xref: /linux/drivers/fpga/altera-cvp.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * FPGA Manager Driver for Altera Arria/Cyclone/Stratix CvP
4  *
5  * Copyright (C) 2017 DENX Software Engineering
6  *
7  * Anatolij Gustschin <agust@denx.de>
8  *
9  * Manage Altera FPGA firmware using PCIe CvP.
10  * Firmware must be in binary "rbf" format.
11  */
12 
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/fpga/fpga-mgr.h>
16 #include <linux/module.h>
17 #include <linux/pci.h>
18 #include <linux/sizes.h>
19 
20 #define CVP_BAR		0	/* BAR used for data transfer in memory mode */
21 #define CVP_DUMMY_WR	244	/* dummy writes to clear CvP state machine */
22 #define TIMEOUT_US	2000	/* CVP STATUS timeout for USERMODE polling */
23 
24 /* Vendor Specific Extended Capability Registers */
25 #define VSE_PCIE_EXT_CAP_ID		0x0
26 #define VSE_PCIE_EXT_CAP_ID_VAL		0x000b	/* 16bit */
27 
28 #define VSE_CVP_STATUS			0x1c	/* 32bit */
29 #define VSE_CVP_STATUS_CFG_RDY		BIT(18)	/* CVP_CONFIG_READY */
30 #define VSE_CVP_STATUS_CFG_ERR		BIT(19)	/* CVP_CONFIG_ERROR */
31 #define VSE_CVP_STATUS_CVP_EN		BIT(20)	/* ctrl block is enabling CVP */
32 #define VSE_CVP_STATUS_USERMODE		BIT(21)	/* USERMODE */
33 #define VSE_CVP_STATUS_CFG_DONE		BIT(23)	/* CVP_CONFIG_DONE */
34 #define VSE_CVP_STATUS_PLD_CLK_IN_USE	BIT(24)	/* PLD_CLK_IN_USE */
35 
36 #define VSE_CVP_MODE_CTRL		0x20	/* 32bit */
37 #define VSE_CVP_MODE_CTRL_CVP_MODE	BIT(0)	/* CVP (1) or normal mode (0) */
38 #define VSE_CVP_MODE_CTRL_HIP_CLK_SEL	BIT(1) /* PMA (1) or fabric clock (0) */
39 #define VSE_CVP_MODE_CTRL_NUMCLKS_OFF	8	/* NUMCLKS bits offset */
40 #define VSE_CVP_MODE_CTRL_NUMCLKS_MASK	GENMASK(15, 8)
41 
42 #define VSE_CVP_DATA			0x28	/* 32bit */
43 #define VSE_CVP_PROG_CTRL		0x2c	/* 32bit */
44 #define VSE_CVP_PROG_CTRL_CONFIG	BIT(0)
45 #define VSE_CVP_PROG_CTRL_START_XFER	BIT(1)
46 #define VSE_CVP_PROG_CTRL_MASK		GENMASK(1, 0)
47 
48 #define VSE_UNCOR_ERR_STATUS		0x34	/* 32bit */
49 #define VSE_UNCOR_ERR_CVP_CFG_ERR	BIT(5)	/* CVP_CONFIG_ERROR_LATCHED */
50 
51 #define V1_VSEC_OFFSET			0x200	/* Vendor Specific Offset V1 */
52 /* V2 Defines */
53 #define VSE_CVP_TX_CREDITS		0x49	/* 8bit */
54 
55 #define V2_CREDIT_TIMEOUT_US		20000
56 #define V2_CHECK_CREDIT_US		10
57 #define V2_POLL_TIMEOUT_US		1000000
58 #define V2_USER_TIMEOUT_US		500000
59 
60 #define V1_POLL_TIMEOUT_US		10
61 
62 #define DRV_NAME		"altera-cvp"
63 #define ALTERA_CVP_MGR_NAME	"Altera CvP FPGA Manager"
64 
65 /* Write block sizes */
66 #define ALTERA_CVP_V1_SIZE	4
67 #define ALTERA_CVP_V2_SIZE	4096
68 
69 /* Optional CvP config error status check for debugging */
70 static bool altera_cvp_chkcfg;
71 
72 struct cvp_priv;
73 
74 struct altera_cvp_conf {
75 	struct pci_dev		*pci_dev;
76 	void __iomem		*map;
77 	void			(*write_data)(struct altera_cvp_conf *conf,
78 					      u32 data);
79 	char			mgr_name[64];
80 	u8			numclks;
81 	u32			sent_packets;
82 	u32			vsec_offset;
83 	const struct cvp_priv	*priv;
84 };
85 
86 struct cvp_priv {
87 	void	(*switch_clk)(struct altera_cvp_conf *conf);
88 	int	(*clear_state)(struct altera_cvp_conf *conf);
89 	int	(*wait_credit)(struct fpga_manager *mgr, u32 blocks);
90 	size_t	block_size;
91 	int	poll_time_us;
