arch/arm/mach-exynos/mcpm-exynos.c

   1 /*
   2  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   3  *              http://www.samsung.com
   4  *
   5  * arch/arm/mach-exynos/mcpm-exynos.c
   6  *
   7  * Based on arch/arm/mach-vexpress/dcscb.c
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/arm-cci.h>
  15 #include <linux/delay.h>
  16 #include <linux/io.h>
  17 #include <linux/of_address.h>
  18
  19 #include <asm/cputype.h>
  20 #include <asm/cp15.h>
  21 #include <asm/mcpm.h>
  22
  23 #include "regs-pmu.h"
  24 #include "common.h"
  25
  26 #define EXYNOS5420_CPUS_PER_CLUSTER     4
  27 #define EXYNOS5420_NR_CLUSTERS          2
  28 #define MCPM_BOOT_ADDR_OFFSET           0x1c
  29
  30 /*
  31  * The common v7_exit_coherency_flush API could not be used because of the
  32  * Erratum 799270 workaround. This macro is the same as the common one (in
  33  * arch/arm/include/asm/cacheflush.h) except for the erratum handling.
  34  */
  35 #define exynos_v7_exit_coherency_flush(level) \
  36         asm volatile( \
  37         "stmfd  sp!, {fp, ip}\n\t"\
  38         "mrc    p15, 0, r0, c1, c0, 0   @ get SCTLR\n\t" \
  39         "bic    r0, r0, #"__stringify(CR_C)"\n\t" \
  40         "mcr    p15, 0, r0, c1, c0, 0   @ set SCTLR\n\t" \
  41         "isb\n\t"\
  42         "bl     v7_flush_dcache_"__stringify(level)"\n\t" \
  43         "clrex\n\t"\
  44         "mrc    p15, 0, r0, c1, c0, 1   @ get ACTLR\n\t" \
  45         "bic    r0, r0, #(1 << 6)       @ disable local coherency\n\t" \
  46         /* Dummy Load of a device register to avoid Erratum 799270 */ \
  47         "ldr    r4, [%0]\n\t" \
  48         "and    r4, r4, #0\n\t" \
  49         "orr    r0, r0, r4\n\t" \
  50         "mcr    p15, 0, r0, c1, c0, 1   @ set ACTLR\n\t" \
  51         "isb\n\t" \
  52         "dsb\n\t" \
  53         "ldmfd  sp!, {fp, ip}" \
  54         : \
  55         : "Ir" (S5P_INFORM0) \
  56         : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", \
  57           "r9", "r10", "lr", "memory")
  58
  59 /*
  60  * We can't use regular spinlocks. In the switcher case, it is possible
  61  * for an outbound CPU to call power_down() after its inbound counterpart
  62  * is already live using the same logical CPU number which trips lockdep
  63  * debugging.
  64  */
  65 static arch_spinlock_t exynos_mcpm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
  66 static int
  67 cpu_use_count[EXYNOS5420_CPUS_PER_CLUSTER][EXYNOS5420_NR_CLUSTERS];
  68
  69 #define exynos_cluster_usecnt(cluster) \
  70         (cpu_use_count[0][cluster] +   \
  71          cpu_use_count[1][cluster] +   \
  72          cpu_use_count[2][cluster] +   \
  73          cpu_use_count[3][cluster])
  74
  75 #define exynos_cluster_unused(cluster) !exynos_cluster_usecnt(cluster)
  76
  77 static int exynos_cluster_power_control(unsigned int cluster, int enable)
  78 {
  79         unsigned int tries = 100;
  80         unsigned int val;
  81
  82         if (enable) {
  83                 exynos_cluster_power_up(cluster);
  84                 val = S5P_CORE_LOCAL_PWR_EN;
  85         } else {
  86                 exynos_cluster_power_down(cluster);
  87                 val = 0;
  88         }
  89
  90         /* Wait until cluster power control is applied */
  91         while (tries--) {
  92                 if (exynos_cluster_power_state(cluster) == val)
  93                         return 0;
  94
  95                 cpu_relax();
  96         }
  97         pr_debug("timed out waiting for cluster %u to power %s\n", cluster,
  98                 enable ? "on" : "off");
  99
 100         return -ETIMEDOUT;
 101 }
 102
 103 static int exynos_power_up(unsigned int cpu, unsigned int cluster)
 104 {
 105         unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
 106         int err = 0;
 107
 108         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 109         if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
 110                 cluster >= EXYNOS5420_NR_CLUSTERS)
 111                 return -EINVAL;
 112
 113         /*
 114          * Since this is called with IRQs enabled, and no arch_spin_lock_irq
 115          * variant exists, we need to disable IRQs manually here.
