target/linux/ramips/patches-3.9/0154-reset-Add-reset-controller-API.patch

   1 From d6cfbdfa001891894efe078a49ad82ac8a932dbb Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Mon, 20 May 2013 15:42:01 +0200
   4 Subject: [PATCH 154/164] reset: Add reset controller API
   5
   6 backport from v3.10-rc1
   7 61fc41317666be400802ac793f47de816ef7bd57
   8 6034bb22d8387708075c083385e5d2e1072a4f33
   9 4e11f848c65b1c87782cb232a6e3b47a9d4c1f98
  10
  11 This adds a simple API for devices to request being reset
  12 by separate reset controller hardware and implements the
  13 reset signal device tree binding.
  14
  15 Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
  16 Reviewed-by: Stephen Warren <swarren@nvidia.com>
  17 Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
  18 Reviewed-by: Marek Vasut <marex@denx.de>
  19 Reviewed-by: Pavel Machek <pavel@ucw.cz>
  20 ---
  21  Documentation/devicetree/bindings/reset/reset.txt |   75 ++++++
  22  drivers/Kconfig                                   |    2 +
  23  drivers/Makefile                                  |    3 +
  24  drivers/reset/Kconfig                             |   13 +
  25  drivers/reset/Makefile                            |    1 +
  26  drivers/reset/core.c                              |  297 +++++++++++++++++++++
  27  include/linux/reset-controller.h                  |   51 ++++
  28  include/linux/reset.h                             |   17 ++
  29  8 files changed, 459 insertions(+)
  30  create mode 100644 Documentation/devicetree/bindings/reset/reset.txt
  31  create mode 100644 drivers/reset/Kconfig
  32  create mode 100644 drivers/reset/Makefile
  33  create mode 100644 drivers/reset/core.c
  34  create mode 100644 include/linux/reset-controller.h
  35  create mode 100644 include/linux/reset.h
  36
  37 diff --git a/Documentation/devicetree/bindings/reset/reset.txt b/Documentation/devicetree/bindings/reset/reset.txt
  38 new file mode 100644
  39 index 0000000..31db6ff
  40 --- /dev/null
  41 +++ b/Documentation/devicetree/bindings/reset/reset.txt
  42 @@ -0,0 +1,75 @@
  43 += Reset Signal Device Tree Bindings =
  44 +
  45 +This binding is intended to represent the hardware reset signals present
  46 +internally in most IC (SoC, FPGA, ...) designs. Reset signals for whole
  47 +standalone chips are most likely better represented as GPIOs, although there
  48 +are likely to be exceptions to this rule.
  49 +
  50 +Hardware blocks typically receive a reset signal. This signal is generated by
  51 +a reset provider (e.g. power management or clock module) and received by a
  52 +reset consumer (the module being reset, or a module managing when a sub-
  53 +ordinate module is reset). This binding exists to represent the provider and
  54 +consumer, and provide a way to couple the two together.
  55 +
  56 +A reset signal is represented by the phandle of the provider, plus a reset
  57 +specifier - a list of DT cells that represents the reset signal within the
  58 +provider. The length (number of cells) and semantics of the reset specifier
  59 +are dictated by the binding of the reset provider, although common schemes
  60 +are described below.
  61 +
  62 +A word on where to place reset signal consumers in device tree: It is possible
  63 +in hardware for a reset signal to affect multiple logically separate HW blocks
  64 +at once. In this case, it would be unwise to represent this reset signal in
  65 +the DT node of each affected HW block, since if activated, an unrelated block
  66 +may be reset. Instead, reset signals should be represented in the DT node
  67 +where it makes most sense to control it; this may be a bus node if all
  68 +children of the bus are affected by the reset signal, or an individual HW
  69 +block node for dedicated reset signals. The intent of this binding is to give
  70 +appropriate software access to the reset signals in order to manage the HW,
  71 +rather than to slavishly enumerate the reset signal that affects each HW
  72 +block.
  73 +
  74 += Reset providers =
  75 +
  76 +Required properties:
  77 +#reset-cells:  Number of cells in a reset specifier; Typically 0 for nodes
  78 +               with a single reset output and 1 for nodes with multiple
  79 +               reset outputs.
  80 +
  81 +For example:
  82 +
  83 +       rst: reset-controller {
  84 +               #reset-cells = <1>;
  85 +       };
  86 +
  87 += Reset consumers =
  88 +
  89 +Required properties:
  90 +resets:                List of phandle and reset specifier pairs, one pair
  91 +               for each reset signal that affects the device, or that the
  92 +               device manages. Note: if the reset provider specifies '0' for
  93 +               #reset-cells, then only the phandle portion of the pair will
  94 +               appear.