92 	int	user_time_us;
93 };
94 
95 static int altera_read_config_byte(struct altera_cvp_conf *conf,
96 				   int where, u8 *val)
97 {
98 	return pci_read_config_byte(conf->pci_dev, conf->vsec_offset + where,
99 				    val);
100 }
101 
102 static int altera_read_config_dword(struct altera_cvp_conf *conf,
103 				    int where, u32 *val)
104 {
105 	return pci_read_config_dword(conf->pci_dev, conf->vsec_offset + where,
106 				     val);
107 }
108 
109 static int altera_write_config_dword(struct altera_cvp_conf *conf,
110 				     int where, u32 val)
111 {
112 	return pci_write_config_dword(conf->pci_dev, conf->vsec_offset + where,
113 				      val);
114 }
115 
116 static enum fpga_mgr_states altera_cvp_state(struct fpga_manager *mgr)
117 {
118 	struct altera_cvp_conf *conf = mgr->priv;
119 	u32 status;
120 
121 	altera_read_config_dword(conf, VSE_CVP_STATUS, &status);
122 
123 	if (status & VSE_CVP_STATUS_CFG_DONE)
124 		return FPGA_MGR_STATE_OPERATING;
125 
126 	if (status & VSE_CVP_STATUS_CVP_EN)
127 		return FPGA_MGR_STATE_POWER_UP;
128 
129 	return FPGA_MGR_STATE_UNKNOWN;
130 }
131 
132 static void altera_cvp_write_data_iomem(struct altera_cvp_conf *conf, u32 val)
133 {
134 	writel(val, conf->map);
135 }
136 
137 static void altera_cvp_write_data_config(struct altera_cvp_conf *conf, u32 val)
138 {
139 	pci_write_config_dword(conf->pci_dev, conf->vsec_offset + VSE_CVP_DATA,
140 			       val);
141 }
142 
143 /* switches between CvP clock and internal clock */
144 static void altera_cvp_dummy_write(struct altera_cvp_conf *conf)
145 {
146 	unsigned int i;
147 	u32 val;
148 
149 	/* set 1 CVP clock cycle for every CVP Data Register Write */
150 	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
151 	val &= ~VSE_CVP_MODE_CTRL_NUMCLKS_MASK;
152 	val |= 1 << VSE_CVP_MODE_CTRL_NUMCLKS_OFF;
153 	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
154 
155 	for (i = 0; i < CVP_DUMMY_WR; i++)
156 		conf->write_data(conf, 0); /* dummy data, could be any value */
157 }
158 
159 static int altera_cvp_wait_status(struct altera_cvp_conf *conf, u32 status_mask,
160 				  u32 status_val, int timeout_us)
161 {
162 	unsigned int retries;
163 	u32 val;
164 
165 	retries = timeout_us / 10;
166 	if (timeout_us % 10)
167 		retries++;
168 
169 	do {
170 		altera_read_config_dword(conf, VSE_CVP_STATUS, &val);
171 		if ((val & status_mask) == status_val)
172 			return 0;
173 
174 		/* use small usleep value to re-check and break early */
175 		usleep_range(10, 11);
176 	} while (--retries);
177 
178 	return -ETIMEDOUT;
179 }
180 
181 static int altera_cvp_chk_error(struct fpga_manager *mgr, size_t bytes)
182 {
183 	struct altera_cvp_conf *conf = mgr->priv;
184 	u32 val;
185 	int ret;
186 
187 	/* STEP 10 (optional) - check CVP_CONFIG_ERROR flag */
188 	ret = altera_read_config_dword(conf, VSE_CVP_STATUS, &val);
189 	if (ret || (val & VSE_CVP_STATUS_CFG_ERR)) {
190 		dev_err(&mgr->dev, "CVP_CONFIG_ERROR after %zu bytes!\n",
191 			bytes);
192 		return -EPROTO;
193 	}
194 	return 0;
195 }
196 
197 /*
198  * CvP Version2 Functions
199  * Recent Intel FPGAs use a credit mechanism to throttle incoming
200  * bitstreams and a different method of clearing the state.
