1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2012-2019 ARM Limited or its affiliates. */
3
4#include <linux/kernel.h>
5#include <linux/module.h>
6
7#include <linux/crypto.h>
8#include <linux/moduleparam.h>
9#include <linux/types.h>
10#include <linux/interrupt.h>
11#include <linux/platform_device.h>
12#include <linux/slab.h>
13#include <linux/spinlock.h>
14#include <linux/of.h>
15#include <linux/clk.h>
16#include <linux/of_address.h>
17#include <linux/of_device.h>
18#include <linux/pm_runtime.h>
19
20#include "cc_driver.h"
21#include "cc_request_mgr.h"
22#include "cc_buffer_mgr.h"
23#include "cc_debugfs.h"
24#include "cc_cipher.h"
25#include "cc_aead.h"
26#include "cc_hash.h"
27#include "cc_sram_mgr.h"
28#include "cc_pm.h"
29#include "cc_fips.h"
30
31bool cc_dump_desc;
32module_param_named(dump_desc, cc_dump_desc, bool, 0600);
33MODULE_PARM_DESC(cc_dump_desc, "Dump descriptors to kernel log as debugging aid");
34bool cc_dump_bytes;
35module_param_named(dump_bytes, cc_dump_bytes, bool, 0600);
36MODULE_PARM_DESC(cc_dump_bytes, "Dump buffers to kernel log as debugging aid");
37
38static bool cc_sec_disable;
39module_param_named(sec_disable, cc_sec_disable, bool, 0600);
40MODULE_PARM_DESC(cc_sec_disable, "Disable security functions");
41
42struct cc_hw_data {
43	char *name;
44	enum cc_hw_rev rev;
45	u32 sig;
46	u32 cidr_0123;
47	u32 pidr_0124;
48	int std_bodies;
49};
50
51#define CC_NUM_IDRS 4
52#define CC_HW_RESET_LOOP_COUNT 10
53
54/* Note: PIDR3 holds CMOD/Rev so ignored for HW identification purposes */
55static const u32 pidr_0124_offsets[CC_NUM_IDRS] = {
56	CC_REG(PERIPHERAL_ID_0), CC_REG(PERIPHERAL_ID_1),
57	CC_REG(PERIPHERAL_ID_2), CC_REG(PERIPHERAL_ID_4)
58};
59
60static const u32 cidr_0123_offsets[CC_NUM_IDRS] = {
61	CC_REG(COMPONENT_ID_0), CC_REG(COMPONENT_ID_1),
62	CC_REG(COMPONENT_ID_2), CC_REG(COMPONENT_ID_3)
63};
64
65/* Hardware revisions defs. */
66
67/* The 703 is a OSCCA only variant of the 713 */
68static const struct cc_hw_data cc703_hw = {
69	.name = "703", .rev = CC_HW_REV_713, .cidr_0123 = 0xB105F00DU,
70	.pidr_0124 = 0x040BB0D0U, .std_bodies = CC_STD_OSCCA
71};
72
73static const struct cc_hw_data cc713_hw = {
74	.name = "713", .rev = CC_HW_REV_713, .cidr_0123 = 0xB105F00DU,
75	.pidr_0124 = 0x040BB0D0U, .std_bodies = CC_STD_ALL
76};
77
78static const struct cc_hw_data cc712_hw = {
79	.name = "712", .rev = CC_HW_REV_712, .sig =  0xDCC71200U,
80	.std_bodies = CC_STD_ALL
81};
82
83static const struct cc_hw_data cc710_hw = {
84	.name = "710", .rev = CC_HW_REV_710, .sig =  0xDCC63200U,
85	.std_bodies = CC_STD_ALL
86};
87
88static const struct cc_hw_data cc630p_hw = {
89	.name = "630P", .rev = CC_HW_REV_630, .sig = 0xDCC63000U,
90	.std_bodies = CC_STD_ALL
91};
92
93static const struct of_device_id arm_ccree_dev_of_match[] = {
94	{ .compatible = "arm,cryptocell-703-ree", .data = &cc703_hw },
95	{ .compatible = "arm,cryptocell-713-ree", .data = &cc713_hw },
96	{ .compatible = "arm,cryptocell-712-ree", .data = &cc712_hw },
97	{ .compatible = "arm,cryptocell-710-ree", .data = &cc710_hw },