  95 +
  96 +Optional properties:
  97 +reset-names:   List of reset signal name strings sorted in the same order as
  98 +               the resets property. Consumers drivers will use reset-names to
  99 +               match reset signal names with reset specifiers.
 100 +
 101 +For example:
 102 +
 103 +       device {
 104 +               resets = <&rst 20>;
 105 +               reset-names = "reset";
 106 +       };
 107 +
 108 +This represents a device with a single reset signal named "reset".
 109 +
 110 +       bus {
 111 +               resets = <&rst 10> <&rst 11> <&rst 12> <&rst 11>;
 112 +               reset-names = "i2s1", "i2s2", "dma", "mixer";
 113 +       };
 114 +
 115 +This represents a bus that controls the reset signal of each of four sub-
 116 +ordinate devices. Consider for example a bus that fails to operate unless no
 117 +child device has reset asserted.
 118 diff --git a/drivers/Kconfig b/drivers/Kconfig
 119 index 202fa6d..847f8e3 100644
 120 --- a/drivers/Kconfig
 121 +++ b/drivers/Kconfig
 122 @@ -162,4 +162,6 @@ source "drivers/irqchip/Kconfig"
 123
 124  source "drivers/ipack/Kconfig"
 125
 126 +source "drivers/reset/Kconfig"
 127 +
 128  endmenu
 129 diff --git a/drivers/Makefile b/drivers/Makefile
 130 index dce39a9..1a64c4c 100644
 131 --- a/drivers/Makefile
 132 +++ b/drivers/Makefile
 133 @@ -37,6 +37,9 @@ obj-$(CONFIG_XEN)             += xen/
 134  # regulators early, since some subsystems rely on them to initialize
 135  obj-$(CONFIG_REGULATOR)                += regulator/
 136
 137 +# reset controllers early, since gpu drivers might rely on them to initialize
 138 +obj-$(CONFIG_RESET_CONTROLLER) += reset/
 139 +
 140  # tty/ comes before char/ so that the VT console is the boot-time
 141  # default.
 142  obj-y                          += tty/
 143 diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
 144 new file mode 100644
 145 index 0000000..c9d04f7
 146 --- /dev/null
 147 +++ b/drivers/reset/Kconfig
 148 @@ -0,0 +1,13 @@
 149 +config ARCH_HAS_RESET_CONTROLLER
 150 +       bool
 151 +
 152 +menuconfig RESET_CONTROLLER
 153 +       bool "Reset Controller Support"
 154 +       default y if ARCH_HAS_RESET_CONTROLLER
 155 +       help
 156 +         Generic Reset Controller support.
 157 +
 158 +         This framework is designed to abstract reset handling of devices
 159 +         via GPIOs or SoC-internal reset controller modules.
 160 +
 161 +         If unsure, say no.
 162 diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
 163 new file mode 100644
 164 index 0000000..1e2d83f
 165 --- /dev/null
 166 +++ b/drivers/reset/Makefile
 167 @@ -0,0 +1 @@
 168 +obj-$(CONFIG_RESET_CONTROLLER) += core.o
 169 diff --git a/drivers/reset/core.c b/drivers/reset/core.c
 170 new file mode 100644
 171 index 0000000..d1b6089
 172 --- /dev/null
 173 +++ b/drivers/reset/core.c
 174 @@ -0,0 +1,297 @@
 175 +/*
 176 + * Reset Controller framework
 177 + *
 178 + * Copyright 2013 Philipp Zabel, Pengutronix
 179 + *
 180 + * This program is free software; you can redistribute it and/or modify
 181 + * it under the terms of the GNU General Public License as published by
 182 + * the Free Software Foundation; either version 2 of the License, or
 183 + * (at your option) any later version.
