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/*
* plat smp support for CSR Marco dual-core SMP SoCs
*
* Copyright (c) 2012 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <asm/page.h>
#include <asm/mach/map.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include "common.h"
static void __iomem *clk_base;
static DEFINE_SPINLOCK(boot_lock);
static void sirfsoc_secondary_init(unsigned int cpu)
{
/*
* let the primary processor know we're out of the
* pen, then head off into the C entry point
*/
pen_release = -1;
smp_wmb();
/*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
spin_unlock(&boot_lock);
}
static const struct of_device_id clk_ids[] = {
{ .compatible = "sirf,atlas7-clkc" },
{},
};
static int sirfsoc_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
struct device_node *np;
np = of_find_matching_node(NULL, clk_ids);
if (!np)
return -ENODEV;
clk_base = of_iomap(np, 0);
if (!clk_base)
return -ENOMEM;
/*
* write the address of secondary startup into the clkc register
* at offset 0x2bC, then write the magic number 0x3CAF5D62 to the
* clkc register at offset 0x2b8, which is what boot rom code is
* waiting for. This would wake up the secondary core from WFE
*/
#define SIRFSOC_CPU1_JUMPADDR_OFFSET 0x2bc
__raw_writel(__pa_symbol(sirfsoc_secondary_startup),
clk_base + SIRFSOC_CPU1_JUMPADDR_OFFSET);
#define SIRFSOC_CPU1_WAKEMAGIC_OFFSET 0x2b8
__raw_writel(0x3CAF5D62,
clk_base + SIRFSOC_CPU1_WAKEMAGIC_OFFSET);
/* make sure write buffer is drained */
mb();
spin_lock(&boot_lock);
/*
* The secondary processor is waiting to be released from
* the holding pen - release it, then wait for it to flag
* that it has been released by resetting pen_release.
*
* Note that "pen_release" is the hardware CPU ID, whereas
* "cpu" is Linux's internal ID.
*/
pen_release = cpu_logical_map(cpu);
sync_cache_w(&pen_release);
/*
* Send the secondary CPU SEV, thereby causing the boot monitor to read
* the JUMPADDR and WAKEMAGIC, and branch to the address found there.
*/
dsb_sev();
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
smp_rmb();
if (pen_release == -1)
break;
udelay(10);
}
/*
* now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
spin_unlock(&boot_lock);
return pen_release != -1 ? -ENOSYS : 0;
}
const struct smp_operations sirfsoc_smp_ops __initconst = {
.smp_secondary_init = sirfsoc_secondary_init,
.smp_boot_secondary = sirfsoc_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = sirfsoc_cpu_die,
#endif
};
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