xref: /linux/drivers/crypto/nx/nx-common-pseries.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for IBM Power 842 compression accelerator
4  *
5  * Copyright (C) IBM Corporation, 2012
6  *
7  * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
8  *          Seth Jennings <sjenning@linux.vnet.ibm.com>
9  */
10 
11 #include <asm/vio.h>
12 #include <asm/hvcall.h>
13 #include <asm/vas.h>
14 
15 #include "nx-842.h"
16 #include "nx_csbcpb.h" /* struct nx_csbcpb */
17 
18 MODULE_LICENSE("GPL");
19 MODULE_AUTHOR("Robert Jennings <rcj@linux.vnet.ibm.com>");
20 MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
21 MODULE_ALIAS_CRYPTO("842");
22 MODULE_ALIAS_CRYPTO("842-nx");
23 
24 /*
25  * Coprocessor type specific capabilities from the hypervisor.
26  */
27 struct hv_nx_cop_caps {
28 	__be64	descriptor;
29 	__be64	req_max_processed_len;	/* Max bytes in one GZIP request */
30 	__be64	min_compress_len;	/* Min compression size in bytes */
31 	__be64	min_decompress_len;	/* Min decompression size in bytes */
32 } __packed __aligned(0x1000);
33 
34 /*
35  * Coprocessor type specific capabilities.
36  */
37 struct nx_cop_caps {
38 	u64	descriptor;
39 	u64	req_max_processed_len;	/* Max bytes in one GZIP request */
40 	u64	min_compress_len;	/* Min compression in bytes */
41 	u64	min_decompress_len;	/* Min decompression in bytes */
42 };
43 
44 static u64 caps_feat;
45 static struct nx_cop_caps nx_cop_caps;
46 
47 static struct nx842_constraints nx842_pseries_constraints = {
48 	.alignment =	DDE_BUFFER_ALIGN,
49 	.multiple =	DDE_BUFFER_LAST_MULT,
50 	.minimum =	DDE_BUFFER_LAST_MULT,
51 	.maximum =	PAGE_SIZE, /* dynamic, max_sync_size */
52 };
53 
54 static int check_constraints(unsigned long buf, unsigned int *len, bool in)
55 {
56 	if (!IS_ALIGNED(buf, nx842_pseries_constraints.alignment)) {
57 		pr_debug("%s buffer 0x%lx not aligned to 0x%x\n",
58 			 in ? "input" : "output", buf,
59 			 nx842_pseries_constraints.alignment);
60 		return -EINVAL;
61 	}
62 	if (*len % nx842_pseries_constraints.multiple) {
63 		pr_debug("%s buffer len 0x%x not multiple of 0x%x\n",
64 			 in ? "input" : "output", *len,
65 			 nx842_pseries_constraints.multiple);
66 		if (in)
67 			return -EINVAL;
68 		*len = round_down(*len, nx842_pseries_constraints.multiple);
69 	}
70 	if (*len < nx842_pseries_constraints.minimum) {
71 		pr_debug("%s buffer len 0x%x under minimum 0x%x\n",
72 			 in ? "input" : "output", *len,
73 			 nx842_pseries_constraints.minimum);
74 		return -EINVAL;
75 	}
76 	if (*len > nx842_pseries_constraints.maximum) {
77 		pr_debug("%s buffer len 0x%x over maximum 0x%x\n",
78 			 in ? "input" : "output", *len,
79 			 nx842_pseries_constraints.maximum);
80 		if (in)
81 			return -EINVAL;
82 		*len = nx842_pseries_constraints.maximum;
83 	}
84 	return 0;
85 }
86 
87 /* I assume we need to align the CSB? */
88 #define WORKMEM_ALIGN	(256)
89 
90 struct nx842_workmem {
91 	/* scatterlist */
92 	char slin[4096];
93 	char slout[4096];
94 	/* coprocessor status/parameter block */
95 	struct nx_csbcpb csbcpb;
96 
97 	char padding[WORKMEM_ALIGN];
98 } __aligned(WORKMEM_ALIGN);
99 
100 /* Macros for fields within nx_csbcpb */
101 /* Check the valid bit within the csbcpb valid field */
102 #define NX842_CSBCBP_VALID_CHK(x) (x & BIT_MASK(7))
103 
104 /* CE macros operate on the completion_extension field bits in the csbcpb.
105  * CE0 0=full completion, 1=partial completion
106  * CE1 0=CE0 indicates completion, 1=termination (output may be modified)
107  * CE2 0=processed_bytes is source bytes, 1=processed_bytes is target bytes */
108 #define NX842_CSBCPB_CE0(x)	(x & BIT_MASK(7))
109 #define NX842_CSBCPB_CE1(x)	(x & BIT_MASK(6))
110 #define NX842_CSBCPB_CE2(x)	(x & BIT_MASK(5))
111 
112 /* The NX unit accepts data only on 4K page boundaries */
113 #define NX842_HW_PAGE_SIZE	(4096)
114 #define NX842_HW_PAGE_MASK	(~(NX842_HW_PAGE_SIZE-1))
115 
116 struct ibm_nx842_counters {
117 	atomic64_t comp_complete;
118 	atomic64_t comp_failed;
119 	atomic64_t decomp_complete;
120 	atomic64_t decomp_failed;
121 	atomic64_t swdecomp;
122 	atomic64_t comp_times[32];
123 	atomic64_t decomp_times[32];
124 };
125 
126 struct nx842_devdata {
127 	struct vio_dev *vdev;
128 	struct device *dev;
129 	struct ibm_nx842_counters *counters;
130 	unsigned int max_sg_len;
131 	unsigned int max_sync_size;
132 	unsigned int max_sync_sg;
133 };
134 
135 static struct nx842_devdata __rcu *devdata;
136 static DEFINE_SPINLOCK(devdata_spinlock);
137 
138 #define NX842_COUNTER_INC(_x) \
139 static inline void nx842_inc_##_x( \
140 	const struct nx842_devdata *dev) { \
141 	if (dev) \
142 		atomic64_inc(&dev->counters->_x); \
143 }
144 NX842_COUNTER_INC(comp_complete);
