arch/mips/kernel/cpufreq/loongson2_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
  10 #include <linux/module.h>
  11 #include <linux/cpufreq.h>
  12 #include <linux/platform_device.h>
  13
  14 #include <asm/clock.h>
  15
  16 #include <loongson.h>
  17
  18 static LIST_HEAD(clock_list);
  19 static DEFINE_SPINLOCK(clock_lock);
  20 static DEFINE_MUTEX(clock_list_sem);
  21
  22 /* Minimum CLK support */
  23 enum {
  24         DC_ZERO, DC_25PT = 2, DC_37PT, DC_50PT, DC_62PT, DC_75PT,
  25         DC_87PT, DC_DISABLE, DC_RESV
  26 };
  27
  28 struct cpufreq_frequency_table loongson2_clockmod_table[] = {
  29         {DC_RESV, CPUFREQ_ENTRY_INVALID},
  30         {DC_ZERO, CPUFREQ_ENTRY_INVALID},
  31         {DC_25PT, 0},
  32         {DC_37PT, 0},
  33         {DC_50PT, 0},
  34         {DC_62PT, 0},
  35         {DC_75PT, 0},
  36         {DC_87PT, 0},
  37         {DC_DISABLE, 0},
  38         {DC_RESV, CPUFREQ_TABLE_END},
  39 };
  40 EXPORT_SYMBOL_GPL(loongson2_clockmod_table);
  41
  42 static struct clk cpu_clk = {
  43         .name = "cpu_clk",
  44         .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
  45         .rate = 800000000,
  46 };
  47
  48 struct clk *clk_get(struct device *dev, const char *id)
  49 {
  50         return &cpu_clk;
  51 }
  52 EXPORT_SYMBOL(clk_get);
  53
  54 static void propagate_rate(struct clk *clk)
  55 {
  56         struct clk *clkp;
  57
  58         list_for_each_entry(clkp, &clock_list, node) {
  59                 if (likely(clkp->parent != clk))
  60                         continue;
  61                 if (likely(clkp->ops && clkp->ops->recalc))
  62                         clkp->ops->recalc(clkp);
  63                 if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
  64                         propagate_rate(clkp);
  65         }
  66 }
  67
  68 int clk_enable(struct clk *clk)
  69 {
  70         return 0;
  71 }
  72 EXPORT_SYMBOL(clk_enable);
  73
  74 void clk_disable(struct clk *clk)
  75 {
  76 }
  77 EXPORT_SYMBOL(clk_disable);
  78
  79 unsigned long clk_get_rate(struct clk *clk)
  80 {
  81         return (unsigned long)clk->rate;
  82 }
  83 EXPORT_SYMBOL(clk_get_rate);
  84
  85 void clk_put(struct clk *clk)
  86 {
  87 }
  88 EXPORT_SYMBOL(clk_put);
  89
  90 int clk_set_rate(struct clk *clk, unsigned long rate)
  91 {
  92         return clk_set_rate_ex(clk, rate, 0);
  93 }
  94 EXPORT_SYMBOL_GPL(clk_set_rate);
  95
  96 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
  97 {
  98         int ret = 0;
  99         int regval;
 100         int i;
 101
 102         if (likely(clk->ops && clk->ops->set_rate)) {
 103                 unsigned long flags;
 104
 105                 spin_lock_irqsave(&clock_lock, flags);
 106                 ret = clk->ops->set_rate(clk, rate, algo_id);
 107                 spin_unlock_irqrestore(&clock_lock, flags);
 108         }
 109
 110         if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
 111                 propagate_rate(clk);
 112
 113         for (i = 0; loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END;
 114              i++) {
 115                 if (loongson2_clockmod_table[i].frequency ==
 116                     CPUFREQ_ENTRY_INVALID)
 117                         continue;
 118                 if (rate == loongson2_clockmod_table[i].frequency)
 119                         break;
 120         }
 121         if (rate != loongson2_clockmod_table[i].frequency)
 122                 return -ENOTSUPP;
 123
 124         clk->rate = rate;
 125
 126         regval = LOONGSON_CHIPCFG0;
 127         regval = (regval & ~0x7) | (loongson2_clockmod_table[i].index - 1);
 128         LOONGSON_CHIPCFG0 = regval;
 129
 130         return ret;
 131 }
 132 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 133
 134 long clk_round_rate(struct clk *clk, unsigned long rate)
 135 {
 136         if (likely(clk->ops && clk->ops->round_rate)) {
 137                 unsigned long flags, rounded;
 138
 139                 spin_lock_irqsave(&clock_lock, flags);
 140                 rounded = clk->ops->round_rate(clk, rate);
 141                 spin_unlock_irqrestore(&clock_lock, flags);
 142
 143                 return rounded;
 144         }
 145
 146         return rate;
 147 }
 148 EXPORT_SYMBOL_GPL(clk_round_rate);
 149
 150 /*
 151  * This is the simple version of Loongson-2 wait, Maybe we need do this in
 152  * interrupt disabled content
 153  */
 154
 155 DEFINE_SPINLOCK(loongson2_wait_lock);
 156 void loongson2_cpu_wait(void)
 157 {
 158         u32 cpu_freq;
 159         unsigned long flags;
 160
 161         spin_lock_irqsave(&loongson2_wait_lock, flags);
 162         cpu_freq = LOONGSON_CHIPCFG0;
 163         LOONGSON_CHIPCFG0 &= ~0x7;      /* Put CPU into wait mode */
 164         LOONGSON_CHIPCFG0 = cpu_freq;   /* Restore CPU state */
 165         spin_unlock_irqrestore(&loongson2_wait_lock, flags);
 166 }
 167 EXPORT_SYMBOL_GPL(loongson2_cpu_wait);
 168
 169 MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
 170 MODULE_DESCRIPTION("cpufreq driver for Loongson 2F");
 171 MODULE_LICENSE("GPL");