 184 + */
 185 +#include <linux/device.h>
 186 +#include <linux/err.h>
 187 +#include <linux/export.h>
 188 +#include <linux/kernel.h>
 189 +#include <linux/module.h>
 190 +#include <linux/of.h>
 191 +#include <linux/reset.h>
 192 +#include <linux/reset-controller.h>
 193 +#include <linux/slab.h>
 194 +
 195 +static DEFINE_MUTEX(reset_controller_list_mutex);
 196 +static LIST_HEAD(reset_controller_list);
 197 +
 198 +/**
 199 + * struct reset_control - a reset control
 200 + * @rcdev: a pointer to the reset controller device
 201 + *         this reset control belongs to
 202 + * @id: ID of the reset controller in the reset
 203 + *      controller device
 204 + */
 205 +struct reset_control {
 206 +       struct reset_controller_dev *rcdev;
 207 +       struct device *dev;
 208 +       unsigned int id;
 209 +};
 210 +
 211 +/**
 212 + * of_reset_simple_xlate - translate reset_spec to the reset line number
 213 + * @rcdev: a pointer to the reset controller device
 214 + * @reset_spec: reset line specifier as found in the device tree
 215 + * @flags: a flags pointer to fill in (optional)
 216 + *
 217 + * This simple translation function should be used for reset controllers
 218 + * with 1:1 mapping, where reset lines can be indexed by number without gaps.
 219 + */
 220 +int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
 221 +                         const struct of_phandle_args *reset_spec)
 222 +{
 223 +       if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
 224 +               return -EINVAL;
 225 +
 226 +       if (reset_spec->args[0] >= rcdev->nr_resets)
 227 +               return -EINVAL;
 228 +
 229 +       return reset_spec->args[0];
 230 +}
 231 +EXPORT_SYMBOL_GPL(of_reset_simple_xlate);
 232 +
 233 +/**
 234 + * reset_controller_register - register a reset controller device
 235 + * @rcdev: a pointer to the initialized reset controller device
 236 + */
 237 +int reset_controller_register(struct reset_controller_dev *rcdev)
 238 +{
 239 +       if (!rcdev->of_xlate) {
 240 +               rcdev->of_reset_n_cells = 1;
 241 +               rcdev->of_xlate = of_reset_simple_xlate;
 242 +       }
 243 +
 244 +       mutex_lock(&reset_controller_list_mutex);
 245 +       list_add(&rcdev->list, &reset_controller_list);
 246 +       mutex_unlock(&reset_controller_list_mutex);
 247 +
 248 +       return 0;
 249 +}
 250 +EXPORT_SYMBOL_GPL(reset_controller_register);
 251 +
 252 +/**
 253 + * reset_controller_unregister - unregister a reset controller device
 254 + * @rcdev: a pointer to the reset controller device
 255 + */
 256 +void reset_controller_unregister(struct reset_controller_dev *rcdev)
 257 +{
 258 +       mutex_lock(&reset_controller_list_mutex);
 259 +       list_del(&rcdev->list);
 260 +       mutex_unlock(&reset_controller_list_mutex);
 261 +}
 262 +EXPORT_SYMBOL_GPL(reset_controller_unregister);
 263 +
 264 +/**
 265 + * reset_control_reset - reset the controlled device
 266 + * @rstc: reset controller
 267 + */
 268 +int reset_control_reset(struct reset_control *rstc)
 269 +{
 270 +       if (rstc->rcdev->ops->reset)
 271 +               return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
 272 +
 273 +       return -ENOSYS;
 274 +}
 275 +EXPORT_SYMBOL_GPL(reset_control_reset);
 276 +
 277 +/**
 278 + * reset_control_assert - asserts the reset line
 279 + * @rstc: reset controller
 280 + */
 281 +int reset_control_assert(struct reset_control *rstc)
 282 +{
 283 +       if (rstc->rcdev->ops->assert)
 284 +               return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
 285 +
 286 +       return -ENOSYS;
 287 +}
 288 +EXPORT_SYMBOL_GPL(reset_control_assert);
 289 +
 290 +/**
 291 + * reset_control_deassert - deasserts the reset line
 292 + * @rstc: reset controller
 293 + */
 294 +int reset_control_deassert(struct reset_control *rstc)
 295 +{
 296 +       if (rstc->rcdev->ops->deassert)
 297 +               return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
 298 +
 299 +       return -ENOSYS;
 300 +}
 301 +EXPORT_SYMBOL_GPL(reset_control_deassert);
 302 +
 303 +/**
 304 + * reset_control_get - Lookup and obtain a reference to a reset controller.
 305 + * @dev: device to be reset by the controller
 306 + * @id: reset line name
 307 + *
 308 + * Returns a struct reset_control or IS_ERR() condition containing errno.
 309 + *
 310 + * Use of id names is optional.