145 NX842_COUNTER_INC(comp_failed);
146 NX842_COUNTER_INC(decomp_complete);
147 NX842_COUNTER_INC(decomp_failed);
148 NX842_COUNTER_INC(swdecomp);
149 
150 #define NX842_HIST_SLOTS 16
151 
152 static void ibm_nx842_incr_hist(atomic64_t *times, unsigned int time)
153 {
154 	int bucket = fls(time);
155 
156 	if (bucket)
157 		bucket = min((NX842_HIST_SLOTS - 1), bucket - 1);
158 
159 	atomic64_inc(&times[bucket]);
160 }
161 
162 /* NX unit operation flags */
163 #define NX842_OP_COMPRESS	0x0
164 #define NX842_OP_CRC		0x1
165 #define NX842_OP_DECOMPRESS	0x2
166 #define NX842_OP_COMPRESS_CRC   (NX842_OP_COMPRESS | NX842_OP_CRC)
167 #define NX842_OP_DECOMPRESS_CRC (NX842_OP_DECOMPRESS | NX842_OP_CRC)
168 #define NX842_OP_ASYNC		(1<<23)
169 #define NX842_OP_NOTIFY		(1<<22)
170 #define NX842_OP_NOTIFY_INT(x)	((x & 0xff)<<8)
171 
172 static unsigned long nx842_get_desired_dma(struct vio_dev *viodev)
173 {
174 	/* No use of DMA mappings within the driver. */
175 	return 0;
176 }
177 
178 struct nx842_slentry {
179 	__be64 ptr; /* Real address (use __pa()) */
180 	__be64 len;
181 };
182 
183 /* pHyp scatterlist entry */
184 struct nx842_scatterlist {
185 	int entry_nr; /* number of slentries */
186 	struct nx842_slentry *entries; /* ptr to array of slentries */
187 };
188 
189 /* Does not include sizeof(entry_nr) in the size */
190 static inline unsigned long nx842_get_scatterlist_size(
191 				struct nx842_scatterlist *sl)
192 {
193 	return sl->entry_nr * sizeof(struct nx842_slentry);
194 }
195 
196 static int nx842_build_scatterlist(unsigned long buf, int len,
197 			struct nx842_scatterlist *sl)
198 {
199 	unsigned long entrylen;
200 	struct nx842_slentry *entry;
201 
202 	sl->entry_nr = 0;
203 
204 	entry = sl->entries;
205 	while (len) {
206 		entry->ptr = cpu_to_be64(nx842_get_pa((void *)buf));
207 		entrylen = min_t(int, len,
208 				 LEN_ON_SIZE(buf, NX842_HW_PAGE_SIZE));
209 		entry->len = cpu_to_be64(entrylen);
210 
211 		len -= entrylen;
212 		buf += entrylen;
213 
214 		sl->entry_nr++;
215 		entry++;
216 	}
217 
218 	return 0;
219 }
220 
221 static int nx842_validate_result(struct device *dev,
222 	struct cop_status_block *csb)
223 {
224 	/* The csb must be valid after returning from vio_h_cop_sync */
225 	if (!NX842_CSBCBP_VALID_CHK(csb->valid)) {
226 		dev_err(dev, "%s: cspcbp not valid upon completion.\n",
227 				__func__);
228 		dev_dbg(dev, "valid:0x%02x cs:0x%02x cc:0x%02x ce:0x%02x\n",
229 				csb->valid,
230 				csb->crb_seq_number,
231 				csb->completion_code,
232 				csb->completion_extension);
233 		dev_dbg(dev, "processed_bytes:%d address:0x%016lx\n",
234 				be32_to_cpu(csb->processed_byte_count),
235 				(unsigned long)be64_to_cpu(csb->address));
236 		return -EIO;
237 	}
238 
239 	/* Check return values from the hardware in the CSB */
240 	switch (csb->completion_code) {
241 	case 0:	/* Completed without error */
242 		break;
243 	case 64: /* Compression ok, but output larger than input */
244 		dev_dbg(dev, "%s: output size larger than input size\n",
245 					__func__);
246 		break;
247 	case 13: /* Output buffer too small */
248 		dev_dbg(dev, "%s: Out of space in output buffer\n",
249 					__func__);
250 		return -ENOSPC;
251 	case 65: /* Calculated CRC doesn't match the passed value */
252 		dev_dbg(dev, "%s: CRC mismatch for decompression\n",
253 					__func__);
254 		return -EINVAL;
255 	case 66: /* Input data contains an illegal template field */
256 	case 67: /* Template indicates data past the end of the input stream */
257 		dev_dbg(dev, "%s: Bad data for decompression (code:%d)\n",
258 					__func__, csb->completion_code);
259 		return -EINVAL;
260 	default:
261 		dev_dbg(dev, "%s: Unspecified error (code:%d)\n",
262 					__func__, csb->completion_code);
263 		return -EIO;
264 	}
265 
266 	/* Hardware sanity check */
267 	if (!NX842_CSBCPB_CE2(csb->completion_extension)) {
268 		dev_err(dev, "%s: No error returned by hardware, but "
269 				"data returned is unusable, contact support.\n"
270 				"(Additional info: csbcbp->processed bytes "
271 				"does not specify processed bytes for the "
272 				"target buffer.)\n", __func__);
273 		return -EIO;
274 	}
275 
276 	return 0;
277 }
278 
279 /**
280  * nx842_pseries_compress - Compress data using the 842 algorithm
281  *
282  * Compression provide by the NX842 coprocessor on IBM Power systems.
283  * The input buffer is compressed and the result is stored in the
284  * provided output buffer.
285  *
286  * Upon return from this function @outlen contains the length of the
287  * compressed data.  If there is an error then @outlen will be 0 and an
288  * error will be specified by the return code from this function.
