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 }; 154 155 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg) 156 { 157 return __raw_readl(priv->base + priv->pdata->regs[reg]); 158 } 159 160 static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg, 161 u32 val) 162 { 163 __raw_writel(val, priv->base + priv->pdata->regs[reg]); 164 } 165 166 167 static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max, 168 bool wait) 169 { 170 struct omap_rng_dev *priv; 171 int i, present; 172 173 priv = (struct omap_rng_dev *)rng->priv; 174 175 if (max < priv->pdata->data_size) 176 return 0; 177 178 for (i = 0; i < 20; i++) { 179 present = priv->pdata->data_present(priv); 180 if (present || !wait) 181 break; 182 183 udelay(10); 184 } 185 if (!present) 186 return 0; 187 188 memcpy_fromio(data, priv->base + priv->pdata->regs[RNG_OUTPUT_0_REG], 189 priv->pdata->data_size); 190 191 if (priv->pdata->regs[RNG_INTACK_REG]) 192 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK); 193 194 return priv->pdata->data_size; 195 } 196 197 static int omap_rng_init(struct hwrng *rng) 198 { 199 struct omap_rng_dev *priv; 200 201 priv = (struct omap_rng_dev *)rng->priv; 202 return priv->pdata->init(priv); 203 } 204 205 static void omap_rng_cleanup(struct hwrng *rng) 206 { 207 struct omap_rng_dev *priv; 208 209 priv = (struct omap_rng_dev *)rng->priv; 210 priv->pdata->cleanup(priv); 211 } 212 213 214 static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv) 215 { 216 return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1; 217 } 218 219 static int omap2_rng_init(struct omap_rng_dev *priv) 220 { 221 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1); 222 return 0; 223 } 224 225 static void omap2_rng_cleanup(struct omap_rng_dev *priv) 226 { 227 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0); 228 } 229 230 static struct omap_rng_pdata omap2_rng_pdata = { 231 .regs = (u16 *)reg_map_omap2, 232 .data_size = OMAP2_RNG_OUTPUT_SIZE, 233 .data_present = omap2_rng_data_present, 234 .init = omap2_rng_init, 235 .cleanup = omap2_rng_cleanup, 236 }; 237 238 #if defined(CONFIG_OF) 239 static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv) 240 { 241 return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY; 242 } 243 244 static int eip76_rng_init(struct omap_rng_dev *priv) 245 { 246 u32 val; 247 248 /* Return if RNG is already running. */ 249 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK) 250 return 0; 251 252 /* Number of 512 bit blocks of raw Noise Source output data that must 253 * be processed by either the Conditioning Function or the 254 * SP 800-90 DRBG ‘BC_DF’ functionality to yield a ‘full entropy’ 255 * output value. 256 */ 257 val = 0x5 << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 258 259 /* Number of FRO samples that are XOR-ed together into one bit to be 260 * shifted into the main shift register 261 */ 262 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 263 omap_rng_write(priv, RNG_CONFIG_REG, val); 264 265 /* Enable all available FROs */ 266 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0); 267 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK); 268 269 /* Enable TRNG */ 270 val = RNG_CONTROL_ENABLE_TRNG_MASK; 271 omap_rng_write(priv, RNG_CONTROL_REG, val); 272 273 return 0; 274 } 275 276 static int omap4_rng_init(struct omap_rng_dev *priv) 277 { 278 u32 val; 279 280 /* Return if RNG is already running. */ 281 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK) 282 return 0; 283 284 val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 285 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 286 omap_rng_write(priv, RNG_CONFIG_REG, val); 287 288 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0); 289 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK); 