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sh_eth: R8A7740 supports packet shecksumming
[linux/fpc-iii.git] / drivers / char / hw_random / xgene-rng.c
blob3c77645405e52019f01304ee2ee5c985f9a90865
1 /*
2 * APM X-Gene SoC RNG Driver
3 *
4 * Copyright (c) 2014, Applied Micro Circuits Corporation
5 * Author: Rameshwar Prasad Sahu <rsahu@apm.com>
6 * Shamal Winchurkar <swinchurkar@apm.com>
7 * Feng Kan <fkan@apm.com>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 *
22 */
23
24 #include <linux/acpi.h>
25 #include <linux/clk.h>
26 #include <linux/delay.h>
27 #include <linux/hw_random.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/module.h>
31 #include <linux/of_platform.h>
32 #include <linux/of_irq.h>
33 #include <linux/of_address.h>
34 #include <linux/timer.h>
35
36 #define RNG_MAX_DATUM 4
37 #define MAX_TRY 100
38 #define XGENE_RNG_RETRY_COUNT 20
39 #define XGENE_RNG_RETRY_INTERVAL 10
40
41 /* RNG Registers */
42 #define RNG_INOUT_0 0x00
43 #define RNG_INTR_STS_ACK 0x10
44 #define RNG_CONTROL 0x14
45 #define RNG_CONFIG 0x18
46 #define RNG_ALARMCNT 0x1c
47 #define RNG_FROENABLE 0x20
48 #define RNG_FRODETUNE 0x24
49 #define RNG_ALARMMASK 0x28
50 #define RNG_ALARMSTOP 0x2c
51 #define RNG_OPTIONS 0x78
52 #define RNG_EIP_REV 0x7c
53
54 #define MONOBIT_FAIL_MASK BIT(7)
55 #define POKER_FAIL_MASK BIT(6)
56 #define LONG_RUN_FAIL_MASK BIT(5)
57 #define RUN_FAIL_MASK BIT(4)
58 #define NOISE_FAIL_MASK BIT(3)
59 #define STUCK_OUT_MASK BIT(2)
60 #define SHUTDOWN_OFLO_MASK BIT(1)
61 #define READY_MASK BIT(0)
62
63 #define MAJOR_HW_REV_RD(src) (((src) & 0x0f000000) >> 24)
64 #define MINOR_HW_REV_RD(src) (((src) & 0x00f00000) >> 20)
65 #define HW_PATCH_LEVEL_RD(src) (((src) & 0x000f0000) >> 16)
66 #define MAX_REFILL_CYCLES_SET(dst, src) \
67 ((dst & ~0xffff0000) | (((u32)src << 16) & 0xffff0000))
68 #define MIN_REFILL_CYCLES_SET(dst, src) \
69 ((dst & ~0x000000ff) | (((u32)src) & 0x000000ff))
70 #define ALARM_THRESHOLD_SET(dst, src) \
71 ((dst & ~0x000000ff) | (((u32)src) & 0x000000ff))
72 #define ENABLE_RNG_SET(dst, src) \
73 ((dst & ~BIT(10)) | (((u32)src << 10) & BIT(10)))
74 #define REGSPEC_TEST_MODE_SET(dst, src) \
75 ((dst & ~BIT(8)) | (((u32)src << 8) & BIT(8)))
76 #define MONOBIT_FAIL_MASK_SET(dst, src) \
77 ((dst & ~BIT(7)) | (((u32)src << 7) & BIT(7)))
78 #define POKER_FAIL_MASK_SET(dst, src) \
79 ((dst & ~BIT(6)) | (((u32)src << 6) & BIT(6)))
80 #define LONG_RUN_FAIL_MASK_SET(dst, src) \
81 ((dst & ~BIT(5)) | (((u32)src << 5) & BIT(5)))
82 #define RUN_FAIL_MASK_SET(dst, src) \
83 ((dst & ~BIT(4)) | (((u32)src << 4) & BIT(4)))
84 #define NOISE_FAIL_MASK_SET(dst, src) \
85 ((dst & ~BIT(3)) | (((u32)src << 3) & BIT(3)))
86 #define STUCK_OUT_MASK_SET(dst, src) \
87 ((dst & ~BIT(2)) | (((u32)src << 2) & BIT(2)))
88 #define SHUTDOWN_OFLO_MASK_SET(dst, src) \
89 ((dst & ~BIT(1)) | (((u32)src << 1) & BIT(1)))
90
91 struct xgene_rng_dev {
92 u32 irq;
93 void __iomem *csr_base;
94 u32 revision;
95 u32 datum_size;
96 u32 failure_cnt; /* Failure count last minute */
97 unsigned long failure_ts;/* First failure timestamp */
98 struct timer_list failure_timer;
99 struct device *dev;
100 struct clk *clk;
101 };
102
