arch/arm/mach-davinci/clock.c

   1 /*
   2  * Clock and PLL control for DaVinci devices
   3  *
   4  * Copyright (C) 2006-2007 Texas Instruments.
   5  * Copyright (C) 2008-2009 Deep Root Systems, LLC
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/errno.h>
  17 #include <linux/clk.h>
  18 #include <linux/err.h>
  19 #include <linux/mutex.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/io.h>
  22
  23 #include <mach/hardware.h>
  24
  25 #include <mach/psc.h>
  26 #include <mach/cputype.h>
  27 #include "clock.h"
  28
  29 static LIST_HEAD(clocks);
  30 static DEFINE_MUTEX(clocks_mutex);
  31 static DEFINE_SPINLOCK(clockfw_lock);
  32
  33 static unsigned psc_domain(struct clk *clk)
  34 {
  35         return (clk->flags & PSC_DSP)
  36                 ? DAVINCI_GPSC_DSPDOMAIN
  37                 : DAVINCI_GPSC_ARMDOMAIN;
  38 }
  39
  40 static void __clk_enable(struct clk *clk)
  41 {
  42         if (clk->parent)
  43                 __clk_enable(clk->parent);
  44         if (clk->usecount++ == 0 && (clk->flags & CLK_PSC))
  45                 davinci_psc_config(psc_domain(clk), clk->psc_ctlr,
  46                                 clk->lpsc, 1);
  47 }
  48
  49 static void __clk_disable(struct clk *clk)
  50 {
  51         if (WARN_ON(clk->usecount == 0))
  52                 return;
  53         if (--clk->usecount == 0 && !(clk->flags & CLK_PLL))
  54                 davinci_psc_config(psc_domain(clk), clk->psc_ctlr,
  55                                 clk->lpsc, 0);
  56         if (clk->parent)
  57                 __clk_disable(clk->parent);
  58 }
  59
  60 int clk_enable(struct clk *clk)
  61 {
  62         unsigned long flags;
  63
  64         if (clk == NULL || IS_ERR(clk))
  65                 return -EINVAL;
  66
  67         spin_lock_irqsave(&clockfw_lock, flags);
  68         __clk_enable(clk);
  69         spin_unlock_irqrestore(&clockfw_lock, flags);
  70
  71         return 0;
  72 }
  73 EXPORT_SYMBOL(clk_enable);
  74
  75 void clk_disable(struct clk *clk)
  76 {
  77         unsigned long flags;
  78
  79         if (clk == NULL || IS_ERR(clk))
  80                 return;
  81
  82         spin_lock_irqsave(&clockfw_lock, flags);
  83         __clk_disable(clk);
  84         spin_unlock_irqrestore(&clockfw_lock, flags);
  85 }
  86 EXPORT_SYMBOL(clk_disable);
  87
  88 unsigned long clk_get_rate(struct clk *clk)
  89 {
  90         if (clk == NULL || IS_ERR(clk))
  91                 return -EINVAL;
  92
  93         return clk->rate;
  94 }
  95 EXPORT_SYMBOL(clk_get_rate);
  96
  97 long clk_round_rate(struct clk *clk, unsigned long rate)
  98 {
  99         if (clk == NULL || IS_ERR(clk))
 100                 return -EINVAL;
 101
 102         return clk->rate;
 103 }
 104 EXPORT_SYMBOL(clk_round_rate);
 105
 106 int clk_set_rate(struct clk *clk, unsigned long rate)
 107 {
 108         if (clk == NULL || IS_ERR(clk))
 109                 return -EINVAL;
 110
 111         /* changing the clk rate is not supported */
 112         return -EINVAL;
 113 }
 114 EXPORT_SYMBOL(clk_set_rate);
 115
 116 int clk_register(struct clk *clk)
 117 {
 118         if (clk == NULL || IS_ERR(clk))
 119                 return -EINVAL;
 120
 121         if (WARN(clk->parent && !clk->parent->rate,
 122                         "CLK: %s parent %s has no rate!\n",
 123                         clk->name, clk->parent->name))
 124                 return -EINVAL;
 125
 126         mutex_lock(&clocks_mutex);
 127         list_add_tail(&clk->node, &clocks);
 128         mutex_unlock(&clocks_mutex);
 129
 130         /* If rate is already set, use it */
 131         if (clk->rate)
 132                 return 0;
 133
 134         /* Otherwise, default to parent rate */
 135         if (clk->parent)
 136                 clk->rate = clk->parent->rate;
 137
 138         return 0;
 139 }
 140 EXPORT_SYMBOL(clk_register);
 141
 142 void clk_unregister(struct clk *clk)
 143 {
 144         if (clk == NULL || IS_ERR(clk))
 145                 return;
 146
 147         mutex_lock(&clocks_mutex);
 148         list_del(&clk->node);
 149         mutex_unlock(&clocks_mutex);
 150 }
