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 67 enum { 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 84 static 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 92 static 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 }; 108 109 struct 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 */ 118 struct 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 }; 125 126 struct omap_rng_dev { 127 void __iomem *base; 128 struct device *dev; 129 const struct omap_rng_pdata *pdata; 130 }; 131 132 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg) 133 { 134 return __raw_readl(priv->base + priv->pdata->regs[reg]); 135 } 136 137 static 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 } 142 143 static 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 } 163 164 static 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 } 179 180 static 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 } 187 188 static 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 } 195 196 static 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 }; 203 204 static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv) 205 { 206 return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1; 207 } 208 209 static int omap2_rng_init(struct omap_rng_dev *priv) 210 { 211 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1); 212 return 0; 213 } 214 215 static void omap2_rng_cleanup(struct omap_rng_dev *priv) 216 { 217 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0); 218 } 219 220 static 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) 229 static 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 } 233 234 static 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 } 258 259 static 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 } 267 268 static 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 } 294 295 static 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 }; 302 303 static 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 }; 314 MODULE_DEVICE_TABLE(of, omap_rng_of_match); 315 316 static 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 350 static 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 356 357 static 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 } 363 364 static 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; 402 403 err_register: 404 priv->base = NULL; 405 pm_runtime_disable(&pdev->dev); 406 err_ioremap: 407 dev_err(dev, "initialization failed.\n"); 408 return ret; 409 } 410 411 static 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 426 427 static 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 } 436 437 static 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 } 446 447 static 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 455 456 static 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 }; 466 467 module_platform_driver(omap_rng_driver); 468 MODULE_ALIAS("platform:omap_rng"); 469 MODULE_AUTHOR("Deepak Saxena (and others)"); 470 MODULE_LICENSE("GPL"); 471