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 #include <linux/module.h>
  31
  32 #include <asm/hw_irq.h>
  33 #include <asm/io.h>
  34 #include <asm/prom.h>
  35 #include <asm/time.h>
  36 #include <asm/smp.h>
  37
  38 #define SDCASR_REG              0x0100
  39 #define SDCASR_REG_STRIDE       0x1000
  40 #define SDCPWR_CFGA0_REG        0x0100
  41 #define SDCPWR_PWST0_REG        0x0000
  42 #define SDCPWR_GIZTIME_REG      0x0440
  43
  44 /* SDCPWR_GIZTIME_REG fields */
  45 #define SDCPWR_GIZTIME_GR       0x80000000
  46 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  47
  48 /* Offset of ASR registers from SDC base */
  49 #define SDCASR_OFFSET           0x120000
  50
  51 static void __iomem *sdcpwr_mapbase;
  52 static void __iomem *sdcasr_mapbase;
  53
  54 static DEFINE_MUTEX(pas_switch_mutex);
  55
  56 /* Current astate, is used when waking up from power savings on
  57  * one core, in case the other core has switched states during
  58  * the idle time.
  59  */
  60 static int current_astate;
  61
  62 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  63 static struct cpufreq_frequency_table pas_freqs[] = {
  64         {0,     0},
  65         {1,     0},
  66         {2,     0},
  67         {3,     0},
  68         {4,     0},
  69         {0,     CPUFREQ_TABLE_END},
  70 };
  71
  72 static struct freq_attr *pas_cpu_freqs_attr[] = {
  73         &cpufreq_freq_attr_scaling_available_freqs,
  74         NULL,
  75 };
  76
  77 /*
  78  * hardware specific functions
  79  */
  80
  81 static int get_astate_freq(int astate)
  82 {
  83         u32 ret;
  84         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  85
  86         return ret & 0x3f;
  87 }
  88
  89 static int get_cur_astate(int cpu)
  90 {
  91         u32 ret;
  92
  93         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  94         ret = (ret >> (cpu * 4)) & 0x7;
  95
  96         return ret;
  97 }
  98
  99 static int get_gizmo_latency(void)
 100 {
 101         u32 giztime, ret;
 102
 103         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 104
 105         /* just provide the upper bound */
 106         if (giztime & SDCPWR_GIZTIME_GR)
 107                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 108         else
 109                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 110
 111         return ret;
 112 }
 113
 114 static void set_astate(int cpu, unsigned int astate)
 115 {
 116         unsigned long flags;
 117
 118         /* Return if called before init has run */
 119         if (unlikely(!sdcasr_mapbase))
 120                 return;
 121
 122         local_irq_save(flags);
 123
 124         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 125
 126         local_irq_restore(flags);
 127 }
 128
 129 int check_astate(void)
 130 {
 131         return get_cur_astate(hard_smp_processor_id());
 132 }
 133
 134 void restore_astate(int cpu)
 135 {
 136         set_astate(cpu, current_astate);
 137 }
 138
 139 /*
 140  * cpufreq functions
 141  */
 142
 143 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 144 {
 145         const u32 *max_freqp;
 146         u32 max_freq;
 147         int i, cur_astate;
 148         struct resource res;
 149         struct device_node *cpu, *dn;
 150         int err = -ENODEV;
 151
 152         cpu = of_get_cpu_node(policy->cpu, NULL);
 153
 154         if (!cpu)
 155                 goto out;
 156
 157         dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 158         if (!dn)
 159                 dn = of_find_compatible_node(NULL, NULL,
 160                                              "pasemi,pwrficient-sdc");
 161         if (!dn)
 162                 goto out;
 163         err = of_address_to_resource(dn, 0, &res);
 164         of_node_put(dn);
 165         if (err)
 166                 goto out;
 167         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 168         if (!sdcasr_mapbase) {
 169                 err = -EINVAL;
 170                 goto out;
 171         }
 172
 173         dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
 174         if (!dn)
 175                 dn = of_find_compatible_node(NULL, NULL,
 176                                              "pasemi,pwrficient-gizmo");
 177         if (!dn) {
 178                 err = -ENODEV;
 179                 goto out_unmap_sdcasr;
 180         }
 181         err = of_address_to_resource(dn, 0, &res);
 182         of_node_put(dn);
 183         if (err)
 184                 goto out_unmap_sdcasr;
 185         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 186         if (!sdcpwr_mapbase) {