289  *
290  * @in: Pointer to input buffer
291  * @inlen: Length of input buffer
292  * @out: Pointer to output buffer
293  * @outlen: Length of output buffer
294  * @wmem: ptr to buffer for working memory, size determined by
295  *        nx842_pseries_driver.workmem_size
296  *
297  * Returns:
298  *   0		Success, output of length @outlen stored in the buffer at @out
299  *   -ENOMEM	Unable to allocate internal buffers
300  *   -ENOSPC	Output buffer is to small
301  *   -EIO	Internal error
302  *   -ENODEV	Hardware unavailable
303  */
304 static int nx842_pseries_compress(const unsigned char *in, unsigned int inlen,
305 				  unsigned char *out, unsigned int *outlen,
306 				  void *wmem)
307 {
308 	struct nx842_devdata *local_devdata;
309 	struct device *dev = NULL;
310 	struct nx842_workmem *workmem;
311 	struct nx842_scatterlist slin, slout;
312 	struct nx_csbcpb *csbcpb;
313 	int ret = 0;
314 	unsigned long inbuf, outbuf;
315 	struct vio_pfo_op op = {
316 		.done = NULL,
317 		.handle = 0,
318 		.timeout = 0,
319 	};
320 	unsigned long start = get_tb();
321 
322 	inbuf = (unsigned long)in;
323 	if (check_constraints(inbuf, &inlen, true))
324 		return -EINVAL;
325 
326 	outbuf = (unsigned long)out;
327 	if (check_constraints(outbuf, outlen, false))
328 		return -EINVAL;
329 
330 	rcu_read_lock();
331 	local_devdata = rcu_dereference(devdata);
332 	if (!local_devdata || !local_devdata->dev) {
333 		rcu_read_unlock();
334 		return -ENODEV;
335 	}
336 	dev = local_devdata->dev;
337 
338 	/* Init scatterlist */
339 	workmem = PTR_ALIGN(wmem, WORKMEM_ALIGN);
340 	slin.entries = (struct nx842_slentry *)workmem->slin;
341 	slout.entries = (struct nx842_slentry *)workmem->slout;
342 
343 	/* Init operation */
344 	op.flags = NX842_OP_COMPRESS_CRC;
345 	csbcpb = &workmem->csbcpb;
346 	memset(csbcpb, 0, sizeof(*csbcpb));
347 	op.csbcpb = nx842_get_pa(csbcpb);
348 
349 	if ((inbuf & NX842_HW_PAGE_MASK) ==
350 	    ((inbuf + inlen - 1) & NX842_HW_PAGE_MASK)) {
351 		/* Create direct DDE */
352 		op.in = nx842_get_pa((void *)inbuf);
353 		op.inlen = inlen;
354 	} else {
355 		/* Create indirect DDE (scatterlist) */
356 		nx842_build_scatterlist(inbuf, inlen, &slin);
357 		op.in = nx842_get_pa(slin.entries);
358 		op.inlen = -nx842_get_scatterlist_size(&slin);
359 	}
360 
361 	if ((outbuf & NX842_HW_PAGE_MASK) ==
362 	    ((outbuf + *outlen - 1) & NX842_HW_PAGE_MASK)) {
363 		/* Create direct DDE */
364 		op.out = nx842_get_pa((void *)outbuf);
365 		op.outlen = *outlen;
366 	} else {
367 		/* Create indirect DDE (scatterlist) */
368 		nx842_build_scatterlist(outbuf, *outlen, &slout);
369 		op.out = nx842_get_pa(slout.entries);
370 		op.outlen = -nx842_get_scatterlist_size(&slout);
371 	}
372 
373 	dev_dbg(dev, "%s: op.in %lx op.inlen %ld op.out %lx op.outlen %ld\n",
374 		__func__, (unsigned long)op.in, (long)op.inlen,
375 		(unsigned long)op.out, (long)op.outlen);
376 
377 	/* Send request to pHyp */
378 	ret = vio_h_cop_sync(local_devdata->vdev, &op);
379 
380 	/* Check for pHyp error */
381 	if (ret) {
382 		dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
383 			__func__, ret, op.hcall_err);
384 		ret = -EIO;
385 		goto unlock;
386 	}
387 
388 	/* Check for hardware error */
389 	ret = nx842_validate_result(dev, &csbcpb->csb);
390 	if (ret)
391 		goto unlock;
392 
393 	*outlen = be32_to_cpu(csbcpb->csb.processed_byte_count);
394 	dev_dbg(dev, "%s: processed_bytes=%d\n", __func__, *outlen);
395 
396 unlock:
397 	if (ret)
398 		nx842_inc_comp_failed(local_devdata);
399 	else {
400 		nx842_inc_comp_complete(local_devdata);
401 		ibm_nx842_incr_hist(local_devdata->counters->comp_times,
402 			(get_tb() - start) / tb_ticks_per_usec);
403 	}
404 	rcu_read_unlock();
405 	return ret;
406 }
407 
408 /**
409  * nx842_pseries_decompress - Decompress data using the 842 algorithm
410  *
411  * Decompression provide by the NX842 coprocessor on IBM Power systems.
412  * The input buffer is decompressed and the result is stored in the
413  * provided output buffer.  The size allocated to the output buffer is
414  * provided by the caller of this function in @outlen.  Upon return from
415  * this function @outlen contains the length of the decompressed data.
416  * If there is an error then @outlen will be 0 and an error will be
417  * specified by the return code from this function.
418  *
419  * @in: Pointer to input buffer
420  * @inlen: Length of input buffer
421  * @out: Pointer to output buffer
422  * @outlen: Length of output buffer
423  * @wmem: ptr to buffer for working memory, size determined by
424  *        nx842_pseries_driver.workmem_size
425  *
426  * Returns:
427  *   0		Success, output of length @outlen stored in the buffer at @out
428  *   -ENODEV	Hardware decompression device is unavailable
429  *   -ENOMEM	Unable to allocate internal buffers
430  *   -ENOSPC	Output buffer is to small
431  *   -EINVAL	Bad input data encountered when attempting decompress
432  *   -EIO	Internal error
433  */
434 static int nx842_pseries_decompress(const unsigned char *in, unsigned int inlen,
435 				    unsigned char *out, unsigned int *outlen,
436 				    void *wmem)
437 {
438 	struct nx842_devdata *local_devdata;
439 	struct device *dev = NULL;
440 	struct nx842_workmem *workmem;
441 	struct nx842_scatterlist slin, slout;
442 	struct nx_csbcpb *csbcpb;
443 	int ret = 0;
444 	unsigned long inbuf, outbuf;
445 	struct vio_pfo_op op = {
446 		.done = NULL,
447 		.handle = 0,
448 		.timeout = 0,
449 	};
450 	unsigned long start = get_tb();
451 
452 	/* Ensure page alignment and size */
453 	inbuf = (unsigned long)in;
454 	if (check_constraints(inbuf, &inlen, true))
455 		return -EINVAL;
456 
457 	outbuf = (unsigned long)out;