 151 EXPORT_SYMBOL(clk_unregister);
 152
 153 #ifdef CONFIG_DAVINCI_RESET_CLOCKS
 154 /*
 155  * Disable any unused clocks left on by the bootloader
 156  */
 157 static int __init clk_disable_unused(void)
 158 {
 159         struct clk *ck;
 160
 161         spin_lock_irq(&clockfw_lock);
 162         list_for_each_entry(ck, &clocks, node) {
 163                 if (ck->usecount > 0)
 164                         continue;
 165                 if (!(ck->flags & CLK_PSC))
 166                         continue;
 167
 168                 /* ignore if in Disabled or SwRstDisable states */
 169                 if (!davinci_psc_is_clk_active(ck->psc_ctlr, ck->lpsc))
 170                         continue;
 171
 172                 pr_info("Clocks: disable unused %s\n", ck->name);
 173                 davinci_psc_config(psc_domain(ck), ck->psc_ctlr, ck->lpsc, 0);
 174         }
 175         spin_unlock_irq(&clockfw_lock);
 176
 177         return 0;
 178 }
 179 late_initcall(clk_disable_unused);
 180 #endif
 181
 182 static void clk_sysclk_recalc(struct clk *clk)
 183 {
 184         u32 v, plldiv;
 185         struct pll_data *pll;
 186
 187         /* If this is the PLL base clock, no more calculations needed */
 188         if (clk->pll_data)
 189                 return;
 190
 191         if (WARN_ON(!clk->parent))
 192                 return;
 193
 194         clk->rate = clk->parent->rate;
 195
 196         /* Otherwise, the parent must be a PLL */
 197         if (WARN_ON(!clk->parent->pll_data))
 198                 return;
 199
 200         pll = clk->parent->pll_data;
 201
 202         /* If pre-PLL, source clock is before the multiplier and divider(s) */
 203         if (clk->flags & PRE_PLL)
 204                 clk->rate = pll->input_rate;
 205
 206         if (!clk->div_reg)
 207                 return;
 208
 209         v = __raw_readl(pll->base + clk->div_reg);
 210         if (v & PLLDIV_EN) {
 211                 plldiv = (v & PLLDIV_RATIO_MASK) + 1;
 212                 if (plldiv)
 213                         clk->rate /= plldiv;
 214         }
 215 }
 216
 217 static void __init clk_pll_init(struct clk *clk)
 218 {
 219         u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
 220         u8 bypass;
 221         struct pll_data *pll = clk->pll_data;
 222
 223         pll->base = IO_ADDRESS(pll->phys_base);
 224         ctrl = __raw_readl(pll->base + PLLCTL);
 225         clk->rate = pll->input_rate = clk->parent->rate;
 226
 227         if (ctrl & PLLCTL_PLLEN) {
 228                 bypass = 0;
 229                 mult = __raw_readl(pll->base + PLLM);
 230                 mult = (mult & PLLM_PLLM_MASK) + 1;
 231         } else
 232                 bypass = 1;
 233
 234         if (pll->flags & PLL_HAS_PREDIV) {
 235                 prediv = __raw_readl(pll->base + PREDIV);
 236                 if (prediv & PLLDIV_EN)
 237                         prediv = (prediv & PLLDIV_RATIO_MASK) + 1;
 238                 else
 239                         prediv = 1;
 240         }
 241
 242         /* pre-divider is fixed, but (some?) chips won't report that */
 243         if (cpu_is_davinci_dm355() && pll->num == 1)
 244                 prediv = 8;
 245
 246         if (pll->flags & PLL_HAS_POSTDIV) {
 247                 postdiv = __raw_readl(pll->base + POSTDIV);
 248                 if (postdiv & PLLDIV_EN)
 249                         postdiv = (postdiv & PLLDIV_RATIO_MASK) + 1;
 250                 else
 251                         postdiv = 1;
 252         }
 253
 254         if (!bypass) {
 255                 clk->rate /= prediv;
 256                 clk->rate *= mult;
 257                 clk->rate /= postdiv;
 258         }
 259
 260         pr_debug("PLL%d: input = %lu MHz [ ",
 261                  pll->num, clk->parent->rate / 1000000);
 262         if (bypass)
 263                 pr_debug("bypass ");
 264         if (prediv > 1)
 265                 pr_debug("/ %d ", prediv);
 266         if (mult > 1)
 267                 pr_debug("* %d ", mult);
 268         if (postdiv > 1)
 269                 pr_debug("/ %d ", postdiv);
