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 #include <linux/clk.h>
32
33 #include <asm/io.h>
34
35 #define RNG_REG_STATUS_RDY (1 << 0)
36
37 #define RNG_REG_INTACK_RDY_MASK (1 << 0)
38 #define RNG_REG_INTACK_SHUTDOWN_OFLO_MASK (1 << 1)
39 #define RNG_SHUTDOWN_OFLO_MASK (1 << 1)
40
41 #define RNG_CONTROL_STARTUP_CYCLES_SHIFT 16
42 #define RNG_CONTROL_STARTUP_CYCLES_MASK (0xffff << 16)
43 #define RNG_CONTROL_ENABLE_TRNG_SHIFT 10
44 #define RNG_CONTROL_ENABLE_TRNG_MASK (1 << 10)
45
46 #define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT 16
47 #define RNG_CONFIG_MAX_REFIL_CYCLES_MASK (0xffff << 16)
48 #define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT 0
49 #define RNG_CONFIG_MIN_REFIL_CYCLES_MASK (0xff << 0)
50
51 #define RNG_CONTROL_STARTUP_CYCLES 0xff
52 #define RNG_CONFIG_MIN_REFIL_CYCLES 0x21
53 #define RNG_CONFIG_MAX_REFIL_CYCLES 0x22
54
55 #define RNG_ALARMCNT_ALARM_TH_SHIFT 0x0
56 #define RNG_ALARMCNT_ALARM_TH_MASK (0xff << 0)
57 #define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT 16
58 #define RNG_ALARMCNT_SHUTDOWN_TH_MASK (0x1f << 16)
59 #define RNG_ALARM_THRESHOLD 0xff
60 #define RNG_SHUTDOWN_THRESHOLD 0x4
61
62 #define RNG_REG_FROENABLE_MASK 0xffffff
63 #define RNG_REG_FRODETUNE_MASK 0xffffff
64
65 #define OMAP2_RNG_OUTPUT_SIZE 0x4
66 #define OMAP4_RNG_OUTPUT_SIZE 0x8
67 #define EIP76_RNG_OUTPUT_SIZE 0x10
68
69 enum {
70 RNG_OUTPUT_0_REG = 0,
71 RNG_OUTPUT_1_REG,
72 RNG_OUTPUT_2_REG,
73 RNG_OUTPUT_3_REG,
74 RNG_STATUS_REG,
75 RNG_INTMASK_REG,
76 RNG_INTACK_REG,
77 RNG_CONTROL_REG,
78 RNG_CONFIG_REG,
79 RNG_ALARMCNT_REG,
80 RNG_FROENABLE_REG,
81 RNG_FRODETUNE_REG,
82 RNG_ALARMMASK_REG,
83 RNG_ALARMSTOP_REG,
84 RNG_REV_REG,
85 RNG_SYSCONFIG_REG,
86 };
87
88 static const u16 reg_map_omap2[] = {
89 [RNG_OUTPUT_0_REG] = 0x0,
90 [RNG_STATUS_REG] = 0x4,
91 [RNG_CONFIG_REG] = 0x28,
92 [RNG_REV_REG] = 0x3c,
93 [RNG_SYSCONFIG_REG] = 0x40,
94 };
95
96 static const u16 reg_map_omap4[] = {
97 [RNG_OUTPUT_0_REG] = 0x0,
98 [RNG_OUTPUT_1_REG] = 0x4,
99 [RNG_STATUS_REG] = 0x8,
100 [RNG_INTMASK_REG] = 0xc,
101 [RNG_INTACK_REG] = 0x10,
102 [RNG_CONTROL_REG] = 0x14,
103 [RNG_CONFIG_REG] = 0x18,
104 [RNG_ALARMCNT_REG] = 0x1c,
105 [RNG_FROENABLE_REG] = 0x20,
106 [RNG_FRODETUNE_REG] = 0x24,
107 [RNG_ALARMMASK_REG] = 0x28,
108 [RNG_ALARMSTOP_REG] = 0x2c,
109 [RNG_REV_REG] = 0x1FE0,
110 [RNG_SYSCONFIG_REG] = 0x1FE4,
111 };
112
113 static const u16 reg_map_eip76[] = {
114 [RNG_OUTPUT_0_REG] = 0x0,
115 [RNG_OUTPUT_1_REG] = 0x4,
116 [RNG_OUTPUT_2_REG] = 0x8,
117 [RNG_OUTPUT_3_REG] = 0xc,
118 [RNG_STATUS_REG] = 0x10,
119 [RNG_INTACK_REG] = 0x10,
120 [RNG_CONTROL_REG] = 0x14,
121 [RNG_CONFIG_REG] = 0x18,
122 [RNG_ALARMCNT_REG] = 0x1c,
123 [RNG_FROENABLE_REG] = 0x20,
124 [RNG_FRODETUNE_REG] = 0x24,
125 [RNG_ALARMMASK_REG] = 0x28,
126 [RNG_ALARMSTOP_REG] = 0x2c,
127 [RNG_REV_REG] = 0x7c,
128 };
129
130 struct omap_rng_dev;
131 /**
132 * struct omap_rng_pdata - RNG IP block-specific data
133 * @regs: Pointer to the register offsets structure.
