arch/arm/mach-tegra/clock.c

   1 /*
   2  *
   3  * Copyright (C) 2010 Google, Inc.
   4  *
   5  * Author:
   6  *      Colin Cross <ccross@google.com>
   7  *
   8  * This software is licensed under the terms of the GNU General Public
   9  * License version 2, as published by the Free Software Foundation, and
  10  * may be copied, distributed, and modified under those terms.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/clk.h>
  21 #include <linux/list.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/slab.h>
  26 #include <linux/seq_file.h>
  27 #include <asm/clkdev.h>
  28
  29 #include "clock.h"
  30
  31 static LIST_HEAD(clocks);
  32
  33 static DEFINE_SPINLOCK(clock_lock);
  34
  35 struct clk *tegra_get_clock_by_name(const char *name)
  36 {
  37         struct clk *c;
  38         struct clk *ret = NULL;
  39         unsigned long flags;
  40         spin_lock_irqsave(&clock_lock, flags);
  41         list_for_each_entry(c, &clocks, node) {
  42                 if (strcmp(c->name, name) == 0) {
  43                         ret = c;
  44                         break;
  45                 }
  46         }
  47         spin_unlock_irqrestore(&clock_lock, flags);
  48         return ret;
  49 }
  50
  51 int clk_reparent(struct clk *c, struct clk *parent)
  52 {
  53         pr_debug("%s: %s\n", __func__, c->name);
  54         if (c->refcnt && c->parent)
  55                 clk_disable_locked(c->parent);
  56         c->parent = parent;
  57         if (c->refcnt && c->parent)
  58                 clk_enable_locked(c->parent);
  59         list_del(&c->sibling);
  60         list_add_tail(&c->sibling, &parent->children);
  61         return 0;
  62 }
  63
  64 static void propagate_rate(struct clk *c)
  65 {
  66         struct clk *clkp;
  67         pr_debug("%s: %s\n", __func__, c->name);
  68         list_for_each_entry(clkp, &c->children, sibling) {
  69                 pr_debug("   %s\n", clkp->name);
  70                 if (clkp->ops->recalculate_rate)
  71                         clkp->ops->recalculate_rate(clkp);
  72                 propagate_rate(clkp);
  73         }
  74 }
  75
  76 void clk_init(struct clk *c)
  77 {
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(&clock_lock, flags);
  81
  82         INIT_LIST_HEAD(&c->children);
  83         INIT_LIST_HEAD(&c->sibling);
  84
  85         if (c->ops && c->ops->init)
  86                 c->ops->init(c);
  87
  88         list_add(&c->node, &clocks);
  89
  90         if (c->parent)
  91                 list_add_tail(&c->sibling, &c->parent->children);
  92
  93         spin_unlock_irqrestore(&clock_lock, flags);
  94 }
  95
  96 int clk_enable_locked(struct clk *c)
  97 {
  98         int ret;
  99         pr_debug("%s: %s\n", __func__, c->name);
 100         if (c->refcnt == 0) {
 101                 if (c->parent) {
 102                         ret = clk_enable_locked(c->parent);
 103                         if (ret)
 104                                 return ret;
 105                 }
 106
 107                 if (c->ops && c->ops->enable) {
 108                         ret = c->ops->enable(c);
 109                         if (ret) {
 110                                 if (c->parent)
 111                                         clk_disable_locked(c->parent);
 112                                 return ret;
 113                         }
 114                         c->state = ON;
 115 #ifdef CONFIG_DEBUG_FS
 116                         c->set = 1;
 117 #endif
 118                 }
 119         }
 120         c->refcnt++;
 121
 122         return 0;
 123 }
 124
 125 int clk_enable(struct clk *c)
 126 {
 127         int ret;
 128         unsigned long flags;
 129         spin_lock_irqsave(&clock_lock, flags);
 130         ret = clk_enable_locked(c);
 131         spin_unlock_irqrestore(&clock_lock, flags);
 132         return ret;
 133 }
 134 EXPORT_SYMBOL(clk_enable);
 135
 136 void clk_disable_locked(struct clk *c)
 137 {
 138         pr_debug("%s: %s\n", __func__, c->name);
 139         if (c->refcnt == 0) {
 140                 WARN(1, "Attempting to disable clock %s with refcnt 0", c->name);
 141                 return;
 142         }
 143         if (c->refcnt == 1) {
 144                 if (c->ops && c->ops->disable)
 145                         c->ops->disable(c);
 146
 147                 if (c->parent)
 148                         clk_disable_locked(c->parent);
 149
 150                 c->state = OFF;
 151         }
 152         c->refcnt--;
 153 }
 154
 155 void clk_disable(struct clk *c)
 156 {
 157         unsigned long flags;
 158         spin_lock_irqsave(&clock_lock, flags);
 159         clk_disable_locked(c);
 160         spin_unlock_irqrestore(&clock_lock, flags);
 161 }
 162 EXPORT_SYMBOL(clk_disable);
 163
 164 int clk_set_parent_locked(struct clk *c, struct clk *parent)
 165 {
 166         int ret;
 167
 168         pr_debug("%s: %s\n", __func__, c->name);
 169
 170         if (!c->ops || !c->ops->set_parent)