98	{ .compatible = "arm,cryptocell-630p-ree", .data = &cc630p_hw },
99	{}
100};
101MODULE_DEVICE_TABLE(of, arm_ccree_dev_of_match);
102
103static u32 cc_read_idr(struct cc_drvdata *drvdata, const u32 *idr_offsets)
104{
105	int i;
106	union {
107		u8 regs[CC_NUM_IDRS];
108		__le32 val;
109	} idr;
110
111	for (i = 0; i < CC_NUM_IDRS; ++i)
112		idr.regs[i] = cc_ioread(drvdata, idr_offsets[i]);
113
114	return le32_to_cpu(idr.val);
115}
116
117void __dump_byte_array(const char *name, const u8 *buf, size_t len)
118{
119	char prefix[64];
120
121	if (!buf)
122		return;
123
124	snprintf(prefix, sizeof(prefix), "%s[%zu]: ", name, len);
125
126	print_hex_dump(KERN_DEBUG, prefix, DUMP_PREFIX_ADDRESS, 16, 1, buf,
127		       len, false);
128}
129
130static irqreturn_t cc_isr(int irq, void *dev_id)
131{
132	struct cc_drvdata *drvdata = (struct cc_drvdata *)dev_id;
133	struct device *dev = drvdata_to_dev(drvdata);
134	u32 irr;
135	u32 imr;
136
137	/* STAT_OP_TYPE_GENERIC STAT_PHASE_0: Interrupt */
138	/* if driver suspended return, probably shared interrupt */
139	if (pm_runtime_suspended(dev))
140		return IRQ_NONE;
141
142	/* read the interrupt status */
143	irr = cc_ioread(drvdata, CC_REG(HOST_IRR));
144	dev_dbg(dev, "Got IRR=0x%08X\n", irr);
145
146	if (irr == 0) /* Probably shared interrupt line */
147		return IRQ_NONE;
148
149	imr = cc_ioread(drvdata, CC_REG(HOST_IMR));
150
151	/* clear interrupt - must be before processing events */
152	cc_iowrite(drvdata, CC_REG(HOST_ICR), irr);
153
154	drvdata->irq = irr;
155	/* Completion interrupt - most probable */
156	if (irr & drvdata->comp_mask) {
157		/* Mask all completion interrupts - will be unmasked in
158		 * deferred service handler
159		 */
160		cc_iowrite(drvdata, CC_REG(HOST_IMR), imr | drvdata->comp_mask);
161		irr &= ~drvdata->comp_mask;
162		complete_request(drvdata);
163	}
164#ifdef CONFIG_CRYPTO_FIPS
165	/* TEE FIPS interrupt */
166	if (irr & CC_GPR0_IRQ_MASK) {
167		/* Mask interrupt - will be unmasked in Deferred service
168		 * handler
169		 */
170		cc_iowrite(drvdata, CC_REG(HOST_IMR), imr | CC_GPR0_IRQ_MASK);
171		irr &= ~CC_GPR0_IRQ_MASK;
172		fips_handler(drvdata);
173	}
174#endif
175	/* AXI error interrupt */
176	if (irr & CC_AXI_ERR_IRQ_MASK) {
177		u32 axi_err;
178
179		/* Read the AXI error ID */
180		axi_err = cc_ioread(drvdata, CC_REG(AXIM_MON_ERR));
181		dev_dbg(dev, "AXI completion error: axim_mon_err=0x%08X\n",
182			axi_err);
183
184		irr &= ~CC_AXI_ERR_IRQ_MASK;
185	}
186
187	if (irr) {
188		dev_dbg_ratelimited(dev, "IRR includes unknown cause bits (0x%08X)\n",
189				    irr);
190		/* Just warning */
191	}
192
193	return IRQ_HANDLED;
194}
195
196bool cc_wait_for_reset_completion(struct cc_drvdata *drvdata)
197{
198	unsigned int val;
199	unsigned int i;
200
201	/* 712/710/63 has no reset completion indication, always return true */
202	if (drvdata->hw_rev <= CC_HW_REV_712)
203		return true;
204
205	for (i = 0; i < CC_HW_RESET_LOOP_COUNT; i++) {
206		/* in cc7x3 NVM_IS_IDLE indicates that CC reset is
207		 *  completed and device is fully functional
208		 */
