arch/arm/mach-exynos/platsmp.c

   1 /* linux/arch/arm/mach-exynos4/platsmp.c
   2  *
   3  * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * Cloned from linux/arch/arm/mach-vexpress/platsmp.c
   7  *
   8  *  Copyright (C) 2002 ARM Ltd.
   9  *  All Rights Reserved
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14 */
  15
  16 #include <linux/init.h>
  17 #include <linux/errno.h>
  18 #include <linux/delay.h>
  19 #include <linux/device.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/smp.h>
  22 #include <linux/io.h>
  23
  24 #include <asm/cacheflush.h>
  25 #include <asm/smp_plat.h>
  26 #include <asm/smp_scu.h>
  27
  28 #include <mach/hardware.h>
  29 #include <mach/regs-clock.h>
  30 #include <mach/regs-pmu.h>
  31
  32 #include <plat/cpu.h>
  33
  34 #include "common.h"
  35
  36 extern void exynos4_secondary_startup(void);
  37
  38 static inline void __iomem *cpu_boot_reg_base(void)
  39 {
  40         if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
  41                 return S5P_INFORM5;
  42         return S5P_VA_SYSRAM;
  43 }
  44
  45 static inline void __iomem *cpu_boot_reg(int cpu)
  46 {
  47         void __iomem *boot_reg;
  48
  49         boot_reg = cpu_boot_reg_base();
  50         if (soc_is_exynos4412())
  51                 boot_reg += 4*cpu;
  52         return boot_reg;
  53 }
  54
  55 /*
  56  * Write pen_release in a way that is guaranteed to be visible to all
  57  * observers, irrespective of whether they're taking part in coherency
  58  * or not.  This is necessary for the hotplug code to work reliably.
  59  */
  60 static void write_pen_release(int val)
  61 {
  62         pen_release = val;
  63         smp_wmb();
  64         __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
  65         outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
  66 }
  67
  68 static void __iomem *scu_base_addr(void)
  69 {
  70         return (void __iomem *)(S5P_VA_SCU);
  71 }
  72
  73 static DEFINE_SPINLOCK(boot_lock);
  74
  75 static void __cpuinit exynos_secondary_init(unsigned int cpu)
  76 {
  77         /*
  78          * let the primary processor know we're out of the
  79          * pen, then head off into the C entry point
  80          */
  81         write_pen_release(-1);
  82
  83         /*
  84          * Synchronise with the boot thread.
  85          */
  86         spin_lock(&boot_lock);
  87         spin_unlock(&boot_lock);
  88 }
  89
  90 static int __cpuinit exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
  91 {
  92         unsigned long timeout;
  93         unsigned long phys_cpu = cpu_logical_map(cpu);
  94
  95         /*
  96          * Set synchronisation state between this boot processor
  97          * and the secondary one
  98          */
  99         spin_lock(&boot_lock);
 100
 101         /*
 102          * The secondary processor is waiting to be released from
 103          * the holding pen - release it, then wait for it to flag
 104          * that it has been released by resetting pen_release.
 105          *
 106          * Note that "pen_release" is the hardware CPU ID, whereas
 107          * "cpu" is Linux's internal ID.
 108          */
 109         write_pen_release(phys_cpu);
 110
 111         if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN)) {
 112                 __raw_writel(S5P_CORE_LOCAL_PWR_EN,
 113                              S5P_ARM_CORE1_CONFIGURATION);
 114
 115                 timeout = 10;
 116
 117                 /* wait max 10 ms until cpu1 is on */
 118                 while ((__raw_readl(S5P_ARM_CORE1_STATUS)
 119                         & S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN) {
 120                         if (timeout-- == 0)
 121                                 break;
 122
 123                         mdelay(1);
 124                 }
 125
 126                 if (timeout == 0) {
 127                         printk(KERN_ERR "cpu1 power enable failed");
 128                         spin_unlock(&boot_lock);
 129                         return -ETIMEDOUT;
 130                 }
 131         }
 132         /*
 133          * Send the secondary CPU a soft interrupt, thereby causing
 134          * the boot monitor to read the system wide flags register,
 135          * and branch to the address found there.
 136          */
 137
 138         timeout = jiffies + (1 * HZ);
 139         while (time_before(jiffies, timeout)) {
 140                 smp_rmb();
 141
 142                 __raw_writel(virt_to_phys(exynos4_secondary_startup),
 143                                                         cpu_boot_reg(phys_cpu));
 144                 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 145
 146                 if (pen_release == -1)
 147                         break;
 148
 149                 udelay(10);
 150         }
 151
 152         /*
 153          * now the secondary core is starting up let it run its
 154          * calibrations, then wait for it to finish
 155          */
 156         spin_unlock(&boot_lock);
 157
 158         return pen_release != -1 ? -ENOSYS : 0;
 159 }
 160
 161 /*
 162  * Initialise the CPU possible map early - this describes the CPUs
 163  * which may be present or become present in the system.
 164  */
 165
 166 static void __init exynos_smp_init_cpus(void)
 167 {
 168         void __iomem *scu_base = scu_base_addr();
 169         unsigned int i, ncores;
 170
 171         if (soc_is_exynos5250())
 172                 ncores = 2;
 173         else
 174                 ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 175
 176         /* sanity check */
 177         if (ncores > nr_cpu_ids) {
 178                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 179                         ncores, nr_cpu_ids);
 180                 ncores = nr_cpu_ids;
 181         }
 182
 183         for (i = 0; i < ncores; i++)
 184                 set_cpu_possible(i, true);
 185 }
 186
 187 static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 188 {
 189         int i;
 190
 191         if (!(soc_is_exynos5250() || soc_is_exynos5440()))
 192                 scu_enable(scu_base_addr());
 193
 194         /*
 195          * Write the address of secondary startup into the
 196          * system-wide flags register. The boot monitor waits
 197          * until it receives a soft interrupt, and then the
 198          * secondary CPU branches to this address.
 199          */
 200         for (i = 1; i < max_cpus; ++i)
 201                 __raw_writel(virt_to_phys(exynos4_secondary_startup),
 202                                         cpu_boot_reg(cpu_logical_map(i)));
 203 }
 204
 205 struct smp_operations exynos_smp_ops __initdata = {
 206         .smp_init_cpus          = exynos_smp_init_cpus,
 207         .smp_prepare_cpus       = exynos_smp_prepare_cpus,
 208         .smp_secondary_init     = exynos_secondary_init,
 209         .smp_boot_secondary     = exynos_boot_secondary,
 210 #ifdef CONFIG_HOTPLUG_CPU
 211         .cpu_die                = exynos_cpu_die,
 212 #endif
 213 };