[go: nahoru, domu]
1/*
2 * omap-rng.c - RNG driver for TI OMAP CPU family
3 *
4 * Author: Deepak Saxena <dsaxena@plexity.net>
5 *
6 * Copyright 2005 (c) MontaVista Software, Inc.
7 *
8 * Mostly based on original driver:
9 *
10 * Copyright (C) 2005 Nokia Corporation
11 * Author: Juha Yrjölä <juha.yrjola@nokia.com>
12 *
13 * This file is licensed under  the terms of the GNU General Public
14 * License version 2. This program is licensed "as is" without any
15 * warranty of any kind, whether express or implied.
16 */
17
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/random.h>
21#include <linux/err.h>
22#include <linux/platform_device.h>
23#include <linux/hw_random.h>
24#include <linux/delay.h>
25#include <linux/slab.h>
26#include <linux/pm_runtime.h>
27#include <linux/of.h>
28#include <linux/of_device.h>
29#include <linux/of_address.h>
30#include <linux/interrupt.h>
31
32#include <asm/io.h>
33
34#define RNG_REG_STATUS_RDY			(1 << 0)
35
36#define RNG_REG_INTACK_RDY_MASK			(1 << 0)
37#define RNG_REG_INTACK_SHUTDOWN_OFLO_MASK	(1 << 1)
38#define RNG_SHUTDOWN_OFLO_MASK			(1 << 1)
39
40#define RNG_CONTROL_STARTUP_CYCLES_SHIFT	16
41#define RNG_CONTROL_STARTUP_CYCLES_MASK		(0xffff << 16)
42#define RNG_CONTROL_ENABLE_TRNG_SHIFT		10
43#define RNG_CONTROL_ENABLE_TRNG_MASK		(1 << 10)
44
45#define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT	16
46#define RNG_CONFIG_MAX_REFIL_CYCLES_MASK	(0xffff << 16)
47#define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT	0
48#define RNG_CONFIG_MIN_REFIL_CYCLES_MASK	(0xff << 0)
49
50#define RNG_CONTROL_STARTUP_CYCLES		0xff
51#define RNG_CONFIG_MIN_REFIL_CYCLES		0x21
52#define RNG_CONFIG_MAX_REFIL_CYCLES		0x22
53
54#define RNG_ALARMCNT_ALARM_TH_SHIFT		0x0
55#define RNG_ALARMCNT_ALARM_TH_MASK		(0xff << 0)
56#define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT		16
57#define RNG_ALARMCNT_SHUTDOWN_TH_MASK		(0x1f << 16)
58#define RNG_ALARM_THRESHOLD			0xff
59#define RNG_SHUTDOWN_THRESHOLD			0x4
60
61#define RNG_REG_FROENABLE_MASK			0xffffff
62#define RNG_REG_FRODETUNE_MASK			0xffffff
63
64#define OMAP2_RNG_OUTPUT_SIZE			0x4
65#define OMAP4_RNG_OUTPUT_SIZE			0x8
66
67enum {
68	RNG_OUTPUT_L_REG = 0,
69	RNG_OUTPUT_H_REG,
70	RNG_STATUS_REG,
71	RNG_INTMASK_REG,
72	RNG_INTACK_REG,
73	RNG_CONTROL_REG,
74	RNG_CONFIG_REG,
75	RNG_ALARMCNT_REG,
76	RNG_FROENABLE_REG,
77	RNG_FRODETUNE_REG,
78	RNG_ALARMMASK_REG,
79	RNG_ALARMSTOP_REG,
80	RNG_REV_REG,
81	RNG_SYSCONFIG_REG,
82};
83
84static const u16 reg_map_omap2[] = {
85	[RNG_OUTPUT_L_REG]	= 0x0,
86	[RNG_STATUS_REG]	= 0x4,
87	[RNG_CONFIG_REG]	= 0x28,
88	[RNG_REV_REG]		= 0x3c,
89	[RNG_SYSCONFIG_REG]	= 0x40,
90};
91
92static const u16 reg_map_omap4[] = {
93	[RNG_OUTPUT_L_REG]	= 0x0,
94	[RNG_OUTPUT_H_REG]	= 0x4,
95	[RNG_STATUS_REG]	= 0x8,
96	[RNG_INTMASK_REG]	= 0xc,
97	[RNG_INTACK_REG]	= 0x10,
98	[RNG_CONTROL_REG]	= 0x14,
99	[RNG_CONFIG_REG]	= 0x18,
100	[RNG_ALARMCNT_REG]	= 0x1c,
101	[RNG_FROENABLE_REG]	= 0x20,
102	[RNG_FRODETUNE_REG]	= 0x24,
103	[RNG_ALARMMASK_REG]	= 0x28,
104	[RNG_ALARMSTOP_REG]	= 0x2c,
105	[RNG_REV_REG]		= 0x1FE0,
106	[RNG_SYSCONFIG_REG]	= 0x1FE4,
107};
108
109struct omap_rng_dev;
110/**
111 * struct omap_rng_pdata - RNG IP block-specific data
112 * @regs: Pointer to the register offsets structure.