209		val = cc_ioread(drvdata, CC_REG(NVM_IS_IDLE));
210		if (val & CC_NVM_IS_IDLE_MASK) {
211			/* hw indicate reset completed */
212			return true;
213		}
214		/* allow scheduling other process on the processor */
215		schedule();
216	}
217	/* reset not completed */
218	return false;
219}
220
221int init_cc_regs(struct cc_drvdata *drvdata, bool is_probe)
222{
223	unsigned int val, cache_params;
224	struct device *dev = drvdata_to_dev(drvdata);
225
226	/* Unmask all AXI interrupt sources AXI_CFG1 register   */
227	/* AXI interrupt config are obsoleted startign at cc7x3 */
228	if (drvdata->hw_rev <= CC_HW_REV_712) {
229		val = cc_ioread(drvdata, CC_REG(AXIM_CFG));
230		cc_iowrite(drvdata, CC_REG(AXIM_CFG), val & ~CC_AXI_IRQ_MASK);
231		dev_dbg(dev, "AXIM_CFG=0x%08X\n",
232			cc_ioread(drvdata, CC_REG(AXIM_CFG)));
233	}
234
235	/* Clear all pending interrupts */
236	val = cc_ioread(drvdata, CC_REG(HOST_IRR));
237	dev_dbg(dev, "IRR=0x%08X\n", val);
238	cc_iowrite(drvdata, CC_REG(HOST_ICR), val);
239
240	/* Unmask relevant interrupt cause */
241	val = drvdata->comp_mask | CC_AXI_ERR_IRQ_MASK;
242
243	if (drvdata->hw_rev >= CC_HW_REV_712)
244		val |= CC_GPR0_IRQ_MASK;
245
246	cc_iowrite(drvdata, CC_REG(HOST_IMR), ~val);
247
248	cache_params = (drvdata->coherent ? CC_COHERENT_CACHE_PARAMS : 0x0);
249
250	val = cc_ioread(drvdata, CC_REG(AXIM_CACHE_PARAMS));
251
252	if (is_probe)
253		dev_dbg(dev, "Cache params previous: 0x%08X\n", val);
254
255	cc_iowrite(drvdata, CC_REG(AXIM_CACHE_PARAMS), cache_params);
256	val = cc_ioread(drvdata, CC_REG(AXIM_CACHE_PARAMS));
257
258	if (is_probe)
259		dev_dbg(dev, "Cache params current: 0x%08X (expect: 0x%08X)\n",
260			val, cache_params);
261
262	return 0;
263}
264
265static int init_cc_resources(struct platform_device *plat_dev)
266{
267	struct resource *req_mem_cc_regs = NULL;
268	struct cc_drvdata *new_drvdata;
269	struct device *dev = &plat_dev->dev;
270	struct device_node *np = dev->of_node;
271	u32 val, hw_rev_pidr, sig_cidr;
272	u64 dma_mask;
273	const struct cc_hw_data *hw_rev;
274	struct clk *clk;
275	int irq;
276	int rc = 0;
277
278	new_drvdata = devm_kzalloc(dev, sizeof(*new_drvdata), GFP_KERNEL);
279	if (!new_drvdata)
280		return -ENOMEM;
281
282	hw_rev = of_device_get_match_data(dev);
283	new_drvdata->hw_rev_name = hw_rev->name;
284	new_drvdata->hw_rev = hw_rev->rev;
285	new_drvdata->std_bodies = hw_rev->std_bodies;
286
287	if (hw_rev->rev >= CC_HW_REV_712) {
288		new_drvdata->axim_mon_offset = CC_REG(AXIM_MON_COMP);
289		new_drvdata->sig_offset = CC_REG(HOST_SIGNATURE_712);
290		new_drvdata->ver_offset = CC_REG(HOST_VERSION_712);
291	} else {
292		new_drvdata->axim_mon_offset = CC_REG(AXIM_MON_COMP8);
293		new_drvdata->sig_offset = CC_REG(HOST_SIGNATURE_630);
294		new_drvdata->ver_offset = CC_REG(HOST_VERSION_630);
295	}
296
297	new_drvdata->comp_mask = CC_COMP_IRQ_MASK;
298
299	platform_set_drvdata(plat_dev, new_drvdata);
300	new_drvdata->plat_dev = plat_dev;
301
302	clk = devm_clk_get_optional(dev, NULL);
303	if (IS_ERR(clk))
304		return dev_err_probe(dev, PTR_ERR(clk), "Error getting clock\n");
