arch/arm/mach-zynq/platsmp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file contains Xilinx specific SMP code, used to start up
   4  * the second processor.
   5  *
   6  * Copyright (C) 2011-2013 Xilinx
   7  *
   8  * based on linux/arch/arm/mach-realview/platsmp.c
   9  *
  10  * Copyright (C) 2002 ARM Ltd.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/jiffies.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <asm/cacheflush.h>
  18 #include <asm/smp_scu.h>
  19 #include <linux/irqchip/arm-gic.h>
  20 #include "common.h"
  21
  22 /*
  23  * Store number of cores in the system
  24  * Because of scu_get_core_count() must be in __init section and can't
  25  * be called from zynq_cpun_start() because it is not in __init section.
  26  */
  27 static int ncores;
  28
  29 int zynq_cpun_start(u32 address, int cpu)
  30 {
  31         u32 trampoline_code_size = &zynq_secondary_trampoline_end -
  32                                                 &zynq_secondary_trampoline;
  33
  34         /* MS: Expectation that SLCR are directly map and accessible */
  35         /* Not possible to jump to non aligned address */
  36         if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
  37                 /* Store pointer to ioremap area which points to address 0x0 */
  38                 static u8 __iomem *zero;
  39                 u32 trampoline_size = &zynq_secondary_trampoline_jump -
  40                                                 &zynq_secondary_trampoline;
  41
  42                 zynq_slcr_cpu_stop(cpu);
  43                 if (address) {
  44                         if (__pa(PAGE_OFFSET)) {
  45                                 zero = ioremap(0, trampoline_code_size);
  46                                 if (!zero) {
  47                                         pr_warn("BOOTUP jump vectors not accessible\n");
  48                                         return -1;
  49                                 }
  50                         } else {
  51                                 zero = (__force u8 __iomem *)PAGE_OFFSET;
  52                         }
  53
  54                         /*
  55                         * This is elegant way how to jump to any address
  56                         * 0x0: Load address at 0x8 to r0
  57                         * 0x4: Jump by mov instruction
  58                         * 0x8: Jumping address
  59                         */
  60                         memcpy((__force void *)zero, &zynq_secondary_trampoline,
  61                                                         trampoline_size);
  62                         writel(address, zero + trampoline_size);
  63
  64                         flush_cache_all();
  65                         outer_flush_range(0, trampoline_code_size);
  66                         smp_wmb();
  67
  68                         if (__pa(PAGE_OFFSET))
  69                                 iounmap(zero);
  70                 }
  71                 zynq_slcr_cpu_start(cpu);
  72
  73                 return 0;
  74         }
  75
  76         pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);
  77
  78         return -1;
  79 }
  80 EXPORT_SYMBOL(zynq_cpun_start);
  81
  82 static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
  83 {
  84         return zynq_cpun_start(__pa_symbol(secondary_startup), cpu);
  85 }
  86
  87 /*
  88  * Initialise the CPU possible map early - this describes the CPUs
  89  * which may be present or become present in the system.
  90  */
  91 static void __init zynq_smp_init_cpus(void)
  92 {
  93         int i;
  94
  95         ncores = scu_get_core_count(zynq_scu_base);
  96
  97         for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
  98                 set_cpu_possible(i, true);
  99 }
 100
 101 static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
 102 {
 103         scu_enable(zynq_scu_base);
 104 }
 105
 106 /**
 107  * zynq_secondary_init - Initialize secondary CPU cores
 108  * @cpu:        CPU that is initialized
 109  *
 110  * This function is in the hotplug path. Don't move it into the
 111  * init section!!
 112  */
 113 static void zynq_secondary_init(unsigned int cpu)
 114 {
 115         zynq_core_pm_init();
 116 }
 117
 118 #ifdef CONFIG_HOTPLUG_CPU
 119 static int zynq_cpu_kill(unsigned cpu)
 120 {
 121         unsigned long timeout = jiffies + msecs_to_jiffies(50);
 122
 123         while (zynq_slcr_cpu_state_read(cpu))
 124                 if (time_after(jiffies, timeout))
 125                         return 0;
 126
 127         zynq_slcr_cpu_stop(cpu);
 128         return 1;
 129 }
 130
 131 /**
 132  * zynq_cpu_die - Let a CPU core die
 133  * @cpu:        Dying CPU
 134  *
 135  * Platform-specific code to shutdown a CPU.
 136  * Called with IRQs disabled on the dying CPU.
 137  */
 138 static void zynq_cpu_die(unsigned int cpu)
 139 {
 140         zynq_slcr_cpu_state_write(cpu, true);
 141
 142         /*
 143          * there is no power-control hardware on this platform, so all
 144          * we can do is put the core into WFI; this is safe as the calling
 145          * code will have already disabled interrupts
 146          */
 147         for (;;)
 148                 cpu_do_idle();
 149 }
 150 #endif
 151
 152 const struct smp_operations zynq_smp_ops __initconst = {
 153         .smp_init_cpus          = zynq_smp_init_cpus,
 154         .smp_prepare_cpus       = zynq_smp_prepare_cpus,
 155         .smp_boot_secondary     = zynq_boot_secondary,
 156         .smp_secondary_init     = zynq_secondary_init,
 157 #ifdef CONFIG_HOTPLUG_CPU
 158         .cpu_die                = zynq_cpu_die,
 159         .cpu_kill               = zynq_cpu_kill,
 160 #endif
 161 };