LXR linux/arch/arm/mach-prima2/platsmp.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * plat smp support for CSR Marco dual-core SMP SoCs
   4 *
   5 * Copyright (c) 2012 Cambridge Silicon Radio Limited, a CSR plc group company.
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/smp.h>
  10#include <linux/delay.h>
  11#include <linux/of.h>
  12#include <linux/of_address.h>
  13#include <asm/page.h>
  14#include <asm/mach/map.h>
  15#include <asm/smp_plat.h>
  16#include <asm/smp_scu.h>
  17#include <asm/cacheflush.h>
  18#include <asm/cputype.h>
  19
  20#include "common.h"
  21
  22static void __iomem *clk_base;
  23
  24static DEFINE_SPINLOCK(boot_lock);
  25
  26/* XXX prima2_pen_release is cargo culted code - DO NOT COPY XXX */
  27volatile int prima2_pen_release = -1;
  28
  29static void sirfsoc_secondary_init(unsigned int cpu)
  30{
  31        /*
  32         * let the primary processor know we're out of the
  33         * pen, then head off into the C entry point
  34         */
  35        prima2_pen_release = -1;
  36        smp_wmb();
  37
  38        /*
  39         * Synchronise with the boot thread.
  40         */
  41        spin_lock(&boot_lock);
  42        spin_unlock(&boot_lock);
  43}
  44
  45static const struct of_device_id clk_ids[]  = {
  46        { .compatible = "sirf,atlas7-clkc" },
  47        {},
  48};
  49
  50static int sirfsoc_boot_secondary(unsigned int cpu, struct task_struct *idle)
  51{
  52        unsigned long timeout;
  53        struct device_node *np;
  54
  55        np = of_find_matching_node(NULL, clk_ids);
  56        if (!np)
  57                return -ENODEV;
  58
  59        clk_base = of_iomap(np, 0);
  60        if (!clk_base)
  61                return -ENOMEM;
  62
  63        /*
  64         * write the address of secondary startup into the clkc register
  65         * at offset 0x2bC, then write the magic number 0x3CAF5D62 to the
  66         * clkc register at offset 0x2b8, which is what boot rom code is
  67         * waiting for. This would wake up the secondary core from WFE
  68         */
  69#define SIRFSOC_CPU1_JUMPADDR_OFFSET 0x2bc
  70        __raw_writel(__pa_symbol(sirfsoc_secondary_startup),
  71                clk_base + SIRFSOC_CPU1_JUMPADDR_OFFSET);
  72
  73#define SIRFSOC_CPU1_WAKEMAGIC_OFFSET 0x2b8
  74        __raw_writel(0x3CAF5D62,
  75                clk_base + SIRFSOC_CPU1_WAKEMAGIC_OFFSET);
  76
  77        /* make sure write buffer is drained */
  78        mb();
  79
  80        spin_lock(&boot_lock);
  81
  82        /*
  83         * The secondary processor is waiting to be released from
  84         * the holding pen - release it, then wait for it to flag
  85         * that it has been released by resetting prima2_pen_release.
  86         *
  87         * Note that "prima2_pen_release" is the hardware CPU ID, whereas
  88         * "cpu" is Linux's internal ID.
  89         */
  90        prima2_pen_release = cpu_logical_map(cpu);
  91        sync_cache_w(&prima2_pen_release);
  92
  93        /*
  94         * Send the secondary CPU SEV, thereby causing the boot monitor to read
  95         * the JUMPADDR and WAKEMAGIC, and branch to the address found there.
  96         */
  97        dsb_sev();
  98
  99        timeout = jiffies + (1 * HZ);
 100        while (time_before(jiffies, timeout)) {
 101                smp_rmb();
 102                if (prima2_pen_release == -1)
 103                        break;
 104
 105                udelay(10);
 106        }
 107
 108        /*
 109         * now the secondary core is starting up let it run its
 110         * calibrations, then wait for it to finish
 111         */
 112        spin_unlock(&boot_lock);
 113
 114        return prima2_pen_release != -1 ? -ENOSYS : 0;
 115}
 116
 117const struct smp_operations sirfsoc_smp_ops __initconst = {
 118        .smp_secondary_init     = sirfsoc_secondary_init,
 119        .smp_boot_secondary     = sirfsoc_boot_secondary,
 120#ifdef CONFIG_HOTPLUG_CPU
 121        .cpu_die                = sirfsoc_cpu_die,
 122#endif
 123};
 124