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/*
* OMAP4 SMP source file. It contains platform specific fucntions
* needed for the linux smp kernel.
*
* Copyright (C) 2009 Texas Instruments, Inc.
*
* Author:
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* Platform file needed for the OMAP4 SMP. This file is based on arm
* realview smp platform.
* * Copyright (c) 2002 ARM Limited.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <asm/localtimer.h>
#include <asm/smp_scu.h>
#include <mach/hardware.h>
/* Registers used for communicating startup information */
#define OMAP4_AUXCOREBOOT_REG0 (OMAP44XX_VA_WKUPGEN_BASE + 0x800)
#define OMAP4_AUXCOREBOOT_REG1 (OMAP44XX_VA_WKUPGEN_BASE + 0x804)
/* SCU base address */
static void __iomem *scu_base = OMAP44XX_VA_SCU_BASE;
/*
* Use SCU config register to count number of cores
*/
static inline unsigned int get_core_count(void)
{
if (scu_base)
return scu_get_core_count(scu_base);
return 1;
}
static DEFINE_SPINLOCK(boot_lock);
void __cpuinit platform_secondary_init(unsigned int cpu)
{
trace_hardirqs_off();
/*
* If any interrupts are already enabled for the primary
* core (e.g. timer irq), then they will not have been enabled
* for us: do so
*/
gic_cpu_init(0, IO_ADDRESS(OMAP44XX_GIC_CPU_BASE));
/*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
spin_unlock(&boot_lock);
}
int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
/*
* Set synchronisation state between this boot processor
* and the secondary one
*/
spin_lock(&boot_lock);
/*
* Update the AuxCoreBoot1 with boot state for secondary core.
* omap_secondary_startup() routine will hold the secondary core till
* the AuxCoreBoot1 register is updated with cpu state
* A barrier is added to ensure that write buffer is drained
*/
__raw_writel(cpu, OMAP4_AUXCOREBOOT_REG1);
smp_wmb();
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout))
;
/*
* Now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
spin_unlock(&boot_lock);
return 0;
}
static void __init wakeup_secondary(void)
{
/*
* Write the address of secondary startup routine into the
* AuxCoreBoot0 where ROM code will jump and start executing
* on secondary core once out of WFE
* A barrier is added to ensure that write buffer is drained
*/
__raw_writel(virt_to_phys(omap_secondary_startup), \
OMAP4_AUXCOREBOOT_REG0);
smp_wmb();
/*
* Send a 'sev' to wake the secondary core from WFE.
*/
set_event();
mb();
}
/*
* Initialise the CPU possible map early - this describes the CPUs
* which may be present or become present in the system.
*/
void __init smp_init_cpus(void)
{
unsigned int i, ncores = get_core_count();
for (i = 0; i < ncores; i++)
set_cpu_possible(i, true);
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int ncores = get_core_count();
unsigned int cpu = smp_processor_id();
int i;
/* sanity check */
if (ncores == 0) {
printk(KERN_ERR
"OMAP4: strange core count of 0? Default to 1\n");
ncores = 1;
}
if (ncores > NR_CPUS) {
printk(KERN_WARNING
"OMAP4: no. of cores (%d) greater than configured "
"maximum of %d - clipping\n",
ncores, NR_CPUS);
ncores = NR_CPUS;
}
smp_store_cpu_info(cpu);
/*
* are we trying to boot more cores than exist?
*/
if (max_cpus > ncores)
max_cpus = ncores;
/*
* Initialise the present map, which describes the set of CPUs
* actually populated at the present time.
*/
for (i = 0; i < max_cpus; i++)
set_cpu_present(i, true);
if (max_cpus > 1) {
/*
* Enable the local timer or broadcast device for the
* boot CPU, but only if we have more than one CPU.
*/
percpu_timer_setup();
/*
* Initialise the SCU and wake up the secondary core using
* wakeup_secondary().
*/
scu_enable(scu_base);
wakeup_secondary();
}
}
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