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/list.h>
  14 #include <linux/mutex.h>
  15 #include <linux/spinlock.h>
  16
  17 #include <asm/clock.h>
  18 #include <asm/mach-loongson/loongson.h>
  19
  20 static LIST_HEAD(clock_list);
  21 static DEFINE_SPINLOCK(clock_lock);
  22 static DEFINE_MUTEX(clock_list_sem);
  23
  24 /* Minimum CLK support */
  25 enum {
  26         DC_ZERO, DC_25PT = 2, DC_37PT, DC_50PT, DC_62PT, DC_75PT,
  27         DC_87PT, DC_DISABLE, DC_RESV
  28 };
  29
  30 struct cpufreq_frequency_table loongson2_clockmod_table[] = {
  31         {0, DC_RESV, CPUFREQ_ENTRY_INVALID},
  32         {0, DC_ZERO, CPUFREQ_ENTRY_INVALID},
  33         {0, DC_25PT, 0},
  34         {0, DC_37PT, 0},
  35         {0, DC_50PT, 0},
  36         {0, DC_62PT, 0},
  37         {0, DC_75PT, 0},
  38         {0, DC_87PT, 0},
  39         {0, DC_DISABLE, 0},
  40         {0, DC_RESV, CPUFREQ_TABLE_END},
  41 };
  42 EXPORT_SYMBOL_GPL(loongson2_clockmod_table);
  43
  44 static struct clk cpu_clk = {
  45         .name = "cpu_clk",
  46         .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
  47         .rate = 800000000,
  48 };
  49
  50 struct clk *clk_get(struct device *dev, const char *id)
  51 {
  52         return &cpu_clk;
  53 }
  54 EXPORT_SYMBOL(clk_get);
  55
  56 static void propagate_rate(struct clk *clk)
  57 {
  58         struct clk *clkp;
  59
  60         list_for_each_entry(clkp, &clock_list, node) {
  61                 if (likely(clkp->parent != clk))
  62                         continue;
  63                 if (likely(clkp->ops && clkp->ops->recalc))
  64                         clkp->ops->recalc(clkp);
  65                 if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
  66                         propagate_rate(clkp);
  67         }
  68 }
  69
  70 int clk_enable(struct clk *clk)
  71 {
  72         return 0;
  73 }
  74 EXPORT_SYMBOL(clk_enable);
  75
  76 void clk_disable(struct clk *clk)
  77 {
  78 }
  79 EXPORT_SYMBOL(clk_disable);
  80
  81 unsigned long clk_get_rate(struct clk *clk)
  82 {
  83         return (unsigned long)clk->rate;
  84 }
  85 EXPORT_SYMBOL(clk_get_rate);
  86
  87 void clk_put(struct clk *clk)
  88 {
  89 }
  90 EXPORT_SYMBOL(clk_put);
  91
  92 int clk_set_rate(struct clk *clk, unsigned long rate)
  93 {
  94         unsigned int rate_khz = rate / 1000;
  95         struct cpufreq_frequency_table *pos;
  96         int ret = 0;
  97         int regval;
  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         cpufreq_for_each_valid_entry(pos, loongson2_clockmod_table)
 111                 if (rate_khz == pos->frequency)
 112                         break;
 113         if (rate_khz != pos->frequency)
 114                 return -ENOTSUPP;
 115
 116         clk->rate = rate;
 117
 118         regval = LOONGSON_CHIPCFG(0);
 119         regval = (regval & ~0x7) | (pos->driver_data - 1);
 120         LOONGSON_CHIPCFG(0) = regval;
 121
 122         return ret;
 123 }
 124 EXPORT_SYMBOL_GPL(clk_set_rate);
 125
 126 long clk_round_rate(struct clk *clk, unsigned long rate)
 127 {
 128         if (likely(clk->ops && clk->ops->round_rate)) {
 129                 unsigned long flags, rounded;
 130
 131                 spin_lock_irqsave(&clock_lock, flags);
 132                 rounded = clk->ops->round_rate(clk, rate);
 133                 spin_unlock_irqrestore(&clock_lock, flags);
 134
 135                 return rounded;
 136         }
 137
 138         return rate;
 139 }
 140 EXPORT_SYMBOL_GPL(clk_round_rate);