458 	if (check_constraints(outbuf, outlen, false))
459 		return -EINVAL;
460 
461 	rcu_read_lock();
462 	local_devdata = rcu_dereference(devdata);
463 	if (!local_devdata || !local_devdata->dev) {
464 		rcu_read_unlock();
465 		return -ENODEV;
466 	}
467 	dev = local_devdata->dev;
468 
469 	workmem = PTR_ALIGN(wmem, WORKMEM_ALIGN);
470 
471 	/* Init scatterlist */
472 	slin.entries = (struct nx842_slentry *)workmem->slin;
473 	slout.entries = (struct nx842_slentry *)workmem->slout;
474 
475 	/* Init operation */
476 	op.flags = NX842_OP_DECOMPRESS_CRC;
477 	csbcpb = &workmem->csbcpb;
478 	memset(csbcpb, 0, sizeof(*csbcpb));
479 	op.csbcpb = nx842_get_pa(csbcpb);
480 
481 	if ((inbuf & NX842_HW_PAGE_MASK) ==
482 	    ((inbuf + inlen - 1) & NX842_HW_PAGE_MASK)) {
483 		/* Create direct DDE */
484 		op.in = nx842_get_pa((void *)inbuf);
485 		op.inlen = inlen;
486 	} else {
487 		/* Create indirect DDE (scatterlist) */
488 		nx842_build_scatterlist(inbuf, inlen, &slin);
489 		op.in = nx842_get_pa(slin.entries);
490 		op.inlen = -nx842_get_scatterlist_size(&slin);
491 	}
492 
493 	if ((outbuf & NX842_HW_PAGE_MASK) ==
494 	    ((outbuf + *outlen - 1) & NX842_HW_PAGE_MASK)) {
495 		/* Create direct DDE */
496 		op.out = nx842_get_pa((void *)outbuf);
497 		op.outlen = *outlen;
498 	} else {
499 		/* Create indirect DDE (scatterlist) */
500 		nx842_build_scatterlist(outbuf, *outlen, &slout);
501 		op.out = nx842_get_pa(slout.entries);
502 		op.outlen = -nx842_get_scatterlist_size(&slout);
503 	}
504 
505 	dev_dbg(dev, "%s: op.in %lx op.inlen %ld op.out %lx op.outlen %ld\n",
506 		__func__, (unsigned long)op.in, (long)op.inlen,
507 		(unsigned long)op.out, (long)op.outlen);
508 
509 	/* Send request to pHyp */
510 	ret = vio_h_cop_sync(local_devdata->vdev, &op);
511 
512 	/* Check for pHyp error */
513 	if (ret) {
514 		dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
515 			__func__, ret, op.hcall_err);
516 		goto unlock;
517 	}
518 
519 	/* Check for hardware error */
520 	ret = nx842_validate_result(dev, &csbcpb->csb);
521 	if (ret)
522 		goto unlock;
523 
524 	*outlen = be32_to_cpu(csbcpb->csb.processed_byte_count);
525 
526 unlock:
527 	if (ret)
528 		/* decompress fail */
529 		nx842_inc_decomp_failed(local_devdata);
530 	else {
531 		nx842_inc_decomp_complete(local_devdata);
532 		ibm_nx842_incr_hist(local_devdata->counters->decomp_times,
533 			(get_tb() - start) / tb_ticks_per_usec);
534 	}
535 
536 	rcu_read_unlock();
537 	return ret;
538 }
539 
540 /**
541  * nx842_OF_set_defaults -- Set default (disabled) values for devdata
542  *
543  * @devdata: struct nx842_devdata to update
544  *
545  * Returns:
546  *  0 on success
547  *  -ENOENT if @devdata ptr is NULL
548  */
549 static int nx842_OF_set_defaults(struct nx842_devdata *devdata)
550 {
551 	if (devdata) {
552 		devdata->max_sync_size = 0;
553 		devdata->max_sync_sg = 0;
554 		devdata->max_sg_len = 0;
555 		return 0;
556 	} else
557 		return -ENOENT;
558 }
559 
560 /**
561  * nx842_OF_upd_status -- Check the device info from OF status prop
562  *
563  * The status property indicates if the accelerator is enabled.  If the
564  * device is in the OF tree it indicates that the hardware is present.
565  * The status field indicates if the device is enabled when the status
566  * is 'okay'.  Otherwise the device driver will be disabled.
567  *
568  * @devdata: struct nx842_devdata to use for dev_info
569  * @prop: struct property point containing the maxsyncop for the update
570  *
571  * Returns:
572  *  0 - Device is available
573  *  -ENODEV - Device is not available
574  */
575 static int nx842_OF_upd_status(struct nx842_devdata *devdata,
576 			       struct property *prop)
577 {
578 	const char *status = (const char *)prop->value;
579 
580 	if (!strncmp(status, "okay", (size_t)prop->length))
581 		return 0;
582 	if (!strncmp(status, "disabled", (size_t)prop->length))
583 		return -ENODEV;
584 	dev_info(devdata->dev, "%s: unknown status '%s'\n", __func__, status);
585 
586 	return -EINVAL;
587 }
588 
589 /**
590  * nx842_OF_upd_maxsglen -- Update the device info from OF maxsglen prop
591  *
592  * Definition of the 'ibm,max-sg-len' OF property:
593  *  This field indicates the maximum byte length of a scatter list
594  *  for the platform facility. It is a single cell encoded as with encode-int.
595  *
596  * Example:
597  *  # od -x ibm,max-sg-len
598  *  0000000 0000 0ff0
599  *
600  *  In this example, the maximum byte length of a scatter list is
601  *  0x0ff0 (4,080).
602  *
603  * @devdata: struct nx842_devdata to update
604  * @prop: struct property point containing the maxsyncop for the update
605  *
606  * Returns:
607  *  0 on success
608  *  -EINVAL on failure
609  */
610 static int nx842_OF_upd_maxsglen(struct nx842_devdata *devdata,
611 					struct property *prop) {
612 	int ret = 0;
613 	const unsigned int maxsglen = of_read_number(prop->value, 1);
614 
615 	if (prop->length != sizeof(maxsglen)) {
616 		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sg-len property\n", __func__);
617 		dev_dbg(devdata->dev, "%s: ibm,max-sg-len is %d bytes long, expected %lu bytes\n", __func__,
618 				prop->length, sizeof(maxsglen));
619 		ret = -EINVAL;
620 	} else {
621 		devdata->max_sg_len = min_t(unsigned int,
622 					    maxsglen, NX842_HW_PAGE_SIZE);
623 	}
624 
625 	return ret;
626 }
627 
628 /**
629  * nx842_OF_upd_maxsyncop -- Update the device info from OF maxsyncop prop
630  *
631  * Definition of the 'ibm,max-sync-cop' OF property:
632  *  Two series of cells.  The first series of cells represents the maximums
633  *  that can be synchronously compressed. The second series of cells
634  *  represents the maximums that can be synchronously decompressed.
