drivers/cpuidle/cpuidle-tegra.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CPU idle driver for Tegra CPUs
   4  *
   5  * Copyright (c) 2010-2013, NVIDIA Corporation.
   6  * Copyright (c) 2011 Google, Inc.
   7  * Author: Colin Cross <ccross@android.com>
   8  *         Gary King <gking@nvidia.com>
   9  *
  10  * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
  11  *
  12  * Tegra20/124 driver unification by Dmitry Osipenko <digetx@gmail.com>
  13  */
  14
  15 #define pr_fmt(fmt)     "tegra-cpuidle: " fmt
  16
  17 #include <linux/atomic.h>
  18 #include <linux/cpuidle.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/cpu_pm.h>
  21 #include <linux/delay.h>
  22 #include <linux/errno.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/types.h>
  25
  26 #include <linux/clk/tegra.h>
  27 #include <linux/firmware/trusted_foundations.h>
  28
  29 #include <soc/tegra/cpuidle.h>
  30 #include <soc/tegra/flowctrl.h>
  31 #include <soc/tegra/fuse.h>
  32 #include <soc/tegra/irq.h>
  33 #include <soc/tegra/pm.h>
  34 #include <soc/tegra/pmc.h>
  35
  36 #include <asm/cpuidle.h>
  37 #include <asm/firmware.h>
  38 #include <asm/smp_plat.h>
  39 #include <asm/suspend.h>
  40
  41 enum tegra_state {
  42         TEGRA_C1,
  43         TEGRA_C7,
  44         TEGRA_CC6,
  45         TEGRA_STATE_COUNT,
  46 };
  47
  48 static atomic_t tegra_idle_barrier;
  49 static atomic_t tegra_abort_flag;
  50
  51 static inline bool tegra_cpuidle_using_firmware(void)
  52 {
  53         return firmware_ops->prepare_idle && firmware_ops->do_idle;
  54 }
  55
  56 static void tegra_cpuidle_report_cpus_state(void)
  57 {
  58         unsigned long cpu, lcpu, csr;
  59
  60         for_each_cpu(lcpu, cpu_possible_mask) {
  61                 cpu = cpu_logical_map(lcpu);
  62                 csr = flowctrl_read_cpu_csr(cpu);
  63
  64                 pr_err("cpu%lu: online=%d flowctrl_csr=0x%08lx\n",
  65                        cpu, cpu_online(lcpu), csr);
  66         }
  67 }
  68
  69 static int tegra_cpuidle_wait_for_secondary_cpus_parking(void)
  70 {
  71         unsigned int retries = 3;
  72
  73         while (retries--) {
  74                 unsigned int delay_us = 10;
  75                 unsigned int timeout_us = 500 * 1000 / delay_us;
  76
  77                 /*
  78                  * The primary CPU0 core shall wait for the secondaries
  79                  * shutdown in order to power-off CPU's cluster safely.
  80                  * The timeout value depends on the current CPU frequency,
  81                  * it takes about 40-150us in average and over 1000us in
  82                  * a worst case scenario.
  83                  */
  84                 do {
  85                         if (tegra_cpu_rail_off_ready())
  86                                 return 0;
  87
  88                         udelay(delay_us);
  89
  90                 } while (timeout_us--);
  91
  92                 pr_err("secondary CPU taking too long to park\n");
  93
  94                 tegra_cpuidle_report_cpus_state();
  95         }
  96
  97         pr_err("timed out waiting secondaries to park\n");
  98
  99         return -ETIMEDOUT;
 100 }
 101
 102 static void tegra_cpuidle_unpark_secondary_cpus(void)
 103 {
 104         unsigned int cpu, lcpu;
 105
 106         for_each_cpu(lcpu, cpu_online_mask) {
 107                 cpu = cpu_logical_map(lcpu);
 108
 109                 if (cpu > 0) {
 110                         tegra_enable_cpu_clock(cpu);
 111                         tegra_cpu_out_of_reset(cpu);
 112                         flowctrl_write_cpu_halt(cpu, 0);
 113                 }
 114         }
 115 }
 116
 117 static int tegra_cpuidle_cc6_enter(unsigned int cpu)
 118 {
 119         int ret;
 120
 121         if (cpu > 0) {
 122                 ret = cpu_suspend(cpu, tegra_pm_park_secondary_cpu);
 123         } else {
 124                 ret = tegra_cpuidle_wait_for_secondary_cpus_parking();
 125                 if (!ret)
 126                         ret = tegra_pm_enter_lp2();
 127
 128                 tegra_cpuidle_unpark_secondary_cpus();
 129         }
 130
 131         return ret;
 132 }
 133
 134 static int tegra_cpuidle_c7_enter(void)
 135 {
 136         int err;
 137
 138         if (tegra_cpuidle_using_firmware()) {
 139                 err = call_firmware_op(prepare_idle, TF_PM_MODE_LP2_NOFLUSH_L2);
 140                 if (err)
 141                         return err;
 142
 143                 return call_firmware_op(do_idle, 0);
 144         }
 145
 146         return cpu_suspend(0, tegra30_pm_secondary_cpu_suspend);
 147 }
 148
 149 static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev)
 150 {
 151         if (tegra_pending_sgi()) {
 152                 /*
 153                  * CPU got local interrupt that will be lost after GIC's
 154                  * shutdown because GIC driver doesn't save/restore the
 155                  * pending SGI state across CPU cluster PM.  Abort and retry
 156                  * next time.
