arch/mips/lantiq/clk.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  *
   6  * Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com>
   7  * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
   8  */
   9 #include <linux/io.h>
  10 #include <linux/export.h>
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/clk.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/err.h>
  17 #include <linux/list.h>
  18
  19 #include <asm/time.h>
  20 #include <asm/irq.h>
  21 #include <asm/div64.h>
  22
  23 #include <lantiq_soc.h>
  24
  25 #include "clk.h"
  26 #include "prom.h"
  27
  28 /* lantiq socs have 3 static clocks */
  29 static struct clk cpu_clk_generic[4];
  30
  31 void clkdev_add_static(unsigned long cpu, unsigned long fpi,
  32                         unsigned long io, unsigned long ppe)
  33 {
  34         cpu_clk_generic[0].rate = cpu;
  35         cpu_clk_generic[1].rate = fpi;
  36         cpu_clk_generic[2].rate = io;
  37         cpu_clk_generic[3].rate = ppe;
  38 }
  39
  40 struct clk *clk_get_cpu(void)
  41 {
  42         return &cpu_clk_generic[0];
  43 }
  44
  45 struct clk *clk_get_fpi(void)
  46 {
  47         return &cpu_clk_generic[1];
  48 }
  49 EXPORT_SYMBOL_GPL(clk_get_fpi);
  50
  51 struct clk *clk_get_io(void)
  52 {
  53         return &cpu_clk_generic[2];
  54 }
  55
  56 struct clk *clk_get_ppe(void)
  57 {
  58         return &cpu_clk_generic[3];
  59 }
  60 EXPORT_SYMBOL_GPL(clk_get_ppe);
  61
  62 static inline int clk_good(struct clk *clk)
  63 {
  64         return clk && !IS_ERR(clk);
  65 }
  66
  67 unsigned long clk_get_rate(struct clk *clk)
  68 {
  69         if (unlikely(!clk_good(clk)))
  70                 return 0;
  71
  72         if (clk->rate != 0)
  73                 return clk->rate;
  74
  75         if (clk->get_rate != NULL)
  76                 return clk->get_rate();
  77
  78         return 0;
  79 }
  80 EXPORT_SYMBOL(clk_get_rate);
  81
  82 int clk_set_rate(struct clk *clk, unsigned long rate)
  83 {
  84         if (unlikely(!clk_good(clk)))
  85                 return 0;
  86         if (clk->rates && *clk->rates) {
  87                 unsigned long *r = clk->rates;
  88
  89                 while (*r && (*r != rate))
  90                         r++;
  91                 if (!*r) {
  92                         pr_err("clk %s.%s: trying to set invalid rate %ld\n",
  93                                 clk->cl.dev_id, clk->cl.con_id, rate);
  94                         return -1;
  95                 }
  96         }
  97         clk->rate = rate;
  98         return 0;
  99 }
 100 EXPORT_SYMBOL(clk_set_rate);
 101
 102 int clk_enable(struct clk *clk)
 103 {
 104         if (unlikely(!clk_good(clk)))
 105                 return -1;
 106
 107         if (clk->enable)
 108                 return clk->enable(clk);
 109
 110         return -1;
 111 }
 112 EXPORT_SYMBOL(clk_enable);
 113
 114 void clk_disable(struct clk *clk)
 115 {
 116         if (unlikely(!clk_good(clk)))
 117                 return;
 118
 119         if (clk->disable)
 120                 clk->disable(clk);
 121 }
 122 EXPORT_SYMBOL(clk_disable);
 123
 124 int clk_activate(struct clk *clk)
 125 {
 126         if (unlikely(!clk_good(clk)))
 127                 return -1;
 128
 129         if (clk->activate)
 130                 return clk->activate(clk);
 131
 132         return -1;
 133 }
 134 EXPORT_SYMBOL(clk_activate);
 135
 136 void clk_deactivate(struct clk *clk)
 137 {
 138         if (unlikely(!clk_good(clk)))
 139                 return;
 140
 141         if (clk->deactivate)
 142                 clk->deactivate(clk);
 143 }
 144 EXPORT_SYMBOL(clk_deactivate);
 145
 146 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 147 {
 148         return NULL;
 149 }
 150
 151 static inline u32 get_counter_resolution(void)
 152 {
 153         u32 res;
 154
 155         __asm__ __volatile__(
 156                 ".set   push\n"
 157                 ".set   mips32r2\n"
 158                 "rdhwr  %0, $3\n"
 159                 ".set pop\n"
 160                 : "=&r" (res)
 161                 : /* no input */
 162                 : "memory");
 163
 164         return res;
 165 }
 166
 167 void __init plat_time_init(void)
 168 {
 169         struct clk *clk;
 170
 171         ltq_soc_init();
 172
 173         clk = clk_get_cpu();
 174         mips_hpt_frequency = clk_get_rate(clk) / get_counter_resolution();
 175         write_c0_compare(read_c0_count());
 176         pr_info("CPU Clock: %ldMHz\n", clk_get_rate(clk) / 1000000);
 177         clk_put(clk);
 178 }