305	new_drvdata->clk = clk;
306
307	new_drvdata->coherent = of_dma_is_coherent(np);
308
309	/* Get device resources */
310	/* First CC registers space */
311	req_mem_cc_regs = platform_get_resource(plat_dev, IORESOURCE_MEM, 0);
312	/* Map registers space */
313	new_drvdata->cc_base = devm_ioremap_resource(dev, req_mem_cc_regs);
314	if (IS_ERR(new_drvdata->cc_base)) {
315		dev_err(dev, "Failed to ioremap registers");
316		return PTR_ERR(new_drvdata->cc_base);
317	}
318
319	dev_dbg(dev, "Got MEM resource (%s): %pR\n", req_mem_cc_regs->name,
320		req_mem_cc_regs);
321	dev_dbg(dev, "CC registers mapped from %pa to 0x%p\n",
322		&req_mem_cc_regs->start, new_drvdata->cc_base);
323
324	/* Then IRQ */
325	irq = platform_get_irq(plat_dev, 0);
326	if (irq < 0)
327		return irq;
328
329	init_completion(&new_drvdata->hw_queue_avail);
330
331	if (!dev->dma_mask)
332		dev->dma_mask = &dev->coherent_dma_mask;
333
334	dma_mask = DMA_BIT_MASK(DMA_BIT_MASK_LEN);
335	while (dma_mask > 0x7fffffffUL) {
336		if (dma_supported(dev, dma_mask)) {
337			rc = dma_set_coherent_mask(dev, dma_mask);
338			if (!rc)
339				break;
340		}
341		dma_mask >>= 1;
342	}
343
344	if (rc) {
345		dev_err(dev, "Failed in dma_set_mask, mask=%llx\n", dma_mask);
346		return rc;
347	}
348
349	rc = clk_prepare_enable(new_drvdata->clk);
350	if (rc) {
351		dev_err(dev, "Failed to enable clock");
352		return rc;
353	}
354
355	new_drvdata->sec_disabled = cc_sec_disable;
356
357	pm_runtime_set_autosuspend_delay(dev, CC_SUSPEND_TIMEOUT);
358	pm_runtime_use_autosuspend(dev);
359	pm_runtime_set_active(dev);
360	pm_runtime_enable(dev);
361	rc = pm_runtime_get_sync(dev);
362	if (rc < 0) {
363		dev_err(dev, "pm_runtime_get_sync() failed: %d\n", rc);
364		goto post_pm_err;
365	}
366
367	/* Wait for Cryptocell reset completion */
368	if (!cc_wait_for_reset_completion(new_drvdata)) {
369		dev_err(dev, "Cryptocell reset not completed");
370	}
371
372	if (hw_rev->rev <= CC_HW_REV_712) {
373		/* Verify correct mapping */
374		val = cc_ioread(new_drvdata, new_drvdata->sig_offset);
375		if (val != hw_rev->sig) {
376			dev_err(dev, "Invalid CC signature: SIGNATURE=0x%08X != expected=0x%08X\n",
377				val, hw_rev->sig);
378			rc = -EINVAL;
379			goto post_pm_err;
380		}
381		sig_cidr = val;
382		hw_rev_pidr = cc_ioread(new_drvdata, new_drvdata->ver_offset);
383	} else {
384		/* Verify correct mapping */
385		val = cc_read_idr(new_drvdata, pidr_0124_offsets);
386		if (val != hw_rev->pidr_0124) {
387			dev_err(dev, "Invalid CC PIDR: PIDR0124=0x%08X != expected=0x%08X\n",
388				val,  hw_rev->pidr_0124);
389			rc = -EINVAL;
390			goto post_pm_err;
391		}
392		hw_rev_pidr = val;
393
394		val = cc_read_idr(new_drvdata, cidr_0123_offsets);
395		if (val != hw_rev->cidr_0123) {
396			dev_err(dev, "Invalid CC CIDR: CIDR0123=0x%08X != expected=0x%08X\n",
397			val,  hw_rev->cidr_0123);
398			rc = -EINVAL;
399			goto post_pm_err;
400		}
401		sig_cidr = val;
402
403		/* Check HW engine configuration */
404		val = cc_ioread(new_drvdata, CC_REG(HOST_REMOVE_INPUT_PINS));
405		switch (val) {