201  */
202 
203 static int altera_cvp_v2_clear_state(struct altera_cvp_conf *conf)
204 {
205 	u32 val;
206 	int ret;
207 
208 	/* Clear the START_XFER and CVP_CONFIG bits */
209 	ret = altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
210 	if (ret) {
211 		dev_err(&conf->pci_dev->dev,
212 			"Error reading CVP Program Control Register\n");
213 		return ret;
214 	}
215 
216 	val &= ~VSE_CVP_PROG_CTRL_MASK;
217 	ret = altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
218 	if (ret) {
219 		dev_err(&conf->pci_dev->dev,
220 			"Error writing CVP Program Control Register\n");
221 		return ret;
222 	}
223 
224 	return altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
225 				      conf->priv->poll_time_us);
226 }
227 
228 static int altera_cvp_v2_wait_for_credit(struct fpga_manager *mgr,
229 					 u32 blocks)
230 {
231 	u32 timeout = V2_CREDIT_TIMEOUT_US / V2_CHECK_CREDIT_US;
232 	struct altera_cvp_conf *conf = mgr->priv;
233 	int ret;
234 	u8 val;
235 
236 	do {
237 		ret = altera_read_config_byte(conf, VSE_CVP_TX_CREDITS, &val);
238 		if (ret) {
239 			dev_err(&conf->pci_dev->dev,
240 				"Error reading CVP Credit Register\n");
241 			return ret;
242 		}
243 
244 		/* Return if there is space in FIFO */
245 		if (val - (u8)conf->sent_packets)
246 			return 0;
247 
248 		ret = altera_cvp_chk_error(mgr, blocks * ALTERA_CVP_V2_SIZE);
249 		if (ret) {
250 			dev_err(&conf->pci_dev->dev,
251 				"CE Bit error credit reg[0x%x]:sent[0x%x]\n",
252 				val, conf->sent_packets);
253 			return -EAGAIN;
254 		}
255 
256 		/* Limit the check credit byte traffic */
257 		usleep_range(V2_CHECK_CREDIT_US, V2_CHECK_CREDIT_US + 1);
258 	} while (timeout--);
259 
260 	dev_err(&conf->pci_dev->dev, "Timeout waiting for credit\n");
261 	return -ETIMEDOUT;
262 }
263 
264 static int altera_cvp_send_block(struct altera_cvp_conf *conf,
265 				 const u32 *data, size_t len)
266 {
267 	u32 mask, words = len / sizeof(u32);
268 	int i, remainder;
269 
270 	for (i = 0; i < words; i++)
271 		conf->write_data(conf, *data++);
272 
273 	/* write up to 3 trailing bytes, if any */
274 	remainder = len % sizeof(u32);
275 	if (remainder) {
276 		mask = BIT(remainder * 8) - 1;
277 		if (mask)
278 			conf->write_data(conf, *data & mask);
279 	}
280 
281 	return 0;
282 }
283 
284 static int altera_cvp_teardown(struct fpga_manager *mgr,
285 			       struct fpga_image_info *info)
286 {
287 	struct altera_cvp_conf *conf = mgr->priv;
288 	int ret;
289 	u32 val;
290 
291 	/* STEP 12 - reset START_XFER bit */
292 	altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
293 	val &= ~VSE_CVP_PROG_CTRL_START_XFER;
294 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
295 
296 	/* STEP 13 - reset CVP_CONFIG bit */
297 	val &= ~VSE_CVP_PROG_CTRL_CONFIG;
298 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
299 
300 	/*
301 	 * STEP 14
302 	 * - set CVP_NUMCLKS to 1 and then issue CVP_DUMMY_WR dummy
303 	 *   writes to the HIP
304 	 */
305 	if (conf->priv->switch_clk)
