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 #include <asm/firmware.h>
  28
  29 #include <mach/hardware.h>
  30
  31 #include <plat/cpu.h>
  32
  33 #include "common.h"
  34 #include "regs-pmu.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         else if (soc_is_exynos5420())
  53                 boot_reg += 4;
  54         return boot_reg;
  55 }
  56
  57 /*
  58  * Write pen_release in a way that is guaranteed to be visible to all
  59  * observers, irrespective of whether they're taking part in coherency
  60  * or not.  This is necessary for the hotplug code to work reliably.
  61  */
  62 static void write_pen_release(int val)
  63 {
  64         pen_release = val;
  65         smp_wmb();
  66         sync_cache_w(&pen_release);
  67 }
  68
  69 static void __iomem *scu_base_addr(void)
  70 {
  71         return (void __iomem *)(S5P_VA_SCU);
  72 }
  73
  74 static DEFINE_SPINLOCK(boot_lock);
  75
  76 static void exynos_secondary_init(unsigned int cpu)
  77 {
  78         /*
  79          * let the primary processor know we're out of the
  80          * pen, then head off into the C entry point
  81          */
  82         write_pen_release(-1);
  83
  84         /*
  85          * Synchronise with the boot thread.
  86          */
  87         spin_lock(&boot_lock);
  88         spin_unlock(&boot_lock);
  89 }
  90
  91 static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
  92 {
  93         unsigned long timeout;
  94         unsigned long phys_cpu = cpu_logical_map(cpu);
  95
  96         /*
  97          * Set synchronisation state between this boot processor
  98          * and the secondary one
  99          */
 100         spin_lock(&boot_lock);
 101
 102         /*
 103          * The secondary processor is waiting to be released from
 104          * the holding pen - release it, then wait for it to flag
 105          * that it has been released by resetting pen_release.
 106          *
 107          * Note that "pen_release" is the hardware CPU ID, whereas
 108          * "cpu" is Linux's internal ID.
 109          */
 110         write_pen_release(phys_cpu);
 111
 112         if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN)) {
 113                 __raw_writel(S5P_CORE_LOCAL_PWR_EN,
 114                              S5P_ARM_CORE1_CONFIGURATION);
 115
 116                 timeout = 10;
 117
 118                 /* wait max 10 ms until cpu1 is on */
 119                 while ((__raw_readl(S5P_ARM_CORE1_STATUS)
 120                         & S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN) {
 121                         if (timeout-- == 0)
 122                                 break;
 123
 124                         mdelay(1);
 125                 }
 126
 127                 if (timeout == 0) {
 128                         printk(KERN_ERR "cpu1 power enable failed");
 129                         spin_unlock(&boot_lock);
 130                         return -ETIMEDOUT;
 131                 }
 132         }
 133         /*
 134          * Send the secondary CPU a soft interrupt, thereby causing
 135          * the boot monitor to read the system wide flags register,
 136          * and branch to the address found there.
 137          */
 138
 139         timeout = jiffies + (1 * HZ);
 140         while (time_before(jiffies, timeout)) {
 141                 unsigned long boot_addr;
 142
 143                 smp_rmb();
 144
 145                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 146
 147                 /*
 148                  * Try to set boot address using firmware first
 149                  * and fall back to boot register if it fails.
 150                  */
 151                 if (call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr))
 152                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 153
 154                 call_firmware_op(cpu_boot, phys_cpu);
 155
 156                 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 157
 158                 if (pen_release == -1)
 159                         break;
 160
 161                 udelay(10);
 162         }
 163
 164         /*
 165          * now the secondary core is starting up let it run its
 166          * calibrations, then wait for it to finish
 167          */
 168         spin_unlock(&boot_lock);
 169
 170         return pen_release != -1 ? -ENOSYS : 0;
 171 }
 172
 173 /*
 174  * Initialise the CPU possible map early - this describes the CPUs
 175  * which may be present or become present in the system.
 176  */
 177
 178 static void __init exynos_smp_init_cpus(void)
 179 {
 180         void __iomem *scu_base = scu_base_addr();
 181         unsigned int i, ncores;
 182
 183         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 184                 ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 185         else
 186                 /*
 187                  * CPU Nodes are passed thru DT and set_cpu_possible
 188                  * is set by "arm_dt_init_cpu_maps".
 189                  */
 190                 return;
 191
 192         /* sanity check */
 193         if (ncores > nr_cpu_ids) {
 194                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 195                         ncores, nr_cpu_ids);
 196                 ncores = nr_cpu_ids;
 197         }
 198
 199         for (i = 0; i < ncores; i++)
 200                 set_cpu_possible(i, true);
 201 }
 202
 203 static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 204 {
 205         int i;
 206
 207         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 208                 scu_enable(scu_base_addr());
 209
 210         /*
 211          * Write the address of secondary startup into the
 212          * system-wide flags register. The boot monitor waits
 213          * until it receives a soft interrupt, and then the
 214          * secondary CPU branches to this address.
 215          *
 216          * Try using firmware operation first and fall back to
 217          * boot register if it fails.
 218          */
 219         for (i = 1; i < max_cpus; ++i) {
 220                 unsigned long phys_cpu;
 221                 unsigned long boot_addr;
 222
 223                 phys_cpu = cpu_logical_map(i);
 224                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 225
 226                 if (call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr))
 227                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 228         }
 229 }
 230
 231 struct smp_operations exynos_smp_ops __initdata = {
 232         .smp_init_cpus          = exynos_smp_init_cpus,
 233         .smp_prepare_cpus       = exynos_smp_prepare_cpus,
 234         .smp_secondary_init     = exynos_secondary_init,
 235         .smp_boot_secondary     = exynos_boot_secondary,
 236 #ifdef CONFIG_HOTPLUG_CPU
 237         .cpu_die                = exynos_cpu_die,
 238 #endif
 239 };