406		case CC_PINS_FULL:
407			/* This is fine */
408			break;
409		case CC_PINS_SLIM:
410			if (new_drvdata->std_bodies & CC_STD_NIST) {
411				dev_warn(dev, "703 mode forced due to HW configuration.\n");
412				new_drvdata->std_bodies = CC_STD_OSCCA;
413			}
414			break;
415		default:
416			dev_err(dev, "Unsupported engines configuration.\n");
417			rc = -EINVAL;
418			goto post_pm_err;
419		}
420
421		/* Check security disable state */
422		val = cc_ioread(new_drvdata, CC_REG(SECURITY_DISABLED));
423		val &= CC_SECURITY_DISABLED_MASK;
424		new_drvdata->sec_disabled |= !!val;
425
426		if (!new_drvdata->sec_disabled) {
427			new_drvdata->comp_mask |= CC_CPP_SM4_ABORT_MASK;
428			if (new_drvdata->std_bodies & CC_STD_NIST)
429				new_drvdata->comp_mask |= CC_CPP_AES_ABORT_MASK;
430		}
431	}
432
433	if (new_drvdata->sec_disabled)
434		dev_info(dev, "Security Disabled mode is in effect. Security functions disabled.\n");
435
436	/* Display HW versions */
437	dev_info(dev, "ARM CryptoCell %s Driver: HW version 0x%08X/0x%8X, Driver version %s\n",
438		 hw_rev->name, hw_rev_pidr, sig_cidr, DRV_MODULE_VERSION);
439	/* register the driver isr function */
440	rc = devm_request_irq(dev, irq, cc_isr, IRQF_SHARED, "ccree",
441			      new_drvdata);
442	if (rc) {
443		dev_err(dev, "Could not register to interrupt %d\n", irq);
444		goto post_pm_err;
445	}
446	dev_dbg(dev, "Registered to IRQ: %d\n", irq);
447
448	rc = init_cc_regs(new_drvdata, true);
449	if (rc) {
450		dev_err(dev, "init_cc_regs failed\n");
451		goto post_pm_err;
452	}
453
454	rc = cc_debugfs_init(new_drvdata);
455	if (rc) {
456		dev_err(dev, "Failed registering debugfs interface\n");
457		goto post_regs_err;
458	}
459
460	rc = cc_fips_init(new_drvdata);
461	if (rc) {
462		dev_err(dev, "cc_fips_init failed 0x%x\n", rc);
463		goto post_debugfs_err;
464	}
465	rc = cc_sram_mgr_init(new_drvdata);
466	if (rc) {
467		dev_err(dev, "cc_sram_mgr_init failed\n");
468		goto post_fips_init_err;
469	}
470
471	new_drvdata->mlli_sram_addr =
472		cc_sram_alloc(new_drvdata, MAX_MLLI_BUFF_SIZE);
473	if (new_drvdata->mlli_sram_addr == NULL_SRAM_ADDR) {
474		rc = -ENOMEM;
475		goto post_fips_init_err;
476	}
477
478	rc = cc_req_mgr_init(new_drvdata);
479	if (rc) {
480		dev_err(dev, "cc_req_mgr_init failed\n");
481		goto post_fips_init_err;
482	}
483
484	rc = cc_buffer_mgr_init(new_drvdata);
485	if (rc) {
486		dev_err(dev, "cc_buffer_mgr_init failed\n");
487		goto post_req_mgr_err;
488	}
489
490	/* Allocate crypto algs */
491	rc = cc_cipher_alloc(new_drvdata);
492	if (rc) {
493		dev_err(dev, "cc_cipher_alloc failed\n");
494		goto post_buf_mgr_err;
495	}
496
497	/* hash must be allocated before aead since hash exports APIs */
498	rc = cc_hash_alloc(new_drvdata);
499	if (rc) {
500		dev_err(dev, "cc_hash_alloc failed\n");
501		goto post_cipher_err;
502	}
503
504	rc = cc_aead_alloc(new_drvdata);
505	if (rc) {
506		dev_err(dev, "cc_aead_alloc failed\n");
507		goto post_hash_err;
508	}
509
510	/* If we got here and FIPS mode is enabled
511	 * it means all FIPS test passed, so let TEE
512	 * know we're good.
