_status, first_error;
193 	u32 status, mask, sev, syserr, exc, log, prefix;
194 	struct pcie_tlp_log tlp_log;
195 	int i;
196 
197 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS, &status);
198 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_MASK, &mask);
199 	pci_err(pdev, "rp_pio_status: %#010x, rp_pio_mask: %#010x\n",
200 		status, mask);
201 
202 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_SEVERITY, &sev);
203 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_SYSERROR, &syserr);
204 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_EXCEPTION, &exc);
205 	pci_err(pdev, "RP PIO severity=%#010x, syserror=%#010x, exception=%#010x\n",
206 		sev, syserr, exc);
207 
208 	/* Get First Error Pointer */
209 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &dpc_status);
210 	first_error = FIELD_GET(PCI_EXP_DPC_RP_PIO_FEP, dpc_status);
211 
212 	for (i = 0; i < ARRAY_SIZE(rp_pio_error_string); i++) {
213 		if ((status & ~mask) & (1 << i))
214 			pci_err(pdev, "[%2d] %s%s\n", i, rp_pio_error_string[i],
215 				first_error == i ? " (First)" : "");
216 	}
217 
218 	if (pdev->dpc_rp_log_size < 4)
219 		goto clear_status;
220 	pcie_read_tlp_log(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG, &tlp_log);
221 	pci_err(pdev, "TLP Header: %#010x %#010x %#010x %#010x\n",
222 		tlp_log.dw[0], tlp_log.dw[1], tlp_log.dw[2], tlp_log.dw[3]);
223 
224 	if (pdev->dpc_rp_log_size < 5)
225 		goto clear_status;
226 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_IMPSPEC_LOG, &log);
227 	pci_err(pdev, "RP PIO ImpSpec Log %#010x\n", log);
228 
229 	for (i = 0; i < pdev->dpc_rp_log_size - 5; i++) {
230 		pci_read_config_dword(pdev,
231 			cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG + i * 4, &prefix);
232 		pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, prefix);
233 	}
234  clear_status:
235 	pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS, status);
236 }
237 
dpc_get_aer_uncorrect_severity(struct pci_dev * dev,struct aer_err_info * info)238 static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
239 					  struct aer_err_info *info)
240 {
241 	int pos = dev->aer_cap;
242 	u32 status, mask, sev;
243 
244 	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
245 	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, &mask);
246 	status &= ~mask;
247 	if (!status)
248 		return 0;
249 
250 	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, &sev);
251 	status &= sev;
252 	if (status)
253 		info->severity = AER_FATAL;
254 	else
255 		info->severity = AER_NONFATAL;
256 
257 	return 1;
258 }
259 
dpc_process_error(struct pci_dev * pdev)260 void dpc_process_error(struct pci_dev *pdev)
261 {
262 	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
263 	struct aer_err_info info;
264 
265 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
266 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
267 
268 	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
269 		 status, source);
270 
271 	reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN;
272 	ext_reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT;
273 	pci_warn(pdev, "%s detected\n",
274 		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR) ?
275 		 "unmasked uncorrectable error" :
276 		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE) ?
277 		 "ERR_NONFATAL" :
278 		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) ?
279 		 "ERR_FATAL" :
280 		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO) ?
281 		 "RP PIO error" :
282 		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER) ?
283 		 "software trigger" :
284 		 "reserved error");
285 
286 	/* show RP PIO error detail information */
287 	if (pdev->dpc_rp_extensions &&
288 	    reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
289 	    ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO)
290 		dpc_process_rp_pio_error(pdev);
291 	else if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR &&
292 		 dpc_get_aer_uncorrect_severity(pdev, &info) &&
293 		 aer_get_device_error_info(pdev, &info)) {
294 		aer_print_error(pdev, &info);
295 		pci_aer_clear_nonfatal_status(pdev);
296 		pci_aer_clear_fatal_status(pdev);
297 	}
298 }
299 
pci_clear_surpdn_errors(struct pci_dev * pdev)300 static void pci_clear_surpdn_errors(struct pci_dev *pdev)
301 {
302 	if (pdev->dpc_rp_extensions)
303 		pci_write_config_dword(pdev, pdev->dpc_cap +
304 				       PCI_EXP_DPC_RP_PIO_STATUS, ~0);
305 
306 	/*
307 	 * In practice, Surprise Down errors have been observed to also set
308 	 * error bits in the Status Register as well as the Fatal Error
309 	 * Detected bit in the Device Status Register.
