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