arch/arm/mach-oxnas/platsmp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
   4  * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
   5  * Copyright (C) 2002 ARM Ltd.
   6  * All Rights Reserved
   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/smp_plat.h>
  16 #include <asm/smp_scu.h>
  17
  18 extern void ox820_secondary_startup(void);
  19
  20 static void __iomem *cpu_ctrl;
  21 static void __iomem *gic_cpu_ctrl;
  22
  23 #define HOLDINGPEN_CPU_OFFSET           0xc8
  24 #define HOLDINGPEN_LOCATION_OFFSET      0xc4
  25
  26 #define GIC_NCPU_OFFSET(cpu)            (0x100 + (cpu)*0x100)
  27 #define GIC_CPU_CTRL                    0x00
  28 #define GIC_CPU_CTRL_ENABLE             1
  29
  30 static int __init ox820_boot_secondary(unsigned int cpu,
  31                 struct task_struct *idle)
  32 {
  33         /*
  34          * Write the address of secondary startup into the
  35          * system-wide flags register. The BootMonitor waits
  36          * until it receives a soft interrupt, and then the
  37          * secondary CPU branches to this address.
  38          */
  39         writel(virt_to_phys(ox820_secondary_startup),
  40                         cpu_ctrl + HOLDINGPEN_LOCATION_OFFSET);
  41
  42         writel(cpu, cpu_ctrl + HOLDINGPEN_CPU_OFFSET);
  43
  44         /*
  45          * Enable GIC cpu interface in CPU Interface Control Register
  46          */
  47         writel(GIC_CPU_CTRL_ENABLE,
  48                 gic_cpu_ctrl + GIC_NCPU_OFFSET(cpu) + GIC_CPU_CTRL);
  49
  50         /*
  51          * Send the secondary CPU a soft interrupt, thereby causing
  52          * the boot monitor to read the system wide flags register,
  53          * and branch to the address found there.
  54          */
  55         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  56
  57         return 0;
  58 }
  59
  60 static void __init ox820_smp_prepare_cpus(unsigned int max_cpus)
  61 {
  62         struct device_node *np;
  63         void __iomem *scu_base;
  64
  65         np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-scu");
  66         scu_base = of_iomap(np, 0);
  67         of_node_put(np);
  68         if (!scu_base)
  69                 return;
  70
  71         /* Remap CPU Interrupt Interface Registers */
  72         np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-gic");
  73         gic_cpu_ctrl = of_iomap(np, 1);
  74         of_node_put(np);
  75         if (!gic_cpu_ctrl)
  76                 goto unmap_scu;
  77
  78         np = of_find_compatible_node(NULL, NULL, "oxsemi,ox820-sys-ctrl");
  79         cpu_ctrl = of_iomap(np, 0);
  80         of_node_put(np);
  81         if (!cpu_ctrl)
  82                 goto unmap_scu;
  83
  84         scu_enable(scu_base);
  85         flush_cache_all();
  86
  87 unmap_scu:
  88         iounmap(scu_base);
  89 }
  90
  91 static const struct smp_operations ox820_smp_ops __initconst = {
  92         .smp_prepare_cpus       = ox820_smp_prepare_cpus,
  93         .smp_boot_secondary     = ox820_boot_secondary,
  94 };
  95
  96 CPU_METHOD_OF_DECLARE(ox820_smp, "oxsemi,ox820-smp", &ox820_smp_ops);