306 		conf->priv->switch_clk(conf);
307 
308 	/* STEP 15 - poll CVP_CONFIG_READY bit for 0 with 10us timeout */
309 	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
310 				     conf->priv->poll_time_us);
311 	if (ret)
312 		dev_err(&mgr->dev, "CFG_RDY == 0 timeout\n");
313 
314 	return ret;
315 }
316 
317 static int altera_cvp_write_init(struct fpga_manager *mgr,
318 				 struct fpga_image_info *info,
319 				 const char *buf, size_t count)
320 {
321 	struct altera_cvp_conf *conf = mgr->priv;
322 	u32 iflags, val;
323 	int ret;
324 
325 	iflags = info ? info->flags : 0;
326 
327 	if (iflags & FPGA_MGR_PARTIAL_RECONFIG) {
328 		dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
329 		return -EINVAL;
330 	}
331 
332 	/* Determine allowed clock to data ratio */
333 	if (iflags & FPGA_MGR_COMPRESSED_BITSTREAM)
334 		conf->numclks = 8; /* ratio for all compressed images */
335 	else if (iflags & FPGA_MGR_ENCRYPTED_BITSTREAM)
336 		conf->numclks = 4; /* for uncompressed and encrypted images */
337 	else
338 		conf->numclks = 1; /* for uncompressed and unencrypted images */
339 
340 	/* STEP 1 - read CVP status and check CVP_EN flag */
341 	altera_read_config_dword(conf, VSE_CVP_STATUS, &val);
342 	if (!(val & VSE_CVP_STATUS_CVP_EN)) {
343 		dev_err(&mgr->dev, "CVP mode off: 0x%04x\n", val);
344 		return -ENODEV;
345 	}
346 
347 	if (val & VSE_CVP_STATUS_CFG_RDY) {
348 		dev_warn(&mgr->dev, "CvP already started, tear down first\n");
349 		ret = altera_cvp_teardown(mgr, info);
350 		if (ret)
351 			return ret;
352 	}
353 
354 	/*
355 	 * STEP 2
356 	 * - set HIP_CLK_SEL and CVP_MODE (must be set in the order mentioned)
357 	 */
358 	/* switch from fabric to PMA clock */
359 	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
360 	val |= VSE_CVP_MODE_CTRL_HIP_CLK_SEL;
361 	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
362 
363 	/* set CVP mode */
364 	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
365 	val |= VSE_CVP_MODE_CTRL_CVP_MODE;
366 	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
367 
368 	/*
369 	 * STEP 3
370 	 * - set CVP_NUMCLKS to 1 and issue CVP_DUMMY_WR dummy writes to the HIP
371 	 */
372 	if (conf->priv->switch_clk)
373 		conf->priv->switch_clk(conf);
374 
375 	if (conf->priv->clear_state) {
376 		ret = conf->priv->clear_state(conf);
377 		if (ret) {
378 			dev_err(&mgr->dev, "Problem clearing out state\n");
379 			return ret;
380 		}
381 	}
382 
383 	conf->sent_packets = 0;
384 
385 	/* STEP 4 - set CVP_CONFIG bit */
386 	altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
387 	/* request control block to begin transfer using CVP */
388 	val |= VSE_CVP_PROG_CTRL_CONFIG;
389 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
390 
391 	/* STEP 5 - poll CVP_CONFIG READY for 1 with timeout */
392 	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY,
393 				     VSE_CVP_STATUS_CFG_RDY,
394 				     conf->priv->poll_time_us);
395 	if (ret) {
396 		dev_warn(&mgr->dev, "CFG_RDY == 1 timeout\n");
