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/kernel.h> 26 #include <linux/slab.h> 27 #include <linux/pm_runtime.h> 28 #include <linux/of.h> 29 #include <linux/interrupt.h> 30 #include <linux/clk.h> 31 #include <linux/io.h> 32 33 #define RNG_REG_STATUS_RDY (1 << 0) 34 35 #define RNG_REG_INTACK_RDY_MASK (1 << 0) 36 #define RNG_REG_INTACK_SHUTDOWN_OFLO_MASK (1 << 1) 37 #define RNG_SHUTDOWN_OFLO_MASK (1 << 1) 38 39 #define RNG_CONTROL_STARTUP_CYCLES_SHIFT 16 40 #define RNG_CONTROL_STARTUP_CYCLES_MASK (0xffff << 16) 41 #define RNG_CONTROL_ENABLE_TRNG_SHIFT 10 42 #define RNG_CONTROL_ENABLE_TRNG_MASK (1 << 10) 43 44 #define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT 16 45 #define RNG_CONFIG_MAX_REFIL_CYCLES_MASK (0xffff << 16) 46 #define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT 0 47 #define RNG_CONFIG_MIN_REFIL_CYCLES_MASK (0xff << 0) 48 49 #define RNG_CONTROL_STARTUP_CYCLES 0xff 50 #define RNG_CONFIG_MIN_REFIL_CYCLES 0x21 51 #define RNG_CONFIG_MAX_REFIL_CYCLES 0x22 52 53 #define RNG_ALARMCNT_ALARM_TH_SHIFT 0x0 54 #define RNG_ALARMCNT_ALARM_TH_MASK (0xff << 0) 55 #define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT 16 56 #define RNG_ALARMCNT_SHUTDOWN_TH_MASK (0x1f << 16) 57 #define RNG_ALARM_THRESHOLD 0xff 58 #define RNG_SHUTDOWN_THRESHOLD 0x4 59 60 #define RNG_REG_FROENABLE_MASK 0xffffff 61 #define RNG_REG_FRODETUNE_MASK 0xffffff 62 63 #define OMAP2_RNG_OUTPUT_SIZE 0x4 64 #define OMAP4_RNG_OUTPUT_SIZE 0x8 65 #define EIP76_RNG_OUTPUT_SIZE 0x10 66 67 /* 68 * EIP76 RNG takes approx. 700us to produce 16 bytes of output data 69 * as per testing results. And to account for the lack of udelay()'s 70 * reliability, we keep the timeout as 1000us. 71 */ 72 #define RNG_DATA_FILL_TIMEOUT 100 73 74 enum { 75 RNG_OUTPUT_0_REG = 0, 76 RNG_OUTPUT_1_REG, 77 RNG_OUTPUT_2_REG, 78 RNG_OUTPUT_3_REG, 79 RNG_STATUS_REG, 80 RNG_INTMASK_REG, 81 RNG_INTACK_REG, 82 RNG_CONTROL_REG, 83 RNG_CONFIG_REG, 84 RNG_ALARMCNT_REG, 85 RNG_FROENABLE_REG, 86 RNG_FRODETUNE_REG, 87 RNG_ALARMMASK_REG, 88 RNG_ALARMSTOP_REG, 89 RNG_REV_REG, 90 RNG_SYSCONFIG_REG, 91 }; 92 93 static const u16 reg_map_omap2[] = { 94 [RNG_OUTPUT_0_REG] = 0x0, 95 [RNG_STATUS_REG] = 0x4, 96 [RNG_CONFIG_REG] = 0x28, 97 [RNG_REV_REG] = 0x3c, 98 [RNG_SYSCONFIG_REG] = 0x40, 99 }; 100 101 static const u16 reg_map_omap4[] = { 102 [RNG_OUTPUT_0_REG] = 0x0, 103 [RNG_OUTPUT_1_REG] = 0x4, 104 [RNG_STATUS_REG] = 0x8, 105 [RNG_INTMASK_REG] = 0xc, 106 [RNG_INTACK_REG] = 0x10, 107 [RNG_CONTROL_REG] = 0x14, 108 [RNG_CONFIG_REG] = 0x18, 109 [RNG_ALARMCNT_REG] = 0x1c, 110 [RNG_FROENABLE_REG] = 0x20, 111 [RNG_FRODETUNE_REG] = 0x24, 112 [RNG_ALARMMASK_REG] = 0x28, 113 [RNG_ALARMSTOP_REG] = 0x2c, 114 [RNG_REV_REG] = 0x1FE0, 115 [RNG_SYSCONFIG_REG] = 0x1FE4, 116 }; 117 118 static const u16 reg_map_eip76[] = { 119 [RNG_OUTPUT_0_REG] = 0x0, 120 [RNG_OUTPUT_1_REG] = 0x4, 121 [RNG_OUTPUT_2_REG] = 0x8, 122 [RNG_OUTPUT_3_REG] = 0xc, 123 [RNG_STATUS_REG] = 0x10, 124 [RNG_INTACK_REG] = 0x10, 125 [RNG_CONTROL_REG] = 0x14, 126 [RNG_CONFIG_REG] = 0x18, 127 [RNG_ALARMCNT_REG] = 0x1c, 128 [RNG_FROENABLE_REG] = 0x20, 129 [RNG_FRODETUNE_REG] = 0x24, 130 [RNG_ALARMMASK_REG] = 0x28, 131 [RNG_ALARMSTOP_REG] = 0x2c, 132 [RNG_REV_REG] = 0x7c, 133 }; 134 135 struct omap_rng_dev; 136 /** 137 * struct omap_rng_pdata - RNG IP block-specific data 138 * @regs: Pointer to the register offsets structure. 139 * @data_size: No. of bytes in RNG output. 140 * @data_present: Callback to determine if data is available. 141 * @init: Callback for IP specific initialization sequence. 142 * @cleanup: Callback for IP specific cleanup sequence. 