platsmp.c
3.37 KB
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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 *scu_base;
static void __iomem *rsc_base;
static DEFINE_SPINLOCK(boot_lock);
static struct map_desc scu_io_desc __initdata = {
.length = SZ_4K,
.type = MT_DEVICE,
};
void __init sirfsoc_map_scu(void)
{
unsigned long base;
/* Get SCU base */
asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
scu_io_desc.virtual = SIRFSOC_VA(base);
scu_io_desc.pfn = __phys_to_pfn(base);
iotable_init(&scu_io_desc, 1);
scu_base = (void __iomem *)SIRFSOC_VA(base);
}
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 struct of_device_id rsc_ids[] = {
{ .compatible = "sirf,marco-rsc" },
{},
};
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, rsc_ids);
if (!np)
return -ENODEV;
rsc_base = of_iomap(np, 0);
if (!rsc_base)
return -ENOMEM;
/*
* write the address of secondary startup into the sram register
* at offset 0x2C, then write the magic number 0x3CAF5D62 to the
* RSC register at offset 0x28, which is what boot rom code is
* waiting for. This would wake up the secondary core from WFE
*/
#define SIRFSOC_CPU1_JUMPADDR_OFFSET 0x2C
__raw_writel(virt_to_phys(sirfsoc_secondary_startup),
rsc_base + SIRFSOC_CPU1_JUMPADDR_OFFSET);
#define SIRFSOC_CPU1_WAKEMAGIC_OFFSET 0x28
__raw_writel(0x3CAF5D62,
rsc_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;
}
static void __init sirfsoc_smp_prepare_cpus(unsigned int max_cpus)
{
scu_enable(scu_base);
}
struct smp_operations sirfsoc_smp_ops __initdata = {
.smp_prepare_cpus = sirfsoc_smp_prepare_cpus,
.smp_secondary_init = sirfsoc_secondary_init,
.smp_boot_secondary = sirfsoc_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = sirfsoc_cpu_die,
#endif
};