 187                 err = -EINVAL;
 188                 goto out_unmap_sdcasr;
 189         }
 190
 191         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 192
 193         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 194         if (!max_freqp) {
 195                 err = -EINVAL;
 196                 goto out_unmap_sdcpwr;
 197         }
 198
 199         /* we need the freq in kHz */
 200         max_freq = *max_freqp / 1000;
 201
 202         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 203         pr_debug("initializing frequency table\n");
 204
 205         /* initialize frequency table */
 206         for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
 207                 pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
 208                 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
 209         }
 210
 211         policy->cpuinfo.transition_latency = get_gizmo_latency();
 212
 213         cur_astate = get_cur_astate(policy->cpu);
 214         pr_debug("current astate is at %d\n",cur_astate);
 215
 216         policy->cur = pas_freqs[cur_astate].frequency;
 217         cpumask_copy(policy->cpus, cpu_online_mask);
 218
 219         ppc_proc_freq = policy->cur * 1000ul;
 220
 221         cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
 222
 223         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
 224          * are set correctly
 225          */
 226         return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
 227
 228 out_unmap_sdcpwr:
 229         iounmap(sdcpwr_mapbase);
 230
 231 out_unmap_sdcasr:
 232         iounmap(sdcasr_mapbase);
 233 out:
 234         return err;
 235 }
 236
 237 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 238 {
 239         if (sdcasr_mapbase)
 240                 iounmap(sdcasr_mapbase);
 241         if (sdcpwr_mapbase)
 242                 iounmap(sdcpwr_mapbase);
 243
 244         cpufreq_frequency_table_put_attr(policy->cpu);
 245         return 0;
 246 }
 247
 248 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
 249 {
 250         return cpufreq_frequency_table_verify(policy, pas_freqs);
 251 }
 252
 253 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 254                               unsigned int target_freq,
 255                               unsigned int relation)
 256 {
 257         struct cpufreq_freqs freqs;
 258         int pas_astate_new;
 259         int i;
 260
 261         cpufreq_frequency_table_target(policy,
 262                                        pas_freqs,
 263                                        target_freq,
 264                                        relation,
 265                                        &pas_astate_new);
 266
 267         freqs.old = policy->cur;
 268         freqs.new = pas_freqs[pas_astate_new].frequency;
 269         freqs.cpu = policy->cpu;
 270
 271         mutex_lock(&pas_switch_mutex);
 272         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 273
 274         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 275                  policy->cpu,
 276                  pas_freqs[pas_astate_new].frequency,
 277                  pas_freqs[pas_astate_new].index);
 278
 279         current_astate = pas_astate_new;
 280
 281         for_each_online_cpu(i)
 282                 set_astate(i, pas_astate_new);
 283
 284         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 285         mutex_unlock(&pas_switch_mutex);
 286
 287         ppc_proc_freq = freqs.new * 1000ul;
 288         return 0;
 289 }
 290
 291 static struct cpufreq_driver pas_cpufreq_driver = {
 292         .name           = "pas-cpufreq",
 293         .owner          = THIS_MODULE,
 294         .flags          = CPUFREQ_CONST_LOOPS,
 295         .init           = pas_cpufreq_cpu_init,
 296         .exit           = pas_cpufreq_cpu_exit,
 297         .verify         = pas_cpufreq_verify,
 298         .target         = pas_cpufreq_target,
 299         .attr           = pas_cpu_freqs_attr,
 300 };
 301
 302 /*
 303  * module init and destoy
 304  */
 305
 306 static int __init pas_cpufreq_init(void)
 307 {
 308         if (!of_machine_is_compatible("PA6T-1682M") &&
 309             !of_machine_is_compatible("pasemi,pwrficient"))
 310                 return -ENODEV;
 311
 312         return cpufreq_register_driver(&pas_cpufreq_driver);
 313 }
 314
 315 static void __exit pas_cpufreq_exit(void)
 316 {
 317         cpufreq_unregister_driver(&pas_cpufreq_driver);
 318 }
 319
 320 module_init(pas_cpufreq_init);
 321 module_exit(pas_cpufreq_exit);
 322
 323 MODULE_LICENSE("GPL");
 324 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");