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

DEFINITIONS

1. ipi_interrupt_handler
2. shx3_smp_setup
3. shx3_prepare_cpus
4. shx3_start_cpu
5. shx3_smp_processor_id
6. shx3_send_ipi
7. shx3_update_boot_vector
8. shx3_cpu_prepare
9. register_shx3_cpu_notifier

   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                 request_irq(104 + i, ipi_interrupt_handler,
  77                             IRQF_PERCPU, "IPI", (void *)(long)i);
  78 
  79         for (i = 0; i < max_cpus; i++)
  80                 set_cpu_present(i, true);
  81 }
  82 
  83 static void shx3_start_cpu(unsigned int cpu, unsigned long entry_point)
  84 {
  85         if (__in_29bit_mode())
  86                 __raw_writel(entry_point, RESET_REG(cpu));
  87         else
  88                 __raw_writel(virt_to_phys(entry_point), RESET_REG(cpu));
  89 
  90         if (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  91                 __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
  92 
  93         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
  94                 cpu_relax();
  95 
  96         /* Start up secondary processor by sending a reset */
  97         __raw_writel(STBCR_RESET | STBCR_LTSLP, STBCR_REG(cpu));
  98 }
  99 
 100 static unsigned int shx3_smp_processor_id(void)
 101 {
 102         return __raw_readl(0xff000048); /* CPIDR */
 103 }
 104 
 105 static void shx3_send_ipi(unsigned int cpu, unsigned int message)
 106 {
 107         unsigned long addr = 0xfe410070 + (cpu * 4);
 108 
 109         BUG_ON(cpu >= 4);
 110 
 111         __raw_writel(1 << (message << 2), addr); /* C0INTICI..CnINTICI */
 112 }
 113 
 114 static void shx3_update_boot_vector(unsigned int cpu)
 115 {
 116         __raw_writel(STBCR_MSTP, STBCR_REG(cpu));
 117         while (!(__raw_readl(STBCR_REG(cpu)) & STBCR_MSTP))
 118                 cpu_relax();
 119         __raw_writel(STBCR_RESET, STBCR_REG(cpu));
 120 }
 121 
 122 static int shx3_cpu_prepare(unsigned int cpu)
 123 {
 124         shx3_update_boot_vector(cpu);
 125         return 0;
 126 }
 127 
 128 static int register_shx3_cpu_notifier(void)
 129 {
 130         cpuhp_setup_state_nocalls(CPUHP_SH_SH3X_PREPARE, "sh/shx3:prepare",
 131                                   shx3_cpu_prepare, NULL);
 132         return 0;
 133 }
 134 late_initcall(register_shx3_cpu_notifier);
 135 
 136 struct plat_smp_ops shx3_smp_ops = {
 137         .smp_setup              = shx3_smp_setup,
 138         .prepare_cpus           = shx3_prepare_cpus,
 139         .start_cpu              = shx3_start_cpu,
 140         .smp_processor_id       = shx3_smp_processor_id,
 141         .send_ipi               = shx3_send_ipi,
 142         .cpu_die                = native_cpu_die,
 143         .cpu_disable            = native_cpu_disable,
 144         .play_dead              = native_play_dead,
 145 };