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
  36 #define SDCASR_REG              0x0100
  37 #define SDCASR_REG_STRIDE       0x1000
  38 #define SDCPWR_CFGA0_REG        0x0100
  39 #define SDCPWR_PWST0_REG        0x0000
  40 #define SDCPWR_GIZTIME_REG      0x0440
  41
  42 /* SDCPWR_GIZTIME_REG fields */
  43 #define SDCPWR_GIZTIME_GR       0x80000000
  44 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  45
  46 /* Offset of ASR registers from SDC base */
  47 #define SDCASR_OFFSET           0x120000
  48
  49 static void __iomem *sdcpwr_mapbase;
  50 static void __iomem *sdcasr_mapbase;
  51
  52 static DEFINE_MUTEX(pas_switch_mutex);
  53
  54 /* Current astate, is used when waking up from power savings on
  55  * one core, in case the other core has switched states during
  56  * the idle time.
  57  */
  58 static int current_astate;
  59
  60 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  61 static struct cpufreq_frequency_table pas_freqs[] = {
  62         {0,     0},
  63         {1,     0},
  64         {2,     0},
  65         {3,     0},
  66         {4,     0},
  67         {0,     CPUFREQ_TABLE_END},
  68 };
  69
  70 static struct freq_attr *pas_cpu_freqs_attr[] = {
  71         &cpufreq_freq_attr_scaling_available_freqs,
  72         NULL,
  73 };
  74
  75 /*
  76  * hardware specific functions
  77  */
  78
  79 static int get_astate_freq(int astate)
  80 {
  81         u32 ret;
  82         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  83
  84         return ret & 0x3f;
  85 }
  86
  87 static int get_cur_astate(int cpu)
  88 {
  89         u32 ret;
  90
  91         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  92         ret = (ret >> (cpu * 4)) & 0x7;
  93
  94         return ret;
  95 }
  96
  97 static int get_gizmo_latency(void)
  98 {
  99         u32 giztime, ret;
 100
 101         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 102
 103         /* just provide the upper bound */
 104         if (giztime & SDCPWR_GIZTIME_GR)
 105                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 106         else
 107                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 108
 109         return ret;
 110 }
 111
 112 static void set_astate(int cpu, unsigned int astate)
 113 {
 114         u64 flags;
 115
 116         /* Return if called before init has run */
 117         if (unlikely(!sdcasr_mapbase))
 118                 return;
 119
 120         local_irq_save(flags);
 121
 122         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 123
 124         local_irq_restore(flags);
 125 }
 126
 127 void restore_astate(int cpu)
 128 {
 129         set_astate(cpu, current_astate);
 130 }
 131
 132 /*
 133  * cpufreq functions
 134  */
 135
 136 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 137 {
 138         const u32 *max_freqp;
 139         u32 max_freq;
 140         int i, cur_astate;
 141         struct resource res;
 142         struct device_node *cpu, *dn;
 143         int err = -ENODEV;
 144
 145         cpu = of_get_cpu_node(policy->cpu, NULL);
 146
 147         if (!cpu)
 148                 goto out;
 149
 150         dn = of_find_compatible_node(NULL, "sdc", "1682m-sdc");
 151         if (!dn)
 152                 goto out;
 153         err = of_address_to_resource(dn, 0, &res);
 154         of_node_put(dn);
 155         if (err)
 156                 goto out;
 157         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 158         if (!sdcasr_mapbase) {
 159                 err = -EINVAL;
 160                 goto out;
 161         }
 162
 163         dn = of_find_compatible_node(NULL, "gizmo", "1682m-gizmo");
 164         if (!dn) {
 165                 err = -ENODEV;
 166                 goto out_unmap_sdcasr;
 167         }
 168         err = of_address_to_resource(dn, 0, &res);
 169         of_node_put(dn);
 170         if (err)
 171                 goto out_unmap_sdcasr;
 172         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 173         if (!sdcpwr_mapbase) {
 174                 err = -EINVAL;
 175                 goto out_unmap_sdcasr;
 176         }
 177
 178         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 179
 180         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 181         if (!max_freqp) {