310 	 */
311 	pci_write_config_word(pdev, PCI_STATUS, 0xffff);
312 
313 	pcie_capability_write_word(pdev, PCI_EXP_DEVSTA, PCI_EXP_DEVSTA_FED);
314 }
315 
dpc_handle_surprise_removal(struct pci_dev * pdev)316 static void dpc_handle_surprise_removal(struct pci_dev *pdev)
317 {
318 	if (!pcie_wait_for_link(pdev, false)) {
319 		pci_info(pdev, "Data Link Layer Link Active not cleared in 1000 msec\n");
320 		goto out;
321 	}
322 
323 	if (pdev->dpc_rp_extensions && dpc_wait_rp_inactive(pdev))
324 		goto out;
325 
326 	pci_aer_raw_clear_status(pdev);
327 	pci_clear_surpdn_errors(pdev);
328 
329 	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_STATUS,
330 			      PCI_EXP_DPC_STATUS_TRIGGER);
331 
332 out:
333 	clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
334 	wake_up_all(&dpc_completed_waitqueue);
335 }
336 
dpc_is_surprise_removal(struct pci_dev * pdev)337 static bool dpc_is_surprise_removal(struct pci_dev *pdev)
338 {
339 	u16 status;
340 
341 	if (!pdev->is_hotplug_bridge)
342 		return false;
343 
344 	if (pci_read_config_word(pdev, pdev->aer_cap + PCI_ERR_UNCOR_STATUS,
345 				 &status))
346 		return false;
347 
348 	return status & PCI_ERR_UNC_SURPDN;
349 }
350 
dpc_handler(int irq,void * context)351 static irqreturn_t dpc_handler(int irq, void *context)
352 {
353 	struct pci_dev *pdev = context;
354 
355 	/*
356 	 * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
357 	 * of async removal and should be ignored by software.
358 	 */
359 	if (dpc_is_surprise_removal(pdev)) {
360 		dpc_handle_surprise_removal(pdev);
361 		return IRQ_HANDLED;
362 	}
363 
364 	dpc_process_error(pdev);
365 
366 	/* We configure DPC so it only triggers on ERR_FATAL */
367 	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
368 
369 	return IRQ_HANDLED;
370 }
371 
dpc_irq(int irq,void * context)372 static irqreturn_t dpc_irq(int irq, void *context)
373 {
374 	struct pci_dev *pdev = context;
375 	u16 cap = pdev->dpc_cap, status;
376 
377 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
378 
379 	if (!(status & PCI_EXP_DPC_STATUS_INTERRUPT) || PCI_POSSIBLE_ERROR(status))
380 		return IRQ_NONE;
381 
382 	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
383 			      PCI_EXP_DPC_STATUS_INTERRUPT);
384 	if (status & PCI_EXP_DPC_STATUS_TRIGGER)
385 		return IRQ_WAKE_THREAD;
386 	return IRQ_HANDLED;
387 }
388 
pci_dpc_init(struct pci_dev * pdev)389 void pci_dpc_init(struct pci_dev *pdev)
390 {
391 	u16 cap;
392 
393 	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
394 	if (!pdev->dpc_cap)
395 		return;
396 
397 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
398 	if (!(cap & PCI_EXP_DPC_CAP_RP_EXT))
399 		return;
400 
401 	pdev->dpc_rp_extensions = true;
402 
403 	/* Quirks may set dpc_rp_log_size if device or firmware is buggy */
404 	if (!pdev->dpc_rp_log_size) {
405 		pdev->dpc_rp_log_size =
406 				FIELD_GET(PCI_EXP_DPC_RP_PIO_LOG_SIZE, cap);
407 		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
408 			pci_err(pdev, "RP PIO log size %u is invalid\n",
409 				pdev->dpc_rp_log_size);
410 			pdev->dpc_rp_log_size = 0;
411 		}
412 	}
413 }
414 
dpc_enable(struct pcie_device * dev)415 static void dpc_enable(struct pcie_device *dev)
416 {
417 	struct pci_dev *pdev = dev->port;
418 	int dpc = pdev->dpc_cap;
419 	u16 ctl;
420 
421 	/*
422 	 * Clear DPC Interrupt Status so we don't get an interrupt for an
423 	 * old event when setting DPC Interrupt Enable.