 171                 return -ENOSYS;
 172
 173         ret = c->ops->set_parent(c, parent);
 174
 175         if (ret)
 176                 return ret;
 177
 178         propagate_rate(c);
 179
 180         return 0;
 181 }
 182
 183 int clk_set_parent(struct clk *c, struct clk *parent)
 184 {
 185         int ret;
 186         unsigned long flags;
 187         spin_lock_irqsave(&clock_lock, flags);
 188         ret = clk_set_parent_locked(c, parent);
 189         spin_unlock_irqrestore(&clock_lock, flags);
 190         return ret;
 191 }
 192 EXPORT_SYMBOL(clk_set_parent);
 193
 194 struct clk *clk_get_parent(struct clk *c)
 195 {
 196         return c->parent;
 197 }
 198 EXPORT_SYMBOL(clk_get_parent);
 199
 200 int clk_set_rate(struct clk *c, unsigned long rate)
 201 {
 202         int ret = 0;
 203         unsigned long flags;
 204
 205         spin_lock_irqsave(&clock_lock, flags);
 206
 207         pr_debug("%s: %s\n", __func__, c->name);
 208
 209         if (c->ops && c->ops->set_rate)
 210                 ret = c->ops->set_rate(c, rate);
 211         else
 212                 ret = -ENOSYS;
 213
 214         propagate_rate(c);
 215
 216         spin_unlock_irqrestore(&clock_lock, flags);
 217
 218         return ret;
 219 }
 220 EXPORT_SYMBOL(clk_set_rate);
 221
 222 unsigned long clk_get_rate(struct clk *c)
 223 {
 224         unsigned long flags;
 225         unsigned long ret;
 226
 227         spin_lock_irqsave(&clock_lock, flags);
 228
 229         pr_debug("%s: %s\n", __func__, c->name);
 230
 231         ret = c->rate;
 232
 233         spin_unlock_irqrestore(&clock_lock, flags);
 234         return ret;
 235 }
 236 EXPORT_SYMBOL(clk_get_rate);
 237
 238 static int tegra_clk_init_one_from_table(struct tegra_clk_init_table *table)
 239 {
 240         struct clk *c;
 241         struct clk *p;
 242
 243         int ret = 0;
 244
 245         c = tegra_get_clock_by_name(table->name);
 246
 247         if (!c) {
 248                 pr_warning("Unable to initialize clock %s\n",
 249                         table->name);
 250                 return -ENODEV;
 251         }
 252
 253         if (table->parent) {
 254                 p = tegra_get_clock_by_name(table->parent);
 255                 if (!p) {
 256                         pr_warning("Unable to find parent %s of clock %s\n",
 257                                 table->parent, table->name);
 258                         return -ENODEV;
 259                 }
 260
 261                 if (c->parent != p) {
 262                         ret = clk_set_parent(c, p);
 263                         if (ret) {
 264                                 pr_warning("Unable to set parent %s of clock %s: %d\n",
 265                                         table->parent, table->name, ret);
 266                                 return -EINVAL;
 267                         }
 268                 }
 269         }
 270
 271         if (table->rate && table->rate != clk_get_rate(c)) {
 272                 ret = clk_set_rate(c, table->rate);
 273                 if (ret) {
 274                         pr_warning("Unable to set clock %s to rate %lu: %d\n",
 275                                 table->name, table->rate, ret);
 276                         return -EINVAL;
 277                 }
 278         }
 279
 280         if (table->enabled) {
 281                 ret = clk_enable(c);
 282                 if (ret) {
 283                         pr_warning("Unable to enable clock %s: %d\n",
 284                                 table->name, ret);
 285                         return -EINVAL;
 286                 }
 287         }
 288
 289         return 0;
 290 }
 291
 292 void tegra_clk_init_from_table(struct tegra_clk_init_table *table)
 293 {
 294         for (; table->name; table++)
 295                 tegra_clk_init_one_from_table(table);
 296 }
 297 EXPORT_SYMBOL(tegra_clk_init_from_table);
 298
 299 void tegra_periph_reset_deassert(struct clk *c)
 300 {
 301         tegra2_periph_reset_deassert(c);
 302 }
 303 EXPORT_SYMBOL(tegra_periph_reset_deassert);
 304
 305 void tegra_periph_reset_assert(struct clk *c)
 306 {
 307         tegra2_periph_reset_assert(c);
 308 }
 309 EXPORT_SYMBOL(tegra_periph_reset_assert);
 310
 311 int __init tegra_init_clock(void)
 312 {
 313         tegra2_init_clocks();
 314
 315         return 0;
 316 }
 317
 318 #ifdef CONFIG_DEBUG_FS
 319 static struct dentry *clk_debugfs_root;
 320
 321
 322 static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
 323 {
 324         struct clk *child;
 325         struct clk *safe;
 326         const char *state = "uninit";
 327         char div[5] = {0};
 328
 329         if (c->state == ON)
 330                 state = "on";
 331         else if (c->state == OFF)
 332                 state = "off";
 333
 334         if (c->mul != 0 && c->div != 0) {
 335                 BUG_ON(c->mul > 2);
 336                 if (c->mul > c->div)
 337                         snprintf(div, sizeof(div), "x%d", c->mul / c->div);