103 static void xgene_rng_expired_timer(unsigned long arg)
104 {
105 struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) arg;
106
107 /* Clear failure counter as timer expired */
108 disable_irq(ctx->irq);
109 ctx->failure_cnt = 0;
110 del_timer(&ctx->failure_timer);
111 enable_irq(ctx->irq);
112 }
113
114 static void xgene_rng_start_timer(struct xgene_rng_dev *ctx)
115 {
116 ctx->failure_timer.data = (unsigned long) ctx;
117 ctx->failure_timer.function = xgene_rng_expired_timer;
118 ctx->failure_timer.expires = jiffies + 120 * HZ;
119 add_timer(&ctx->failure_timer);
120 }
121
122 /*
123 * Initialize or reinit free running oscillators (FROs)
124 */
125 static void xgene_rng_init_fro(struct xgene_rng_dev *ctx, u32 fro_val)
126 {
127 writel(fro_val, ctx->csr_base + RNG_FRODETUNE);
128 writel(0x00000000, ctx->csr_base + RNG_ALARMMASK);
129 writel(0x00000000, ctx->csr_base + RNG_ALARMSTOP);
130 writel(0xFFFFFFFF, ctx->csr_base + RNG_FROENABLE);
131 }
132
133 static void xgene_rng_chk_overflow(struct xgene_rng_dev *ctx)
134 {
135 u32 val;
136
137 val = readl(ctx->csr_base + RNG_INTR_STS_ACK);
138 if (val & MONOBIT_FAIL_MASK)
139 /*
140 * LFSR detected an out-of-bounds number of 1s after
141 * checking 20,000 bits (test T1 as specified in the
142 * AIS-31 standard)
143 */
144 dev_err(ctx->dev, "test monobit failure error 0x%08X\n", val);
145 if (val & POKER_FAIL_MASK)
146 /*
147 * LFSR detected an out-of-bounds value in at least one
148 * of the 16 poker_count_X counters or an out of bounds sum
149 * of squares value after checking 20,000 bits (test T2 as
150 * specified in the AIS-31 standard)
151 */
152 dev_err(ctx->dev, "test poker failure error 0x%08X\n", val);
153 if (val & LONG_RUN_FAIL_MASK)
154 /*
155 * LFSR detected a sequence of 34 identical bits
156 * (test T4 as specified in the AIS-31 standard)
157 */
158 dev_err(ctx->dev, "test long run failure error 0x%08X\n", val);
159 if (val & RUN_FAIL_MASK)
160 /*
161 * LFSR detected an outof-bounds value for at least one
162 * of the running counters after checking 20,000 bits
163 * (test T3 as specified in the AIS-31 standard)
164 */
165 dev_err(ctx->dev, "test run failure error 0x%08X\n", val);
166 if (val & NOISE_FAIL_MASK)
167 /* LFSR detected a sequence of 48 identical bits */
168 dev_err(ctx->dev, "noise failure error 0x%08X\n", val);
169 if (val & STUCK_OUT_MASK)
170 /*
171 * Detected output data registers generated same value twice
172 * in a row
173 */
174 dev_err(ctx->dev, "stuck out failure error 0x%08X\n", val);
175
176 if (val & SHUTDOWN_OFLO_MASK) {
177 u32 frostopped;
178
179 /* FROs shut down after a second error event. Try recover. */
180 if (++ctx->failure_cnt == 1) {
181 /* 1st time, just recover */
182 ctx->failure_ts = jiffies;
183 frostopped = readl(ctx->csr_base + RNG_ALARMSTOP);
184 xgene_rng_init_fro(ctx, frostopped);
185
186 /*
187 * We must start a timer to clear out this error
188 * in case the system timer wrap around
189 */
190 xgene_rng_start_timer(ctx);
191 } else {
192 /* 2nd time failure in lesser than 1 minute? */
193 if (time_after(ctx->failure_ts + 60 * HZ, jiffies)) {
194 dev_err(ctx->dev,
195 "FRO shutdown failure error 0x%08X\n",
