arch/arm/mach-msm/platsmp.c

   1 /*
   2  *  Copyright (C) 2002 ARM Ltd.
   3  *  All Rights Reserved
   4  *  Copyright (c) 2010, Code Aurora Forum. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/errno.h>
  13 #include <linux/delay.h>
  14 #include <linux/device.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/smp.h>
  17 #include <linux/io.h>
  18
  19 #include <asm/cacheflush.h>
  20 #include <asm/cputype.h>
  21 #include <asm/mach-types.h>
  22 #include <asm/smp_plat.h>
  23
  24 #include "scm-boot.h"
  25 #include "common.h"
  26
  27 #define VDD_SC1_ARRAY_CLAMP_GFS_CTL 0x15A0
  28 #define SCSS_CPU1CORE_RESET 0xD80
  29 #define SCSS_DBG_STATUS_CORE_PWRDUP 0xE64
  30
  31 extern void msm_secondary_startup(void);
  32
  33 static DEFINE_SPINLOCK(boot_lock);
  34
  35 static inline int get_core_count(void)
  36 {
  37         /* 1 + the PART[1:0] field of MIDR */
  38         return ((read_cpuid_id() >> 4) & 3) + 1;
  39 }
  40
  41 static void msm_secondary_init(unsigned int cpu)
  42 {
  43         /*
  44          * let the primary processor know we're out of the
  45          * pen, then head off into the C entry point
  46          */
  47         pen_release = -1;
  48         smp_wmb();
  49
  50         /*
  51          * Synchronise with the boot thread.
  52          */
  53         spin_lock(&boot_lock);
  54         spin_unlock(&boot_lock);
  55 }
  56
  57 static void prepare_cold_cpu(unsigned int cpu)
  58 {
  59         int ret;
  60         ret = scm_set_boot_addr(virt_to_phys(msm_secondary_startup),
  61                                 SCM_FLAG_COLDBOOT_CPU1);
  62         if (ret == 0) {
  63                 void __iomem *sc1_base_ptr;
  64                 sc1_base_ptr = ioremap_nocache(0x00902000, SZ_4K*2);
  65                 if (sc1_base_ptr) {
  66                         writel(0, sc1_base_ptr + VDD_SC1_ARRAY_CLAMP_GFS_CTL);
  67                         writel(0, sc1_base_ptr + SCSS_CPU1CORE_RESET);
  68                         writel(3, sc1_base_ptr + SCSS_DBG_STATUS_CORE_PWRDUP);
  69                         iounmap(sc1_base_ptr);
  70                 }
  71         } else
  72                 printk(KERN_DEBUG "Failed to set secondary core boot "
  73                                   "address\n");
  74 }
  75
  76 static int msm_boot_secondary(unsigned int cpu, struct task_struct *idle)
  77 {
  78         unsigned long timeout;
  79         static int cold_boot_done;
  80
  81         /* Only need to bring cpu out of reset this way once */
  82         if (cold_boot_done == false) {
  83                 prepare_cold_cpu(cpu);
  84                 cold_boot_done = true;
  85         }
  86
  87         /*
  88          * set synchronisation state between this boot processor
  89          * and the secondary one
  90          */
  91         spin_lock(&boot_lock);
  92
  93         /*
  94          * The secondary processor is waiting to be released from
  95          * the holding pen - release it, then wait for it to flag
  96          * that it has been released by resetting pen_release.
  97          *
  98          * Note that "pen_release" is the hardware CPU ID, whereas
  99          * "cpu" is Linux's internal ID.
 100          */
 101         pen_release = cpu_logical_map(cpu);
 102         sync_cache_w(&pen_release);
 103
 104         /*
 105          * Send the secondary CPU a soft interrupt, thereby causing
 106          * the boot monitor to read the system wide flags register,
 107          * and branch to the address found there.
 108          */
 109         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 110
 111         timeout = jiffies + (1 * HZ);
 112         while (time_before(jiffies, timeout)) {
 113                 smp_rmb();
 114                 if (pen_release == -1)
 115                         break;
 116
 117                 udelay(10);
 118         }
 119
 120         /*
 121          * now the secondary core is starting up let it run its
 122          * calibrations, then wait for it to finish
 123          */
 124         spin_unlock(&boot_lock);
 125
 126         return pen_release != -1 ? -ENOSYS : 0;
 127 }
 128
 129 /*
 130  * Initialise the CPU possible map early - this describes the CPUs
 131  * which may be present or become present in the system. The msm8x60
 132  * does not support the ARM SCU, so just set the possible cpu mask to
 133  * NR_CPUS.
 134  */
 135 static void __init msm_smp_init_cpus(void)
 136 {
 137         unsigned int i, ncores = get_core_count();
 138
 139         if (ncores > nr_cpu_ids) {
 140                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 141                         ncores, nr_cpu_ids);
 142                 ncores = nr_cpu_ids;
 143         }
 144
 145         for (i = 0; i < ncores; i++)
 146                 set_cpu_possible(i, true);
 147 }
 148
 149 static void __init msm_smp_prepare_cpus(unsigned int max_cpus)
 150 {
 151 }
 152
 153 struct smp_operations msm_smp_ops __initdata = {
 154         .smp_init_cpus          = msm_smp_init_cpus,
 155         .smp_prepare_cpus       = msm_smp_prepare_cpus,
 156         .smp_secondary_init     = msm_secondary_init,
 157         .smp_boot_secondary     = msm_boot_secondary,
 158 #ifdef CONFIG_HOTPLUG_CPU
 159         .cpu_die                = msm_cpu_die,
 160 #endif
 161 };