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 struct hwrng rng; 131 }; 132 133 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg) 134 { 135 return __raw_readl(priv->base + priv->pdata->regs[reg]); 136 } 137 138 static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg, 139 u32 val) 140 { 141 __raw_writel(val, priv->base + priv->pdata->regs[reg]); 142 } 143 144 145 static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max, 146 bool wait) 147 { 148 struct omap_rng_dev *priv; 149 int i, present; 150 151 priv = (struct omap_rng_dev *)rng->priv; 152 153 if (max < priv->pdata->data_size) 154 return 0; 155 156 for (i = 0; i < 20; i++) { 157 present = priv->pdata->data_present(priv); 158 if (present || !wait) 159 break; 160 161 udelay(10); 162 } 163 if (!present) 164 return 0; 165 166 memcpy_fromio(data, priv->base + priv->pdata->regs[RNG_OUTPUT_L_REG], 167 priv->pdata->data_size); 168 169 if (priv->pdata->regs[RNG_INTACK_REG]) 170 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK); 171 172 return priv->pdata->data_size; 173 } 174 175 static int omap_rng_init(struct hwrng *rng) 176 { 177 struct omap_rng_dev *priv; 178 179 priv = (struct omap_rng_dev *)rng->priv; 180 return priv->pdata->init(priv); 181 } 182 183 static void omap_rng_cleanup(struct hwrng *rng) 184 { 185 struct omap_rng_dev *priv; 186 187 priv = (struct omap_rng_dev *)rng->priv; 188 priv->pdata->cleanup(priv); 189 } 190 191 192 static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv) 193 { 194 return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1; 195 } 196 197 static int omap2_rng_init(struct omap_rng_dev *priv) 198 { 199 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1); 200 return 0; 201 } 202 203 static void omap2_rng_cleanup(struct omap_rng_dev *priv) 204 { 205 omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0); 206 } 207 208 static struct omap_rng_pdata omap2_rng_pdata = { 209 .regs = (u16 *)reg_map_omap2, 210 .data_size = OMAP2_RNG_OUTPUT_SIZE, 211 .data_present = omap2_rng_data_present, 212 .init = omap2_rng_init, 213 .cleanup = omap2_rng_cleanup, 214 }; 215 216 #if defined(CONFIG_OF) 217 static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv) 218 { 219 return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY; 220 } 221 222 static int omap4_rng_init(struct omap_rng_dev *priv) 223 { 224 u32 val; 225 226 /* Return if RNG is already running. */ 227 if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK) 228 return 0; 229 230 val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 231 val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 232 omap_rng_write(priv, RNG_CONFIG_REG, val); 233 234 omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0); 235 omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK); 236 val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT; 237 val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT; 238 omap_rng_write(priv, RNG_ALARMCNT_REG, val); 239 240 val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT; 241 val |= RNG_CONTROL_ENABLE_TRNG_MASK; 242 omap_rng_write(priv, RNG_CONTROL_REG, val); 243 244 return 0; 245 } 246 247 static void omap4_rng_cleanup(struct omap_rng_dev *priv) 248 { 249 int val; 250 251 val = omap_rng_read(priv, RNG_CONTROL_REG); 252 val &= ~RNG_CONTROL_ENABLE_TRNG_MASK; 253 omap_rng_write(priv, RNG_CONTROL_REG, val); 254 } 255 256 static irqreturn_t omap4_rng_irq(int irq, void *dev_id) 257 { 258 struct omap_rng_dev *priv = dev_id; 259 u32 fro_detune, fro_enable; 260 261 /* 262 * Interrupt raised by a fro shutdown threshold, do the following: 263 * 1. Clear the alarm events. 264 * 2. De tune the FROs which are shutdown. 265 * 3. Re enable the shutdown FROs. 266 */ 267 omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0); 268 omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0); 269 270 fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG); 271 fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK; 272 fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG); 273 fro_enable = RNG_REG_FROENABLE_MASK; 274 275 omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune); 276 omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable); 277 278 omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK); 279 280 return IRQ_HANDLED; 281 } 282 283 static struct omap_rng_pdata omap4_rng_pdata = { 284 .regs = (u16 *)reg_map_omap4, 285 .data_size = OMAP4_RNG_OUTPUT_SIZE, 286 .data_present = omap4_rng_data_present, 