drivers/cpufreq/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 #include <linux/module.h>
  31 #include <linux/of_address.h>
  32
  33 #include <asm/hw_irq.h>
  34 #include <asm/io.h>
  35 #include <asm/prom.h>
  36 #include <asm/time.h>
  37 #include <asm/smp.h>
  38
  39 #define SDCASR_REG              0x0100
  40 #define SDCASR_REG_STRIDE       0x1000
  41 #define SDCPWR_CFGA0_REG        0x0100
  42 #define SDCPWR_PWST0_REG        0x0000
  43 #define SDCPWR_GIZTIME_REG      0x0440
  44
  45 /* SDCPWR_GIZTIME_REG fields */
  46 #define SDCPWR_GIZTIME_GR       0x80000000
  47 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  48
  49 /* Offset of ASR registers from SDC base */
  50 #define SDCASR_OFFSET           0x120000
  51
  52 static void __iomem *sdcpwr_mapbase;
  53 static void __iomem *sdcasr_mapbase;
  54
  55 static DEFINE_MUTEX(pas_switch_mutex);
  56
  57 /* Current astate, is used when waking up from power savings on
  58  * one core, in case the other core has switched states during
  59  * the idle time.
  60  */
  61 static int current_astate;
  62
  63 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  64 static struct cpufreq_frequency_table pas_freqs[] = {
  65         {0,     0},
  66         {1,     0},
  67         {2,     0},
  68         {3,     0},
  69         {4,     0},
  70         {0,     CPUFREQ_TABLE_END},
  71 };
  72
  73 static struct freq_attr *pas_cpu_freqs_attr[] = {
  74         &cpufreq_freq_attr_scaling_available_freqs,
  75         NULL,
  76 };
  77
  78 /*
  79  * hardware specific functions
  80  */
  81
  82 static int get_astate_freq(int astate)
  83 {
  84         u32 ret;
  85         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  86
  87         return ret & 0x3f;
  88 }
  89
  90 static int get_cur_astate(int cpu)
  91 {
  92         u32 ret;
  93
  94         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  95         ret = (ret >> (cpu * 4)) & 0x7;
  96
  97         return ret;
  98 }
  99
 100 static int get_gizmo_latency(void)
 101 {
 102         u32 giztime, ret;
 103
 104         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 105
 106         /* just provide the upper bound */
 107         if (giztime & SDCPWR_GIZTIME_GR)
 108                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 109         else
 110                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 111
 112         return ret;
 113 }
 114
 115 static void set_astate(int cpu, unsigned int astate)
 116 {
 117         unsigned long flags;
 118
 119         /* Return if called before init has run */
 120         if (unlikely(!sdcasr_mapbase))
 121                 return;
 122
 123         local_irq_save(flags);
 124
 125         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 126
 127         local_irq_restore(flags);
 128 }
 129
 130 int check_astate(void)
 131 {
 132         return get_cur_astate(hard_smp_processor_id());
 133 }
 134
 135 void restore_astate(int cpu)
 136 {
 137         set_astate(cpu, current_astate);
 138 }
 139
 140 /*
 141  * cpufreq functions
 142  */
 143
 144 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 145 {
 146         const u32 *max_freqp;
 147         u32 max_freq;
 148         int i, cur_astate;
 149         struct resource res;
 150         struct device_node *cpu, *dn;
 151         int err = -ENODEV;
 152
 153         cpu = of_get_cpu_node(policy->cpu, NULL);
 154
 155         if (!cpu)
 156                 goto out;
 157
 158         dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 159         if (!dn)
 160                 dn = of_find_compatible_node(NULL, NULL,
 161                                              "pasemi,pwrficient-sdc");
 162         if (!dn)
 163                 goto out;
 164         err = of_address_to_resource(dn, 0, &res);
 165         of_node_put(dn);
 166         if (err)
 167                 goto out;
 168         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 169         if (!sdcasr_mapbase) {
 170                 err = -EINVAL;
 171                 goto out;
 172         }
 173
 174         dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
 175         if (!dn)
 176                 dn = of_find_compatible_node(NULL, NULL,
 177                                              "pasemi,pwrficient-gizmo");
 178         if (!dn) {
 179                 err = -ENODEV;
 180                 goto out_unmap_sdcasr;
 181         }
 182         err = of_address_to_resource(dn, 0, &res);
 183         of_node_put(dn);
 184         if (err)
 185                 goto out_unmap_sdcasr;
 186         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 187         if (!sdcpwr_mapbase) {
 188                 err = -EINVAL;
 189                 goto out_unmap_sdcasr;
 190         }
