arch/mips/loongson/lemote-2f/clock.c

   1 /*
   2  * Copyright (C) 2006 - 2008 Lemote Inc. & Insititute of Computing Technology
   3  * Author: Yanhua, yanh@lemote.com
   4  *
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  */
   9 #include <linux/clk.h>
  10 #include <linux/cpufreq.h>
  11 #include <linux/errno.h>
  12 #include <linux/export.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/mutex.h>
  16 #include <linux/spinlock.h>
  17
  18 #include <asm/clock.h>
  19 #include <asm/mach-loongson/loongson.h>
  20
  21 static LIST_HEAD(clock_list);
  22 static DEFINE_SPINLOCK(clock_lock);
  23 static DEFINE_MUTEX(clock_list_sem);
  24
  25 /* Minimum CLK support */
  26 enum {
  27         DC_ZERO, DC_25PT = 2, DC_37PT, DC_50PT, DC_62PT, DC_75PT,
  28         DC_87PT, DC_DISABLE, DC_RESV
  29 };
  30
  31 struct cpufreq_frequency_table loongson2_clockmod_table[] = {
  32         {DC_RESV, CPUFREQ_ENTRY_INVALID},
  33         {DC_ZERO, CPUFREQ_ENTRY_INVALID},
  34         {DC_25PT, 0},
  35         {DC_37PT, 0},
  36         {DC_50PT, 0},
  37         {DC_62PT, 0},
  38         {DC_75PT, 0},
  39         {DC_87PT, 0},
  40         {DC_DISABLE, 0},
  41         {DC_RESV, CPUFREQ_TABLE_END},
  42 };
  43 EXPORT_SYMBOL_GPL(loongson2_clockmod_table);
  44
  45 static struct clk cpu_clk = {
  46         .name = "cpu_clk",
  47         .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
  48         .rate = 800000000,
  49 };
  50
  51 struct clk *clk_get(struct device *dev, const char *id)
  52 {
  53         return &cpu_clk;
  54 }
  55 EXPORT_SYMBOL(clk_get);
  56
  57 static void propagate_rate(struct clk *clk)
  58 {
  59         struct clk *clkp;
  60
  61         list_for_each_entry(clkp, &clock_list, node) {
  62                 if (likely(clkp->parent != clk))
  63                         continue;
  64                 if (likely(clkp->ops && clkp->ops->recalc))
  65                         clkp->ops->recalc(clkp);
  66                 if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
  67                         propagate_rate(clkp);
  68         }
  69 }
  70
  71 int clk_enable(struct clk *clk)
  72 {
  73         return 0;
  74 }
  75 EXPORT_SYMBOL(clk_enable);
  76
  77 void clk_disable(struct clk *clk)
  78 {
  79 }
  80 EXPORT_SYMBOL(clk_disable);
  81
  82 unsigned long clk_get_rate(struct clk *clk)
  83 {
  84         return (unsigned long)clk->rate;
  85 }
  86 EXPORT_SYMBOL(clk_get_rate);
  87
  88 void clk_put(struct clk *clk)
  89 {
  90 }
  91 EXPORT_SYMBOL(clk_put);
  92
  93 int clk_set_rate(struct clk *clk, unsigned long rate)
  94 {
  95         int ret = 0;
  96         int regval;
  97         int i;
  98
  99         if (likely(clk->ops && clk->ops->set_rate)) {
 100                 unsigned long flags;
 101
 102                 spin_lock_irqsave(&clock_lock, flags);
 103                 ret = clk->ops->set_rate(clk, rate, 0);
 104                 spin_unlock_irqrestore(&clock_lock, flags);
 105         }
 106
 107         if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
 108                 propagate_rate(clk);
 109
 110         for (i = 0; loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END;
 111              i++) {
 112                 if (loongson2_clockmod_table[i].frequency ==
 113                     CPUFREQ_ENTRY_INVALID)
 114                         continue;
 115                 if (rate == loongson2_clockmod_table[i].frequency)
 116                         break;
 117         }
 118         if (rate != loongson2_clockmod_table[i].frequency)
 119                 return -ENOTSUPP;
 120
 121         clk->rate = rate;
 122
 123         regval = LOONGSON_CHIPCFG0;
 124         regval = (regval & ~0x7) | (loongson2_clockmod_table[i].index - 1);
 125         LOONGSON_CHIPCFG0 = regval;
 126
 127         return ret;
 128 }
 129 EXPORT_SYMBOL_GPL(clk_set_rate);
 130
 131 long clk_round_rate(struct clk *clk, unsigned long rate)
 132 {
 133         if (likely(clk->ops && clk->ops->round_rate)) {
 134                 unsigned long flags, rounded;
 135
 136                 spin_lock_irqsave(&clock_lock, flags);
 137                 rounded = clk->ops->round_rate(clk, rate);
 138                 spin_unlock_irqrestore(&clock_lock, flags);
 139
 140                 return rounded;
 141         }
 142
 143         return rate;
 144 }
 145 EXPORT_SYMBOL_GPL(clk_round_rate);