635  *  1. The first cell in each series contains the count of the number of
636  *     data length, scatter list elements pairs that follow – each being
637  *     of the form
638  *    a. One cell data byte length
639  *    b. One cell total number of scatter list elements
640  *
641  * Example:
642  *  # od -x ibm,max-sync-cop
643  *  0000000 0000 0001 0000 1000 0000 01fe 0000 0001
644  *  0000020 0000 1000 0000 01fe
645  *
646  *  In this example, compression supports 0x1000 (4,096) data byte length
647  *  and 0x1fe (510) total scatter list elements.  Decompression supports
648  *  0x1000 (4,096) data byte length and 0x1f3 (510) total scatter list
649  *  elements.
650  *
651  * @devdata: struct nx842_devdata to update
652  * @prop: struct property point containing the maxsyncop for the update
653  *
654  * Returns:
655  *  0 on success
656  *  -EINVAL on failure
657  */
658 static int nx842_OF_upd_maxsyncop(struct nx842_devdata *devdata,
659 					struct property *prop) {
660 	int ret = 0;
661 	unsigned int comp_data_limit, decomp_data_limit;
662 	unsigned int comp_sg_limit, decomp_sg_limit;
663 	const struct maxsynccop_t {
664 		__be32 comp_elements;
665 		__be32 comp_data_limit;
666 		__be32 comp_sg_limit;
667 		__be32 decomp_elements;
668 		__be32 decomp_data_limit;
669 		__be32 decomp_sg_limit;
670 	} *maxsynccop;
671 
672 	if (prop->length != sizeof(*maxsynccop)) {
673 		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sync-cop property\n", __func__);
674 		dev_dbg(devdata->dev, "%s: ibm,max-sync-cop is %d bytes long, expected %lu bytes\n", __func__, prop->length,
675 				sizeof(*maxsynccop));
676 		ret = -EINVAL;
677 		goto out;
678 	}
679 
680 	maxsynccop = (const struct maxsynccop_t *)prop->value;
681 	comp_data_limit = be32_to_cpu(maxsynccop->comp_data_limit);
682 	comp_sg_limit = be32_to_cpu(maxsynccop->comp_sg_limit);
683 	decomp_data_limit = be32_to_cpu(maxsynccop->decomp_data_limit);
684 	decomp_sg_limit = be32_to_cpu(maxsynccop->decomp_sg_limit);
685 
686 	/* Use one limit rather than separate limits for compression and
687 	 * decompression. Set a maximum for this so as not to exceed the
688 	 * size that the header can support and round the value down to
689 	 * the hardware page size (4K) */
690 	devdata->max_sync_size = min(comp_data_limit, decomp_data_limit);
691 
692 	devdata->max_sync_size = min_t(unsigned int, devdata->max_sync_size,
693 					65536);
694 
695 	if (devdata->max_sync_size < 4096) {
696 		dev_err(devdata->dev, "%s: hardware max data size (%u) is "
697 				"less than the driver minimum, unable to use "
698 				"the hardware device\n",
699 				__func__, devdata->max_sync_size);
700 		ret = -EINVAL;
701 		goto out;
702 	}
703 
704 	nx842_pseries_constraints.maximum = devdata->max_sync_size;
705 
706 	devdata->max_sync_sg = min(comp_sg_limit, decomp_sg_limit);
707 	if (devdata->max_sync_sg < 1) {
708 		dev_err(devdata->dev, "%s: hardware max sg size (%u) is "
709 				"less than the driver minimum, unable to use "
710 				"the hardware device\n",
711 				__func__, devdata->max_sync_sg);
712 		ret = -EINVAL;
713 		goto out;
714 	}
715 
716 out:
717 	return ret;
718 }
719 
720 /**
721  * nx842_OF_upd -- Handle OF properties updates for the device.
722  *
723  * Set all properties from the OF tree.  Optionally, a new property
724  * can be provided by the @new_prop pointer to overwrite an existing value.
725  * The device will remain disabled until all values are valid, this function
726  * will return an error for updates unless all values are valid.
727  *
728  * @new_prop: If not NULL, this property is being updated.  If NULL, update
729  *  all properties from the current values in the OF tree.
730  *
731  * Returns:
732  *  0 - Success
733  *  -ENOMEM - Could not allocate memory for new devdata structure
734  *  -EINVAL - property value not found, new_prop is not a recognized
735  *	property for the device or property value is not valid.
736  *  -ENODEV - Device is not available
737  */
738 static int nx842_OF_upd(struct property *new_prop)
739 {
740 	struct nx842_devdata *old_devdata = NULL;
741 	struct nx842_devdata *new_devdata = NULL;
742 	struct device_node *of_node = NULL;
743 	struct property *status = NULL;
744 	struct property *maxsglen = NULL;
745 	struct property *maxsyncop = NULL;
746 	int ret = 0;
747 	unsigned long flags;
748 
749 	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
750 	if (!new_devdata)
751 		return -ENOMEM;
752 
753 	spin_lock_irqsave(&devdata_spinlock, flags);
754 	old_devdata = rcu_dereference_check(devdata,
755 			lockdep_is_held(&devdata_spinlock));
756 	if (old_devdata)
757 		of_node = old_devdata->dev->of_node;
758 
759 	if (!old_devdata || !of_node) {
760 		pr_err("%s: device is not available\n", __func__);
761 		spin_unlock_irqrestore(&devdata_spinlock, flags);
762 		kfree(new_devdata);
763 		return -ENODEV;
764 	}
765 
766 	memcpy(new_devdata, old_devdata, sizeof(*old_devdata));
767 	new_devdata->counters = old_devdata->counters;
768 
769 	/* Set ptrs for existing properties */
770 	status = of_find_property(of_node, "status", NULL);
771 	maxsglen = of_find_property(of_node, "ibm,max-sg-len", NULL);
772 	maxsyncop = of_find_property(of_node, "ibm,max-sync-cop", NULL);
773 	if (!status || !maxsglen || !maxsyncop) {
774 		dev_err(old_devdata->dev, "%s: Could not locate device properties\n", __func__);
775 		ret = -EINVAL;
776 		goto error_out;
777 	}
778 
779 	/*
780 	 * If this is a property update, there are only certain properties that
781 	 * we care about. Bail if it isn't in the below list
782 	 */