397 		return ret;
398 	}
399 
400 	/*
401 	 * STEP 6
402 	 * - set CVP_NUMCLKS to 1 and issue CVP_DUMMY_WR dummy writes to the HIP
403 	 */
404 	if (conf->priv->switch_clk)
405 		conf->priv->switch_clk(conf);
406 
407 	if (altera_cvp_chkcfg) {
408 		ret = altera_cvp_chk_error(mgr, 0);
409 		if (ret) {
410 			dev_warn(&mgr->dev, "CFG_RDY == 1 timeout\n");
411 			return ret;
412 		}
413 	}
414 
415 	/* STEP 7 - set START_XFER */
416 	altera_read_config_dword(conf, VSE_CVP_PROG_CTRL, &val);
417 	val |= VSE_CVP_PROG_CTRL_START_XFER;
418 	altera_write_config_dword(conf, VSE_CVP_PROG_CTRL, val);
419 
420 	/* STEP 8 - start transfer (set CVP_NUMCLKS for bitstream) */
421 	if (conf->priv->switch_clk) {
422 		altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
423 		val &= ~VSE_CVP_MODE_CTRL_NUMCLKS_MASK;
424 		val |= conf->numclks << VSE_CVP_MODE_CTRL_NUMCLKS_OFF;
425 		altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
426 	}
427 	return 0;
428 }
429 
430 static int altera_cvp_write(struct fpga_manager *mgr, const char *buf,
431 			    size_t count)
432 {
433 	struct altera_cvp_conf *conf = mgr->priv;
434 	size_t done, remaining, len;
435 	const u32 *data;
436 	int status = 0;
437 
438 	/* STEP 9 - write 32-bit data from RBF file to CVP data register */
439 	data = (u32 *)buf;
440 	remaining = count;
441 	done = 0;
442 
443 	while (remaining) {
444 		/* Use credit throttling if available */
445 		if (conf->priv->wait_credit) {
446 			status = conf->priv->wait_credit(mgr, done);
447 			if (status) {
448 				dev_err(&conf->pci_dev->dev,
449 					"Wait Credit ERR: 0x%x\n", status);
450 				return status;
451 			}
452 		}
453 
454 		len = min(conf->priv->block_size, remaining);
455 		altera_cvp_send_block(conf, data, len);
456 		data += len / sizeof(u32);
457 		done += len;
458 		remaining -= len;
459 		conf->sent_packets++;
460 
461 		/*
462 		 * STEP 10 (optional) and STEP 11
463 		 * - check error flag
464 		 * - loop until data transfer completed
465 		 * Config images can be huge (more than 40 MiB), so
466 		 * only check after a new 4k data block has been written.
467 		 * This reduces the number of checks and speeds up the
468 		 * configuration process.
469 		 */
470 		if (altera_cvp_chkcfg && !(done % SZ_4K)) {
471 			status = altera_cvp_chk_error(mgr, done);
472 			if (status < 0)
473 				return status;
474 		}
475 	}
476 
477 	if (altera_cvp_chkcfg)
478 		status = altera_cvp_chk_error(mgr, count);
479 
480 	return status;
481 }
482 
483 static int altera_cvp_write_complete(struct fpga_manager *mgr,
484 				     struct fpga_image_info *info)
485 {
486 	struct altera_cvp_conf *conf = mgr->priv;
487 	u32 mask, val;
488 	int ret;
489 
490 	ret = altera_cvp_teardown(mgr, info);
491 	if (ret)
492 		return ret;
493 
494 	/* STEP 16 - check CVP_CONFIG_ERROR_LATCHED bit */
495 	altera_read_config_dword(conf, VSE_UNCOR_ERR_STATUS, &val);
496 	if (val & VSE_UNCOR_ERR_CVP_CFG_ERR) {
497 		dev_err(&mgr->dev, "detected CVP_CONFIG_ERROR_LATCHED!\n");
