release/src-rt-6.x.4708/linux/linux-2.6.36/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 #include <asm/time.h>
  35 #include <asm/smp.h>
  36
  37 #define SDCASR_REG              0x0100
  38 #define SDCASR_REG_STRIDE       0x1000
  39 #define SDCPWR_CFGA0_REG        0x0100
  40 #define SDCPWR_PWST0_REG        0x0000
  41 #define SDCPWR_GIZTIME_REG      0x0440
  42
  43 /* SDCPWR_GIZTIME_REG fields */
  44 #define SDCPWR_GIZTIME_GR       0x80000000
  45 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  46
  47 /* Offset of ASR registers from SDC base */
  48 #define SDCASR_OFFSET           0x120000
  49
  50 static void __iomem *sdcpwr_mapbase;
  51 static void __iomem *sdcasr_mapbase;
  52
  53 static DEFINE_MUTEX(pas_switch_mutex);
  54
  55 /* Current astate, is used when waking up from power savings on
  56  * one core, in case the other core has switched states during
  57  * the idle time.
  58  */
  59 static int current_astate;
  60
  61 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  62 static struct cpufreq_frequency_table pas_freqs[] = {
  63         {0,     0},
  64         {1,     0},
  65         {2,     0},
  66         {3,     0},
  67         {4,     0},
  68         {0,     CPUFREQ_TABLE_END},
  69 };
  70
  71 static struct freq_attr *pas_cpu_freqs_attr[] = {
  72         &cpufreq_freq_attr_scaling_available_freqs,
  73         NULL,
  74 };
  75
  76 /*
  77  * hardware specific functions
  78  */
  79
  80 static int get_astate_freq(int astate)
  81 {
  82         u32 ret;
  83         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  84
  85         return ret & 0x3f;
  86 }
  87
  88 static int get_cur_astate(int cpu)
  89 {
  90         u32 ret;
  91
  92         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  93         ret = (ret >> (cpu * 4)) & 0x7;
  94
  95         return ret;
  96 }
  97
  98 static int get_gizmo_latency(void)
  99 {
 100         u32 giztime, ret;
 101
 102         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 103
 104         /* just provide the upper bound */
 105         if (giztime & SDCPWR_GIZTIME_GR)
 106                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 107         else
 108                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 109
 110         return ret;
 111 }
 112
 113 static void set_astate(int cpu, unsigned int astate)
 114 {
 115         unsigned long flags;
 116
 117         /* Return if called before init has run */
 118         if (unlikely(!sdcasr_mapbase))
 119                 return;
 120
 121         local_irq_save(flags);
 122
 123         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 124
 125         local_irq_restore(flags);
 126 }
 127
 128 int check_astate(void)
 129 {
 130         return get_cur_astate(hard_smp_processor_id());
 131 }
 132
 133 void restore_astate(int cpu)
 134 {
 135         set_astate(cpu, current_astate);
 136 }
 137
 138 /*
 139  * cpufreq functions
 140  */
 141
 142 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 143 {
 144         const u32 *max_freqp;
 145         u32 max_freq;
 146         int i, cur_astate;
 147         struct resource res;
 148         struct device_node *cpu, *dn;
 149         int err = -ENODEV;
 150
 151         cpu = of_get_cpu_node(policy->cpu, NULL);
 152
 153         if (!cpu)
 154                 goto out;
 155
 156         dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 157         if (!dn)
 158                 dn = of_find_compatible_node(NULL, NULL,
 159                                              "pasemi,pwrficient-sdc");
 160         if (!dn)
 161                 goto out;
 162         err = of_address_to_resource(dn, 0, &res);
 163         of_node_put(dn);
 164         if (err)
 165                 goto out;
 166         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 167         if (!sdcasr_mapbase) {
 168                 err = -EINVAL;
 169                 goto out;
 170         }
 171
 172         dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
 173         if (!dn)
 174                 dn = of_find_compatible_node(NULL, NULL,
 175                                              "pasemi,pwrficient-gizmo");
 176         if (!dn) {
 177                 err = -ENODEV;
 178                 goto out_unmap_sdcasr;
 179         }
 180         err = of_address_to_resource(dn, 0, &res);
 181         of_node_put(dn);
 182         if (err)
 183                 goto out_unmap_sdcasr;
 184         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 185         if (!sdcpwr_mapbase) {
 186                 err = -EINVAL;