 116          */
 117         local_irq_disable();
 118         arch_spin_lock(&exynos_mcpm_lock);
 119
 120         cpu_use_count[cpu][cluster]++;
 121         if (cpu_use_count[cpu][cluster] == 1) {
 122                 bool was_cluster_down =
 123                         (exynos_cluster_usecnt(cluster) == 1);
 124
 125                 /*
 126                  * Turn on the cluster (L2/COMMON) and then power on the
 127                  * cores.
 128                  */
 129                 if (was_cluster_down)
 130                         err = exynos_cluster_power_control(cluster, 1);
 131
 132                 if (!err)
 133                         exynos_cpu_power_up(cpunr);
 134                 else
 135                         exynos_cluster_power_control(cluster, 0);
 136         } else if (cpu_use_count[cpu][cluster] != 2) {
 137                 /*
 138                  * The only possible values are:
 139                  * 0 = CPU down
 140                  * 1 = CPU (still) up
 141                  * 2 = CPU requested to be up before it had a chance
 142                  *     to actually make itself down.
 143                  * Any other value is a bug.
 144                  */
 145                 BUG();
 146         }
 147
 148         arch_spin_unlock(&exynos_mcpm_lock);
 149         local_irq_enable();
 150
 151         return err;
 152 }
 153
 154 /*
 155  * NOTE: This function requires the stack data to be visible through power down
 156  * and can only be executed on processors like A15 and A7 that hit the cache
 157  * with the C bit clear in the SCTLR register.
 158  */
 159 static void exynos_power_down(void)
 160 {
 161         unsigned int mpidr, cpu, cluster;
 162         bool last_man = false, skip_wfi = false;
 163         unsigned int cpunr;
 164
 165         mpidr = read_cpuid_mpidr();
 166         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 167         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 168         cpunr =  cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
 169
 170         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 171         BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
 172                         cluster >= EXYNOS5420_NR_CLUSTERS);
 173
 174         __mcpm_cpu_going_down(cpu, cluster);
 175
 176         arch_spin_lock(&exynos_mcpm_lock);
 177         BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
 178         cpu_use_count[cpu][cluster]--;
 179         if (cpu_use_count[cpu][cluster] == 0) {
 180                 exynos_cpu_power_down(cpunr);
 181
 182                 if (exynos_cluster_unused(cluster))
 183                         /* TODO: Turn off the cluster here to save power. */
 184                         last_man = true;
 185         } else if (cpu_use_count[cpu][cluster] == 1) {
 186                 /*
 187                  * A power_up request went ahead of us.
 188                  * Even if we do not want to shut this CPU down,
 189                  * the caller expects a certain state as if the WFI
 190                  * was aborted.  So let's continue with cache cleaning.
 191                  */
 192                 skip_wfi = true;
 193         } else {
 194                 BUG();
 195         }
 196
 197         if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
 198                 arch_spin_unlock(&exynos_mcpm_lock);
 199
 200                 if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
 201                         /*
 202                          * On the Cortex-A15 we need to disable
 203                          * L2 prefetching before flushing the cache.
