arch/powerpc/platforms/pasemi/cpufreq.c

   1 /*
   2  * Copyright (C) 2007 PA Semi, Inc
   3  *
   4  * Authors: Egor Martovetsky <egor@pasemi.com>
   5  *          Olof Johansson <olof@lixom.net>
   6  *
   7  * Maintained by: Olof Johansson <olof@lixom.net>
   8  *
   9  * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
  10  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2, or (at your option)
  15  * any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  *
  26  */
  27
  28 #include <linux/cpufreq.h>
  29 #include <linux/timer.h>
  30
  31 #include <asm/hw_irq.h>
  32 #include <asm/io.h>
  33 #include <asm/prom.h>
  34
  35 #define SDCASR_REG              0x0100
  36 #define SDCASR_REG_STRIDE       0x1000
  37 #define SDCPWR_CFGA0_REG        0x0100
  38 #define SDCPWR_PWST0_REG        0x0000
  39 #define SDCPWR_GIZTIME_REG      0x0440
  40
  41 /* SDCPWR_GIZTIME_REG fields */
  42 #define SDCPWR_GIZTIME_GR       0x80000000
  43 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  44
  45 /* Offset of ASR registers from SDC base */
  46 #define SDCASR_OFFSET           0x120000
  47
  48 static void __iomem *sdcpwr_mapbase;
  49 static void __iomem *sdcasr_mapbase;
  50
  51 static DEFINE_MUTEX(pas_switch_mutex);
  52
  53 /* Current astate, is used when waking up from power savings on
  54  * one core, in case the other core has switched states during
  55  * the idle time.
  56  */
  57 static int current_astate;
  58
  59 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  60 static struct cpufreq_frequency_table pas_freqs[] = {
  61         {0,     0},
  62         {1,     0},
  63         {2,     0},
  64         {3,     0},
  65         {4,     0},
  66         {0,     CPUFREQ_TABLE_END},
  67 };
  68
  69 static struct freq_attr *pas_cpu_freqs_attr[] = {
  70         &cpufreq_freq_attr_scaling_available_freqs,
  71         NULL,
  72 };
  73
  74 /*
  75  * hardware specific functions
  76  */
  77
  78 static int get_astate_freq(int astate)
  79 {
  80         u32 ret;
  81         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  82
  83         return ret & 0x3f;
  84 }
  85
  86 static int get_cur_astate(int cpu)
  87 {
  88         u32 ret;
  89
  90         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  91         ret = (ret >> (cpu * 4)) & 0x7;
  92
  93         return ret;
  94 }
  95
  96 static int get_gizmo_latency(void)
  97 {
  98         u32 giztime, ret;
  99
 100         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 101
 102         /* just provide the upper bound */
 103         if (giztime & SDCPWR_GIZTIME_GR)
 104                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 105         else
 106                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 107
 108         return ret;
 109 }
 110
 111 static void set_astate(int cpu, unsigned int astate)
 112 {
 113         u64 flags;
 114
 115         /* Return if called before init has run */
 116         if (unlikely(!sdcasr_mapbase))
 117                 return;
 118
 119         local_irq_save(flags);
 120
 121         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 122
 123         local_irq_restore(flags);
 124 }
 125
 126 void restore_astate(int cpu)
 127 {
 128         set_astate(cpu, current_astate);
 129 }
 130
 131 /*
 132  * cpufreq functions
 133  */
 134
 135 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 136 {
 137         const u32 *max_freqp;
 138         u32 max_freq;
 139         int i, cur_astate;
 140         struct resource res;
 141         struct device_node *cpu, *dn;
 142         int err = -ENODEV;
 143
 144         cpu = of_get_cpu_node(policy->cpu, NULL);
 145
 146         if (!cpu)
 147                 goto out;
 148
 149         dn = of_find_compatible_node(NULL, "sdc", "1682m-sdc");
 150         if (!dn)
 151                 goto out;
 152         err = of_address_to_resource(dn, 0, &res);
 153         of_node_put(dn);
 154         if (err)
 155                 goto out;
 156         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 157         if (!sdcasr_mapbase) {
 158                 err = -EINVAL;
 159                 goto out;
 160         }
 161
 162         dn = of_find_compatible_node(NULL, "gizmo", "1682m-gizmo");
 163         if (!dn) {
 164                 err = -ENODEV;
 165                 goto out_unmap_sdcasr;
 166         }
 167         err = of_address_to_resource(dn, 0, &res);
 168         of_node_put(dn);
 169         if (err)
 170                 goto out_unmap_sdcasr;
 171         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 172         if (!sdcpwr_mapbase) {
