arch/arm/mach-zynq/platsmp.c

   1 /*
   2  * This file contains Xilinx specific SMP code, used to start up
   3  * the second processor.
   4  *
   5  * Copyright (C) 2011-2013 Xilinx
   6  *
   7  * based on linux/arch/arm/mach-realview/platsmp.c
   8  *
   9  * Copyright (C) 2002 ARM Ltd.
  10  *
  11  * This software is licensed under the terms of the GNU General Public
  12  * License version 2, as published by the Free Software Foundation, and
  13  * may be copied, distributed, and modified under those terms.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/export.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/init.h>
  24 #include <linux/io.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/smp_scu.h>
  27 #include <linux/irqchip/arm-gic.h>
  28 #include "common.h"
  29
  30 /*
  31  * Store number of cores in the system
  32  * Because of scu_get_core_count() must be in __init section and can't
  33  * be called from zynq_cpun_start() because it is not in __init section.
  34  */
  35 static int ncores;
  36
  37 int zynq_cpun_start(u32 address, int cpu)
  38 {
  39         u32 trampoline_code_size = &zynq_secondary_trampoline_end -
  40                                                 &zynq_secondary_trampoline;
  41
  42         /* MS: Expectation that SLCR are directly map and accessible */
  43         /* Not possible to jump to non aligned address */
  44         if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
  45                 /* Store pointer to ioremap area which points to address 0x0 */
  46                 static u8 __iomem *zero;
  47                 u32 trampoline_size = &zynq_secondary_trampoline_jump -
  48                                                 &zynq_secondary_trampoline;
  49
  50                 zynq_slcr_cpu_stop(cpu);
  51                 if (address) {
  52                         if (__pa(PAGE_OFFSET)) {
  53                                 zero = ioremap(0, trampoline_code_size);
  54                                 if (!zero) {
  55                                         pr_warn("BOOTUP jump vectors not accessible\n");
  56                                         return -1;
  57                                 }
  58                         } else {
  59                                 zero = (__force u8 __iomem *)PAGE_OFFSET;
  60                         }
  61
  62                         /*
  63                         * This is elegant way how to jump to any address
  64                         * 0x0: Load address at 0x8 to r0
  65                         * 0x4: Jump by mov instruction
  66                         * 0x8: Jumping address
  67                         */
  68                         memcpy((__force void *)zero, &zynq_secondary_trampoline,
  69                                                         trampoline_size);
  70                         writel(address, zero + trampoline_size);
  71
  72                         flush_cache_all();
  73                         outer_flush_range(0, trampoline_code_size);
  74                         smp_wmb();
  75
  76                         if (__pa(PAGE_OFFSET))
  77                                 iounmap(zero);
  78                 }
  79                 zynq_slcr_cpu_start(cpu);
  80
  81                 return 0;
  82         }
  83
  84         pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);
  85
  86         return -1;
  87 }
  88 EXPORT_SYMBOL(zynq_cpun_start);
  89
  90 static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
  91 {
  92         return zynq_cpun_start(__pa_symbol(secondary_startup), cpu);
  93 }
  94
  95 /*
  96  * Initialise the CPU possible map early - this describes the CPUs
  97  * which may be present or become present in the system.
  98  */
  99 static void __init zynq_smp_init_cpus(void)
 100 {
 101         int i;
 102
 103         ncores = scu_get_core_count(zynq_scu_base);
 104
 105         for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
 106                 set_cpu_possible(i, true);
 107 }
 108
 109 static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
 110 {
 111         scu_enable(zynq_scu_base);
 112 }
 113
 114 /**
 115  * zynq_secondary_init - Initialize secondary CPU cores
 116  * @cpu:        CPU that is initialized
 117  *
 118  * This function is in the hotplug path. Don't move it into the
 119  * init section!!
 120  */
 121 static void zynq_secondary_init(unsigned int cpu)
 122 {
 123         zynq_core_pm_init();
 124 }
 125
 126 #ifdef CONFIG_HOTPLUG_CPU
 127 static int zynq_cpu_kill(unsigned cpu)
 128 {
 129         unsigned long timeout = jiffies + msecs_to_jiffies(50);
 130
 131         while (zynq_slcr_cpu_state_read(cpu))
 132                 if (time_after(jiffies, timeout))
 133                         return 0;
 134
 135         zynq_slcr_cpu_stop(cpu);
 136         return 1;
 137 }
 138
 139 /**
 140  * zynq_cpu_die - Let a CPU core die
 141  * @cpu:        Dying CPU
 142  *
 143  * Platform-specific code to shutdown a CPU.
 144  * Called with IRQs disabled on the dying CPU.
 145  */
 146 static void zynq_cpu_die(unsigned int cpu)
 147 {
 148         zynq_slcr_cpu_state_write(cpu, true);
 149
 150         /*
 151          * there is no power-control hardware on this platform, so all
 152          * we can do is put the core into WFI; this is safe as the calling
 153          * code will have already disabled interrupts
 154          */
 155         for (;;)
 156                 cpu_do_idle();
 157 }
 158 #endif
 159
 160 const struct smp_operations zynq_smp_ops __initconst = {
 161         .smp_init_cpus          = zynq_smp_init_cpus,
 162         .smp_prepare_cpus       = zynq_smp_prepare_cpus,
 163         .smp_boot_secondary     = zynq_boot_secondary,
 164         .smp_secondary_init     = zynq_secondary_init,
 165 #ifdef CONFIG_HOTPLUG_CPU
 166         .cpu_die                = zynq_cpu_die,
 167         .cpu_kill               = zynq_cpu_kill,
 168 #endif
 169 };