290 val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT; 291 val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT; 292 omap_rng_write(priv, RNG_ALARMCNT_REG, val); 293 294 val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT; 295 val |= RNG_CONTROL_ENABLE_TRNG_MASK; 296 omap_rng_write(priv, RNG_CONTROL_REG, val); 297 298 return 0; 299 } 300 301 static void omap4_rng_cleanup(struct omap_rng_dev *priv) 302 { 303 int val; 304 305 val = omap_rng_read(priv, RNG_CONTROL_REG); 306 val &= ~RNG_CONTROL_ENABLE_TRNG_MASK; 307 omap_rng_write(priv, RNG_CONTROL_REG, val); 308 } 309 310 static irqreturn_t omap4_rng_irq(int irq, void *dev_id) 311 { 312 struct omap_rng_dev *priv = dev_id; 313 u32 fro_detune, fro_enable; 314 315 /* 316 * Interrupt raised by a fro shutdown threshold, do the following: 317 * 1. Clear the alarm events. 318 * 2. De tune the FROs which are shutdown. 319 * 3. Re enable the shutdown FROs. 320 */ 321 omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0); 322 omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0); 323 324 fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG); 325 fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK; 326 fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG); 327 fro_enable = RNG_REG_FROENABLE_MASK; 328 329 omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune); 330 omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable); 331 332 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK); 333 334 return IRQ_HANDLED; 335 } 336 337 static struct omap_rng_pdata omap4_rng_pdata = { 338 .regs = (u16 *)reg_map_omap4, 339 .data_size = OMAP4_RNG_OUTPUT_SIZE, 340 .data_present = omap4_rng_data_present, 341 .init = omap4_rng_init, 342 .cleanup = omap4_rng_cleanup, 343 }; 344 345 static struct omap_rng_pdata eip76_rng_pdata = { 346 .regs = (u16 *)reg_map_eip76, 347 .data_size = EIP76_RNG_OUTPUT_SIZE, 348 .data_present = omap4_rng_data_present, 349 .init = eip76_rng_init, 350 .cleanup = omap4_rng_cleanup, 351 }; 352 353 static const struct of_device_id omap_rng_of_match[] = { 354 { 355 .compatible = "ti,omap2-rng", 356 .data = &omap2_rng_pdata, 357 }, 358 { 359 .compatible = "ti,omap4-rng", 360 .data = &omap4_rng_pdata, 361 }, 362 { 363 .compatible = "inside-secure,safexcel-eip76", 364 .data = &eip76_rng_pdata, 365 }, 366 {}, 367 }; 368 MODULE_DEVICE_TABLE(of, omap_rng_of_match); 369 370 static int of_get_omap_rng_device_details(struct omap_rng_dev *priv, 371 struct platform_device *pdev) 372 { 373 const struct of_device_id *match; 374 struct device *dev = &pdev->dev; 375 int irq, err; 376 377 match = of_match_device(of_match_ptr(omap_rng_of_match), dev); 378 if (!match) { 379 dev_err(dev, "no compatible OF match\n"); 380 return -EINVAL; 381 } 382 priv->pdata = match->data; 383 384 if (of_device_is_compatible(dev->of_node, "ti,omap4-rng") || 385 of_device_is_compatible(dev->of_node, "inside-secure,safexcel-eip76")) { 386 irq = platform_get_irq(pdev, 0); 387 if (irq < 0) { 388 dev_err(dev, "%s: error getting IRQ resource - %d\n", 389 __func__, irq); 390 return irq; 391 } 392 393 err = devm_request_irq(dev, irq, omap4_rng_irq, 394 IRQF_TRIGGER_NONE, dev_name(dev), priv); 395 if (err) { 396 dev_err(dev, "unable to request irq %d, err = %d\n", 397 irq, err); 398 return err; 399 } 400 401 priv->clk = devm_clk_get(&pdev->dev, NULL); 402 if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER) 403 return -EPROBE_DEFER; 404 if (!IS_ERR(priv->clk)) { 405 err = clk_prepare_enable(priv->clk); 406 if (err) 407 dev_err(&pdev->dev, "unable to enable the clk, " 408 "err = %d\n", err); 409 } 410 411 /* 412 * On OMAP4, enabling the shutdown_oflo interrupt is 413 * done in the interrupt mask register. There is no 414 * such register on EIP76, and it's enabled