 173                 err = -EINVAL;
 174                 goto out_unmap_sdcasr;
 175         }
 176
 177         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 178
 179         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 180         if (!max_freqp) {
 181                 err = -EINVAL;
 182                 goto out_unmap_sdcpwr;
 183         }
 184
 185         /* we need the freq in kHz */
 186         max_freq = *max_freqp / 1000;
 187
 188         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 189         pr_debug("initializing frequency table\n");
 190
 191         /* initialize frequency table */
 192         for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
 193                 pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
 194                 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
 195         }
 196
 197         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 198
 199         policy->cpuinfo.transition_latency = get_gizmo_latency();
 200
 201         cur_astate = get_cur_astate(policy->cpu);
 202         pr_debug("current astate is at %d\n",cur_astate);
 203
 204         policy->cur = pas_freqs[cur_astate].frequency;
 205         policy->cpus = cpu_online_map;
 206
 207         cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
 208
 209         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
 210          * are set correctly
 211          */
 212         return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
 213
 214 out_unmap_sdcpwr:
 215         iounmap(sdcpwr_mapbase);
 216
 217 out_unmap_sdcasr:
 218         iounmap(sdcasr_mapbase);
 219 out:
 220         return err;
 221 }
 222
 223 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 224 {
 225         if (sdcasr_mapbase)
 226                 iounmap(sdcasr_mapbase);
 227         if (sdcpwr_mapbase)
 228                 iounmap(sdcpwr_mapbase);
 229
 230         cpufreq_frequency_table_put_attr(policy->cpu);
 231         return 0;
 232 }
 233
 234 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
 235 {
 236         return cpufreq_frequency_table_verify(policy, pas_freqs);
 237 }
 238
 239 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 240                               unsigned int target_freq,
 241                               unsigned int relation)
 242 {
 243         struct cpufreq_freqs freqs;
 244         int pas_astate_new;
 245         int i;
 246
 247         cpufreq_frequency_table_target(policy,
 248                                        pas_freqs,
 249                                        target_freq,
 250                                        relation,
 251                                        &pas_astate_new);
 252
 253         freqs.old = policy->cur;
 254         freqs.new = pas_freqs[pas_astate_new].frequency;
 255         freqs.cpu = policy->cpu;
 256
 257         mutex_lock(&pas_switch_mutex);
 258         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 259
 260         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 261                  policy->cpu,
 262                  pas_freqs[pas_astate_new].frequency,
 263                  pas_freqs[pas_astate_new].index);
 264
 265         current_astate = pas_astate_new;
 266
 267         for_each_online_cpu(i)
 268                 set_astate(i, pas_astate_new);
 269
 270         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 271         mutex_unlock(&pas_switch_mutex);
 272
 273         return 0;
 274 }
 275
 276 static struct cpufreq_driver pas_cpufreq_driver = {
 277         .name           = "pas-cpufreq",
 278         .owner          = THIS_MODULE,
 279         .flags          = CPUFREQ_CONST_LOOPS,
 280         .init           = pas_cpufreq_cpu_init,
 281         .exit           = pas_cpufreq_cpu_exit,
 282         .verify         = pas_cpufreq_verify,
 283         .target         = pas_cpufreq_target,
 284         .attr           = pas_cpu_freqs_attr,
 285 };
 286
 287 /*
 288  * module init and destoy
 289  */
 290
 291 static int __init pas_cpufreq_init(void)
 292 {
 293         if (!machine_is_compatible("PA6T-1682M"))
 294                 return -ENODEV;
 295
 296         return cpufreq_register_driver(&pas_cpufreq_driver);
 297 }
 298
 299 static void __exit pas_cpufreq_exit(void)
 300 {
 301         cpufreq_unregister_driver(&pas_cpufreq_driver);
 302 }
 303
 304 module_init(pas_cpufreq_init);
 305 module_exit(pas_cpufreq_exit);
 306
 307 MODULE_LICENSE("GPL");
 308 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");