113 * @data_size: No. of bytes in RNG output.
114 * @data_present: Callback to determine if data is available.
115 * @init: Callback for IP specific initialization sequence.
116 * @cleanup: Callback for IP specific cleanup sequence.
117 */
118struct omap_rng_pdata {
119	u16	*regs;
120	u32	data_size;
121	u32	(*data_present)(struct omap_rng_dev *priv);
122	int	(*init)(struct omap_rng_dev *priv);
123	void	(*cleanup)(struct omap_rng_dev *priv);
124};
125
126struct omap_rng_dev {
127	void __iomem			*base;
128	struct device			*dev;
129	const struct omap_rng_pdata	*pdata;
130};
131
132static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg)
133{
134	return __raw_readl(priv->base + priv->pdata->regs[reg]);
135}
136
137static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg,
138				      u32 val)
139{
140	__raw_writel(val, priv->base + priv->pdata->regs[reg]);
141}
142
143static int omap_rng_data_present(struct hwrng *rng, int wait)
144{
145	struct omap_rng_dev *priv;
146	int data, i;
147
148	priv = (struct omap_rng_dev *)rng->priv;
149
150	for (i = 0; i < 20; i++) {
151		data = priv->pdata->data_present(priv);
152		if (data || !wait)
153			break;
154		/* RNG produces data fast enough (2+ MBit/sec, even
155		 * during "rngtest" loads, that these delays don't
156		 * seem to trigger.  We *could* use the RNG IRQ, but
157		 * that'd be higher overhead ... so why bother?
158		 */
159		udelay(10);
160	}
161	return data;
162}
163
164static int omap_rng_data_read(struct hwrng *rng, u32 *data)
165{
166	struct omap_rng_dev *priv;
167	u32 data_size, i;
168
169	priv = (struct omap_rng_dev *)rng->priv;
170	data_size = priv->pdata->data_size;
171
172	for (i = 0; i < data_size / sizeof(u32); i++)
173		data[i] = omap_rng_read(priv, RNG_OUTPUT_L_REG + i);
174
175	if (priv->pdata->regs[RNG_INTACK_REG])
176		omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK);
177	return data_size;
178}
179
180static int omap_rng_init(struct hwrng *rng)
181{
182	struct omap_rng_dev *priv;
183
184	priv = (struct omap_rng_dev *)rng->priv;
185	return priv->pdata->init(priv);
186}
187
188static void omap_rng_cleanup(struct hwrng *rng)
189{
190	struct omap_rng_dev *priv;
191
192	priv = (struct omap_rng_dev *)rng->priv;
193	priv->pdata->cleanup(priv);
194}
195
196static struct hwrng omap_rng_ops = {
197	.name		= "omap",
198	.data_present	= omap_rng_data_present,
199	.data_read	= omap_rng_data_read,
200	.init		= omap_rng_init,
201	.cleanup	= omap_rng_cleanup,
202};
203
204static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv)
205{
206	return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1;
207}
208
209static int omap2_rng_init(struct omap_rng_dev *priv)
210{
211	omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1);
212	return 0;
213}
214
215static void omap2_rng_cleanup(struct omap_rng_dev *priv)
216{
217	omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0);
218}
219
220static struct omap_rng_pdata omap2_rng_pdata = {
221	.regs		= (u16 *)reg_map_omap2,
222	.data_size	= OMAP2_RNG_OUTPUT_SIZE,
223	.data_present	= omap2_rng_data_present,
224	.init		= omap2_rng_init,
225	.cleanup	= omap2_rng_cleanup,
226};
227
228#if defined(CONFIG_OF)
229static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv)
230{