 270         pr_debug("] --> %lu MHz output.\n", clk->rate / 1000000);
 271 }
 272
 273 int __init davinci_clk_init(struct davinci_clk *clocks)
 274   {
 275         struct davinci_clk *c;
 276         struct clk *clk;
 277
 278         for (c = clocks; c->lk.clk; c++) {
 279                 clk = c->lk.clk;
 280
 281                 if (clk->pll_data)
 282                         clk_pll_init(clk);
 283
 284                 /* Calculate rates for PLL-derived clocks */
 285                 else if (clk->flags & CLK_PLL)
 286                         clk_sysclk_recalc(clk);
 287
 288                 if (clk->lpsc)
 289                         clk->flags |= CLK_PSC;
 290
 291                 clkdev_add(&c->lk);
 292                 clk_register(clk);
 293
 294                 /* Turn on clocks that Linux doesn't otherwise manage */
 295                 if (clk->flags & ALWAYS_ENABLED)
 296                         clk_enable(clk);
 297         }
 298
 299         return 0;
 300 }
 301
 302 #ifdef CONFIG_PROC_FS
 303 #include <linux/proc_fs.h>
 304 #include <linux/seq_file.h>
 305
 306 static void *davinci_ck_start(struct seq_file *m, loff_t *pos)
 307 {
 308         return *pos < 1 ? (void *)1 : NULL;
 309 }
 310
 311 static void *davinci_ck_next(struct seq_file *m, void *v, loff_t *pos)
 312 {
 313         ++*pos;
 314         return NULL;
 315 }
 316
 317 static void davinci_ck_stop(struct seq_file *m, void *v)
 318 {
 319 }
 320
 321 #define CLKNAME_MAX     10              /* longest clock name */
 322 #define NEST_DELTA      2
 323 #define NEST_MAX        4
 324
 325 static void
 326 dump_clock(struct seq_file *s, unsigned nest, struct clk *parent)
 327 {
 328         char            *state;
 329         char            buf[CLKNAME_MAX + NEST_DELTA * NEST_MAX];
 330         struct clk      *clk;
 331         unsigned        i;
 332
 333         if (parent->flags & CLK_PLL)
 334                 state = "pll";
 335         else if (parent->flags & CLK_PSC)
 336                 state = "psc";
 337         else
 338                 state = "";
 339
 340         /* <nest spaces> name <pad to end> */
 341         memset(buf, ' ', sizeof(buf) - 1);
 342         buf[sizeof(buf) - 1] = 0;
 343         i = strlen(parent->name);
 344         memcpy(buf + nest, parent->name,
 345                         min(i, (unsigned)(sizeof(buf) - 1 - nest)));
 346
 347         seq_printf(s, "%s users=%2d %-3s %9ld Hz\n",
 348                    buf, parent->usecount, state, clk_get_rate(parent));
 349         /* REVISIT show device associations too */
 350
 351         /* cost is now small, but not linear... */
 352         list_for_each_entry(clk, &clocks, node) {
 353                 if (clk->parent == parent)
 354                         dump_clock(s, nest + NEST_DELTA, clk);
 355         }
 356 }
 357
 358 static int davinci_ck_show(struct seq_file *m, void *v)
 359 {
 360         /* Show clock tree; we know the main oscillator is first.
 361          * We trust nonzero usecounts equate to PSC enables...
 362          */
 363         mutex_lock(&clocks_mutex);
 364         if (!list_empty(&clocks))
 365                 dump_clock(m, 0, list_first_entry(&clocks, struct clk, node));
 366         mutex_unlock(&clocks_mutex);
 367
 368         return 0;
 369 }
 370
 371 static const struct seq_operations davinci_ck_op = {
 372         .start  = davinci_ck_start,
 373         .next   = davinci_ck_next,
 374         .stop   = davinci_ck_stop,
 375         .show   = davinci_ck_show
 376 };
 377
 378 static int davinci_ck_open(struct inode *inode, struct file *file)
 379 {
 380         return seq_open(file, &davinci_ck_op);
 381 }
 382
 383 static const struct file_operations proc_davinci_ck_operations = {
 384         .open           = davinci_ck_open,
 385         .read           = seq_read,
 386         .llseek         = seq_lseek,
 387         .release        = seq_release,
 388 };
 389
 390 static int __init davinci_ck_proc_init(void)
 391 {
 392         proc_create("davinci_clocks", 0, NULL, &proc_davinci_ck_operations);
 393         return 0;
 394
 395 }
 396 __initcall(davinci_ck_proc_init);
 397 #endif /* CONFIG_DEBUG_PROC_FS */