513	 */
514	cc_set_ree_fips_status(new_drvdata, true);
515
516	pm_runtime_put(dev);
517	return 0;
518
519post_hash_err:
520	cc_hash_free(new_drvdata);
521post_cipher_err:
522	cc_cipher_free(new_drvdata);
523post_buf_mgr_err:
524	 cc_buffer_mgr_fini(new_drvdata);
525post_req_mgr_err:
526	cc_req_mgr_fini(new_drvdata);
527post_fips_init_err:
528	cc_fips_fini(new_drvdata);
529post_debugfs_err:
530	cc_debugfs_fini(new_drvdata);
531post_regs_err:
532	fini_cc_regs(new_drvdata);
533post_pm_err:
534	pm_runtime_put_noidle(dev);
535	pm_runtime_disable(dev);
536	pm_runtime_set_suspended(dev);
537	clk_disable_unprepare(new_drvdata->clk);
538	return rc;
539}
540
541void fini_cc_regs(struct cc_drvdata *drvdata)
542{
543	/* Mask all interrupts */
544	cc_iowrite(drvdata, CC_REG(HOST_IMR), 0xFFFFFFFF);
545}
546
547static void cleanup_cc_resources(struct platform_device *plat_dev)
548{
549	struct device *dev = &plat_dev->dev;
550	struct cc_drvdata *drvdata =
551		(struct cc_drvdata *)platform_get_drvdata(plat_dev);
552
553	cc_aead_free(drvdata);
554	cc_hash_free(drvdata);
555	cc_cipher_free(drvdata);
556	cc_buffer_mgr_fini(drvdata);
557	cc_req_mgr_fini(drvdata);
558	cc_fips_fini(drvdata);
559	cc_debugfs_fini(drvdata);
560	fini_cc_regs(drvdata);
561	pm_runtime_put_noidle(dev);
562	pm_runtime_disable(dev);
563	pm_runtime_set_suspended(dev);
564	clk_disable_unprepare(drvdata->clk);
565}
566
567unsigned int cc_get_default_hash_len(struct cc_drvdata *drvdata)
568{
569	if (drvdata->hw_rev >= CC_HW_REV_712)
570		return HASH_LEN_SIZE_712;
571	else
572		return HASH_LEN_SIZE_630;
573}
574
575static int ccree_probe(struct platform_device *plat_dev)
576{
577	int rc;
578	struct device *dev = &plat_dev->dev;
579
580	/* Map registers space */
581	rc = init_cc_resources(plat_dev);
582	if (rc)
583		return rc;
584
585	dev_info(dev, "ARM ccree device initialized\n");
586
587	return 0;
588}
589
590static int ccree_remove(struct platform_device *plat_dev)
591{
592	struct device *dev = &plat_dev->dev;
593
594	dev_dbg(dev, "Releasing ccree resources...\n");
595
596	cleanup_cc_resources(plat_dev);
597
598	dev_info(dev, "ARM ccree device terminated\n");
599
600	return 0;
601}
602
603static struct platform_driver ccree_driver = {
604	.driver = {
605		   .name = "ccree",
606		   .of_match_table = arm_ccree_dev_of_match,
607#ifdef CONFIG_PM
608		   .pm = &ccree_pm,
609#endif
610	},
611	.probe = ccree_probe,
612	.remove = ccree_remove,
613};
614
615static int __init ccree_init(void)
616{
617	int rc;
618
619	cc_debugfs_global_init();
620
621	rc = platform_driver_register(&ccree_driver);
622	if (rc) {
623		cc_debugfs_global_fini();
624		return rc;
625	}
626
627	return 0;
628}
629module_init(ccree_init);
630
631static void __exit ccree_exit(void)
632{
633	platform_driver_unregister(&ccree_driver);
634	cc_debugfs_global_fini();
635}
636module_exit(ccree_exit);
637
638/* Module description */
639MODULE_DESCRIPTION("ARM TrustZone CryptoCell REE Driver");
640MODULE_VERSION(DRV_MODULE_VERSION);
641MODULE_AUTHOR("ARM");
642MODULE_LICENSE("GPL v2");
643