231	return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY;
232}
233
234static int omap4_rng_init(struct omap_rng_dev *priv)
235{
236	u32 val;
237
238	/* Return if RNG is already running. */
239	if (omap_rng_read(priv, RNG_CONFIG_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
240		return 0;
241
242	val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
243	val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
244	omap_rng_write(priv, RNG_CONFIG_REG, val);
245
246	omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
247	omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
248	val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT;
249	val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT;
250	omap_rng_write(priv, RNG_ALARMCNT_REG, val);
251
252	val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT;
253	val |= RNG_CONTROL_ENABLE_TRNG_MASK;
254	omap_rng_write(priv, RNG_CONTROL_REG, val);
255
256	return 0;
257}
258
259static void omap4_rng_cleanup(struct omap_rng_dev *priv)
260{
261	int val;
262
263	val = omap_rng_read(priv, RNG_CONTROL_REG);
264	val &= ~RNG_CONTROL_ENABLE_TRNG_MASK;
265	omap_rng_write(priv, RNG_CONFIG_REG, val);
266}
267
268static irqreturn_t omap4_rng_irq(int irq, void *dev_id)
269{
270	struct omap_rng_dev *priv = dev_id;
271	u32 fro_detune, fro_enable;
272
273	/*
274	 * Interrupt raised by a fro shutdown threshold, do the following:
275	 * 1. Clear the alarm events.
276	 * 2. De tune the FROs which are shutdown.
277	 * 3. Re enable the shutdown FROs.
278	 */
279	omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0);
280	omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0);
281
282	fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG);
283	fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK;
284	fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG);
285	fro_enable = RNG_REG_FROENABLE_MASK;
286
287	omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune);
288	omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable);
289
290	omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK);
291
292	return IRQ_HANDLED;
293}
294
295static struct omap_rng_pdata omap4_rng_pdata = {
296	.regs		= (u16 *)reg_map_omap4,
297	.data_size	= OMAP4_RNG_OUTPUT_SIZE,
298	.data_present	= omap4_rng_data_present,
299	.init		= omap4_rng_init,
300	.cleanup	= omap4_rng_cleanup,
301};
302
303static const struct of_device_id omap_rng_of_match[] = {
304		{
305			.compatible	= "ti,omap2-rng",
306			.data		= &omap2_rng_pdata,
307		},
308		{
309			.compatible	= "ti,omap4-rng",
310			.data		= &omap4_rng_pdata,
311		},
312		{},
313};
314MODULE_DEVICE_TABLE(of, omap_rng_of_match);
315
316static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
317					  struct platform_device *pdev)
318{
319	const struct of_device_id *match;
320	struct device *dev = &pdev->dev;
321	int irq, err;
322
323	match = of_match_device(of_match_ptr(omap_rng_of_match), dev);
324	if (!match) {
325		dev_err(dev, "no compatible OF match\n");
326		return -EINVAL;
327	}
328	priv->pdata = match->data;
329
330	if (of_device_is_compatible(dev->of_node, "ti,omap4-rng")) {
331		irq = platform_get_irq(pdev, 0);
332		if (irq < 0) {
333			dev_err(dev, "%s: error getting IRQ resource - %d\n",