783 	if (new_prop && (strncmp(new_prop->name, "status", new_prop->length) ||
784 		         strncmp(new_prop->name, "ibm,max-sg-len", new_prop->length) ||
785 		         strncmp(new_prop->name, "ibm,max-sync-cop", new_prop->length)))
786 		goto out;
787 
788 	/* Perform property updates */
789 	ret = nx842_OF_upd_status(new_devdata, status);
790 	if (ret)
791 		goto error_out;
792 
793 	ret = nx842_OF_upd_maxsglen(new_devdata, maxsglen);
794 	if (ret)
795 		goto error_out;
796 
797 	ret = nx842_OF_upd_maxsyncop(new_devdata, maxsyncop);
798 	if (ret)
799 		goto error_out;
800 
801 out:
802 	dev_info(old_devdata->dev, "%s: max_sync_size new:%u old:%u\n",
803 			__func__, new_devdata->max_sync_size,
804 			old_devdata->max_sync_size);
805 	dev_info(old_devdata->dev, "%s: max_sync_sg new:%u old:%u\n",
806 			__func__, new_devdata->max_sync_sg,
807 			old_devdata->max_sync_sg);
808 	dev_info(old_devdata->dev, "%s: max_sg_len new:%u old:%u\n",
809 			__func__, new_devdata->max_sg_len,
810 			old_devdata->max_sg_len);
811 
812 	rcu_assign_pointer(devdata, new_devdata);
813 	spin_unlock_irqrestore(&devdata_spinlock, flags);
814 	synchronize_rcu();
815 	dev_set_drvdata(new_devdata->dev, new_devdata);
816 	kfree(old_devdata);
817 	return 0;
818 
819 error_out:
820 	if (new_devdata) {
821 		dev_info(old_devdata->dev, "%s: device disabled\n", __func__);
822 		nx842_OF_set_defaults(new_devdata);
823 		rcu_assign_pointer(devdata, new_devdata);
824 		spin_unlock_irqrestore(&devdata_spinlock, flags);
825 		synchronize_rcu();
826 		dev_set_drvdata(new_devdata->dev, new_devdata);
827 		kfree(old_devdata);
828 	} else {
829 		dev_err(old_devdata->dev, "%s: could not update driver from hardware\n", __func__);
830 		spin_unlock_irqrestore(&devdata_spinlock, flags);
831 	}
832 
833 	if (!ret)
834 		ret = -EINVAL;
835 	return ret;
836 }
837 
838 /**
839  * nx842_OF_notifier - Process updates to OF properties for the device
840  *
841  * @np: notifier block
842  * @action: notifier action
843  * @data: struct of_reconfig_data pointer
844  *
845  * Returns:
846  *	NOTIFY_OK on success
847  *	NOTIFY_BAD encoded with error number on failure, use
848  *		notifier_to_errno() to decode this value
849  */
850 static int nx842_OF_notifier(struct notifier_block *np, unsigned long action,
851 			     void *data)
852 {
853 	struct of_reconfig_data *upd = data;
854 	struct nx842_devdata *local_devdata;
855 	struct device_node *node = NULL;
856 
857 	rcu_read_lock();
858 	local_devdata = rcu_dereference(devdata);
859 	if (local_devdata)
860 		node = local_devdata->dev->of_node;
861 
862 	if (local_devdata &&
863 			action == OF_RECONFIG_UPDATE_PROPERTY &&
864 			!strcmp(upd->dn->name, node->name)) {
865 		rcu_read_unlock();
866 		nx842_OF_upd(upd->prop);
867 	} else
868 		rcu_read_unlock();
869 
870 	return NOTIFY_OK;
871 }
872 
873 static struct notifier_block nx842_of_nb = {
874 	.notifier_call = nx842_OF_notifier,
875 };
876 
877 #define nx842_counter_read(_name)					\
878 static ssize_t nx842_##_name##_show(struct device *dev,		\
879 		struct device_attribute *attr,				\
880 		char *buf) {						\
881 	struct nx842_devdata *local_devdata;			\
882 	int p = 0;							\
883 	rcu_read_lock();						\
884 	local_devdata = rcu_dereference(devdata);			\
885 	if (local_devdata)						\
886 		p = snprintf(buf, PAGE_SIZE, "%lld\n",			\
887 		       atomic64_read(&local_devdata->counters->_name));	\
888 	rcu_read_unlock();						\
889 	return p;							\
890 }
891 
892 #define NX842DEV_COUNTER_ATTR_RO(_name)					\
893 	nx842_counter_read(_name);					\
894 	static struct device_attribute dev_attr_##_name = __ATTR(_name,	\
895 						0444,			\
896 						nx842_##_name##_show,\
897 						NULL);
898 
899 NX842DEV_COUNTER_ATTR_RO(comp_complete);
900 NX842DEV_COUNTER_ATTR_RO(comp_failed);
901 NX842DEV_COUNTER_ATTR_RO(decomp_complete);
902 NX842DEV_COUNTER_ATTR_RO(decomp_failed);
903 NX842DEV_COUNTER_ATTR_RO(swdecomp);
904 
905 static ssize_t nx842_timehist_show(struct device *,
906 		struct device_attribute *, char *);
907 
908 static struct device_attribute dev_attr_comp_times = __ATTR(comp_times, 0444,
909 		nx842_timehist_show, NULL);
910 static struct device_attribute dev_attr_decomp_times = __ATTR(decomp_times,
911 		0444, nx842_timehist_show, NULL);
912 
913 static ssize_t nx842_timehist_show(struct device *dev,
914 		struct device_attribute *attr, char *buf) {
915 	char *p = buf;
916 	struct nx842_devdata *local_devdata;
917 	atomic64_t *times;
918 	int bytes_remain = PAGE_SIZE;
919 	int bytes;
920 	int i;
921 
922 	rcu_read_lock();
923 	local_devdata = rcu_dereference(devdata);
924 	if (!local_devdata) {
925 		rcu_read_unlock();
926 		return 0;
927 	}
928 
929 	if (attr == &dev_attr_comp_times)
930 		times = local_devdata->counters->comp_times;
931 	else if (attr == &dev_attr_decomp_times)
932 		times = local_devdata->counters->decomp_times;
933 	else {
934 		rcu_read_unlock();
935 		return 0;
936 	}
937 
938 	for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) {
939 		bytes = snprintf(p, bytes_remain, "%u-%uus:\t%lld\n",
940 			       i ? (2<<(i-1)) : 0, (2<<i)-1,
941 			       atomic64_read(&times[i]));
942 		bytes_remain -= bytes;
943 		p += bytes;
944 	}
945 	/* The last bucket holds everything over
946 	 * 2<<(NX842_HIST_SLOTS - 2) us */
947 	bytes = snprintf(p, bytes_remain, "%uus - :\t%lld\n",
948 			2<<(NX842_HIST_SLOTS - 2),
949 			atomic64_read(&times[(NX842_HIST_SLOTS - 1)]));
950 	p += bytes;
951 
952 	rcu_read_unlock();
953 	return p - buf;
954 }
955 
956 static struct attribute *nx842_sysfs_entries[] = {
957 	&dev_attr_comp_complete.attr,