498 		return -EPROTO;
499 	}
500 
501 	/* STEP 17 - reset CVP_MODE and HIP_CLK_SEL bit */
502 	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
503 	val &= ~VSE_CVP_MODE_CTRL_HIP_CLK_SEL;
504 	val &= ~VSE_CVP_MODE_CTRL_CVP_MODE;
505 	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
506 
507 	/* STEP 18 - poll PLD_CLK_IN_USE and USER_MODE bits */
508 	mask = VSE_CVP_STATUS_PLD_CLK_IN_USE | VSE_CVP_STATUS_USERMODE;
509 	ret = altera_cvp_wait_status(conf, mask, mask,
510 				     conf->priv->user_time_us);
511 	if (ret)
512 		dev_err(&mgr->dev, "PLD_CLK_IN_USE|USERMODE timeout\n");
513 
514 	return ret;
515 }
516 
517 static const struct fpga_manager_ops altera_cvp_ops = {
518 	.state		= altera_cvp_state,
519 	.write_init	= altera_cvp_write_init,
520 	.write		= altera_cvp_write,
521 	.write_complete	= altera_cvp_write_complete,
522 };
523 
524 static const struct cvp_priv cvp_priv_v1 = {
525 	.switch_clk	= altera_cvp_dummy_write,
526 	.block_size	= ALTERA_CVP_V1_SIZE,
527 	.poll_time_us	= V1_POLL_TIMEOUT_US,
528 	.user_time_us	= TIMEOUT_US,
529 };
530 
531 static const struct cvp_priv cvp_priv_v2 = {
532 	.clear_state	= altera_cvp_v2_clear_state,
533 	.wait_credit	= altera_cvp_v2_wait_for_credit,
534 	.block_size	= ALTERA_CVP_V2_SIZE,
535 	.poll_time_us	= V2_POLL_TIMEOUT_US,
536 	.user_time_us	= V2_USER_TIMEOUT_US,
537 };
538 
539 static ssize_t chkcfg_show(struct device_driver *dev, char *buf)
540 {
541 	return snprintf(buf, 3, "%d\n", altera_cvp_chkcfg);
542 }
543 
544 static ssize_t chkcfg_store(struct device_driver *drv, const char *buf,
545 			    size_t count)
546 {
547 	int ret;
548 
549 	ret = kstrtobool(buf, &altera_cvp_chkcfg);
550 	if (ret)
551 		return ret;
552 
553 	return count;
554 }
555 
556 static DRIVER_ATTR_RW(chkcfg);
557 
558 static int altera_cvp_probe(struct pci_dev *pdev,
559 			    const struct pci_device_id *dev_id);
560 static void altera_cvp_remove(struct pci_dev *pdev);
561 
562 static struct pci_device_id altera_cvp_id_tbl[] = {
563 	{ PCI_VDEVICE(ALTERA, PCI_ANY_ID) },
564 	{ }
565 };
566 MODULE_DEVICE_TABLE(pci, altera_cvp_id_tbl);
567 
568 static struct pci_driver altera_cvp_driver = {
569 	.name   = DRV_NAME,
570 	.id_table = altera_cvp_id_tbl,
571 	.probe  = altera_cvp_probe,
572 	.remove = altera_cvp_remove,
573 };
574 
575 static int altera_cvp_probe(struct pci_dev *pdev,
576 			    const struct pci_device_id *dev_id)
577 {
578 	struct altera_cvp_conf *conf;
579 	struct fpga_manager *mgr;
580 	int ret, offset;
581 	u16 cmd, val;
582 	u32 regval;
583 
584 	/* Discover the Vendor Specific Offset for this device */
585 	offset = pci_find_next_ext_capability(pdev, 0, PCI_EXT_CAP_ID_VNDR);
586 	if (!offset) {
587 		dev_err(&pdev->dev, "No Vendor Specific Offset.\n");
588 		return -ENODEV;
589 	}
590 
591 	/*
592 	 * First check if this is the expected FPGA device. PCI config
593 	 * space access works without enabling the PCI device, memory
594 	 * space access is enabled further down.