334				__func__, irq);
335			return irq;
336		}
337
338		err = devm_request_irq(dev, irq, omap4_rng_irq,
339				       IRQF_TRIGGER_NONE, dev_name(dev), priv);
340		if (err) {
341			dev_err(dev, "unable to request irq %d, err = %d\n",
342				irq, err);
343			return err;
344		}
345		omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK);
346	}
347	return 0;
348}
349#else
350static int of_get_omap_rng_device_details(struct omap_rng_dev *omap_rng,
351					  struct platform_device *pdev)
352{
353	return -EINVAL;
354}
355#endif
356
357static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng)
358{
359	/* Only OMAP2/3 can be non-DT */
360	omap_rng->pdata = &omap2_rng_pdata;
361	return 0;
362}
363
364static int omap_rng_probe(struct platform_device *pdev)
365{
366	struct omap_rng_dev *priv;
367	struct resource *res;
368	struct device *dev = &pdev->dev;
369	int ret;
370
371	priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL);
372	if (!priv)
373		return -ENOMEM;
374
375	omap_rng_ops.priv = (unsigned long)priv;
376	platform_set_drvdata(pdev, priv);
377	priv->dev = dev;
378
379	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
380	priv->base = devm_ioremap_resource(dev, res);
381	if (IS_ERR(priv->base)) {
382		ret = PTR_ERR(priv->base);
383		goto err_ioremap;
384	}
385
386	pm_runtime_enable(&pdev->dev);
387	pm_runtime_get_sync(&pdev->dev);
388
389	ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) :
390				get_omap_rng_device_details(priv);
391	if (ret)
392		goto err_ioremap;
393
394	ret = hwrng_register(&omap_rng_ops);
395	if (ret)
396		goto err_register;
397
398	dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
399		 omap_rng_read(priv, RNG_REV_REG));
400
401	return 0;
402
403err_register:
404	priv->base = NULL;
405	pm_runtime_disable(&pdev->dev);
406err_ioremap:
407	dev_err(dev, "initialization failed.\n");
408	return ret;
409}
410
411static int __exit omap_rng_remove(struct platform_device *pdev)
412{
413	struct omap_rng_dev *priv = platform_get_drvdata(pdev);
414
415	hwrng_unregister(&omap_rng_ops);
416
417	priv->pdata->cleanup(priv);
418
419	pm_runtime_put_sync(&pdev->dev);
420	pm_runtime_disable(&pdev->dev);
421
422	return 0;
423}
424
425#ifdef CONFIG_PM_SLEEP
426
427static int omap_rng_suspend(struct device *dev)
428{
429	struct omap_rng_dev *priv = dev_get_drvdata(dev);
430
431	priv->pdata->cleanup(priv);
432	pm_runtime_put_sync(dev);
433
434	return 0;
435}
436
437static int omap_rng_resume(struct device *dev)
438{
439	struct omap_rng_dev *priv = dev_get_drvdata(dev);
440
441	pm_runtime_get_sync(dev);
442	priv->pdata->init(priv);
443
444	return 0;
445}
446
447static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
448#define	OMAP_RNG_PM	(&omap_rng_pm)
449
450#else
451
452#define	OMAP_RNG_PM	NULL
453
454#endif
455
456static struct platform_driver omap_rng_driver = {
457	.driver = {
458		.name		= "omap_rng",
459		.owner		= THIS_MODULE,
460		.pm		= OMAP_RNG_PM,
461		.of_match_table = of_match_ptr(omap_rng_of_match),
462	},
463	.probe		= omap_rng_probe,
464	.remove		= __exit_p(omap_rng_remove),
465};
466
467module_platform_driver(omap_rng_driver);
468MODULE_ALIAS("platform:omap_rng");
469MODULE_AUTHOR("Deepak Saxena (and others)");
470MODULE_LICENSE("GPL");
471