 191
 192         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 193
 194         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 195         if (!max_freqp) {
 196                 err = -EINVAL;
 197                 goto out_unmap_sdcpwr;
 198         }
 199
 200         /* we need the freq in kHz */
 201         max_freq = *max_freqp / 1000;
 202
 203         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 204         pr_debug("initializing frequency table\n");
 205
 206         /* initialize frequency table */
 207         for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
 208                 pas_freqs[i].frequency =
 209                         get_astate_freq(pas_freqs[i].driver_data) * 100000;
 210                 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
 211         }
 212
 213         policy->cpuinfo.transition_latency = get_gizmo_latency();
 214
 215         cur_astate = get_cur_astate(policy->cpu);
 216         pr_debug("current astate is at %d\n",cur_astate);
 217
 218         policy->cur = pas_freqs[cur_astate].frequency;
 219         cpumask_copy(policy->cpus, cpu_online_mask);
 220
 221         ppc_proc_freq = policy->cur * 1000ul;
 222
 223         cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
 224
 225         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
 226          * are set correctly
 227          */
 228         return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
 229
 230 out_unmap_sdcpwr:
 231         iounmap(sdcpwr_mapbase);
 232
 233 out_unmap_sdcasr:
 234         iounmap(sdcasr_mapbase);
 235 out:
 236         return err;
 237 }
 238
 239 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 240 {
 241         /*
 242          * We don't support CPU hotplug. Don't unmap after the system
 243          * has already made it to a running state.
 244          */
 245         if (system_state != SYSTEM_BOOTING)
 246                 return 0;
 247
 248         if (sdcasr_mapbase)
 249                 iounmap(sdcasr_mapbase);
 250         if (sdcpwr_mapbase)
 251                 iounmap(sdcpwr_mapbase);
 252
 253         cpufreq_frequency_table_put_attr(policy->cpu);
 254         return 0;
 255 }
 256
 257 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
 258 {
 259         return cpufreq_frequency_table_verify(policy, pas_freqs);
 260 }
 261
 262 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 263                               unsigned int target_freq,
 264                               unsigned int relation)
 265 {
 266         struct cpufreq_freqs freqs;
 267         int pas_astate_new;
 268         int i;
 269
 270         cpufreq_frequency_table_target(policy,
 271                                        pas_freqs,
 272                                        target_freq,
 273                                        relation,
 274                                        &pas_astate_new);
 275
 276         freqs.old = policy->cur;
 277         freqs.new = pas_freqs[pas_astate_new].frequency;
 278
 279         mutex_lock(&pas_switch_mutex);
 280         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 281
 282         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 283                  policy->cpu,
 284                  pas_freqs[pas_astate_new].frequency,
 285                  pas_freqs[pas_astate_new].driver_data);
 286
 287         current_astate = pas_astate_new;
 288
 289         for_each_online_cpu(i)
 290                 set_astate(i, pas_astate_new);
 291
 292         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 293         mutex_unlock(&pas_switch_mutex);
 294
 295         ppc_proc_freq = freqs.new * 1000ul;
 296         return 0;
 297 }
 298
 299 static struct cpufreq_driver pas_cpufreq_driver = {
 300         .name           = "pas-cpufreq",
 301         .flags          = CPUFREQ_CONST_LOOPS,
 302         .init           = pas_cpufreq_cpu_init,
 303         .exit           = pas_cpufreq_cpu_exit,
 304         .verify         = pas_cpufreq_verify,
 305         .target         = pas_cpufreq_target,
 306         .attr           = pas_cpu_freqs_attr,
 307 };
 308
 309 /*
 310  * module init and destoy
 311  */
 312
 313 static int __init pas_cpufreq_init(void)
 314 {
 315         if (!of_machine_is_compatible("PA6T-1682M") &&
 316             !of_machine_is_compatible("pasemi,pwrficient"))
 317                 return -ENODEV;
 318
 319         return cpufreq_register_driver(&pas_cpufreq_driver);
 320 }
 321
 322 static void __exit pas_cpufreq_exit(void)
 323 {
 324         cpufreq_unregister_driver(&pas_cpufreq_driver);
 325 }
 326
 327 module_init(pas_cpufreq_init);
 328 module_exit(pas_cpufreq_exit);
 329
 330 MODULE_LICENSE("GPL");
 331 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");