287 .init = omap4_rng_init, 288 .cleanup = omap4_rng_cleanup, 289 }; 290 291 static const struct of_device_id omap_rng_of_match[] = { 292 { 293 .compatible = "ti,omap2-rng", 294 .data = &omap2_rng_pdata, 295 }, 296 { 297 .compatible = "ti,omap4-rng", 298 .data = &omap4_rng_pdata, 299 }, 300 {}, 301 }; 302 MODULE_DEVICE_TABLE(of, omap_rng_of_match); 303 304 static int of_get_omap_rng_device_details(struct omap_rng_dev *priv, 305 struct platform_device *pdev) 306 { 307 const struct of_device_id *match; 308 struct device *dev = &pdev->dev; 309 int irq, err; 310 311 match = of_match_device(of_match_ptr(omap_rng_of_match), dev); 312 if (!match) { 313 dev_err(dev, "no compatible OF match\n"); 314 return -EINVAL; 315 } 316 priv->pdata = match->data; 317 318 if (of_device_is_compatible(dev->of_node, "ti,omap4-rng")) { 319 irq = platform_get_irq(pdev, 0); 320 if (irq < 0) { 321 dev_err(dev, "%s: error getting IRQ resource - %d\n", 322 __func__, irq); 323 return irq; 324 } 325 326 err = devm_request_irq(dev, irq, omap4_rng_irq, 327 IRQF_TRIGGER_NONE, dev_name(dev), priv); 328 if (err) { 329 dev_err(dev, "unable to request irq %d, err = %d\n", 330 irq, err); 331 return err; 332 } 333 omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK); 334 } 335 return 0; 336 } 337 #else 338 static int of_get_omap_rng_device_details(struct omap_rng_dev *omap_rng, 339 struct platform_device *pdev) 340 { 341 return -EINVAL; 342 } 343 #endif 344 345 static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng) 346 { 347 /* Only OMAP2/3 can be non-DT */ 348 omap_rng->pdata = &omap2_rng_pdata; 349 return 0; 350 } 351 352 static int omap_rng_probe(struct platform_device *pdev) 353 { 354 struct omap_rng_dev *priv; 355 struct resource *res; 356 struct device *dev = &pdev->dev; 357 int ret; 358 359 priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL); 360 if (!priv) 361 return -ENOMEM; 362 363 priv->rng.read = omap_rng_do_read; 364 priv->rng.init = omap_rng_init; 365 priv->rng.cleanup = omap_rng_cleanup; 366 367 priv->rng.priv = (unsigned long)priv; 368 platform_set_drvdata(pdev, priv); 369 priv->dev = dev; 370 371 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 372 priv->base = devm_ioremap_resource(dev, res); 373 if (IS_ERR(priv->base)) { 374 ret = PTR_ERR(priv->base); 375 goto err_ioremap; 376 } 377 378 priv->rng.name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL); 379 if (!priv->rng.name) { 380 ret = -ENOMEM; 381 goto err_ioremap; 382 } 383 384 pm_runtime_enable(&pdev->dev); 385 ret = pm_runtime_get_sync(&pdev->dev); 386 if (ret < 0) { 387 dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret); 388 pm_runtime_put_noidle(&pdev->dev); 389 goto err_ioremap; 390 } 391 392 ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) : 393 get_omap_rng_device_details(priv); 394 if (ret) 395 goto err_ioremap; 396 397 ret = hwrng_register(&priv->rng); 398 if (ret) 399 goto err_register; 400 401 dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n", 402 omap_rng_read(priv, RNG_REV_REG)); 403 404 return 0; 405 406 err_register: 407 priv->base = NULL; 408 pm_runtime_disable(&pdev->dev); 409 err_ioremap: 410 dev_err(dev, "initialization failed.\n"); 411 return ret; 412 } 413 414 static int omap_rng_remove(struct platform_device *pdev) 415 { 416 struct omap_rng_dev *priv = platform_get_drvdata(pdev); 417 418 hwrng_unregister(&priv->rng); 419 420 priv->pdata->cleanup(priv); 421 422 pm_runtime_put_sync(&pdev->dev); 423 pm_runtime_disable(&pdev->dev); 424 425 return 0; 426 } 427 428 static int __maybe_unused omap_rng_suspend(struct device *dev) 429 { 430 struct omap_rng_dev *priv = dev_get_drvdata(dev); 431 432 priv->pdata->cleanup(priv); 433 pm_runtime_put_sync(dev); 434 435 return 0; 436 } 437 438 static int __maybe_unused omap_rng_resume(struct device *dev) 439 { 440 struct omap_rng_dev *priv = dev_get_drvdata(dev); 441 int ret; 442 443 ret = pm_runtime_get_sync(dev); 444 if (ret < 0) { 445 dev_err(dev, "Failed to runtime_get device: %d\n", ret); 446 pm_runtime_put_noidle(dev); 447 return ret; 448 } 449 450 priv->pdata->init(priv); 451 452 return 0; 453 } 454 455 static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume); 456 457 static struct platform_driver omap_rng_driver = { 458 .driver = { 459 .name = "omap_rng", 460 .pm = &omap_rng_pm, 461 .of_match_table = of_match_ptr(omap_rng_of_match), 462 }, 463 .probe = omap_rng_probe, 464 .remove = 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