134 * @data_size: No. of bytes in RNG output.
135 * @data_present: Callback to determine if data is available.
136 * @init: Callback for IP specific initialization sequence.
137 * @cleanup: Callback for IP specific cleanup sequence.
138 */
139 struct omap_rng_pdata {
140 u16 *regs;
141 u32 data_size;
142 u32 (*data_present)(struct omap_rng_dev *priv);
143 int (*init)(struct omap_rng_dev *priv);
144 void (*cleanup)(struct omap_rng_dev *priv);
145 };
146
147 struct omap_rng_dev {
148 void __iomem *base;
149 struct device *dev;
150 const struct omap_rng_pdata *pdata;
151 struct hwrng rng;
152 struct clk *clk;
153 struct clk *clk_reg;
154 };
155
omap_rng_read(struct omap_rng_dev * priv,u16 reg)156 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg)
157 {
158 return __raw_readl(priv->base + priv->pdata->regs[reg]);
159 }
160
omap_rng_write(struct omap_rng_dev * priv,u16 reg,u32 val)161 static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg,
162 u32 val)
163 {
164 __raw_writel(val, priv->base + priv->pdata->regs[reg]);
165 }
166
167
omap_rng_do_read(struct hwrng * rng,void * data,size_t max,bool wait)168 static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max,
169 bool wait)
170 {
171 struct omap_rng_dev *priv;
172 int i, present;
173
174 priv = (struct omap_rng_dev *)rng->priv;
175
176 if (max < priv->pdata->data_size)
177 return 0;
178
179 for (i = 0; i < 20; i++) {
180 present = priv->pdata->data_present(priv);
181 if (present || !wait)
182 break;
183
184 udelay(10);
185 }
186 if (!present)
187 return 0;
188
189 memcpy_fromio(data, priv->base + priv->pdata->regs[RNG_OUTPUT_0_REG],
190 priv->pdata->data_size);
191
192 if (priv->pdata->regs[RNG_INTACK_REG])
193 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK);
194
195 return priv->pdata->data_size;
196 }
197
omap_rng_init(struct hwrng * rng)198 static int omap_rng_init(struct hwrng *rng)
199 {
200 struct omap_rng_dev *priv;
201
202 priv = (struct omap_rng_dev *)rng->priv;
203 return priv->pdata->init(priv);
204 }
205
omap_rng_cleanup(struct hwrng * rng)206 static void omap_rng_cleanup(struct hwrng *rng)
207 {
208 struct omap_rng_dev *priv;
209
210 priv = (struct omap_rng_dev *)rng->priv;
211 priv->pdata->cleanup(priv);
212 }
213
214
omap2_rng_data_present(struct omap_rng_dev * priv)215 static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv)
216 {
217 return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1;
218 }
219
omap2_rng_init(struct omap_rng_dev * priv)220 static int omap2_rng_init(struct omap_rng_dev *priv)
221 {
222 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1);
223 return 0;
224 }
225
omap2_rng_cleanup(struct omap_rng_dev * priv)226 static void omap2_rng_cleanup(struct omap_rng_dev *priv)
227 {
228 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0);
229 }
230
231 static struct omap_rng_pdata omap2_rng_pdata = {
232 .regs = (u16 *)reg_map_omap2,
233 .data_size = OMAP2_RNG_OUTPUT_SIZE,
234 .data_present = omap2_rng_data_present,
235 .init = omap2_rng_init,
236 .cleanup = omap2_rng_cleanup,
237 };
238
239 #if defined(CONFIG_OF)
omap4_rng_data_present(struct omap_rng_dev * priv)240 static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv)
241 {
242 return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY;
243 }
244
eip76_rng_init(struct omap_rng_dev * priv)245 static int eip76_rng_init(struct omap_rng_dev *priv)
246 {
247 u32 val;
248
249 /* Return if RNG is already running. */
250 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
251 return 0;
252
253 /* Number of 512 bit blocks of raw Noise Source output data that must
254 * be processed by either the Conditioning Function or the
255 * SP 800-90 DRBG ‘BC_DF’ functionality to yield a ‘full entropy’
256 * output value.
