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_plat.h>
  19 #include <asm/smp_scu.h>
  20 #include <linux/irqchip/arm-gic.h>
  21 #include "common.h"
  22
  23 /*
  24  * Store number of cores in the system
  25  * Because of scu_get_core_count() must be in __init section and can't
  26  * be called from zynq_cpun_start() because it is not in __init section.
  27  */
  28 static int ncores;
  29
  30 int zynq_cpun_start(u32 address, int cpu)
  31 {
  32         u32 trampoline_code_size = &zynq_secondary_trampoline_end -
  33                                                 &zynq_secondary_trampoline;
  34         u32 phy_cpuid = cpu_logical_map(cpu);
  35
  36         /* MS: Expectation that SLCR are directly map and accessible */
  37         /* Not possible to jump to non aligned address */
  38         if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
  39                 /* Store pointer to ioremap area which points to address 0x0 */
  40                 static u8 __iomem *zero;
  41                 u32 trampoline_size = &zynq_secondary_trampoline_jump -
  42                                                 &zynq_secondary_trampoline;
  43
  44                 zynq_slcr_cpu_stop(phy_cpuid);
  45                 if (address) {
  46                         if (__pa(PAGE_OFFSET)) {
  47                                 zero = ioremap(0, trampoline_code_size);
  48                                 if (!zero) {
  49                                         pr_warn("BOOTUP jump vectors not accessible\n");
  50                                         return -1;
  51                                 }
  52                         } else {
  53                                 zero = (__force u8 __iomem *)PAGE_OFFSET;
  54                         }
  55
  56                         /*
  57                         * This is elegant way how to jump to any address
  58                         * 0x0: Load address at 0x8 to r0
  59                         * 0x4: Jump by mov instruction
  60                         * 0x8: Jumping address
  61                         */
  62                         memcpy_toio(zero, &zynq_secondary_trampoline,
  63                                                         trampoline_size);
  64                         writel(address, zero + trampoline_size);
  65
  66                         flush_cache_all();
  67                         outer_flush_range(0, trampoline_code_size);
  68                         smp_wmb();
  69
  70                         if (__pa(PAGE_OFFSET))
  71                                 iounmap(zero);
  72                 }
  73                 zynq_slcr_cpu_start(phy_cpuid);
  74
  75                 return 0;
  76         }
  77
  78         pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);
  79
  80         return -1;
  81 }
  82 EXPORT_SYMBOL(zynq_cpun_start);
  83
  84 static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
  85 {
  86         return zynq_cpun_start(__pa_symbol(secondary_startup_arm), cpu);
  87 }
  88
  89 /*
  90  * Initialise the CPU possible map early - this describes the CPUs
  91  * which may be present or become present in the system.
  92  */
  93 static void __init zynq_smp_init_cpus(void)
  94 {
  95         int i;
  96
  97         ncores = scu_get_core_count(zynq_scu_base);
  98
  99         for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
 100                 set_cpu_possible(i, true);
 101 }
 102
 103 static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
 104 {
 105         scu_enable(zynq_scu_base);
 106 }
 107
 108 /**
 109  * zynq_secondary_init - Initialize secondary CPU cores
 110  * @cpu:        CPU that is initialized
 111  *
 112  * This function is in the hotplug path. Don't move it into the
 113  * init section!!
 114  */
 115 static void zynq_secondary_init(unsigned int cpu)
 116 {
 117         zynq_core_pm_init();
 118 }
 119
 120 #ifdef CONFIG_HOTPLUG_CPU
 121 static int zynq_cpu_kill(unsigned cpu)
 122 {
 123         unsigned long timeout = jiffies + msecs_to_jiffies(50);
 124
 125         while (zynq_slcr_cpu_state_read(cpu))
 126                 if (time_after(jiffies, timeout))
 127                         return 0;
 128
 129         zynq_slcr_cpu_stop(cpu);
 130         return 1;
 131 }
 132
 133 /**
 134  * zynq_cpu_die - Let a CPU core die
 135  * @cpu:        Dying CPU
 136  *
 137  * Platform-specific code to shutdown a CPU.
 138  * Called with IRQs disabled on the dying CPU.
 139  */
 140 static void zynq_cpu_die(unsigned int cpu)
 141 {
 142         zynq_slcr_cpu_state_write(cpu, true);
 143
 144         /*
 145          * there is no power-control hardware on this platform, so all
 146          * we can do is put the core into WFI; this is safe as the calling
 147          * code will have already disabled interrupts
 148          */
 149         for (;;)
 150                 cpu_do_idle();
 151 }
 152 #endif
 153
 154 const struct smp_operations zynq_smp_ops __initconst = {
 155         .smp_init_cpus          = zynq_smp_init_cpus,
 156         .smp_prepare_cpus       = zynq_smp_prepare_cpus,
 157         .smp_boot_secondary     = zynq_boot_secondary,
 158         .smp_secondary_init     = zynq_secondary_init,
 159 #ifdef CONFIG_HOTPLUG_CPU
 160         .cpu_die                = zynq_cpu_die,
 161         .cpu_kill               = zynq_cpu_kill,
 162 #endif
 163 };