by the 415 * same bit in the control register 416 */ 417 if (priv->pdata->regs[RNG_INTMASK_REG]) 418 omap_rng_write(priv, RNG_INTMASK_REG, 419 RNG_SHUTDOWN_OFLO_MASK); 420 else 421 omap_rng_write(priv, RNG_CONTROL_REG, 422 RNG_SHUTDOWN_OFLO_MASK); 423 } 424 return 0; 425 } 426 #else 427 static int of_get_omap_rng_device_details(struct omap_rng_dev *omap_rng, 428 struct platform_device *pdev) 429 { 430 return -EINVAL; 431 } 432 #endif 433 434 static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng) 435 { 436 /* Only OMAP2/3 can be non-DT */ 437 omap_rng->pdata = &omap2_rng_pdata; 438 return 0; 439 } 440 441 static int omap_rng_probe(struct platform_device *pdev) 442 { 443 struct omap_rng_dev *priv; 444 struct resource *res; 445 struct device *dev = &pdev->dev; 446 int ret; 447 448 priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL); 449 if (!priv) 450 return -ENOMEM; 451 452 priv->rng.read = omap_rng_do_read; 453 priv->rng.init = omap_rng_init; 454 priv->rng.cleanup = omap_rng_cleanup; 455 456 priv->rng.priv = (unsigned long)priv; 457 platform_set_drvdata(pdev, priv); 458 priv->dev = dev; 459 460 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 461 priv->base = devm_ioremap_resource(dev, res); 462 if (IS_ERR(priv->base)) { 463 ret = PTR_ERR(priv->base); 464 goto err_ioremap; 465 } 466 467 priv->rng.name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL); 468 if (!priv->rng.name) { 469 ret = -ENOMEM; 470 goto err_ioremap; 471 } 472 473 pm_runtime_enable(&pdev->dev); 474 ret = pm_runtime_get_sync(&pdev->dev); 475 if (ret < 0) { 476 dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret); 477 pm_runtime_put_noidle(&pdev->dev); 478 goto err_ioremap; 479 } 480 481 ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) : 482 get_omap_rng_device_details(priv); 483 if (ret) 484 goto err_register; 485 486 ret = hwrng_register(&priv->rng); 487 if (ret) 488 goto err_register; 489 490 dev_info(&pdev->dev, "Random Number Generator ver. %02x\n", 491 omap_rng_read(priv, RNG_REV_REG)); 492 493 return 0; 494 495 err_register: 496 priv->base = NULL; 497 pm_runtime_put_sync(&pdev->dev); 498 pm_runtime_disable(&pdev->dev); 499 500 if (!IS_ERR(priv->clk)) 501 clk_disable_unprepare(priv->clk); 502 err_ioremap: 503 dev_err(dev, "initialization failed.\n"); 504 return ret; 505 } 506 507 static int omap_rng_remove(struct platform_device *pdev) 508 { 509 struct omap_rng_dev *priv = platform_get_drvdata(pdev); 510 511 hwrng_unregister(&priv->rng); 512 513 priv->pdata->cleanup(priv); 514 515 pm_runtime_put_sync(&pdev->dev); 516 pm_runtime_disable(&pdev->dev); 517 518 if (!IS_ERR(priv->clk)) 519 clk_disable_unprepare(priv->clk); 520 521 return 0; 522 } 523 524 static int __maybe_unused omap_rng_suspend(struct device *dev) 525 { 526 struct omap_rng_dev *priv = dev_get_drvdata(dev); 527 528 priv->pdata->cleanup(priv); 529 pm_runtime_put_sync(dev); 530 531 return 0; 532 } 533 534 static int __maybe_unused omap_rng_resume(struct device *dev) 535 { 536 struct omap_rng_dev *priv = dev_get_drvdata(dev); 537 int ret; 538 539 ret = pm_runtime_get_sync(dev); 540 if (ret < 0) { 541 dev_err(dev, "Failed to runtime_get device: %d\n", ret); 542 pm_runtime_put_noidle(dev); 543 return ret; 544 } 545 546 priv->pdata->init(priv); 547 548 return 0; 549 } 550 551 static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume); 552 553 static struct platform_driver omap_rng_driver = { 554 .driver = { 555 .name = "omap_rng", 556 .pm = &omap_rng_pm, 557 .of_match_table = of_match_ptr(omap_rng_of_match), 558 }, 559 .probe = omap_rng_probe, 560 .remove = omap_rng_remove, 561 }; 562 563 module_platform_driver(omap_rng_driver); 564 MODULE_ALIAS("platform:omap_rng"); 565 MODULE_AUTHOR("Deepak Saxena (and others)"); 566 MODULE_LICENSE("GPL"); 567