 182                 err = -EINVAL;
 183                 goto out_unmap_sdcpwr;
 184         }
 185
 186         /* we need the freq in kHz */
 187         max_freq = *max_freqp / 1000;
 188
 189         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 190         pr_debug("initializing frequency table\n");
 191
 192         /* initialize frequency table */
 193         for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
 194                 pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
 195                 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
 196         }
 197
 198         policy->cpuinfo.transition_latency = get_gizmo_latency();
 199
 200         cur_astate = get_cur_astate(policy->cpu);
 201         pr_debug("current astate is at %d\n",cur_astate);
 202
 203         policy->cur = pas_freqs[cur_astate].frequency;
 204         policy->cpus = cpu_online_map;
 205
 206         ppc_proc_freq = policy->cur * 1000ul;
 207
 208         cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
 209
 210         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
 211          * are set correctly
 212          */
 213         return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
 214
 215 out_unmap_sdcpwr:
 216         iounmap(sdcpwr_mapbase);
 217
 218 out_unmap_sdcasr:
 219         iounmap(sdcasr_mapbase);
 220 out:
 221         return err;
 222 }
 223
 224 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 225 {
 226         if (sdcasr_mapbase)
 227                 iounmap(sdcasr_mapbase);
 228         if (sdcpwr_mapbase)
 229                 iounmap(sdcpwr_mapbase);
 230
 231         cpufreq_frequency_table_put_attr(policy->cpu);
 232         return 0;
 233 }
 234
 235 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
 236 {
 237         return cpufreq_frequency_table_verify(policy, pas_freqs);
 238 }
 239
 240 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 241                               unsigned int target_freq,
 242                               unsigned int relation)
 243 {
 244         struct cpufreq_freqs freqs;
 245         int pas_astate_new;
 246         int i;
 247
 248         cpufreq_frequency_table_target(policy,
 249                                        pas_freqs,
 250                                        target_freq,
 251                                        relation,
 252                                        &pas_astate_new);
 253
 254         freqs.old = policy->cur;
 255         freqs.new = pas_freqs[pas_astate_new].frequency;
 256         freqs.cpu = policy->cpu;
 257
 258         mutex_lock(&pas_switch_mutex);
 259         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 260
 261         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 262                  policy->cpu,
 263                  pas_freqs[pas_astate_new].frequency,
 264                  pas_freqs[pas_astate_new].index);
 265
 266         current_astate = pas_astate_new;
 267
 268         for_each_online_cpu(i)
 269                 set_astate(i, pas_astate_new);
 270
 271         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 272         mutex_unlock(&pas_switch_mutex);
 273
 274         ppc_proc_freq = freqs.new * 1000ul;
 275         return 0;
 276 }
 277
 278 static struct cpufreq_driver pas_cpufreq_driver = {
 279         .name           = "pas-cpufreq",
 280         .owner          = THIS_MODULE,
 281         .flags          = CPUFREQ_CONST_LOOPS,
 282         .init           = pas_cpufreq_cpu_init,
 283         .exit           = pas_cpufreq_cpu_exit,
 284         .verify         = pas_cpufreq_verify,
 285         .target         = pas_cpufreq_target,
 286         .attr           = pas_cpu_freqs_attr,
 287 };
 288
 289 /*
 290  * module init and destoy
 291  */
 292
 293 static int __init pas_cpufreq_init(void)
 294 {
 295         if (!machine_is_compatible("PA6T-1682M"))
 296                 return -ENODEV;
 297
 298         return cpufreq_register_driver(&pas_cpufreq_driver);
 299 }
 300
 301 static void __exit pas_cpufreq_exit(void)
 302 {
 303         cpufreq_unregister_driver(&pas_cpufreq_driver);
 304 }
 305
 306 module_init(pas_cpufreq_init);
 307 module_exit(pas_cpufreq_exit);
 308
 309 MODULE_LICENSE("GPL");
 310 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");