drivers/cpufreq/pasemi-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2007 PA Semi, Inc
   4  *
   5  * Authors: Egor Martovetsky <egor@pasemi.com>
   6  *          Olof Johansson <olof@lixom.net>
   7  *
   8  * Maintained by: Olof Johansson <olof@lixom.net>
   9  *
  10  * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
  11  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
  12  */
  13
  14 #include <linux/cpufreq.h>
  15 #include <linux/timer.h>
  16 #include <linux/module.h>
  17 #include <linux/of_address.h>
  18
  19 #include <asm/hw_irq.h>
  20 #include <asm/io.h>
  21 #include <asm/prom.h>
  22 #include <asm/time.h>
  23 #include <asm/smp.h>
  24
  25 #include <platforms/pasemi/pasemi.h>
  26
  27 #define SDCASR_REG              0x0100
  28 #define SDCASR_REG_STRIDE       0x1000
  29 #define SDCPWR_CFGA0_REG        0x0100
  30 #define SDCPWR_PWST0_REG        0x0000
  31 #define SDCPWR_GIZTIME_REG      0x0440
  32
  33 /* SDCPWR_GIZTIME_REG fields */
  34 #define SDCPWR_GIZTIME_GR       0x80000000
  35 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
  36
  37 /* Offset of ASR registers from SDC base */
  38 #define SDCASR_OFFSET           0x120000
  39
  40 static void __iomem *sdcpwr_mapbase;
  41 static void __iomem *sdcasr_mapbase;
  42
  43 /* Current astate, is used when waking up from power savings on
  44  * one core, in case the other core has switched states during
  45  * the idle time.
  46  */
  47 static int current_astate;
  48
  49 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  50 static struct cpufreq_frequency_table pas_freqs[] = {
  51         {0, 0,  0},
  52         {0, 1,  0},
  53         {0, 2,  0},
  54         {0, 3,  0},
  55         {0, 4,  0},
  56         {0, 0,  CPUFREQ_TABLE_END},
  57 };
  58
  59 /*
  60  * hardware specific functions
  61  */
  62
  63 static int get_astate_freq(int astate)
  64 {
  65         u32 ret;
  66         ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
  67
  68         return ret & 0x3f;
  69 }
  70
  71 static int get_cur_astate(int cpu)
  72 {
  73         u32 ret;
  74
  75         ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
  76         ret = (ret >> (cpu * 4)) & 0x7;
  77
  78         return ret;
  79 }
  80
  81 static int get_gizmo_latency(void)
  82 {
  83         u32 giztime, ret;
  84
  85         giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
  86
  87         /* just provide the upper bound */
  88         if (giztime & SDCPWR_GIZTIME_GR)
  89                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
  90         else
  91                 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
  92
  93         return ret;
  94 }
  95
  96 static void set_astate(int cpu, unsigned int astate)
  97 {
  98         unsigned long flags;
  99
 100         /* Return if called before init has run */
 101         if (unlikely(!sdcasr_mapbase))
 102                 return;
 103
 104         local_irq_save(flags);
 105
 106         out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
 107
 108         local_irq_restore(flags);
 109 }
 110
 111 int check_astate(void)
 112 {
 113         return get_cur_astate(hard_smp_processor_id());
 114 }
 115
 116 void restore_astate(int cpu)
 117 {
 118         set_astate(cpu, current_astate);
 119 }
 120
 121 /*
 122  * cpufreq functions
 123  */
 124
 125 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 126 {
 127         struct cpufreq_frequency_table *pos;
 128         const u32 *max_freqp;
 129         u32 max_freq;
 130         int cur_astate, idx;
 131         struct resource res;
 132         struct device_node *cpu, *dn;
 133         int err = -ENODEV;
 134
 135         cpu = of_get_cpu_node(policy->cpu, NULL);
 136         if (!cpu)
 137                 goto out;
 138
 139         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 140         of_node_put(cpu);
 141         if (!max_freqp) {
 142                 err = -EINVAL;
 143                 goto out;
 144         }
 145
 146         /* we need the freq in kHz */
 147         max_freq = *max_freqp / 1000;
 148
 149         dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 150         if (!dn)
 151                 dn = of_find_compatible_node(NULL, NULL,
