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 #include <mach/regs-clock.h>
  31 #include <mach/regs-pmu.h>
  32
  33 #include <plat/cpu.h>
  34
  35 #include "common.h"
  36
  37 extern void exynos4_secondary_startup(void);
  38
  39 static inline void __iomem *cpu_boot_reg_base(void)
  40 {
  41         if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
  42                 return S5P_INFORM5;
  43         return S5P_VA_SYSRAM;
  44 }
  45
  46 static inline void __iomem *cpu_boot_reg(int cpu)
  47 {
  48         void __iomem *boot_reg;
  49
  50         boot_reg = cpu_boot_reg_base();
  51         if (soc_is_exynos4412())
  52                 boot_reg += 4*cpu;
  53         else if (soc_is_exynos5420())
  54                 boot_reg += 4;
  55         return boot_reg;
  56 }
  57
  58 /*
  59  * Write pen_release in a way that is guaranteed to be visible to all
  60  * observers, irrespective of whether they're taking part in coherency
  61  * or not.  This is necessary for the hotplug code to work reliably.
  62  */
  63 static void write_pen_release(int val)
  64 {
  65         pen_release = val;
  66         smp_wmb();
  67         __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
  68         outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
  69 }
  70
  71 static void __iomem *scu_base_addr(void)
  72 {
  73         return (void __iomem *)(S5P_VA_SCU);
  74 }
  75
  76 static DEFINE_SPINLOCK(boot_lock);
  77
  78 static void __cpuinit exynos_secondary_init(unsigned int cpu)
  79 {
  80         /*
  81          * let the primary processor know we're out of the
  82          * pen, then head off into the C entry point
  83          */
  84         write_pen_release(-1);
  85
  86         /*
  87          * Synchronise with the boot thread.
  88          */
  89         spin_lock(&boot_lock);
  90         spin_unlock(&boot_lock);
  91 }
  92
  93 static int __cpuinit exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
  94 {
  95         unsigned long timeout;
  96         unsigned long phys_cpu = cpu_logical_map(cpu);
  97
  98         /*
  99          * Set synchronisation state between this boot processor
 100          * and the secondary one
 101          */
 102         spin_lock(&boot_lock);
 103
 104         /*
 105          * The secondary processor is waiting to be released from
 106          * the holding pen - release it, then wait for it to flag
 107          * that it has been released by resetting pen_release.
 108          *
 109          * Note that "pen_release" is the hardware CPU ID, whereas
 110          * "cpu" is Linux's internal ID.
 111          */
 112         write_pen_release(phys_cpu);
 113
 114         if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN)) {
 115                 __raw_writel(S5P_CORE_LOCAL_PWR_EN,
 116                              S5P_ARM_CORE1_CONFIGURATION);
 117
 118                 timeout = 10;
 119
 120                 /* wait max 10 ms until cpu1 is on */
 121                 while ((__raw_readl(S5P_ARM_CORE1_STATUS)
 122                         & S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN) {
 123                         if (timeout-- == 0)
 124                                 break;
 125
 126                         mdelay(1);
 127                 }
 128
 129                 if (timeout == 0) {
 130                         printk(KERN_ERR "cpu1 power enable failed");
 131                         spin_unlock(&boot_lock);
 132                         return -ETIMEDOUT;
 133                 }
 134         }
 135         /*
 136          * Send the secondary CPU a soft interrupt, thereby causing
 137          * the boot monitor to read the system wide flags register,
 138          * and branch to the address found there.
 139          */
 140
 141         timeout = jiffies + (1 * HZ);
 142         while (time_before(jiffies, timeout)) {
 143                 unsigned long boot_addr;
 144
 145                 smp_rmb();
 146
 147                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 148
 149                 /*
 150                  * Try to set boot address using firmware first
 151                  * and fall back to boot register if it fails.
 152                  */
 153                 if (call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr))
 154                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 155
 156                 call_firmware_op(cpu_boot, phys_cpu);
 157
 158                 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 159
 160                 if (pen_release == -1)
 161                         break;
 162
 163                 udelay(10);
 164         }
 165
 166         /*
 167          * now the secondary core is starting up let it run its
 168          * calibrations, then wait for it to finish
 169          */
 170         spin_unlock(&boot_lock);
 171
 172         return pen_release != -1 ? -ENOSYS : 0;
 173 }
 174
 175 /*
 176  * Initialise the CPU possible map early - this describes the CPUs
 177  * which may be present or become present in the system.
 178  */
 179
 180 static void __init exynos_smp_init_cpus(void)
 181 {
 182         void __iomem *scu_base = scu_base_addr();
 183         unsigned int i, ncores;
 184
 185         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 186                 ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 187         else
 188                 /*
 189                  * CPU Nodes are passed thru DT and set_cpu_possible
 190                  * is set by "arm_dt_init_cpu_maps".
 191                  */
 192                 return;
 193
 194         /* sanity check */
 195         if (ncores > nr_cpu_ids) {
 196                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 197                         ncores, nr_cpu_ids);
 198                 ncores = nr_cpu_ids;
 199         }
 200
 201         for (i = 0; i < ncores; i++)
 202                 set_cpu_possible(i, true);
 203 }
 204
 205 static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 206 {
 207         int i;
 208
 209         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 210                 scu_enable(scu_base_addr());
 211
 212         /*
 213          * Write the address of secondary startup into the
 214          * system-wide flags register. The boot monitor waits
 215          * until it receives a soft interrupt, and then the
 216          * secondary CPU branches to this address.
 217          *
 218          * Try using firmware operation first and fall back to
 219          * boot register if it fails.
 220          */
 221         for (i = 1; i < max_cpus; ++i) {
 222                 unsigned long phys_cpu;
 223                 unsigned long boot_addr;
 224
 225                 phys_cpu = cpu_logical_map(i);
 226                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 227
 228                 if (call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr))
 229                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 230         }
 231 }
 232
 233 struct smp_operations exynos_smp_ops __initdata = {
 234         .smp_init_cpus          = exynos_smp_init_cpus,
 235         .smp_prepare_cpus       = exynos_smp_prepare_cpus,
 236         .smp_secondary_init     = exynos_secondary_init,
 237         .smp_boot_secondary     = exynos_boot_secondary,
 238 #ifdef CONFIG_HOTPLUG_CPU
 239         .cpu_die                = exynos_cpu_die,
 240 #endif
 241 };