arch/arm/mach-prima2/platsmp.c

   1 /*
   2  * plat smp support for CSR Marco dual-core SMP SoCs
   3  *
   4  * Copyright (c) 2012 Cambridge Silicon Radio Limited, a CSR plc group company.
   5  *
   6  * Licensed under GPLv2 or later.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/smp.h>
  11 #include <linux/delay.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <asm/page.h>
  15 #include <asm/mach/map.h>
  16 #include <asm/smp_plat.h>
  17 #include <asm/smp_scu.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/cputype.h>
  20
  21 #include "common.h"
  22
  23 static void __iomem *scu_base;
  24 static void __iomem *rsc_base;
  25
  26 static DEFINE_SPINLOCK(boot_lock);
  27
  28 static struct map_desc scu_io_desc __initdata = {
  29         .length         = SZ_4K,
  30         .type           = MT_DEVICE,
  31 };
  32
  33 void __init sirfsoc_map_scu(void)
  34 {
  35         unsigned long base;
  36
  37         /* Get SCU base */
  38         asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
  39
  40         scu_io_desc.virtual = SIRFSOC_VA(base);
  41         scu_io_desc.pfn = __phys_to_pfn(base);
  42         iotable_init(&scu_io_desc, 1);
  43
  44         scu_base = (void __iomem *)SIRFSOC_VA(base);
  45 }
  46
  47 static void sirfsoc_secondary_init(unsigned int cpu)
  48 {
  49         /*
  50          * let the primary processor know we're out of the
  51          * pen, then head off into the C entry point
  52          */
  53         pen_release = -1;
  54         smp_wmb();
  55
  56         /*
  57          * Synchronise with the boot thread.
  58          */
  59         spin_lock(&boot_lock);
  60         spin_unlock(&boot_lock);
  61 }
  62
  63 static struct of_device_id rsc_ids[]  = {
  64         { .compatible = "sirf,marco-rsc" },
  65         {},
  66 };
  67
  68 static int sirfsoc_boot_secondary(unsigned int cpu, struct task_struct *idle)
  69 {
  70         unsigned long timeout;
  71         struct device_node *np;
  72
  73         np = of_find_matching_node(NULL, rsc_ids);
  74         if (!np)
  75                 return -ENODEV;
  76
  77         rsc_base = of_iomap(np, 0);
  78         if (!rsc_base)
  79                 return -ENOMEM;
  80
  81         /*
  82          * write the address of secondary startup into the sram register
  83          * at offset 0x2C, then write the magic number 0x3CAF5D62 to the
  84          * RSC register at offset 0x28, which is what boot rom code is
  85          * waiting for. This would wake up the secondary core from WFE
  86          */
  87 #define SIRFSOC_CPU1_JUMPADDR_OFFSET 0x2C
  88         __raw_writel(virt_to_phys(sirfsoc_secondary_startup),
  89                 rsc_base + SIRFSOC_CPU1_JUMPADDR_OFFSET);
  90
  91 #define SIRFSOC_CPU1_WAKEMAGIC_OFFSET 0x28
  92         __raw_writel(0x3CAF5D62,
  93                 rsc_base + SIRFSOC_CPU1_WAKEMAGIC_OFFSET);
  94
  95         /* make sure write buffer is drained */
  96         mb();
  97
  98         spin_lock(&boot_lock);
  99
 100         /*
 101          * The secondary processor is waiting to be released from
 102          * the holding pen - release it, then wait for it to flag
 103          * that it has been released by resetting pen_release.
 104          *
 105          * Note that "pen_release" is the hardware CPU ID, whereas
 106          * "cpu" is Linux's internal ID.
 107          */
 108         pen_release = cpu_logical_map(cpu);
 109         __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
 110         outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
 111
 112         /*
 113          * Send the secondary CPU SEV, thereby causing the boot monitor to read
 114          * the JUMPADDR and WAKEMAGIC, and branch to the address found there.
 115          */
 116         dsb_sev();
 117
 118         timeout = jiffies + (1 * HZ);
 119         while (time_before(jiffies, timeout)) {
 120                 smp_rmb();
 121                 if (pen_release == -1)
 122                         break;
 123
 124                 udelay(10);
 125         }
 126
 127         /*
 128          * now the secondary core is starting up let it run its
 129          * calibrations, then wait for it to finish
 130          */
 131         spin_unlock(&boot_lock);
 132
 133         return pen_release != -1 ? -ENOSYS : 0;
 134 }
 135
 136 static void __init sirfsoc_smp_prepare_cpus(unsigned int max_cpus)
 137 {
 138         scu_enable(scu_base);
 139 }
 140
 141 struct smp_operations sirfsoc_smp_ops __initdata = {
 142         .smp_prepare_cpus       = sirfsoc_smp_prepare_cpus,
 143         .smp_secondary_init     = sirfsoc_secondary_init,
 144         .smp_boot_secondary     = sirfsoc_boot_secondary,
 145 #ifdef CONFIG_HOTPLUG_CPU
 146         .cpu_die                = sirfsoc_cpu_die,
 147 #endif
 148 };