arch/sh/kernel/cpu/sh4a/smp-shx3.c

   1 /*
   2  * SH-X3 SMP
   3  *
   4  *  Copyright (C) 2007 - 2010  Paul Mundt
   5  *  Copyright (C) 2007  Magnus Damm
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License.  See the file "COPYING" in the main directory of this archive
   9  * for more details.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/cpumask.h>
  14 #include <linux/smp.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/io.h>
  17 #include <linux/sched.h>
  18 #include <linux/delay.h>
  19 #include <linux/cpu.h>
  20 #include <asm/sections.h>
  21
  22 #define STBCR_REG(phys_id) (0xfe400004 | (phys_id << 12))
  23 #define RESET_REG(phys_id) (0xfe400008 | (phys_id << 12))
  24
  25 #define STBCR_MSTP      0x00000001
  26 #define STBCR_RESET     0x00000002
  27 #define STBCR_SLEEP     0x00000004
  28 #define STBCR_LTSLP     0x80000000
  29
  30 static irqreturn_t ipi_interrupt_handler(int irq, void *arg)
  31 {
  32         unsigned int message = (unsigned int)(long)arg;
  33         unsigned int cpu = hard_smp_processor_id();
  34         unsigned int offs = 4 * cpu;
  35         unsigned int x;
  36
  37         x = __raw_readl(0xfe410070 + offs); /* C0INITICI..CnINTICI */
  38         x &= (1 << (message << 2));
  39         __raw_writel(x, 0xfe410080 + offs); /* C0INTICICLR..CnINTICICLR */
  40
  41         smp_message_recv(message);
  42
  43         return IRQ_HANDLED;
  44 }
  45
  46 static void shx3_smp_setup(void)
  47 {
  48         unsigned int cpu = 0;
  49         int i, num;
  50
  51         init_cpu_possible(cpumask_of(cpu));
  52
  53         /* Enable light sleep for the boot CPU */
  54         __raw_writel(__raw_readl(STBCR_REG(cpu)) | STBCR_LTSLP, STBCR_REG(cpu));
  55
  56         __cpu_number_map[0] = 0;
  57         __cpu_logical_map[0] = 0;
  58
  59         /*
  60          * Do this stupidly for now.. we don't have an easy way to probe
  61          * for the total number of cores.
  62          */
  63         for (i = 1, num = 0; i < NR_CPUS; i++) {
  64                 set_cpu_possible(i, true);
  65                 __cpu_number_map[i] = ++num;
  66                 __cpu_logical_map[num] = i;
  67         }
  68
  69         printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
  70 }
  71
  72 static void shx3_prepare_cpus(unsigned int max_cpus)
  73 {
  74         int i;
  75
  76         local_timer_setup(0);
  77
  78         BUILD_BUG_ON(SMP_MSG_NR >= 8);
  79
  80         for (i = 0; i < SMP_MSG_NR; i++)
  81                 request_irq(104 + i, ipi_interrupt_handler,
  82                             IRQF_PERCPU, "IPI", (void *)(long)i);
  83
  84         for (i = 0; i < max_cpus; i++)
  85                 set_cpu_present(i, true);
  86 }
  87
  88 static void shx3_start_cpu(unsigned int cpu, unsigned long entry_point)
  89 {
  90         if (__in_29bit_mode())
  91                 __raw_writel(entry_point, RESET_REG(cpu));
  92         else
  93                 __raw_writel(virt_to_phys(entry_point), RESET_REG(cpu));
  94
  95         if (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  96                 __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
  97
  98         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  99                 cpu_relax();
 100
 101         /* Start up secondary processor by sending a reset */
 102         __raw_writel(STBCR_RESET | STBCR_LTSLP, STBCR_REG(cpu));
 103 }
 104
 105 static unsigned int shx3_smp_processor_id(void)
 106 {
 107         return __raw_readl(0xff000048); /* CPIDR */
 108 }
 109
 110 static void shx3_send_ipi(unsigned int cpu, unsigned int message)
 111 {
 112         unsigned long addr = 0xfe410070 + (cpu * 4);
 113
 114         BUG_ON(cpu >= 4);
 115
 116         __raw_writel(1 << (message << 2), addr); /* C0INTICI..CnINTICI */
 117 }
 118
 119 static void shx3_update_boot_vector(unsigned int cpu)
 120 {
 121         __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
 122         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
 123                 cpu_relax();
 124         __raw_writel(STBCR_RESET, STBCR_REG(cpu));
 125 }
 126
 127 static int
 128 shx3_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 129 {
 130         unsigned int cpu = (unsigned int)hcpu;
 131
 132         switch (action) {
 133         case CPU_UP_PREPARE:
 134                 shx3_update_boot_vector(cpu);
 135                 break;
 136         case CPU_ONLINE:
 137                 pr_info("CPU %u is now online\n", cpu);
 138                 break;
 139         case CPU_DEAD:
 140                 break;
 141         }
 142
 143         return NOTIFY_OK;
 144 }
 145
 146 static struct notifier_block shx3_cpu_notifier = {
 147         .notifier_call          = shx3_cpu_callback,
 148 };
 149
 150 static int register_shx3_cpu_notifier(void)
 151 {
 152         register_hotcpu_notifier(&shx3_cpu_notifier);
 153         return 0;
 154 }
 155 late_initcall(register_shx3_cpu_notifier);
 156
 157 struct plat_smp_ops shx3_smp_ops = {
 158         .smp_setup              = shx3_smp_setup,
 159         .prepare_cpus           = shx3_prepare_cpus,
 160         .start_cpu              = shx3_start_cpu,
 161         .smp_processor_id       = shx3_smp_processor_id,
 162         .send_ipi               = shx3_send_ipi,
 163         .cpu_die                = native_cpu_die,
 164         .cpu_disable            = native_cpu_disable,
 165         .play_dead              = native_play_dead,
 166 };