 204                          */
 205                         asm volatile(
 206                         "mcr    p15, 1, %0, c15, c0, 3\n\t"
 207                         "isb\n\t"
 208                         "dsb"
 209                         : : "r" (0x400));
 210                 }
 211
 212                 /* Flush all cache levels for this cluster. */
 213                 exynos_v7_exit_coherency_flush(all);
 214
 215                 /*
 216                  * Disable cluster-level coherency by masking
 217                  * incoming snoops and DVM messages:
 218                  */
 219                 cci_disable_port_by_cpu(mpidr);
 220
 221                 __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
 222         } else {
 223                 arch_spin_unlock(&exynos_mcpm_lock);
 224
 225                 /* Disable and flush the local CPU cache. */
 226                 exynos_v7_exit_coherency_flush(louis);
 227         }
 228
 229         __mcpm_cpu_down(cpu, cluster);
 230
 231         /* Now we are prepared for power-down, do it: */
 232         if (!skip_wfi)
 233                 wfi();
 234
 235         /* Not dead at this point?  Let our caller cope. */
 236 }
 237
 238 static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
 239 {
 240         unsigned int tries = 100;
 241         unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
 242
 243         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 244         BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
 245                         cluster >= EXYNOS5420_NR_CLUSTERS);
 246
 247         /* Wait for the core state to be OFF */
 248         while (tries--) {
 249                 if (ACCESS_ONCE(cpu_use_count[cpu][cluster]) == 0) {
 250                         if ((exynos_cpu_power_state(cpunr) == 0))
 251                                 return 0; /* success: the CPU is halted */
 252                 }
 253
 254                 /* Otherwise, wait and retry: */
 255                 msleep(1);
 256         }
 257
 258         return -ETIMEDOUT; /* timeout */
 259 }
 260
 261 static const struct mcpm_platform_ops exynos_power_ops = {
 262         .power_up               = exynos_power_up,
 263         .power_down             = exynos_power_down,
 264         .wait_for_powerdown     = exynos_wait_for_powerdown,
 265 };
 266
 267 static void __init exynos_mcpm_usage_count_init(void)
 268 {
 269         unsigned int mpidr, cpu, cluster;
 270
 271         mpidr = read_cpuid_mpidr();
 272         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 273         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 274
 275         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 276         BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER  ||
 277                         cluster >= EXYNOS5420_NR_CLUSTERS);
 278
 279         cpu_use_count[cpu][cluster] = 1;
 280 }
 281
 282 /*
 283  * Enable cluster-level coherency, in preparation for turning on the MMU.
 284  */
 285 static void __naked exynos_pm_power_up_setup(unsigned int affinity_level)
 286 {
 287         asm volatile ("\n"
 288         "cmp    r0, #1\n"
 289         "bxne   lr\n"
 290         "b      cci_enable_port_for_self");
 291 }
 292
 293 static const struct of_device_id exynos_dt_mcpm_match[] = {
 294         { .compatible = "samsung,exynos5420" },
 295         { .compatible = "samsung,exynos5800" },
 296         {},
 297 };
 298
 299 static int __init exynos_mcpm_init(void)
 300 {
 301         struct device_node *node;
 302         void __iomem *ns_sram_base_addr;
 303         int ret;
 304
 305         node = of_find_matching_node(NULL, exynos_dt_mcpm_match);
 306         if (!node)
 307                 return -ENODEV;
 308         of_node_put(node);
 309
 310         if (!cci_probed())
 311                 return -ENODEV;
 312
 313         node = of_find_compatible_node(NULL, NULL,
 314                         "samsung,exynos4210-sysram-ns");
 315         if (!node)
 316                 return -ENODEV;
 317
 318         ns_sram_base_addr = of_iomap(node, 0);
 319         of_node_put(node);
 320         if (!ns_sram_base_addr) {
 321                 pr_err("failed to map non-secure iRAM base address\n");
 322                 return -ENOMEM;
 323         }
 324
 325         /*
 326          * To increase the stability of KFC reset we need to program
 327          * the PMU SPARE3 register
 328          */
 329         __raw_writel(EXYNOS5420_SWRESET_KFC_SEL, S5P_PMU_SPARE3);
 330
 331         exynos_mcpm_usage_count_init();
 332
 333         ret = mcpm_platform_register(&exynos_power_ops);
 334         if (!ret)
 335                 ret = mcpm_sync_init(exynos_pm_power_up_setup);
 336         if (ret) {
 337                 iounmap(ns_sram_base_addr);
 338                 return ret;
 339         }
 340
 341         mcpm_smp_set_ops();
 342
 343         pr_info("Exynos MCPM support installed\n");
 344
 345         /*
 346          * Future entries into the kernel can now go
 347          * through the cluster entry vectors.
 348          */
 349         __raw_writel(virt_to_phys(mcpm_entry_point),
 350                         ns_sram_base_addr + MCPM_BOOT_ADDR_OFFSET);
 351
 352         iounmap(ns_sram_base_addr);
 353
 354         return ret;
 355 }
 356
 357 early_initcall(exynos_mcpm_init);