arch/arm/mach-berlin/platsmp.c

   1 /*
   2  * Copyright (C) 2014 Marvell Technology Group Ltd.
   3  *
   4  * Antoine Ténart <antoine.tenart@free-electrons.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/io.h>
  12 #include <linux/delay.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/cp15.h>
  18 #include <asm/smp_plat.h>
  19 #include <asm/smp_scu.h>
  20
  21 /*
  22  * There are two reset registers, one with self-clearing (SC)
  23  * reset and one with non-self-clearing reset (NON_SC).
  24  */
  25 #define CPU_RESET_SC            0x00
  26 #define CPU_RESET_NON_SC        0x20
  27
  28 #define RESET_VECT              0x00
  29 #define SW_RESET_ADDR           0x94
  30
  31 extern u32 boot_inst;
  32
  33 static void __iomem *cpu_ctrl;
  34
  35 static inline void berlin_perform_reset_cpu(unsigned int cpu)
  36 {
  37         u32 val;
  38
  39         val = readl(cpu_ctrl + CPU_RESET_NON_SC);
  40         val &= ~BIT(cpu_logical_map(cpu));
  41         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
  42         val |= BIT(cpu_logical_map(cpu));
  43         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
  44 }
  45
  46 static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle)
  47 {
  48         if (!cpu_ctrl)
  49                 return -EFAULT;
  50
  51         /*
  52          * Reset the CPU, making it to execute the instruction in the reset
  53          * exception vector.
  54          */
  55         berlin_perform_reset_cpu(cpu);
  56
  57         return 0;
  58 }
  59
  60 static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
  61 {
  62         struct device_node *np;
  63         void __iomem *scu_base;
  64         void __iomem *vectors_base;
  65
  66         np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
  67         scu_base = of_iomap(np, 0);
  68         of_node_put(np);
  69         if (!scu_base)
  70                 return;
  71
  72         np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl");
  73         cpu_ctrl = of_iomap(np, 0);
  74         of_node_put(np);
  75         if (!cpu_ctrl)
  76                 goto unmap_scu;
  77
  78         vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);
  79         if (!vectors_base)
  80                 goto unmap_scu;
  81
  82         scu_enable(scu_base);
  83         flush_cache_all();
  84
  85         /*
  86          * Write the first instruction the CPU will execute after being reset
  87          * in the reset exception vector.
  88          */
  89         writel(boot_inst, vectors_base + RESET_VECT);
  90
  91         /*
  92          * Write the secondary startup address into the SW reset address
  93          * vector. This is used by boot_inst.
  94          */
  95         writel(virt_to_phys(secondary_startup), vectors_base + SW_RESET_ADDR);
  96
  97         iounmap(vectors_base);
  98 unmap_scu:
  99         iounmap(scu_base);
 100 }
 101
 102 #ifdef CONFIG_HOTPLUG_CPU
 103 static void berlin_cpu_die(unsigned int cpu)
 104 {
 105         v7_exit_coherency_flush(louis);
 106         while (1)
 107                 cpu_do_idle();
 108 }
 109
 110 static int berlin_cpu_kill(unsigned int cpu)
 111 {
 112         u32 val;
 113
 114         val = readl(cpu_ctrl + CPU_RESET_NON_SC);
 115         val &= ~BIT(cpu_logical_map(cpu));
 116         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
 117
 118         return 1;
 119 }
 120 #endif
 121
 122 static const struct smp_operations berlin_smp_ops __initconst = {
 123         .smp_prepare_cpus       = berlin_smp_prepare_cpus,
 124         .smp_boot_secondary     = berlin_boot_secondary,
 125 #ifdef CONFIG_HOTPLUG_CPU
 126         .cpu_die                = berlin_cpu_die,
 127         .cpu_kill               = berlin_cpu_kill,
 128 #endif
 129 };
 130 CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);