143 */ 144 struct omap_rng_pdata { 145 u16 *regs; 146 u32 data_size; 147 u32 (*data_present)(struct omap_rng_dev *priv); 148 int (*init)(struct omap_rng_dev *priv); 149 void (*cleanup)(struct omap_rng_dev *priv); 150 }; 151 152 struct omap_rng_dev { 153 void __iomem *base; 154 struct device *dev; 155 const struct omap_rng_pdata *pdata; 156 struct hwrng rng; 157 struct clk *clk; 158 struct clk *clk_reg; 159 }; 160 161 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg) 162 { 163 return __raw_readl(priv->base + priv->pdata->regs[reg]); 164 } 165 166 static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg, 167 u32 val) 168 { 169 __raw_writel(val, priv->base + priv->pdata->regs[reg]); 170 } 171 172 173 static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max, 174 bool wait) 175 { 176 struct omap_rng_dev *priv; 177 int i, present; 178 179 priv = (struct omap_rng_dev *)rng->priv; 180 181 if (max < priv->pdata->data_size) 182 return 0; 183 184 for (i = 0; i < RNG_DATA_FILL_TIMEOUT; i++) { 185 present = priv->pdata->data_present(priv); 186 if (present || !wait) 187 break; 188 189 udelay(10); 190 } 191 if (!present) 192 return 0; 193 194 memcpy_fromio(data, priv->base + priv->pdata->regs[RNG_OUTPUT_0_REG], 195 priv->pdata->data_size); 196 197 if (priv->pdata->regs[RNG_INTACK_REG]) 198 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK); 199 200 return priv->pdata->data_size; 201 } 202 203 static int omap_rng_init(struct hwrng *rng) 204 { 205 struct omap_rng_dev *priv; 206 207 priv = (struct omap_rng_dev *)rng->priv; 208 return priv->pdata->init(priv); 209 } 210 211 static void omap_rng_cleanup(struct hwrng *rng) 212 { 213 struct omap_rng_dev *priv; 214 215 priv = (struct omap_rng_dev *)rng->priv; 216 priv->pdata->cleanup(priv); 217 } 218 219 220 static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv) 221 { 222 return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1; 223 } 224 225 static int omap2_rng_init(struct omap_rng_dev *priv) 226 { 227 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1); 228 return 0; 229 } 230 231 static void omap2_rng_cleanup(struct omap_rng_dev *priv) 232 { 233 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0); 234 } 235 236 static struct omap_rng_pdata omap2_rng_pdata = { 237 .regs = (u16 *)reg_map_omap2, 238 .data_size = OMAP2_RNG_OUTPUT_SIZE, 239 .data_present = omap2_rng_data_present, 240 .init = omap2_rng_init, 241 .cleanup = omap2_rng_cleanup, 242 }; 243 244 static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv) 245 { 246 return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY; 247 } 248 249 static int eip76_rng_init(struct omap_rng_dev *priv) 250 { 251 u32 val; 252 253 /* Return if RNG is already running. */ 254 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK) 255 return 0; 256 257 /* Number of 512 bit blocks of raw Noise Source output data that must 258 * be processed by either the Conditioning Function or the 259 * SP 800-90 DRBG ‘BC_DF’ functionality to yield a ‘full entropy’ 260 * output value. 261 */ 262 val = 0x5 << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 263 264 /* Number of FRO samples that are XOR-ed together into one bit to be 265 * shifted into the main shift register 266 */ 267 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 268 omap_rng_write(priv, RNG_CONFIG_REG, val); 269 270 /* Enable all available FROs */ 271 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0); 272 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK); 273 274 /* Enable TRNG */ 275 val = RNG_CONTROL_ENABLE_TRNG_MASK; 276 omap_rng_write(priv, RNG_CONTROL_REG, val); 277 278 return 0; 279 } 280 281 static int omap4_rng_init(struct omap_rng_dev *priv) 282 { 283 u32 val; 284 285 /* Return if RNG is already running. */ 286 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK) 287 return 0; 288 289 val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 290 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 291 