linux/drivers/cpufreq/pasemi-cpufreq.c
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   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
  40static void __iomem *sdcpwr_mapbase;
  41static 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 */
  47static int current_astate;
  48
  49/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
  50static 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
  63static 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
  71static 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
  81static 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
  96static 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
 111int check_astate(void)
 112{
 113        return get_cur_astate(hard_smp_processor_id());
 114}
 115
 116void restore_astate(int cpu)
 117{
 118        set_astate(cpu, current_astate);
 119}
 120
 121/*
 122 * cpufreq functions
 123 */
 124
 125static 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
 202out_unmap_sdcasr:
 203        iounmap(sdcasr_mapbase);
 204out:
 205        return err;
 206}
 207
 208static 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
 225static 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
 244static 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
 258static 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
 267static void __exit pas_cpufreq_exit(void)
 268{
 269        cpufreq_unregister_driver(&pas_cpufreq_driver);
 270}
 271
 272module_init(pas_cpufreq_init);
 273module_exit(pas_cpufreq_exit);
 274
 275MODULE_LICENSE("GPL");
 276MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
 277