arch/arm/mach-berlin/platsmp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014 Marvell Technology Group Ltd.
   4  *
   5  * Antoine Ténart <antoine.tenart@free-electrons.com>
   6  */
   7
   8 #include <linux/io.h>
   9 #include <linux/delay.h>
  10 #include <linux/of.h>
  11 #include <linux/of_address.h>
  12
  13 #include <asm/cacheflush.h>
  14 #include <asm/cp15.h>
  15 #include <asm/memory.h>
  16 #include <asm/smp_plat.h>
  17 #include <asm/smp_scu.h>
  18
  19 /*
  20  * There are two reset registers, one with self-clearing (SC)
  21  * reset and one with non-self-clearing reset (NON_SC).
  22  */
  23 #define CPU_RESET_SC            0x00
  24 #define CPU_RESET_NON_SC        0x20
  25
  26 #define RESET_VECT              0x00
  27 #define SW_RESET_ADDR           0x94
  28
  29 extern u32 boot_inst;
  30
  31 static void __iomem *cpu_ctrl;
  32
  33 static inline void berlin_perform_reset_cpu(unsigned int cpu)
  34 {
  35         u32 val;
  36
  37         val = readl(cpu_ctrl + CPU_RESET_NON_SC);
  38         val &= ~BIT(cpu_logical_map(cpu));
  39         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
  40         val |= BIT(cpu_logical_map(cpu));
  41         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
  42 }
  43
  44 static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle)
  45 {
  46         if (!cpu_ctrl)
  47                 return -EFAULT;
  48
  49         /*
  50          * Reset the CPU, making it to execute the instruction in the reset
  51          * exception vector.
  52          */
  53         berlin_perform_reset_cpu(cpu);
  54
  55         return 0;
  56 }
  57
  58 static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
  59 {
  60         struct device_node *np;
  61         void __iomem *scu_base;
  62         void __iomem *vectors_base;
  63
  64         np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
  65         scu_base = of_iomap(np, 0);
  66         of_node_put(np);
  67         if (!scu_base)
  68                 return;
  69
  70         np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl");
  71         cpu_ctrl = of_iomap(np, 0);
  72         of_node_put(np);
  73         if (!cpu_ctrl)
  74                 goto unmap_scu;
  75
  76         vectors_base = ioremap(VECTORS_BASE, SZ_32K);
  77         if (!vectors_base)
  78                 goto unmap_scu;
  79
  80         scu_enable(scu_base);
  81
  82         /*
  83          * Write the first instruction the CPU will execute after being reset
  84          * in the reset exception vector.
  85          */
  86         writel(boot_inst, vectors_base + RESET_VECT);
  87
  88         /*
  89          * Write the secondary startup address into the SW reset address
  90          * vector. This is used by boot_inst.
  91          */
  92         writel(__pa_symbol(secondary_startup), vectors_base + SW_RESET_ADDR);
  93
  94         iounmap(vectors_base);
  95 unmap_scu:
  96         iounmap(scu_base);
  97 }
  98
  99 #ifdef CONFIG_HOTPLUG_CPU
 100 static void berlin_cpu_die(unsigned int cpu)
 101 {
 102         v7_exit_coherency_flush(louis);
 103         while (1)
 104                 cpu_do_idle();
 105 }
 106
 107 static int berlin_cpu_kill(unsigned int cpu)
 108 {
 109         u32 val;
 110
 111         val = readl(cpu_ctrl + CPU_RESET_NON_SC);
 112         val &= ~BIT(cpu_logical_map(cpu));
 113         writel(val, cpu_ctrl + CPU_RESET_NON_SC);
 114
 115         return 1;
 116 }
 117 #endif
 118
 119 static const struct smp_operations berlin_smp_ops __initconst = {
 120         .smp_prepare_cpus       = berlin_smp_prepare_cpus,
 121         .smp_boot_secondary     = berlin_boot_secondary,
 122 #ifdef CONFIG_HOTPLUG_CPU
 123         .cpu_die                = berlin_cpu_die,
 124         .cpu_kill               = berlin_cpu_kill,
 125 #endif
 126 };
 127 CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);