257 */
258 val = 0x5 << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
259
260 /* Number of FRO samples that are XOR-ed together into one bit to be
261 * shifted into the main shift register
262 */
263 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
264 omap_rng_write(priv, RNG_CONFIG_REG, val);
265
266 /* Enable all available FROs */
267 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
268 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
269
270 /* Enable TRNG */
271 val = RNG_CONTROL_ENABLE_TRNG_MASK;
272 omap_rng_write(priv, RNG_CONTROL_REG, val);
273
274 return 0;
275 }
276
omap4_rng_init(struct omap_rng_dev * priv)277 static int omap4_rng_init(struct omap_rng_dev *priv)
278 {
279 u32 val;
280
281 /* Return if RNG is already running. */
282 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
283 return 0;
284
285 val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
286 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
287 omap_rng_write(priv, RNG_CONFIG_REG, val);
288
289 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
290 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
291 val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT;
292 val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT;
293 omap_rng_write(priv, RNG_ALARMCNT_REG, val);
294
295 val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT;
296 val |= RNG_CONTROL_ENABLE_TRNG_MASK;
297 omap_rng_write(priv, RNG_CONTROL_REG, val);
298
299 return 0;
300 }
301
omap4_rng_cleanup(struct omap_rng_dev * priv)302 static void omap4_rng_cleanup(struct omap_rng_dev *priv)
303 {
304 int val;
305
306 val = omap_rng_read(priv, RNG_CONTROL_REG);
307 val &= ~RNG_CONTROL_ENABLE_TRNG_MASK;
308 omap_rng_write(priv, RNG_CONTROL_REG, val);
309 }
310
omap4_rng_irq(int irq,void * dev_id)311 static irqreturn_t omap4_rng_irq(int irq, void *dev_id)
312 {
313 struct omap_rng_dev *priv = dev_id;
314 u32 fro_detune, fro_enable;
315
316 /*
317 * Interrupt raised by a fro shutdown threshold, do the following:
318 * 1. Clear the alarm events.
319 * 2. De tune the FROs which are shutdown.
320 * 3. Re enable the shutdown FROs.