omap_rng_write(priv, RNG_CONFIG_REG, val); 292 293 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0); 294 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK); 295 val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT; 296 val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT; 297 omap_rng_write(priv, RNG_ALARMCNT_REG, val); 298 299 val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT; 300 val |= RNG_CONTROL_ENABLE_TRNG_MASK; 301 omap_rng_write(priv, RNG_CONTROL_REG, val); 302 303 return 0; 304 } 305 306 static void omap4_rng_cleanup(struct omap_rng_dev *priv) 307 { 308 int val; 309 310 val = omap_rng_read(priv, RNG_CONTROL_REG); 311 val &= ~RNG_CONTROL_ENABLE_TRNG_MASK; 312 omap_rng_write(priv, RNG_CONTROL_REG, val); 313 } 314 315 static irqreturn_t omap4_rng_irq(int irq, void *dev_id) 316 { 317 struct omap_rng_dev *priv = dev_id; 318 u32 fro_detune, fro_enable; 319 320 /* 321 * Interrupt raised by a fro shutdown threshold, do the following: 322 * 1. Clear the alarm events. 323 * 2. De tune the FROs which are shutdown. 324 * 3. Re enable the shutdown FROs. 325 */ 326 omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0); 327 omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0); 328 329 fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG); 330 fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK; 331 fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG); 332 fro_enable = RNG_REG_FROENABLE_MASK; 333 334 omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune); 335 omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable); 336 337 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK); 338 339 return IRQ_HANDLED; 340 } 341 342 static struct omap_rng_pdata omap4_rng_pdata = { 343 .regs = (u16 *)reg_map_omap4, 344 .data_size = OMAP4_RNG_OUTPUT_SIZE, 345 .data_present = omap4_rng_data_present, 346 .init = omap4_rng_init, 347 .cleanup = omap4_rng_cleanup, 348 }; 349 350 static struct omap_rng_pdata eip76_rng_pdata = { 351 .regs = (u16 *)reg_map_eip76, 352 .data_size = EIP76_RNG_OUTPUT_SIZE, 353 .data_present = omap4_rng_data_present, 354 .init = eip76_rng_init, 355 .cleanup = omap4_rng_cleanup, 356 }; 357 358 static const struct of_device_id omap_rng_of_match[] __maybe_unused = { 359 { 360 .compatible = "ti,omap2-rng", 361 .data = &omap2_rng_pdata, 362 }, 363 { 364 .compatible = "ti,omap4-rng", 365 .data = &omap4_rng_pdata, 366 }, 367 { 368 .compatible = "inside-secure,safexcel-eip76", 369 .data = &eip76_rng_pdata, 370 }, 371 {}, 372 }; 373 MODULE_DEVICE_TABLE(of, omap_rng_of_match); 374 375 static int of_get_omap_rng_device_details(struct omap_rng_dev *priv, 376 struct platform_device *pdev) 377 { 378 struct device *dev = &pdev->dev; 379 int irq, err; 380 381 priv->pdata = of_device_get_match_data(dev); 382 if (!priv->pdata) 383 return -ENODEV; 384 385 386 if (of_device_is_compatible(dev->of_node, "ti,omap4-rng") || 387 of_device_is_compatible(dev->of_node, "inside-secure,safexcel-eip76")) { 388 irq = platform_get_irq(pdev, 0); 389 if (irq < 0) 390 return irq; 391 392 err = devm_request_irq(dev, irq, omap4_rng_irq, 393 IRQF_TRIGGER_NONE, dev_name(dev), priv); 394 if (err) { 395 dev_err(dev, "unable to request irq %d, err = %d\n", 396 irq, err); 397 return err; 398 } 399 400 /* 401 * On OMAP4, enabling the shutdown_oflo interrupt is 402 * done in the interrupt mask register. There is no 403 * such register on EIP76, and it's enabled by the 404 * same bit in the control register 405 */ 406 if (priv->pdata->regs[RNG_INTMASK_REG]) 407 omap_rng_write(priv, RNG_INTMASK_REG, 408 RNG_SHUTDOWN_OFLO_MASK); 409 else 410 omap_rng_write(priv, RNG_CONTROL_REG, 411 RNG_SHUTDOWN_OFLO_MASK); 412 } 413 return 0; 414 } 415 416 static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng) 417 { 418 /* Only OMAP2/3 can