 152                                              "pasemi,pwrficient-sdc");
 153         if (!dn)
 154                 goto out;
 155         err = of_address_to_resource(dn, 0, &res);
 156         of_node_put(dn);
 157         if (err)
 158                 goto out;
 159         sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
 160         if (!sdcasr_mapbase) {
 161                 err = -EINVAL;
 162                 goto out;
 163         }
 164
 165         dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
 166         if (!dn)
 167                 dn = of_find_compatible_node(NULL, NULL,
 168                                              "pasemi,pwrficient-gizmo");
 169         if (!dn) {
 170                 err = -ENODEV;
 171                 goto out_unmap_sdcasr;
 172         }
 173         err = of_address_to_resource(dn, 0, &res);
 174         of_node_put(dn);
 175         if (err)
 176                 goto out_unmap_sdcasr;
 177         sdcpwr_mapbase = ioremap(res.start, 0x1000);
 178         if (!sdcpwr_mapbase) {
 179                 err = -EINVAL;
 180                 goto out_unmap_sdcasr;
 181         }
 182
 183         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 184         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 185         pr_debug("initializing frequency table\n");
 186
 187         /* initialize frequency table */
 188         cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
 189                 pos->frequency = get_astate_freq(pos->driver_data) * 100000;
 190                 pr_debug("%d: %d\n", idx, pos->frequency);
 191         }
 192
 193         cur_astate = get_cur_astate(policy->cpu);
 194         pr_debug("current astate is at %d\n",cur_astate);
 195
 196         policy->cur = pas_freqs[cur_astate].frequency;
 197         ppc_proc_freq = policy->cur * 1000ul;
 198
 199         cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
 200         return 0;
 201
 202 out_unmap_sdcasr:
 203         iounmap(sdcasr_mapbase);
 204 out:
 205         return err;
 206 }
 207
 208 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 209 {
 210         /*
 211          * We don't support CPU hotplug. Don't unmap after the system
 212          * has already made it to a running state.
 213          */
 214         if (system_state >= SYSTEM_RUNNING)
 215                 return 0;
 216
 217         if (sdcasr_mapbase)
 218                 iounmap(sdcasr_mapbase);
 219         if (sdcpwr_mapbase)
 220                 iounmap(sdcpwr_mapbase);
 221
 222         return 0;
 223 }
 224
 225 static int pas_cpufreq_target(struct cpufreq_policy *policy,
 226                               unsigned int pas_astate_new)
 227 {
 228         int i;
 229
 230         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
 231                  policy->cpu,
 232                  pas_freqs[pas_astate_new].frequency,
 233                  pas_freqs[pas_astate_new].driver_data);
 234
 235         current_astate = pas_astate_new;
 236
 237         for_each_online_cpu(i)
 238                 set_astate(i, pas_astate_new);
 239
 240         ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
 241         return 0;
 242 }
 243
 244 static struct cpufreq_driver pas_cpufreq_driver = {
 245         .name           = "pas-cpufreq",
 246         .flags          = CPUFREQ_CONST_LOOPS,
 247         .init           = pas_cpufreq_cpu_init,
 248         .exit           = pas_cpufreq_cpu_exit,
 249         .verify         = cpufreq_generic_frequency_table_verify,
 250         .target_index   = pas_cpufreq_target,
 251         .attr           = cpufreq_generic_attr,
 252 };
 253
 254 /*
 255  * module init and destoy
 256  */
 257
 258 static int __init pas_cpufreq_init(void)
 259 {
 260         if (!of_machine_is_compatible("PA6T-1682M") &&
 261             !of_machine_is_compatible("pasemi,pwrficient"))
 262                 return -ENODEV;
 263
 264         return cpufreq_register_driver(&pas_cpufreq_driver);
 265 }
 266
 267 static void __exit pas_cpufreq_exit(void)
 268 {
 269         cpufreq_unregister_driver(&pas_cpufreq_driver);
 270 }
 271
 272 module_init(pas_cpufreq_init);
 273 module_exit(pas_cpufreq_exit);
 274
 275 MODULE_LICENSE("GPL");
 276 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");