321 */
322 omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0);
323 omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0);
324
325 fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG);
326 fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK;
327 fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG);
328 fro_enable = RNG_REG_FROENABLE_MASK;
329
330 omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune);
331 omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable);
332
333 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK);
334
335 return IRQ_HANDLED;
336 }
337
338 static struct omap_rng_pdata omap4_rng_pdata = {
339 .regs = (u16 *)reg_map_omap4,
340 .data_size = OMAP4_RNG_OUTPUT_SIZE,
341 .data_present = omap4_rng_data_present,
342 .init = omap4_rng_init,
343 .cleanup = omap4_rng_cleanup,
344 };
345
346 static struct omap_rng_pdata eip76_rng_pdata = {
347 .regs = (u16 *)reg_map_eip76,
348 .data_size = EIP76_RNG_OUTPUT_SIZE,
349 .data_present = omap4_rng_data_present,
350 .init = eip76_rng_init,
351 .cleanup = omap4_rng_cleanup,
352 };
353
354 static const struct of_device_id omap_rng_of_match[] = {
355 {
356 .compatible = "ti,omap2-rng",
357 .data = &omap2_rng_pdata,
358 },
359 {
360 .compatible = "ti,omap4-rng",
361 .data = &omap4_rng_pdata,
362 },
363 {
364 .compatible = "inside-secure,safexcel-eip76",
365 .data = &eip76_rng_pdata,
366 },
367 {},
368 };
369 MODULE_DEVICE_TABLE(of, omap_rng_of_match);
370
of_get_omap_rng_device_details(struct omap_rng_dev * priv,struct platform_device * pdev)371 static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
372 struct platform_device *pdev)
373 {
374 const struct of_device_id *match;
375 struct device *dev = &pdev->dev;
376 int irq, err;
377
378 match = of_match_device(of_match_ptr(omap_rng_of_match), dev);
379 if (!match) {
380 dev_err(dev, "no compatible OF match\n");
381 return -EINVAL;
382 }
383 priv->pdata = match->data;
384
385 if (of_device_is_compatible(dev->of_node, "ti,omap4-rng") ||
386 of_device_is_compatible(dev->of_node, "inside-secure,safexcel-eip76")) {
387 irq = platform_get_irq(pdev, 0);
388 if (irq < 0) {
389 dev_err(dev, "%s: error getting IRQ resource - %d\n",
390 __func__, irq);
391 return irq;
392 }
393
394 err = devm_request_irq(dev, irq, omap4_rng_irq,
395 IRQF_TRIGGER_NONE, dev_name(dev), priv);
396 if (err) {
397 dev_err(dev, "unable to request irq %d, err = %d\n",
398 irq, err);
399 return err;
400 }
401
402 /*
403 * On OMAP4, enabling the shutdown_oflo interrupt is
404 * done in the interrupt mask register. There is no
405 * such register on EIP76, and it's enabled by the
406 * same bit in the control register
407 */
408 if (priv->pdata->regs[RNG_INTMASK_REG])
409 omap_rng_write(priv, RNG_INTMASK_REG,
410 RNG_SHUTDOWN_OFLO_MASK);
411 else
412 omap_rng_write(priv, RNG_CONTROL_REG,
413 RNG_SHUTDOWN_OFLO_MASK);
414 }
415 return 0;
416 }
417 #else
of_get_omap_rng_device_details(struct omap_rng_dev * omap_rng,struct platform_device * pdev)418 static int of_get_omap_rng_device_details(struct omap_rng_dev *omap_rng,
419 struct platform_device *pdev)
420 {
421 return -EINVAL;
422 }
423 #endif
424
get_omap_rng_device_details(struct omap_rng_dev * omap_rng)425 static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng)
426 {
427 /* Only OMAP2/3 can be non-DT */
428 omap_rng->pdata = &omap2_rng_pdata;
429 return 0;
430 }
431
omap_rng_probe(struct platform_device * pdev)432 static int omap_rng_probe(struct platform_device *pdev)
433 {
434 struct omap_rng_dev *priv;
435 struct resource *res;
436 struct device *dev = &pdev->dev;
437 int ret;
438
439 priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL);
440 if (!priv)
441 return -ENOMEM;
442