 187                 goto out_unmap_sdcasr;
 188         }
 189
 190         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 191
 192         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 193         if (!max_freqp) {
 194                 err = -EINVAL;
 195                 goto out_unmap_sdcpwr;
 196         }
 197
 198         /* we need the freq in kHz */
 199         max_freq = *max_freqp / 1000;
 200
 201         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 202         pr_debug("initializing frequency table\n");
 203
 204         /* initialize frequency table */
 205         for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
 206                 pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
 207                 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
 208         }
 209
 210         policy->cpuinfo.transition_latency = get_gizmo_latency();
 211
 212         cur_astate = get_cur_astate(policy->cpu);
 213         pr_debug("current astate is at %d\n",cur_astate);
 214
 215         policy->cur = pas_freqs[cur_astate].frequency;
 216         cpumask_copy(policy->cpus, cpu_online_mask);
 217
 218         ppc_proc_freq = policy->cur * 1000ul;
 219
 220         cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
 221
 222         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
 223          * are set correctly
 224          */
 225         return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
 226
 227 out_unmap_sdcpwr:
 228         iounmap(sdcpwr_mapbase);
 229
 230 out_unmap_sdcasr:
 231         iounmap(sdcasr_mapbase);
 232 out:
 233         return err;
 234 }
 235
 236 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 237 {
 238         if (sdcasr_mapbase)
 239                 iounmap(sdcasr_mapbase);
 240         if (sdcpwr_mapbase)
 241                 iounmap(sdcpwr_mapbase);
 242
 243         cpufreq_frequency_table_put_attr(policy->cpu);
 244         return 0;
 245 }
 246
 247 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
 248 {
 249         return cpufreq_frequency_table_verify(policy, pas_freqs);
 250 }
 251
 252 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 253                               unsigned int target_freq,
 254                               unsigned int relation)
 255 {
 256         struct cpufreq_freqs freqs;
 257         int pas_astate_new;
 258         int i;
 259
 260         cpufreq_frequency_table_target(policy,
 261                                        pas_freqs,
 262                                        target_freq,
 263                                        relation,
 264                                        &pas_astate_new);
 265
 266         freqs.old = policy->cur;
 267         freqs.new = pas_freqs[pas_astate_new].frequency;
 268         freqs.cpu = policy->cpu;
 269
 270         mutex_lock(&pas_switch_mutex);
 271         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 272
 273         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 274                  policy->cpu,
 275                  pas_freqs[pas_astate_new].frequency,
 276                  pas_freqs[pas_astate_new].index);
 277
 278         current_astate = pas_astate_new;
 279
 280         for_each_online_cpu(i)
 281                 set_astate(i, pas_astate_new);
 282
 283         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 284         mutex_unlock(&pas_switch_mutex);
 285
 286         ppc_proc_freq = freqs.new * 1000ul;
 287         return 0;
 288 }
 289
 290 static struct cpufreq_driver pas_cpufreq_driver = {
 291         .name           = "pas-cpufreq",
 292         .owner          = THIS_MODULE,
 293         .flags          = CPUFREQ_CONST_LOOPS,
 294         .init           = pas_cpufreq_cpu_init,
 295         .exit           = pas_cpufreq_cpu_exit,
 296         .verify         = pas_cpufreq_verify,
 297         .target         = pas_cpufreq_target,
 298         .attr           = pas_cpu_freqs_attr,
 299 };
 300
 301 /*
 302  * module init and destoy
 303  */
 304
 305 static int __init pas_cpufreq_init(void)
 306 {
 307         if (!of_machine_is_compatible("PA6T-1682M") &&
 308             !of_machine_is_compatible("pasemi,pwrficient"))
 309                 return -ENODEV;
 310
 311         return cpufreq_register_driver(&pas_cpufreq_driver);
 312 }
 313
 314 static void __exit pas_cpufreq_exit(void)
 315 {
 316         cpufreq_unregister_driver(&pas_cpufreq_driver);
 317 }
 318
 319 module_init(pas_cpufreq_init);
 320 module_exit(pas_cpufreq_exit);
 321
 322 MODULE_LICENSE("GPL");
 323 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");