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/smp_plat.h>
  18 #include <asm/smp_scu.h>
  19
  20 #define CPU_RESET               0x00
  21
  22 #define RESET_VECT              0x00
  23 #define SW_RESET_ADDR           0x94
  24
  25 extern u32 boot_inst;
  26
  27 static void __iomem *cpu_ctrl;
  28
  29 static inline void berlin_perform_reset_cpu(unsigned int cpu)
  30 {
  31         u32 val;
  32
  33         val = readl(cpu_ctrl + CPU_RESET);
  34         val |= BIT(cpu_logical_map(cpu));
  35         writel(val, cpu_ctrl + CPU_RESET);
  36 }
  37
  38 static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle)
  39 {
  40         if (!cpu_ctrl)
  41                 return -EFAULT;
  42
  43         /*
  44          * Reset the CPU, making it to execute the instruction in the reset
  45          * exception vector.
  46          */
  47         berlin_perform_reset_cpu(cpu);
  48
  49         return 0;
  50 }
  51
  52 static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
  53 {
  54         struct device_node *np;
  55         void __iomem *scu_base;
  56         void __iomem *vectors_base;
  57
  58         np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
  59         scu_base = of_iomap(np, 0);
  60         of_node_put(np);
  61         if (!scu_base)
  62                 return;
  63
  64         np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl");
  65         cpu_ctrl = of_iomap(np, 0);
  66         of_node_put(np);
  67         if (!cpu_ctrl)
  68                 goto unmap_scu;
  69
  70         vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);
  71         if (!vectors_base)
  72                 goto unmap_scu;
  73
  74         scu_enable(scu_base);
  75         flush_cache_all();
  76
  77         /*
  78          * Write the first instruction the CPU will execute after being reset
  79          * in the reset exception vector.
  80          */
  81         writel(boot_inst, vectors_base + RESET_VECT);
  82
  83         /*
  84          * Write the secondary startup address into the SW reset address
  85          * vector. This is used by boot_inst.
  86          */
  87         writel(virt_to_phys(secondary_startup), vectors_base + SW_RESET_ADDR);
  88
  89         iounmap(vectors_base);
  90 unmap_scu:
  91         iounmap(scu_base);
  92 }
  93
  94 static struct smp_operations berlin_smp_ops __initdata = {
  95         .smp_prepare_cpus       = berlin_smp_prepare_cpus,
  96         .smp_boot_secondary     = berlin_boot_secondary,
  97 };
  98 CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);