595 	 */
596 	pci_read_config_word(pdev, offset + VSE_PCIE_EXT_CAP_ID, &val);
597 	if (val != VSE_PCIE_EXT_CAP_ID_VAL) {
598 		dev_err(&pdev->dev, "Wrong EXT_CAP_ID value 0x%x\n", val);
599 		return -ENODEV;
600 	}
601 
602 	pci_read_config_dword(pdev, offset + VSE_CVP_STATUS, &regval);
603 	if (!(regval & VSE_CVP_STATUS_CVP_EN)) {
604 		dev_err(&pdev->dev,
605 			"CVP is disabled for this device: CVP_STATUS Reg 0x%x\n",
606 			regval);
607 		return -ENODEV;
608 	}
609 
610 	conf = devm_kzalloc(&pdev->dev, sizeof(*conf), GFP_KERNEL);
611 	if (!conf)
612 		return -ENOMEM;
613 
614 	conf->vsec_offset = offset;
615 
616 	/*
617 	 * Enable memory BAR access. We cannot use pci_enable_device() here
618 	 * because it will make the driver unusable with FPGA devices that
619 	 * have additional big IOMEM resources (e.g. 4GiB BARs) on 32-bit
620 	 * platform. Such BARs will not have an assigned address range and
621 	 * pci_enable_device() will fail, complaining about not claimed BAR,
622 	 * even if the concerned BAR is not needed for FPGA configuration
623 	 * at all. Thus, enable the device via PCI config space command.
624 	 */
625 	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
626 	if (!(cmd & PCI_COMMAND_MEMORY)) {
627 		cmd |= PCI_COMMAND_MEMORY;
628 		pci_write_config_word(pdev, PCI_COMMAND, cmd);
629 	}
630 
631 	ret = pci_request_region(pdev, CVP_BAR, "CVP");
632 	if (ret) {
633 		dev_err(&pdev->dev, "Requesting CVP BAR region failed\n");
634 		goto err_disable;
635 	}
636 
637 	conf->pci_dev = pdev;
638 	conf->write_data = altera_cvp_write_data_iomem;
639 
640 	if (conf->vsec_offset == V1_VSEC_OFFSET)
641 		conf->priv = &cvp_priv_v1;
642 	else
643 		conf->priv = &cvp_priv_v2;
644 
645 	conf->map = pci_iomap(pdev, CVP_BAR, 0);
646 	if (!conf->map) {
647 		dev_warn(&pdev->dev, "Mapping CVP BAR failed\n");
648 		conf->write_data = altera_cvp_write_data_config;
649 	}
650 
651 	snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s @%s",
652 		 ALTERA_CVP_MGR_NAME, pci_name(pdev));
653 
654 	mgr = fpga_mgr_register(&pdev->dev, conf->mgr_name,
655 				&altera_cvp_ops, conf);
656 	if (IS_ERR(mgr)) {
657 		ret = PTR_ERR(mgr);
658 		goto err_unmap;
659 	}
660 
661 	pci_set_drvdata(pdev, mgr);
662 
663 	return 0;
664 
665 err_unmap:
666 	if (conf->map)
667 		pci_iounmap(pdev, conf->map);
668 	pci_release_region(pdev, CVP_BAR);
669 err_disable:
670 	cmd &= ~PCI_COMMAND_MEMORY;
671 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
672 	return ret;
673 }
674 
675 static void altera_cvp_remove(struct pci_dev *pdev)
676 {
677 	struct fpga_manager *mgr = pci_get_drvdata(pdev);
678 	struct altera_cvp_conf *conf = mgr->priv;
679 	u16 cmd;
680 
681 	fpga_mgr_unregister(mgr);
682 	if (conf->map)
683 		pci_iounmap(pdev, conf->map);
684 	pci_release_region(pdev, CVP_BAR);
685 	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
686 	cmd &= ~PCI_COMMAND_MEMORY;
687 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
688 }
689 
690 static int __init altera_cvp_init(void)
691 {
692 	int ret;
693 
694 	ret = pci_register_driver(&altera_cvp_driver);
695 	if (ret)
696 		return ret;
697 
698 	ret = driver_create_file(&altera_cvp_driver.driver,
699 				 &driver_attr_chkcfg);
700 	if (ret)
701 		pr_warn("Can't create sysfs chkcfg file\n");
702 
703 	return 0;
704 }
705 
706 static void __exit altera_cvp_exit(void)
707 {
708 	driver_remove_file(&altera_cvp_driver.driver, &driver_attr_chkcfg);
709 	pci_unregister_driver(&altera_cvp_driver);
710 }
711 
712 module_init(altera_cvp_init);
713 module_exit(altera_cvp_exit);
714 
715 MODULE_LICENSE("GPL v2");
716 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
717 MODULE_DESCRIPTION("Module to load Altera FPGA over CvP");
718