 157                  */
 158                 atomic_set(&tegra_abort_flag, 1);
 159         }
 160
 161         cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
 162
 163         if (atomic_read(&tegra_abort_flag)) {
 164                 cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
 165                 atomic_set(&tegra_abort_flag, 0);
 166                 return -EINTR;
 167         }
 168
 169         return 0;
 170 }
 171
 172 static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 173                                      int index, unsigned int cpu)
 174 {
 175         int ret;
 176
 177         /*
 178          * CC6 state is the "CPU cluster power-off" state.  In order to
 179          * enter this state, at first the secondary CPU cores need to be
 180          * parked into offline mode, then the last CPU should clean out
 181          * remaining dirty cache lines into DRAM and trigger Flow Controller
 182          * logic that turns off the cluster's power domain (which includes
 183          * CPU cores, GIC and L2 cache).
 184          */
 185         if (index == TEGRA_CC6) {
 186                 ret = tegra_cpuidle_coupled_barrier(dev);
 187                 if (ret)
 188                         return ret;
 189         }
 190
 191         local_fiq_disable();
 192         tegra_pm_set_cpu_in_lp2();
 193         cpu_pm_enter();
 194
 195         switch (index) {
 196         case TEGRA_C7:
 197                 ret = tegra_cpuidle_c7_enter();
 198                 break;
 199
 200         case TEGRA_CC6:
 201                 ret = tegra_cpuidle_cc6_enter(cpu);
 202                 break;
 203
 204         default:
 205                 ret = -EINVAL;
 206                 break;
 207         }
 208
 209         cpu_pm_exit();
 210         tegra_pm_clear_cpu_in_lp2();
 211         local_fiq_enable();
 212
 213         return ret;
 214 }
 215
 216 static int tegra_cpuidle_adjust_state_index(int index, unsigned int cpu)
 217 {
 218         /*
 219          * On Tegra30 CPU0 can't be power-gated separately from secondary
 220          * cores because it gates the whole CPU cluster.
 221          */
 222         if (cpu > 0 || index != TEGRA_C7 || tegra_get_chip_id() != TEGRA30)
 223                 return index;
 224
 225         /* put CPU0 into C1 if C7 is requested and secondaries are online */
 226         if (!IS_ENABLED(CONFIG_PM_SLEEP) || num_online_cpus() > 1)
 227                 index = TEGRA_C1;
 228         else
 229                 index = TEGRA_CC6;
 230
 231         return index;
 232 }
 233
 234 static int tegra_cpuidle_enter(struct cpuidle_device *dev,
 235                                struct cpuidle_driver *drv,
 236                                int index)
 237 {
 238         unsigned int cpu = cpu_logical_map(dev->cpu);
 239         int err;
 240
 241         index = tegra_cpuidle_adjust_state_index(index, cpu);
 242         if (dev->states_usage[index].disable)
 243                 return -1;
 244
 245         if (index == TEGRA_C1)
 246                 err = arm_cpuidle_simple_enter(dev, drv, index);
 247         else
 248                 err = tegra_cpuidle_state_enter(dev, index, cpu);
 249
 250         if (err && (err != -EINTR || index != TEGRA_CC6))
 251                 pr_err_once("failed to enter state %d err: %d\n", index, err);
 252
 253         return err ? -1 : index;
 254 }
 255
 256 static int tegra114_enter_s2idle(struct cpuidle_device *dev,
 257                                  struct cpuidle_driver *drv,
 258                                  int index)
 259 {
 260         tegra_cpuidle_enter(dev, drv, index);
 261
 262         return 0;
 263 }
 264
 265 /*
 266  * The previous versions of Tegra CPUIDLE driver used a different "legacy"
 267  * terminology for naming of the idling states, while this driver uses the
 268  * new terminology.
 269  *
 270  * Mapping of the old terms into the new ones:
 271  *
 272  * Old | New
 273  * ---------
 274  * LP3 | C1     (CPU core clock gating)
 275  * LP2 | C7     (CPU core power gating)
 276  * LP2 | CC6    (CPU cluster power gating)
 277  *
 278  * Note that that the older CPUIDLE driver versions didn't explicitly
 279  * differentiate the LP2 states because these states either used the same
 280  * code path or because CC6 wasn't supported.
