arch/arm/mach-shmobile/smp-emev2.c

   1 /*
   2  * SMP support for Emma Mobile EV2
   3  *
   4  * Copyright (C) 2012  Renesas Solutions Corp.
   5  * Copyright (C) 2012  Magnus Damm
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; version 2 of the License.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20 #include <linux/kernel.h>
  21 #include <linux/init.h>
  22 #include <linux/smp.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/io.h>
  25 #include <linux/delay.h>
  26 #include <mach/common.h>
  27 #include <mach/emev2.h>
  28 #include <asm/smp_plat.h>
  29 #include <asm/smp_scu.h>
  30 #include <asm/hardware/gic.h>
  31 #include <asm/cacheflush.h>
  32
  33 #define EMEV2_SCU_BASE 0x1e000000
  34
  35 static DEFINE_SPINLOCK(scu_lock);
  36 static void __iomem *scu_base;
  37
  38 static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
  39 {
  40         unsigned long tmp;
  41
  42         /* we assume this code is running on a different cpu
  43          * than the one that is changing coherency setting */
  44         spin_lock(&scu_lock);
  45         tmp = readl(scu_base + 8);
  46         tmp &= ~clr;
  47         tmp |= set;
  48         writel(tmp, scu_base + 8);
  49         spin_unlock(&scu_lock);
  50
  51 }
  52
  53 static unsigned int __init emev2_get_core_count(void)
  54 {
  55         if (!scu_base) {
  56                 scu_base = ioremap(EMEV2_SCU_BASE, PAGE_SIZE);
  57                 emev2_clock_init(); /* need ioremapped SMU */
  58         }
  59
  60         WARN_ON_ONCE(!scu_base);
  61
  62         return scu_base ? scu_get_core_count(scu_base) : 1;
  63 }
  64
  65 static int emev2_platform_cpu_kill(unsigned int cpu)
  66 {
  67         return 0; /* not supported yet */
  68 }
  69
  70 static int __maybe_unused emev2_cpu_kill(unsigned int cpu)
  71 {
  72         int k;
  73
  74         /* this function is running on another CPU than the offline target,
  75          * here we need wait for shutdown code in platform_cpu_die() to
  76          * finish before asking SoC-specific code to power off the CPU core.
  77          */
  78         for (k = 0; k < 1000; k++) {
  79                 if (shmobile_cpu_is_dead(cpu))
  80                         return emev2_platform_cpu_kill(cpu);
  81                 mdelay(1);
  82         }
  83
  84         return 0;
  85 }
  86
  87
  88 static void __cpuinit emev2_secondary_init(unsigned int cpu)
  89 {
  90         gic_secondary_init(0);
  91 }
  92
  93 static int __cpuinit emev2_boot_secondary(unsigned int cpu, struct task_struct *idle)
  94 {
  95         cpu = cpu_logical_map(cpu);
  96
  97         /* enable cache coherency */
  98         modify_scu_cpu_psr(0, 3 << (cpu * 8));
  99
 100         /* Tell ROM loader about our vector (in headsmp.S) */
 101         emev2_set_boot_vector(__pa(shmobile_secondary_vector));
 102
 103         gic_raise_softirq(cpumask_of(cpu), 0);
 104         return 0;
 105 }
 106
 107 static void __init emev2_smp_prepare_cpus(unsigned int max_cpus)
 108 {
 109         int cpu = cpu_logical_map(0);
 110
 111         scu_enable(scu_base);
 112
 113         /* enable cache coherency on CPU0 */
 114         modify_scu_cpu_psr(0, 3 << (cpu * 8));
 115 }
 116
 117 static void __init emev2_smp_init_cpus(void)
 118 {
 119         unsigned int ncores = emev2_get_core_count();
 120
 121         shmobile_smp_init_cpus(ncores);
 122 }
 123
 124 struct smp_operations emev2_smp_ops __initdata = {
 125         .smp_init_cpus          = emev2_smp_init_cpus,
 126         .smp_prepare_cpus       = emev2_smp_prepare_cpus,
 127         .smp_secondary_init     = emev2_secondary_init,
 128         .smp_boot_secondary     = emev2_boot_secondary,
 129 #ifdef CONFIG_HOTPLUG_CPU
 130         .cpu_kill               = emev2_cpu_kill,
 131         .cpu_die                = shmobile_cpu_die,
 132         .cpu_disable            = shmobile_cpu_disable,
 133 #endif
 134 };