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 /* 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,  0},
  64         {0, 1,  0},
  65         {0, 2,  0},
  66         {0, 3,  0},
  67         {0, 4,  0},
  68         {0, 0,  CPUFREQ_TABLE_END},
  69 };
  70
  71 /*
  72  * hardware specific functions
  73  */
  74
  75 static int get_astate_freq(int astate)
  76 {
  77         u32 ret;
  78         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  79
  80         return ret & 0x3f;
  81 }
  82
  83 static int get_cur_astate(int cpu)
  84 {
  85         u32 ret;
  86
  87         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  88         ret = (ret >> (cpu * 4)) & 0x7;
  89
  90         return ret;
  91 }
  92
  93 static int get_gizmo_latency(void)
  94 {
  95         u32 giztime, ret;
  96
  97         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
  98
  99         /* just provide the upper bound */
 100         if (giztime & SDCPWR_GIZTIME_GR)
 101                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 102         else
 103                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 104
 105         return ret;
 106 }
 107
 108 static void set_astate(int cpu, unsigned int astate)
 109 {
 110         unsigned long flags;
 111
 112         /* Return if called before init has run */
 113         if (unlikely(!sdcasr_mapbase))
 114                 return;
 115
 116         local_irq_save(flags);
 117
 118         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 119
 120         local_irq_restore(flags);
 121 }
 122
 123 int check_astate(void)
 124 {
 125         return get_cur_astate(hard_smp_processor_id());
 126 }
 127
 128 void restore_astate(int cpu)
 129 {
 130         set_astate(cpu, current_astate);
 131 }
 132
 133 /*
 134  * cpufreq functions
 135  */
 136
 137 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 138 {
 139         struct cpufreq_frequency_table *pos;
 140         const u32 *max_freqp;
 141         u32 max_freq;
 142         int cur_astate, idx;
 143         struct resource res;
 144         struct device_node *cpu, *dn;
 145         int err = -ENODEV;
 146
 147         cpu = of_get_cpu_node(policy->cpu, NULL);
 148
 149         if (!cpu)
 150                 goto out;
 151
 152         dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 153         if (!dn)
 154                 dn = of_find_compatible_node(NULL, NULL,
 155                                              "pasemi,pwrficient-sdc");
 156         if (!dn)
 157                 goto out;
 158         err = of_address_to_resource(dn, 0, &res);
 159         of_node_put(dn);
 160         if (err)
 161                 goto out;
 162         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 163         if (!sdcasr_mapbase) {
 164                 err = -EINVAL;
 165                 goto out;
 166         }
 167
 168         dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
 169         if (!dn)
 170                 dn = of_find_compatible_node(NULL, NULL,
 171                                              "pasemi,pwrficient-gizmo");
 172         if (!dn) {
 173                 err = -ENODEV;
 174                 goto out_unmap_sdcasr;
 175         }
 176         err = of_address_to_resource(dn, 0, &res);
 177         of_node_put(dn);
 178         if (err)
 179                 goto out_unmap_sdcasr;
 180         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 181         if (!sdcpwr_mapbase) {
 182                 err = -EINVAL;
 183                 goto out_unmap_sdcasr;
 184         }
 185
 186         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 187
 188         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 189         if (!max_freqp) {
 190                 err = -EINVAL;
 191                 goto out_unmap_sdcpwr;
 192         }
 193
 194         /* we need the freq in kHz */
 195         max_freq = *max_freqp / 1000;
 196
 197         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 198         pr_debug("initializing frequency table\n");
 199
 200         /* initialize frequency table */
 201         cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
 202                 pos->frequency = get_astate_freq(pos->driver_data) * 100000;
 203                 pr_debug("%d: %d\n", idx, pos->frequency);
 204         }
 205
 206         cur_astate = get_cur_astate(policy->cpu);
 207         pr_debug("current astate is at %d\n",cur_astate);
 208
 209         policy->cur = pas_freqs[cur_astate].frequency;
 210         ppc_proc_freq = policy->cur * 1000ul;
 211
 212         return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
 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         /*
 226          * We don't support CPU hotplug. Don't unmap after the system
 227          * has already made it to a running state.
 228          */
 229         if (system_state >= SYSTEM_RUNNING)
 230                 return 0;
 231
 232         if (sdcasr_mapbase)
 233                 iounmap(sdcasr_mapbase);
 234         if (sdcpwr_mapbase)
 235                 iounmap(sdcpwr_mapbase);
 236
 237         return 0;
 238 }
 239
 240 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 241                               unsigned int pas_astate_new)
 242 {
 243         int i;
 244
 245         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 246                  policy->cpu,
 247                  pas_freqs[pas_astate_new].frequency,
 248                  pas_freqs[pas_astate_new].driver_data);
 249
 250         current_astate = pas_astate_new;
 251
 252         for_each_online_cpu(i)
 253                 set_astate(i, pas_astate_new);
 254
 255         ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
 256         return 0;
 257 }
 258
 259 static struct cpufreq_driver pas_cpufreq_driver = {
 260         .name           = "pas-cpufreq",
 261         .flags          = CPUFREQ_CONST_LOOPS,
 262         .init           = pas_cpufreq_cpu_init,
 263         .exit           = pas_cpufreq_cpu_exit,
 264         .verify         = cpufreq_generic_frequency_table_verify,
 265         .target_index   = pas_cpufreq_target,
 266         .attr           = cpufreq_generic_attr,
 267 };
 268
 269 /*
 270  * module init and destoy
 271  */
 272
 273 static int __init pas_cpufreq_init(void)
 274 {
 275         if (!of_machine_is_compatible("PA6T-1682M") &&
 276             !of_machine_is_compatible("pasemi,pwrficient"))
 277                 return -ENODEV;
 278
 279         return cpufreq_register_driver(&pas_cpufreq_driver);
 280 }
 281
 282 static void __exit pas_cpufreq_exit(void)
 283 {
 284         cpufreq_unregister_driver(&pas_cpufreq_driver);
 285 }
 286
 287 module_init(pas_cpufreq_init);
 288 module_exit(pas_cpufreq_exit);
 289
 290 MODULE_LICENSE("GPL");
 291 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");