 311 + */
 312 +struct reset_control *reset_control_get(struct device *dev, const char *id)
 313 +{
 314 +       struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER);
 315 +       struct reset_controller_dev *r, *rcdev;
 316 +       struct of_phandle_args args;
 317 +       int index = 0;
 318 +       int rstc_id;
 319 +       int ret;
 320 +
 321 +       if (!dev)
 322 +               return ERR_PTR(-EINVAL);
 323 +
 324 +       if (id)
 325 +               index = of_property_match_string(dev->of_node,
 326 +                                                "reset-names", id);
 327 +       ret = of_parse_phandle_with_args(dev->of_node, "resets", "#reset-cells",
 328 +                                        index, &args);
 329 +       if (ret)
 330 +               return ERR_PTR(ret);
 331 +
 332 +       mutex_lock(&reset_controller_list_mutex);
 333 +       rcdev = NULL;
 334 +       list_for_each_entry(r, &reset_controller_list, list) {
 335 +               if (args.np == r->of_node) {
 336 +                       rcdev = r;
 337 +                       break;
 338 +               }
 339 +       }
 340 +       of_node_put(args.np);
 341 +
 342 +       if (!rcdev) {
 343 +               mutex_unlock(&reset_controller_list_mutex);
 344 +               return ERR_PTR(-ENODEV);
 345 +       }
 346 +
 347 +       rstc_id = rcdev->of_xlate(rcdev, &args);
 348 +       if (rstc_id < 0) {
 349 +               mutex_unlock(&reset_controller_list_mutex);
 350 +               return ERR_PTR(rstc_id);
 351 +       }
 352 +
 353 +       try_module_get(rcdev->owner);
 354 +       mutex_unlock(&reset_controller_list_mutex);
 355 +
 356 +       rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
 357 +       if (!rstc) {
 358 +               module_put(rcdev->owner);
 359 +               return ERR_PTR(-ENOMEM);
 360 +       }
 361 +
 362 +       rstc->dev = dev;
 363 +       rstc->rcdev = rcdev;
 364 +       rstc->id = rstc_id;
 365 +
 366 +       return rstc;
 367 +}
 368 +EXPORT_SYMBOL_GPL(reset_control_get);
 369 +
 370 +/**
 371 + * reset_control_put - free the reset controller
 372 + * @rstc: reset controller
 373 + */
 374 +
 375 +void reset_control_put(struct reset_control *rstc)
 376 +{
 377 +       if (IS_ERR(rstc))
 378 +               return;
 379 +
 380 +       module_put(rstc->rcdev->owner);
 381 +       kfree(rstc);
 382 +}
 383 +EXPORT_SYMBOL_GPL(reset_control_put);
 384 +
 385 +static void devm_reset_control_release(struct device *dev, void *res)
 386 +{
 387 +       reset_control_put(*(struct reset_control **)res);
 388 +}
 389 +
 390 +/**
 391 + * devm_reset_control_get - resource managed reset_control_get()
 392 + * @dev: device to be reset by the controller
 393 + * @id: reset line name
 394 + *
 395 + * Managed reset_control_get(). For reset controllers returned from this
 396 + * function, reset_control_put() is called automatically on driver detach.
 397 + * See reset_control_get() for more information.
 398 + */
 399 +struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
 400 +{
 401 +       struct reset_control **ptr, *rstc;
 402 +
 403 +       ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
 404 +                          GFP_KERNEL);
 405 +       if (!ptr)
 406 +               return ERR_PTR(-ENOMEM);
 407 +
 408 +       rstc = reset_control_get(dev, id);
 409 +       if (!IS_ERR(rstc)) {
 410 +               *ptr = rstc;
 411 +               devres_add(dev, ptr);
 412 +       } else {
 413 +               devres_free(ptr);
 414 +       }
 415 +
 416 +       return rstc;
 417 +}
 418 +EXPORT_SYMBOL_GPL(devm_reset_control_get);
 419 +
 420 +static int devm_reset_control_match(struct device *dev, void *res, void *data)
 421 +{
 422 +       struct reset_control **rstc = res;
 423 +       if (WARN_ON(!rstc || !*rstc))
 424 +               return 0;
 425 +       return *rstc == data;
 426 +}
 427 +
 428 +/**
 429 + * devm_reset_control_put - resource managed reset_control_put()
 430 + * @rstc: reset controller to free
 431 + *
 432 + * Deallocate a reset control allocated withd devm_reset_control_get().
 433 + * This function will not need to be called normally, as devres will take
 434 + * care of freeing the resource.