443 priv->rng.read = omap_rng_do_read;
444 priv->rng.init = omap_rng_init;
445 priv->rng.cleanup = omap_rng_cleanup;
446
447 priv->rng.priv = (unsigned long)priv;
448 platform_set_drvdata(pdev, priv);
449 priv->dev = dev;
450
451 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
452 priv->base = devm_ioremap_resource(dev, res);
453 if (IS_ERR(priv->base)) {
454 ret = PTR_ERR(priv->base);
455 goto err_ioremap;
456 }
457
458 priv->rng.name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
459 if (!priv->rng.name) {
460 ret = -ENOMEM;
461 goto err_ioremap;
462 }
463
464 pm_runtime_enable(&pdev->dev);
465 ret = pm_runtime_get_sync(&pdev->dev);
466 if (ret < 0) {
467 dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret);
468 pm_runtime_put_noidle(&pdev->dev);
469 goto err_ioremap;
470 }
471
472 priv->clk = devm_clk_get(&pdev->dev, NULL);
473 if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER)
474 return -EPROBE_DEFER;
475 if (!IS_ERR(priv->clk)) {
476 ret = clk_prepare_enable(priv->clk);
477 if (ret) {
478 dev_err(&pdev->dev,
479 "Unable to enable the clk: %d\n", ret);
480 goto err_register;
481 }
482 }
483
484 priv->clk_reg = devm_clk_get(&pdev->dev, "reg");
485 if (IS_ERR(priv->clk_reg) && PTR_ERR(priv->clk_reg) == -EPROBE_DEFER)
486 return -EPROBE_DEFER;
487 if (!IS_ERR(priv->clk_reg)) {
488 ret = clk_prepare_enable(priv->clk_reg);
489 if (ret) {
490 dev_err(&pdev->dev,
491 "Unable to enable the register clk: %d\n",
492 ret);
493 goto err_register;
494 }
495 }
496
497 ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) :
498 get_omap_rng_device_details(priv);
499 if (ret)
500 goto err_register;
501
502 ret = hwrng_register(&priv->rng);
503 if (ret)
504 goto err_register;
505
506 dev_info(&pdev->dev, "Random Number Generator ver. %02x\n",
507 omap_rng_read(priv, RNG_REV_REG));
508
509 return 0;
510
511 err_register:
512 priv->base = NULL;
513 pm_runtime_put_sync(&pdev->dev);
514 pm_runtime_disable(&pdev->dev);
515
516 clk_disable_unprepare(priv->clk_reg);
517 clk_disable_unprepare(priv->clk);
518 err_ioremap:
519 dev_err(dev, "initialization failed.\n");
520 return ret;
521 }
522
omap_rng_remove(struct platform_device * pdev)523 static int omap_rng_remove(struct platform_device *pdev)
524 {
525 struct omap_rng_dev *priv = platform_get_drvdata(pdev);
526
527 hwrng_unregister(&priv->rng);
528
529 priv->pdata->cleanup(priv);
530
531 pm_runtime_put_sync(&pdev->dev);
532 pm_runtime_disable(&pdev->dev);
533
534 clk_disable_unprepare(priv->clk);
535 clk_disable_unprepare(priv->clk_reg);
536
537 return 0;
538 }
539
omap_rng_suspend(struct device * dev)540 static int __maybe_unused omap_rng_suspend(struct device *dev)
541 {
542 struct omap_rng_dev *priv = dev_get_drvdata(dev);
543
544 priv->pdata->cleanup(priv);
545 pm_runtime_put_sync(dev);
546
547 return 0;
548 }
549
omap_rng_resume(struct device * dev)550 static int __maybe_unused omap_rng_resume(struct device *dev)
551 {
552 struct omap_rng_dev *priv = dev_get_drvdata(dev);
553 int ret;
554
555 ret = pm_runtime_get_sync(dev);
556 if (ret < 0) {
557 dev_err(dev, "Failed to runtime_get device: %d\n", ret);
558 pm_runtime_put_noidle(dev);
559 return ret;
560 }
561
562 priv->pdata->init(priv);
563
564 return 0;
565 }
566
567 static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
568
569 static struct platform_driver omap_rng_driver = {
570 .driver = {
571 .name = "omap_rng",
572 .pm = &omap_rng_pm,
573 .of_match_table = of_match_ptr(omap_rng_of_match),
574 },
575 .probe = omap_rng_probe,
576 .remove = omap_rng_remove,
577 };
578
579 module_platform_driver(omap_rng_driver);
580 MODULE_ALIAS("platform:omap_rng");
581 MODULE_AUTHOR("Deepak Saxena (and others)");
582 MODULE_LICENSE("GPL");
583