196 val);
197 } else {
198 /* 2nd time failure after 1 minutes, recover */
199 ctx->failure_ts = jiffies;
200 ctx->failure_cnt = 1;
201 /*
202 * We must start a timer to clear out this
203 * error in case the system timer wrap
204 * around
205 */
206 xgene_rng_start_timer(ctx);
207 }
208 frostopped = readl(ctx->csr_base + RNG_ALARMSTOP);
209 xgene_rng_init_fro(ctx, frostopped);
210 }
211 }
212 /* Clear them all */
213 writel(val, ctx->csr_base + RNG_INTR_STS_ACK);
214 }
215
216 static irqreturn_t xgene_rng_irq_handler(int irq, void *id)
217 {
218 struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) id;
219
220 /* RNG Alarm Counter overflow */
221 xgene_rng_chk_overflow(ctx);
222
223 return IRQ_HANDLED;
224 }
225
226 static int xgene_rng_data_present(struct hwrng *rng, int wait)
227 {
228 struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
229 u32 i, val = 0;
230
231 for (i = 0; i < XGENE_RNG_RETRY_COUNT; i++) {
232 val = readl(ctx->csr_base + RNG_INTR_STS_ACK);
233 if ((val & READY_MASK) || !wait)
234 break;
235 udelay(XGENE_RNG_RETRY_INTERVAL);
236 }
237
238 return (val & READY_MASK);
239 }
240
241 static int xgene_rng_data_read(struct hwrng *rng, u32 *data)
242 {
243 struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
244 int i;
245
246 for (i = 0; i < ctx->datum_size; i++)
247 data[i] = readl(ctx->csr_base + RNG_INOUT_0 + i * 4);
248
249 /* Clear ready bit to start next transaction */
250 writel(READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK);
251
252 return ctx->datum_size << 2;
253 }
254
255 static void xgene_rng_init_internal(struct xgene_rng_dev *ctx)
256 {
257 u32 val;
258
259 writel(0x00000000, ctx->csr_base + RNG_CONTROL);
260
261 val = MAX_REFILL_CYCLES_SET(0, 10);
262 val = MIN_REFILL_CYCLES_SET(val, 10);
263 writel(val, ctx->csr_base + RNG_CONFIG);
264
265 val = ALARM_THRESHOLD_SET(0, 0xFF);
266 writel(val, ctx->csr_base + RNG_ALARMCNT);
267
268 xgene_rng_init_fro(ctx, 0);
269
270 writel(MONOBIT_FAIL_MASK |
271 POKER_FAIL_MASK |
272 LONG_RUN_FAIL_MASK |
273 RUN_FAIL_MASK |
274 NOISE_FAIL_MASK |
275 STUCK_OUT_MASK |
276 SHUTDOWN_OFLO_MASK |
277 READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK);
278
279 val = ENABLE_RNG_SET(0, 1);
280 val = MONOBIT_FAIL_MASK_SET(val, 1);
281 val = POKER_FAIL_MASK_SET(val, 1);
282 val = LONG_RUN_FAIL_MASK_SET(val, 1);
283 val = RUN_FAIL_MASK_SET(val, 1);
284 val = NOISE_FAIL_MASK_SET(val, 1);
285 val = STUCK_OUT_MASK_SET(val, 1);
286 val = SHUTDOWN_OFLO_MASK_SET(val, 1);
287 writel(val, ctx->csr_base + RNG_CONTROL);
288 }
289
290 static int xgene_rng_init(struct hwrng *rng)
291 {
292 struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
293
294 ctx->failure_cnt = 0;
295 init_timer(&ctx->failure_timer);
296
297 ctx->revision = readl(ctx->csr_base + RNG_EIP_REV);
298
299 dev_dbg(ctx->dev, "Rev %d.%d.%d\n",
300 MAJOR_HW_REV_RD(ctx->revision),
301 MINOR_HW_REV_RD(ctx->revision),
302 HW_PATCH_LEVEL_RD(ctx->revision));
303
304 dev_dbg(ctx->dev, "Options 0x%08X",
305 readl(ctx->csr_base + RNG_OPTIONS));
306
307 xgene_rng_init_internal(ctx);
308
309 ctx->datum_size = RNG_MAX_DATUM;
310
311 return 0;
312 }
313
314 #ifdef CONFIG_ACPI