 281  */
 282 static struct cpuidle_driver tegra_idle_driver = {
 283         .name = "tegra_idle",
 284         .states = {
 285                 [TEGRA_C1] = ARM_CPUIDLE_WFI_STATE_PWR(600),
 286                 [TEGRA_C7] = {
 287                         .enter                  = tegra_cpuidle_enter,
 288                         .exit_latency           = 2000,
 289                         .target_residency       = 2200,
 290                         .power_usage            = 100,
 291                         .flags                  = CPUIDLE_FLAG_TIMER_STOP,
 292                         .name                   = "C7",
 293                         .desc                   = "CPU core powered off",
 294                 },
 295                 [TEGRA_CC6] = {
 296                         .enter                  = tegra_cpuidle_enter,
 297                         .exit_latency           = 5000,
 298                         .target_residency       = 10000,
 299                         .power_usage            = 0,
 300                         .flags                  = CPUIDLE_FLAG_TIMER_STOP |
 301                                                   CPUIDLE_FLAG_COUPLED,
 302                         .name                   = "CC6",
 303                         .desc                   = "CPU cluster powered off",
 304                 },
 305         },
 306         .state_count = TEGRA_STATE_COUNT,
 307         .safe_state_index = TEGRA_C1,
 308 };
 309
 310 static inline void tegra_cpuidle_disable_state(enum tegra_state state)
 311 {
 312         cpuidle_driver_state_disabled(&tegra_idle_driver, state, true);
 313 }
 314
 315 /*
 316  * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
 317  * they are legacy IRQs or MSI, are lost when CC6 is enabled.  To work around
 318  * this, simply disable CC6 if the PCI driver and DT node are both enabled.
 319  */
 320 void tegra_cpuidle_pcie_irqs_in_use(void)
 321 {
 322         struct cpuidle_state *state_cc6 = &tegra_idle_driver.states[TEGRA_CC6];
 323
 324         if ((state_cc6->flags & CPUIDLE_FLAG_UNUSABLE) ||
 325             tegra_get_chip_id() != TEGRA20)
 326                 return;
 327
 328         pr_info("disabling CC6 state, since PCIe IRQs are in use\n");
 329         tegra_cpuidle_disable_state(TEGRA_CC6);
 330 }
 331
 332 static void tegra_cpuidle_setup_tegra114_c7_state(void)
 333 {
 334         struct cpuidle_state *s = &tegra_idle_driver.states[TEGRA_C7];
 335
 336         s->enter_s2idle = tegra114_enter_s2idle;
 337         s->target_residency = 1000;
 338         s->exit_latency = 500;
 339 }
 340
 341 static int tegra_cpuidle_probe(struct platform_device *pdev)
 342 {
 343         /* LP2 could be disabled in device-tree */
 344         if (tegra_pmc_get_suspend_mode() < TEGRA_SUSPEND_LP2)
 345                 tegra_cpuidle_disable_state(TEGRA_CC6);
 346
 347         /*
 348          * Required suspend-resume functionality, which is provided by the
 349          * Tegra-arch core and PMC driver, is unavailable if PM-sleep option
 350          * is disabled.
 351          */
 352         if (!IS_ENABLED(CONFIG_PM_SLEEP)) {
 353                 if (!tegra_cpuidle_using_firmware())
 354                         tegra_cpuidle_disable_state(TEGRA_C7);
 355
 356                 tegra_cpuidle_disable_state(TEGRA_CC6);
 357         }
 358
 359         /*
 360          * Generic WFI state (also known as C1 or LP3) and the coupled CPU
 361          * cluster power-off (CC6 or LP2) states are common for all Tegra SoCs.
 362          */
 363         switch (tegra_get_chip_id()) {
 364         case TEGRA20:
 365                 /* Tegra20 isn't capable to power-off individual CPU cores */
 366                 tegra_cpuidle_disable_state(TEGRA_C7);
 367                 break;
 368
 369         case TEGRA30:
 370                 break;
 371
 372         case TEGRA114:
 373         case TEGRA124:
 374                 tegra_cpuidle_setup_tegra114_c7_state();
 375
 376                 /* coupled CC6 (LP2) state isn't implemented yet */
 377                 tegra_cpuidle_disable_state(TEGRA_CC6);
 378                 break;
 379
 380         default:
 381                 return -EINVAL;
 382         }
 383
 384         return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
 385 }
 386
 387 static struct platform_driver tegra_cpuidle_driver = {
 388         .probe = tegra_cpuidle_probe,
 389         .driver = {
 390                 .name = "tegra-cpuidle",
 391         },
 392 };
 393 builtin_platform_driver(tegra_cpuidle_driver);