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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SH-X3 SMP
   4  *
   5  *  Copyright (C) 2007 - 2010  Paul Mundt
   6  *  Copyright (C) 2007  Magnus Damm
   7  */
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/cpumask.h>
  11 #include <linux/smp.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/sched.h>
  15 #include <linux/delay.h>
  16 #include <linux/cpu.h>
  17 #include <asm/sections.h>
  18
  19 #define STBCR_REG(phys_id) (0xfe400004 | (phys_id << 12))
  20 #define RESET_REG(phys_id) (0xfe400008 | (phys_id << 12))
  21
  22 #define STBCR_MSTP      0x00000001
  23 #define STBCR_RESET     0x00000002
  24 #define STBCR_SLEEP     0x00000004
  25 #define STBCR_LTSLP     0x80000000
  26
  27 static irqreturn_t ipi_interrupt_handler(int irq, void *arg)
  28 {
  29         unsigned int message = (unsigned int)(long)arg;
  30         unsigned int cpu = hard_smp_processor_id();
  31         unsigned int offs = 4 * cpu;
  32         unsigned int x;
  33
  34         x = __raw_readl(0xfe410070 + offs); /* C0INITICI..CnINTICI */
  35         x &= (1 << (message << 2));
  36         __raw_writel(x, 0xfe410080 + offs); /* C0INTICICLR..CnINTICICLR */
  37
  38         smp_message_recv(message);
  39
  40         return IRQ_HANDLED;
  41 }
  42
  43 static void shx3_smp_setup(void)
  44 {
  45         unsigned int cpu = 0;
  46         int i, num;
  47
  48         init_cpu_possible(cpumask_of(cpu));
  49
  50         /* Enable light sleep for the boot CPU */
  51         __raw_writel(__raw_readl(STBCR_REG(cpu)) | STBCR_LTSLP, STBCR_REG(cpu));
  52
  53         __cpu_number_map[0] = 0;
  54         __cpu_logical_map[0] = 0;
  55
  56         /*
  57          * Do this stupidly for now.. we don't have an easy way to probe
  58          * for the total number of cores.
  59          */
  60         for (i = 1, num = 0; i < NR_CPUS; i++) {
  61                 set_cpu_possible(i, true);
  62                 __cpu_number_map[i] = ++num;
  63                 __cpu_logical_map[num] = i;
  64         }
  65
  66         printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
  67 }
  68
  69 static void shx3_prepare_cpus(unsigned int max_cpus)
  70 {
  71         int i;
  72
  73         BUILD_BUG_ON(SMP_MSG_NR >= 8);
  74
  75         for (i = 0; i < SMP_MSG_NR; i++)
  76                 if (request_irq(104 + i, ipi_interrupt_handler,
  77                             IRQF_PERCPU, "IPI", (void *)(long)i))
  78                         pr_err("Failed to request irq %d\n", i);
  79
  80         for (i = 0; i < max_cpus; i++)
  81                 set_cpu_present(i, true);
  82 }
  83
  84 static void shx3_start_cpu(unsigned int cpu, unsigned long entry_point)
  85 {
  86         if (__in_29bit_mode())
  87                 __raw_writel(entry_point, RESET_REG(cpu));
  88         else
  89                 __raw_writel(virt_to_phys(entry_point), RESET_REG(cpu));
  90
  91         if (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  92                 __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
  93
  94         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  95                 cpu_relax();
  96
  97         /* Start up secondary processor by sending a reset */
  98         __raw_writel(STBCR_RESET | STBCR_LTSLP, STBCR_REG(cpu));
  99 }
 100
 101 static unsigned int shx3_smp_processor_id(void)
 102 {
 103         return __raw_readl(0xff000048); /* CPIDR */
 104 }
 105
 106 static void shx3_send_ipi(unsigned int cpu, unsigned int message)
 107 {
 108         unsigned long addr = 0xfe410070 + (cpu * 4);
 109
 110         BUG_ON(cpu >= 4);
 111
 112         __raw_writel(1 << (message << 2), addr); /* C0INTICI..CnINTICI */
 113 }
 114
 115 static void shx3_update_boot_vector(unsigned int cpu)
 116 {
 117         __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
 118         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
 119                 cpu_relax();
 120         __raw_writel(STBCR_RESET, STBCR_REG(cpu));
 121 }
 122
 123 static int shx3_cpu_prepare(unsigned int cpu)
 124 {
 125         shx3_update_boot_vector(cpu);
 126         return 0;
 127 }
 128
 129 static int register_shx3_cpu_notifier(void)
 130 {
 131         cpuhp_setup_state_nocalls(CPUHP_SH_SH3X_PREPARE, "sh/shx3:prepare",
 132                                   shx3_cpu_prepare, NULL);
 133         return 0;
 134 }
 135 late_initcall(register_shx3_cpu_notifier);
 136
 137 struct plat_smp_ops shx3_smp_ops = {
 138         .smp_setup              = shx3_smp_setup,
 139         .prepare_cpus           = shx3_prepare_cpus,
 140         .start_cpu              = shx3_start_cpu,
 141         .smp_processor_id       = shx3_smp_processor_id,
 142         .send_ipi               = shx3_send_ipi,
 143         .cpu_die                = native_cpu_die,
 144         .cpu_disable            = native_cpu_disable,
 145         .play_dead              = native_play_dead,
 146 };