be non-DT */ 419 omap_rng->pdata = &omap2_rng_pdata; 420 return 0; 421 } 422 423 static int omap_rng_probe(struct platform_device *pdev) 424 { 425 struct omap_rng_dev *priv; 426 struct device *dev = &pdev->dev; 427 int ret; 428 429 priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL); 430 if (!priv) 431 return -ENOMEM; 432 433 priv->rng.read = omap_rng_do_read; 434 priv->rng.init = omap_rng_init; 435 priv->rng.cleanup = omap_rng_cleanup; 436 priv->rng.quality = 900; 437 438 priv->rng.priv = (unsigned long)priv; 439 platform_set_drvdata(pdev, priv); 440 priv->dev = dev; 441 442 priv->base = devm_platform_ioremap_resource(pdev, 0); 443 if (IS_ERR(priv->base)) { 444 ret = PTR_ERR(priv->base); 445 goto err_ioremap; 446 } 447 448 priv->rng.name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL); 449 if (!priv->rng.name) { 450 ret = -ENOMEM; 451 goto err_ioremap; 452 } 453 454 pm_runtime_enable(&pdev->dev); 455 ret = pm_runtime_resume_and_get(&pdev->dev); 456 if (ret < 0) { 457 dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret); 458 goto err_ioremap; 459 } 460 461 priv->clk = devm_clk_get(&pdev->dev, NULL); 462 if (PTR_ERR(priv->clk) == -EPROBE_DEFER) 463 return -EPROBE_DEFER; 464 if (!IS_ERR(priv->clk)) { 465 ret = clk_prepare_enable(priv->clk); 466 if (ret) { 467 dev_err(&pdev->dev, 468 "Unable to enable the clk: %d\n", ret); 469 goto err_register; 470 } 471 } 472 473 priv->clk_reg = devm_clk_get(&pdev->dev, "reg"); 474 if (PTR_ERR(priv->clk_reg) == -EPROBE_DEFER) 475 return -EPROBE_DEFER; 476 if (!IS_ERR(priv->clk_reg)) { 477 ret = clk_prepare_enable(priv->clk_reg); 478 if (ret) { 479 dev_err(&pdev->dev, 480 "Unable to enable the register clk: %d\n", 481 ret); 482 goto err_register; 483 } 484 } 485 486 ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) : 487 get_omap_rng_device_details(priv); 488 if (ret) 489 goto err_register; 490 491 ret = devm_hwrng_register(&pdev->dev, &priv->rng); 492 if (ret) 493 goto err_register; 494 495 dev_info(&pdev->dev, "Random Number Generator ver. %02x\n", 496 omap_rng_read(priv, RNG_REV_REG)); 497 498 return 0; 499 500 err_register: 501 priv->base = NULL; 502 pm_runtime_put_sync(&pdev->dev); 503 pm_runtime_disable(&pdev->dev); 504 505 clk_disable_unprepare(priv->clk_reg); 506 clk_disable_unprepare(priv->clk); 507 err_ioremap: 508 dev_err(dev, "initialization failed.\n"); 509 return ret; 510 } 511 512 static int omap_rng_remove(struct platform_device *pdev) 513 { 514 struct omap_rng_dev *priv = platform_get_drvdata(pdev); 515 516 517 priv->pdata->cleanup(priv); 518 519 pm_runtime_put_sync(&pdev->dev); 520 pm_runtime_disable(&pdev->dev); 521 522 clk_disable_unprepare(priv->clk); 523 clk_disable_unprepare(priv->clk_reg); 524 525 return 0; 526 } 527 528 static int __maybe_unused omap_rng_suspend(struct device *dev) 529 { 530 struct omap_rng_dev *priv = dev_get_drvdata(dev); 531 532 priv->pdata->cleanup(priv); 533 pm_runtime_put_sync(dev); 534 535 return 0; 536 } 537 538 static int __maybe_unused omap_rng_resume(struct device *dev) 539 { 540 struct omap_rng_dev *priv = dev_get_drvdata(dev); 541 int ret; 542 543 ret = pm_runtime_resume_and_get(dev); 544 if (ret < 0) { 545 dev_err(dev, "Failed to runtime_get device: %d\n", ret); 546 return ret; 547 } 548 549 priv->pdata->init(priv); 550 551 return 0; 552 } 553 554 static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume); 555 556 static struct platform_driver omap_rng_driver = { 557 .driver = { 558 .name = "omap_rng", 559 .pm = &omap_rng_pm, 560 .of_match_table = of_match_ptr(omap_rng_of_match), 561 }, 562 .probe = omap_rng_probe, 563 .remove = omap_rng_remove, 564 }; 565 566 module_platform_driver(omap_rng_driver); 567 MODULE_ALIAS("platform:omap_rng"); 568 MODULE_AUTHOR("Deepak Saxena (and others)"); 569 MODULE_LICENSE("GPL"); 570