958 	&dev_attr_comp_failed.attr,
959 	&dev_attr_decomp_complete.attr,
960 	&dev_attr_decomp_failed.attr,
961 	&dev_attr_swdecomp.attr,
962 	&dev_attr_comp_times.attr,
963 	&dev_attr_decomp_times.attr,
964 	NULL,
965 };
966 
967 static const struct attribute_group nx842_attribute_group = {
968 	.name = NULL,		/* put in device directory */
969 	.attrs = nx842_sysfs_entries,
970 };
971 
972 #define	nxcop_caps_read(_name)						\
973 static ssize_t nxcop_##_name##_show(struct device *dev,			\
974 			struct device_attribute *attr, char *buf)	\
975 {									\
976 	return sprintf(buf, "%lld\n", nx_cop_caps._name);		\
977 }
978 
979 #define NXCT_ATTR_RO(_name)						\
980 	nxcop_caps_read(_name);						\
981 	static struct device_attribute dev_attr_##_name = __ATTR(_name,	\
982 						0444,			\
983 						nxcop_##_name##_show,	\
984 						NULL);
985 
986 NXCT_ATTR_RO(req_max_processed_len);
987 NXCT_ATTR_RO(min_compress_len);
988 NXCT_ATTR_RO(min_decompress_len);
989 
990 static struct attribute *nxcop_caps_sysfs_entries[] = {
991 	&dev_attr_req_max_processed_len.attr,
992 	&dev_attr_min_compress_len.attr,
993 	&dev_attr_min_decompress_len.attr,
994 	NULL,
995 };
996 
997 static const struct attribute_group nxcop_caps_attr_group = {
998 	.name	=	"nx_gzip_caps",
999 	.attrs	=	nxcop_caps_sysfs_entries,
1000 };
1001 
1002 static struct nx842_driver nx842_pseries_driver = {
1003 	.name =		KBUILD_MODNAME,
1004 	.owner =	THIS_MODULE,
1005 	.workmem_size =	sizeof(struct nx842_workmem),
1006 	.constraints =	&nx842_pseries_constraints,
1007 	.compress =	nx842_pseries_compress,
1008 	.decompress =	nx842_pseries_decompress,
1009 };
1010 
1011 static int nx842_pseries_crypto_init(struct crypto_tfm *tfm)
1012 {
1013 	return nx842_crypto_init(tfm, &nx842_pseries_driver);
1014 }
1015 
1016 static struct crypto_alg nx842_pseries_alg = {
1017 	.cra_name		= "842",
1018 	.cra_driver_name	= "842-nx",
1019 	.cra_priority		= 300,
1020 	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
1021 	.cra_ctxsize		= sizeof(struct nx842_crypto_ctx),
1022 	.cra_module		= THIS_MODULE,
1023 	.cra_init		= nx842_pseries_crypto_init,
1024 	.cra_exit		= nx842_crypto_exit,
1025 	.cra_u			= { .compress = {
1026 	.coa_compress		= nx842_crypto_compress,
1027 	.coa_decompress		= nx842_crypto_decompress } }
1028 };
1029 
1030 static int nx842_probe(struct vio_dev *viodev,
1031 		       const struct vio_device_id *id)
1032 {
1033 	struct nx842_devdata *old_devdata, *new_devdata = NULL;
1034 	unsigned long flags;
1035 	int ret = 0;
1036 
1037 	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
1038 	if (!new_devdata)
1039 		return -ENOMEM;
1040 
1041 	new_devdata->counters = kzalloc(sizeof(*new_devdata->counters),
1042 			GFP_NOFS);
1043 	if (!new_devdata->counters) {
1044 		kfree(new_devdata);
1045 		return -ENOMEM;
1046 	}
1047 
1048 	spin_lock_irqsave(&devdata_spinlock, flags);
1049 	old_devdata = rcu_dereference_check(devdata,
1050 			lockdep_is_held(&devdata_spinlock));
1051 
1052 	if (old_devdata && old_devdata->vdev != NULL) {
1053 		dev_err(&viodev->dev, "%s: Attempt to register more than one instance of the hardware\n", __func__);
1054 		ret = -1;
1055 		goto error_unlock;
1056 	}
1057 
1058 	dev_set_drvdata(&viodev->dev, NULL);
1059 
1060 	new_devdata->vdev = viodev;
1061 	new_devdata->dev = &viodev->dev;
1062 	nx842_OF_set_defaults(new_devdata);
1063 
1064 	rcu_assign_pointer(devdata, new_devdata);
1065 	spin_unlock_irqrestore(&devdata_spinlock, flags);
1066 	synchronize_rcu();
1067 	kfree(old_devdata);
1068 
1069 	of_reconfig_notifier_register(&nx842_of_nb);
1070 
1071 	ret = nx842_OF_upd(NULL);
1072 	if (ret)
1073 		goto error;
1074 
1075 	ret = crypto_register_alg(&nx842_pseries_alg);
1076 	if (ret) {
1077 		dev_err(&viodev->dev, "could not register comp alg: %d\n", ret);
1078 		goto error;
1079 	}
1080 
1081 	rcu_read_lock();
1082 	dev_set_drvdata(&viodev->dev, rcu_dereference(devdata));
1083 	rcu_read_unlock();
1084 
1085 	if (sysfs_create_group(&viodev->dev.kobj, &nx842_attribute_group)) {
1086 		dev_err(&viodev->dev, "could not create sysfs device attributes\n");
1087 		ret = -1;
1088 		goto error;
1089 	}
1090 
1091 	if (caps_feat) {
1092 		if (sysfs_create_group(&viodev->dev.kobj,
1093 					&nxcop_caps_attr_group)) {
1094 			dev_err(&viodev->dev,
1095 				"Could not create sysfs NX capability entries\n");
1096 			ret = -1;
1097 			goto error;
1098 		}
1099 	}
1100 
1101 	return 0;
1102 
1103 error_unlock:
1104 	spin_unlock_irqrestore(&devdata_spinlock, flags);
1105 	if (new_devdata)
1106 		kfree(new_devdata->counters);
1107 	kfree(new_devdata);
1108 error:
1109 	return ret;
1110 }
1111 
1112 static void nx842_remove(struct vio_dev *viodev)
1113 {
1114 	struct nx842_devdata *old_devdata;
1115 	unsigned long flags;
1116 
1117 	pr_info("Removing IBM Power 842 compression device\n");
1118 	sysfs_remove_group(&viodev->dev.kobj, &nx842_attribute_group);
1119 
1120 	if (caps_feat)
1121 		sysfs_remove_group(&viodev->dev.kobj, &nxcop_caps_attr_group);
1122 
1123 	crypto_unregister_alg(&nx842_pseries_alg);
1124 
1125 	of_reconfig_notifier_unregister(&nx842_of_nb);
1126 
1127 	spin_lock_irqsave(&devdata_spinlock, flags);
1128 	old_devdata = rcu_dereference_check(devdata,
1129 			lockdep_is_held(&devdata_spinlock));
1130 	RCU_INIT_POINTER(devdata, NULL);
1131 	spin_unlock_irqrestore(&devdata_spinlock, flags);
1132 	synchronize_rcu();
1133 	dev_set_drvdata(&viodev->dev, NULL);
1134 	if (old_devdata)
1135 		kfree(old_devdata->counters);
1136 	kfree(old_devdata);
1137 }
1138 
1139 /*
1140  * Get NX capabilities from the hypervisor.
