arch/arm/mach-oxnas/platsmp.c

   1 /*
   2  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
   3  * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
   4  * Copyright (C) 2002 ARM Ltd.
   5  * All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  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 extern void ox820_secondary_startup(void);
  22 extern void ox820_cpu_die(unsigned int cpu);
  23
  24 static void __iomem *cpu_ctrl;
  25 static void __iomem *gic_cpu_ctrl;
  26
  27 #define HOLDINGPEN_CPU_OFFSET           0xc8
  28 #define HOLDINGPEN_LOCATION_OFFSET      0xc4
  29
  30 #define GIC_NCPU_OFFSET(cpu)            (0x100 + (cpu)*0x100)
  31 #define GIC_CPU_CTRL                    0x00
  32 #define GIC_CPU_CTRL_ENABLE             1
  33
  34 int __init ox820_boot_secondary(unsigned int cpu, struct task_struct *idle)
  35 {
  36         /*
  37          * Write the address of secondary startup into the
  38          * system-wide flags register. The BootMonitor waits
  39          * until it receives a soft interrupt, and then the
  40          * secondary CPU branches to this address.
  41          */
  42         writel(virt_to_phys(ox820_secondary_startup),
  43                         cpu_ctrl + HOLDINGPEN_LOCATION_OFFSET);
  44
  45         writel(cpu, cpu_ctrl + HOLDINGPEN_CPU_OFFSET);
  46
  47         /*
  48          * Enable GIC cpu interface in CPU Interface Control Register
  49          */
  50         writel(GIC_CPU_CTRL_ENABLE,
  51                 gic_cpu_ctrl + GIC_NCPU_OFFSET(cpu) + GIC_CPU_CTRL);
  52
  53         /*
  54          * Send the secondary CPU a soft interrupt, thereby causing
  55          * the boot monitor to read the system wide flags register,
  56          * and branch to the address found there.
  57          */
  58         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  59
  60         return 0;
  61 }
  62
  63 static void __init ox820_smp_prepare_cpus(unsigned int max_cpus)
  64 {
  65         struct device_node *np;
  66         void __iomem *scu_base;
  67
  68         np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-scu");
  69         scu_base = of_iomap(np, 0);
  70         of_node_put(np);
  71         if (!scu_base)
  72                 return;
  73
  74         /* Remap CPU Interrupt Interface Registers */
  75         np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-gic");
  76         gic_cpu_ctrl = of_iomap(np, 1);
  77         of_node_put(np);
  78         if (!gic_cpu_ctrl)
  79                 goto unmap_scu;
  80
  81         np = of_find_compatible_node(NULL, NULL, "oxsemi,ox820-sys-ctrl");
  82         cpu_ctrl = of_iomap(np, 0);
  83         of_node_put(np);
  84         if (!cpu_ctrl)
  85                 goto unmap_scu;
  86
  87         scu_enable(scu_base);
  88         flush_cache_all();
  89
  90 unmap_scu:
  91         iounmap(scu_base);
  92 }
  93
  94 static const struct smp_operations ox820_smp_ops __initconst = {
  95         .smp_prepare_cpus       = ox820_smp_prepare_cpus,
  96         .smp_boot_secondary     = ox820_boot_secondary,
  97 #ifdef CONFIG_HOTPLUG_CPU
  98         .cpu_die                = ox820_cpu_die,
  99 #endif
 100 };
 101
 102 CPU_METHOD_OF_DECLARE(ox820_smp, "oxsemi,ox820-smp", &ox820_smp_ops);