 435 + */
 436 +void devm_reset_control_put(struct reset_control *rstc)
 437 +{
 438 +       int ret;
 439 +
 440 +       ret = devres_release(rstc->dev, devm_reset_control_release,
 441 +                            devm_reset_control_match, rstc);
 442 +       if (ret)
 443 +               WARN_ON(ret);
 444 +}
 445 +EXPORT_SYMBOL_GPL(devm_reset_control_put);
 446 +
 447 +/**
 448 + * device_reset - find reset controller associated with the device
 449 + *                and perform reset
 450 + * @dev: device to be reset by the controller
 451 + *
 452 + * Convenience wrapper for reset_control_get() and reset_control_reset().
 453 + * This is useful for the common case of devices with single, dedicated reset
 454 + * lines.
 455 + */
 456 +int device_reset(struct device *dev)
 457 +{
 458 +       struct reset_control *rstc;
 459 +       int ret;
 460 +
 461 +       rstc = reset_control_get(dev, NULL);
 462 +       if (IS_ERR(rstc))
 463 +               return PTR_ERR(rstc);
 464 +
 465 +       ret = reset_control_reset(rstc);
 466 +
 467 +       reset_control_put(rstc);
 468 +
 469 +       return ret;
 470 +}
 471 +EXPORT_SYMBOL_GPL(device_reset);
 472 diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
 473 new file mode 100644
 474 index 0000000..2f61311
 475 --- /dev/null
 476 +++ b/include/linux/reset-controller.h
 477 @@ -0,0 +1,51 @@
 478 +#ifndef _LINUX_RESET_CONTROLLER_H_
 479 +#define _LINUX_RESET_CONTROLLER_H_
 480 +
 481 +#include <linux/list.h>
 482 +
 483 +struct reset_controller_dev;
 484 +
 485 +/**
 486 + * struct reset_control_ops
 487 + *
 488 + * @reset: for self-deasserting resets, does all necessary
 489 + *         things to reset the device
 490 + * @assert: manually assert the reset line, if supported
 491 + * @deassert: manually deassert the reset line, if supported
 492 + */
 493 +struct reset_control_ops {
 494 +       int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
 495 +       int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
 496 +       int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
 497 +};
 498 +
 499 +struct module;
 500 +struct device_node;
 501 +
 502 +/**
 503 + * struct reset_controller_dev - reset controller entity that might
 504 + *                               provide multiple reset controls
 505 + * @ops: a pointer to device specific struct reset_control_ops
 506 + * @owner: kernel module of the reset controller driver
 507 + * @list: internal list of reset controller devices
 508 + * @of_node: corresponding device tree node as phandle target
 509 + * @of_reset_n_cells: number of cells in reset line specifiers
 510 + * @of_xlate: translation function to translate from specifier as found in the
 511 + *            device tree to id as given to the reset control ops
 512 + * @nr_resets: number of reset controls in this reset controller device
 513 + */
 514 +struct reset_controller_dev {
 515 +       struct reset_control_ops *ops;
 516 +       struct module *owner;
 517 +       struct list_head list;
 518 +       struct device_node *of_node;
 519 +       int of_reset_n_cells;
 520 +       int (*of_xlate)(struct reset_controller_dev *rcdev,
 521 +                       const struct of_phandle_args *reset_spec);
 522 +       unsigned int nr_resets;
 523 +};
 524 +
 525 +int reset_controller_register(struct reset_controller_dev *rcdev);
 526 +void reset_controller_unregister(struct reset_controller_dev *rcdev);
 527 +
 528 +#endif
 529 diff --git a/include/linux/reset.h b/include/linux/reset.h
 530 new file mode 100644
 531 index 0000000..6082247
 532 --- /dev/null
 533 +++ b/include/linux/reset.h
 534 @@ -0,0 +1,17 @@
 535 +#ifndef _LINUX_RESET_H_
 536 +#define _LINUX_RESET_H_
 537 +
 538 +struct device;
 539 +struct reset_control;
 540 +
 541 +int reset_control_reset(struct reset_control *rstc);
 542 +int reset_control_assert(struct reset_control *rstc);
 543 +int reset_control_deassert(struct reset_control *rstc);
 544 +
 545 +struct reset_control *reset_control_get(struct device *dev, const char *id);
 546 +void reset_control_put(struct reset_control *rstc);
 547 +struct reset_control *devm_reset_control_get(struct device *dev, const char *id);
 548 +
 549 +int device_reset(struct device *dev);
 550 +
 551 +#endif
 552 --
 553 1.7.10.4
 554