424 	 */
425 	pci_write_config_word(pdev, dpc + PCI_EXP_DPC_STATUS,
426 			      PCI_EXP_DPC_STATUS_INTERRUPT);
427 
428 	pci_read_config_word(pdev, dpc + PCI_EXP_DPC_CTL, &ctl);
429 	ctl &= ~PCI_EXP_DPC_CTL_EN_MASK;
430 	ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
431 	pci_write_config_word(pdev, dpc + PCI_EXP_DPC_CTL, ctl);
432 }
433 
dpc_disable(struct pcie_device * dev)434 static void dpc_disable(struct pcie_device *dev)
435 {
436 	struct pci_dev *pdev = dev->port;
437 	int dpc = pdev->dpc_cap;
438 	u16 ctl;
439 
440 	/* Disable DPC triggering and DPC interrupts */
441 	pci_read_config_word(pdev, dpc + PCI_EXP_DPC_CTL, &ctl);
442 	ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
443 	pci_write_config_word(pdev, dpc + PCI_EXP_DPC_CTL, ctl);
444 }
445 
446 #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
dpc_probe(struct pcie_device * dev)447 static int dpc_probe(struct pcie_device *dev)
448 {
449 	struct pci_dev *pdev = dev->port;
450 	struct device *device = &dev->device;
451 	int status;
452 	u16 cap;
453 
454 	if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native)
455 		return -ENOTSUPP;
456 
457 	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
458 					   dpc_handler, IRQF_SHARED,
459 					   "pcie-dpc", pdev);
460 	if (status) {
461 		pci_warn(pdev, "request IRQ%d failed: %d\n", dev->irq,
462 			 status);
463 		return status;
464 	}
465 
466 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
467 	dpc_enable(dev);
468 
469 	pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
470 	pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
471 		 cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
472 		 FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
473 		 FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), pdev->dpc_rp_log_size,
474 		 FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
475 
476 	pci_add_ext_cap_save_buffer(pdev, PCI_EXT_CAP_ID_DPC, sizeof(u16));
477 	return status;
478 }
479 
dpc_suspend(struct pcie_device * dev)480 static int dpc_suspend(struct pcie_device *dev)
481 {
482 	dpc_disable(dev);
483 	return 0;
484 }
485 
dpc_resume(struct pcie_device * dev)486 static int dpc_resume(struct pcie_device *dev)
487 {
488 	dpc_enable(dev);
489 	return 0;
490 }
491 
dpc_remove(struct pcie_device * dev)492 static void dpc_remove(struct pcie_device *dev)
493 {
494 	dpc_disable(dev);
495 }
496 
497 static struct pcie_port_service_driver dpcdriver = {
498 	.name		= "dpc",
499 	.port_type	= PCIE_ANY_PORT,
500 	.service	= PCIE_PORT_SERVICE_DPC,
501 	.probe		= dpc_probe,
502 	.suspend	= dpc_suspend,
503 	.resume		= dpc_resume,
504 	.remove		= dpc_remove,
505 };
506 
pcie_dpc_init(void)507 int __init pcie_dpc_init(void)
508 {
509 	return pcie_port_service_register(&dpcdriver);
510 }
511