1141  * Only NXGZIP capabilities are provided by the hypersvisor right
1142  * now and these values are available to user space with sysfs.
1143  */
1144 static void __init nxcop_get_capabilities(void)
1145 {
1146 	struct hv_vas_all_caps *hv_caps;
1147 	struct hv_nx_cop_caps *hv_nxc;
1148 	int rc;
1149 
1150 	hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
1151 	if (!hv_caps)
1152 		return;
1153 	/*
1154 	 * Get NX overall capabilities with feature type=0
1155 	 */
1156 	rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES, 0,
1157 					  (u64)virt_to_phys(hv_caps));
1158 	if (rc)
1159 		goto out;
1160 
1161 	caps_feat = be64_to_cpu(hv_caps->feat_type);
1162 	/*
1163 	 * NX-GZIP feature available
1164 	 */
1165 	if (caps_feat & VAS_NX_GZIP_FEAT_BIT) {
1166 		hv_nxc = kmalloc(sizeof(*hv_nxc), GFP_KERNEL);
1167 		if (!hv_nxc)
1168 			goto out;
1169 		/*
1170 		 * Get capabilities for NX-GZIP feature
1171 		 */
1172 		rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES,
1173 						  VAS_NX_GZIP_FEAT,
1174 						  (u64)virt_to_phys(hv_nxc));
1175 	} else {
1176 		pr_err("NX-GZIP feature is not available\n");
1177 		rc = -EINVAL;
1178 	}
1179 
1180 	if (!rc) {
1181 		nx_cop_caps.descriptor = be64_to_cpu(hv_nxc->descriptor);
1182 		nx_cop_caps.req_max_processed_len =
1183 				be64_to_cpu(hv_nxc->req_max_processed_len);
1184 		nx_cop_caps.min_compress_len =
1185 				be64_to_cpu(hv_nxc->min_compress_len);
1186 		nx_cop_caps.min_decompress_len =
1187 				be64_to_cpu(hv_nxc->min_decompress_len);
1188 	} else {
1189 		caps_feat = 0;
1190 	}
1191 
1192 	kfree(hv_nxc);
1193 out:
1194 	kfree(hv_caps);
1195 }
1196 
1197 static const struct vio_device_id nx842_vio_driver_ids[] = {
1198 	{"ibm,compression-v1", "ibm,compression"},
1199 	{"", ""},
1200 };
1201 MODULE_DEVICE_TABLE(vio, nx842_vio_driver_ids);
1202 
1203 static struct vio_driver nx842_vio_driver = {
1204 	.name = KBUILD_MODNAME,
1205 	.probe = nx842_probe,
1206 	.remove = nx842_remove,
1207 	.get_desired_dma = nx842_get_desired_dma,
1208 	.id_table = nx842_vio_driver_ids,
1209 };
1210 
1211 static int __init nx842_pseries_init(void)
1212 {
1213 	struct nx842_devdata *new_devdata;
1214 	struct device_node *np;
1215 	int ret;
1216 
1217 	np = of_find_compatible_node(NULL, NULL, "ibm,compression");
1218 	if (!np)
1219 		return -ENODEV;
1220 	of_node_put(np);
1221 
1222 	RCU_INIT_POINTER(devdata, NULL);
1223 	new_devdata = kzalloc(sizeof(*new_devdata), GFP_KERNEL);
1224 	if (!new_devdata)
1225 		return -ENOMEM;
1226 
1227 	RCU_INIT_POINTER(devdata, new_devdata);
1228 	/*
1229 	 * Get NX capabilities from the hypervisor.
1230 	 */
1231 	nxcop_get_capabilities();
1232 
1233 	ret = vio_register_driver(&nx842_vio_driver);
1234 	if (ret) {
1235 		pr_err("Could not register VIO driver %d\n", ret);
1236 
1237 		kfree(new_devdata);
1238 		return ret;
1239 	}
1240 
1241 	ret = vas_register_api_pseries(THIS_MODULE, VAS_COP_TYPE_GZIP,
1242 				       "nx-gzip");
1243 
1244 	if (ret)
1245 		pr_err("NX-GZIP is not supported. Returned=%d\n", ret);
1246 
1247 	return 0;
1248 }
1249 
1250 module_init(nx842_pseries_init);
1251 
1252 static void __exit nx842_pseries_exit(void)
1253 {
1254 	struct nx842_devdata *old_devdata;
1255 	unsigned long flags;
1256 
1257 	vas_unregister_api_pseries();
1258 
1259 	crypto_unregister_alg(&nx842_pseries_alg);
1260 
1261 	spin_lock_irqsave(&devdata_spinlock, flags);
1262 	old_devdata = rcu_dereference_check(devdata,
1263 			lockdep_is_held(&devdata_spinlock));
1264 	RCU_INIT_POINTER(devdata, NULL);
1265 	spin_unlock_irqrestore(&devdata_spinlock, flags);
1266 	synchronize_rcu();
1267 	if (old_devdata && old_devdata->dev)
1268 		dev_set_drvdata(old_devdata->dev, NULL);
1269 	kfree(old_devdata);
1270 	vio_unregister_driver(&nx842_vio_driver);
1271 }
1272 
1273 module_exit(nx842_pseries_exit);
1274 
1275