315 static const struct acpi_device_id xgene_rng_acpi_match[] = {
316 { "APMC0D18", },
317 { }
318 };
319 MODULE_DEVICE_TABLE(acpi, xgene_rng_acpi_match);
320 #endif
321
322 static struct hwrng xgene_rng_func = {
323 .name = "xgene-rng",
324 .init = xgene_rng_init,
325 .data_present = xgene_rng_data_present,
326 .data_read = xgene_rng_data_read,
327 };
328
329 static int xgene_rng_probe(struct platform_device *pdev)
330 {
331 struct resource *res;
332 struct xgene_rng_dev *ctx;
333 int rc = 0;
334
335 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
336 if (!ctx)
337 return -ENOMEM;
338
339 ctx->dev = &pdev->dev;
340 platform_set_drvdata(pdev, ctx);
341
342 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
343 ctx->csr_base = devm_ioremap_resource(&pdev->dev, res);
344 if (IS_ERR(ctx->csr_base))
345 return PTR_ERR(ctx->csr_base);
346
347 rc = platform_get_irq(pdev, 0);
348 if (rc < 0) {
349 dev_err(&pdev->dev, "No IRQ resource\n");
350 return rc;
351 }
352 ctx->irq = rc;
353
354 dev_dbg(&pdev->dev, "APM X-Gene RNG BASE %p ALARM IRQ %d",
355 ctx->csr_base, ctx->irq);
356
357 rc = devm_request_irq(&pdev->dev, ctx->irq, xgene_rng_irq_handler, 0,
358 dev_name(&pdev->dev), ctx);
359 if (rc) {
360 dev_err(&pdev->dev, "Could not request RNG alarm IRQ\n");
361 return rc;
362 }
363
364 /* Enable IP clock */
365 ctx->clk = devm_clk_get(&pdev->dev, NULL);
366 if (IS_ERR(ctx->clk)) {
367 dev_warn(&pdev->dev, "Couldn't get the clock for RNG\n");
368 } else {
369 rc = clk_prepare_enable(ctx->clk);
370 if (rc) {
371 dev_warn(&pdev->dev,
372 "clock prepare enable failed for RNG");
373 return rc;
374 }
375 }
376
377 xgene_rng_func.priv = (unsigned long) ctx;
378
379 rc = hwrng_register(&xgene_rng_func);
380 if (rc) {
381 dev_err(&pdev->dev, "RNG registering failed error %d\n", rc);
382 if (!IS_ERR(ctx->clk))
383 clk_disable_unprepare(ctx->clk);
384 return rc;
385 }
386
387 rc = device_init_wakeup(&pdev->dev, 1);
388 if (rc) {
389 dev_err(&pdev->dev, "RNG device_init_wakeup failed error %d\n",
390 rc);
391 if (!IS_ERR(ctx->clk))
392 clk_disable_unprepare(ctx->clk);
393 hwrng_unregister(&xgene_rng_func);
394 return rc;
395 }
396
397 return 0;
398 }
399
400 static int xgene_rng_remove(struct platform_device *pdev)
401 {
402 struct xgene_rng_dev *ctx = platform_get_drvdata(pdev);
403 int rc;
404
405 rc = device_init_wakeup(&pdev->dev, 0);
406 if (rc)
407 dev_err(&pdev->dev, "RNG init wakeup failed error %d\n", rc);
408 if (!IS_ERR(ctx->clk))
409 clk_disable_unprepare(ctx->clk);
410 hwrng_unregister(&xgene_rng_func);
411
412 return rc;
413 }
414
415 static const struct of_device_id xgene_rng_of_match[] = {
416 { .compatible = "apm,xgene-rng" },
417 { }
418 };
419
420 MODULE_DEVICE_TABLE(of, xgene_rng_of_match);
421
422 static struct platform_driver xgene_rng_driver = {
423 .probe = xgene_rng_probe,
424 .remove = xgene_rng_remove,
425 .driver = {
426 .name = "xgene-rng",
427 .of_match_table = xgene_rng_of_match,
428 .acpi_match_table = ACPI_PTR(xgene_rng_acpi_match),
429 },
430 };
431
432 module_platform_driver(xgene_rng_driver);
433 MODULE_DESCRIPTION("APM X-Gene RNG driver");
434 MODULE_LICENSE("GPL");
Linux with added FPC-III support