 338                 else
 339                         snprintf(div, sizeof(div), "%d%s", c->div / c->mul,
 340                                 (c->div % c->mul) ? ".5" : "");
 341         }
 342
 343         seq_printf(s, "%*s%-*s %-6s %-3d %-5s %-10lu\n",
 344                 level * 3 + 1, c->set ? "" : "*",
 345                 30 - level * 3, c->name,
 346                 state, c->refcnt, div, c->rate);
 347         list_for_each_entry_safe(child, safe, &c->children, sibling) {
 348                 clock_tree_show_one(s, child, level + 1);
 349         }
 350 }
 351
 352 static int clock_tree_show(struct seq_file *s, void *data)
 353 {
 354         struct clk *c;
 355         unsigned long flags;
 356         seq_printf(s, " clock                          state  ref div   rate      \n");
 357         seq_printf(s, "-----------------------------------------------------------\n");
 358         spin_lock_irqsave(&clock_lock, flags);
 359         list_for_each_entry(c, &clocks, node)
 360                 if (c->parent == NULL)
 361                         clock_tree_show_one(s, c, 0);
 362         spin_unlock_irqrestore(&clock_lock, flags);
 363         return 0;
 364 }
 365
 366 static int clock_tree_open(struct inode *inode, struct file *file)
 367 {
 368         return single_open(file, clock_tree_show, inode->i_private);
 369 }
 370
 371 static const struct file_operations clock_tree_fops = {
 372         .open           = clock_tree_open,
 373         .read           = seq_read,
 374         .llseek         = seq_lseek,
 375         .release        = single_release,
 376 };
 377
 378 static int possible_parents_show(struct seq_file *s, void *data)
 379 {
 380         struct clk *c = s->private;
 381         int i;
 382
 383         for (i = 0; c->inputs[i].input; i++) {
 384                 char *first = (i == 0) ? "" : " ";
 385                 seq_printf(s, "%s%s", first, c->inputs[i].input->name);
 386         }
 387         seq_printf(s, "\n");
 388         return 0;
 389 }
 390
 391 static int possible_parents_open(struct inode *inode, struct file *file)
 392 {
 393         return single_open(file, possible_parents_show, inode->i_private);
 394 }
 395
 396 static const struct file_operations possible_parents_fops = {
 397         .open           = possible_parents_open,
 398         .read           = seq_read,
 399         .llseek         = seq_lseek,
 400         .release        = single_release,
 401 };
 402
 403 static int clk_debugfs_register_one(struct clk *c)
 404 {
 405         struct dentry *d, *child, *child_tmp;
 406
 407         d = debugfs_create_dir(c->name, clk_debugfs_root);
 408         if (!d)
 409                 return -ENOMEM;
 410         c->dent = d;
 411
 412         d = debugfs_create_u8("refcnt", S_IRUGO, c->dent, (u8 *)&c->refcnt);
 413         if (!d)
 414                 goto err_out;
 415
 416         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 417         if (!d)
 418                 goto err_out;
 419
 420         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 421         if (!d)
 422                 goto err_out;
 423
 424         if (c->inputs) {
 425                 d = debugfs_create_file("possible_parents", S_IRUGO, c->dent,
 426                         c, &possible_parents_fops);
 427                 if (!d)
 428                         goto err_out;
 429         }
 430
 431         return 0;
 432
 433 err_out:
 434         d = c->dent;
 435         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 436                 debugfs_remove(child);
 437         debugfs_remove(c->dent);
 438         return -ENOMEM;
 439 }
 440
 441 static int clk_debugfs_register(struct clk *c)
 442 {
 443         int err;
 444         struct clk *pa = c->parent;
 445
 446         if (pa && !pa->dent) {
 447                 err = clk_debugfs_register(pa);
 448                 if (err)
 449                         return err;
 450         }
 451
 452         if (!c->dent) {
 453                 err = clk_debugfs_register_one(c);
 454                 if (err)
 455                         return err;
 456         }
 457         return 0;
 458 }
 459
 460 static int __init clk_debugfs_init(void)
 461 {
 462         struct clk *c;
 463         struct dentry *d;
 464         int err = -ENOMEM;
 465
 466         d = debugfs_create_dir("clock", NULL);
 467         if (!d)
 468                 return -ENOMEM;
 469         clk_debugfs_root = d;
 470
 471         d = debugfs_create_file("clock_tree", S_IRUGO, clk_debugfs_root, NULL,
 472                 &clock_tree_fops);
 473         if (!d)
 474                 goto err_out;
 475
 476         list_for_each_entry(c, &clocks, node) {
 477                 err = clk_debugfs_register(c);
 478                 if (err)
 479                         goto err_out;
 480         }
 481         return 0;
 482 err_out:
 483         debugfs_remove_recursive(clk_debugfs_root);
 484         return err;
 485 }
 486
 487 late_initcall(clk_debugfs_init);
 488 #endif