diff options
Diffstat (limited to 'arch/arm/mach-realview/platsmp.c')
| -rw-r--r-- | arch/arm/mach-realview/platsmp.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c new file mode 100644 index 000000000000..9844644d0fb5 --- /dev/null +++ b/arch/arm/mach-realview/platsmp.c @@ -0,0 +1,195 @@ +/* + * linux/arch/arm/mach-realview/platsmp.c + * + * Copyright (C) 2002 ARM Ltd. + * All Rights Reserved + * + * 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/errno.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/smp.h> + +#include <asm/cacheflush.h> +#include <asm/hardware/arm_scu.h> +#include <asm/hardware.h> + +#include "core.h" + +extern void realview_secondary_startup(void); + +/* + * control for which core is the next to come out of the secondary + * boot "holding pen" + */ +volatile int __cpuinitdata pen_release = -1; + +static unsigned int __init get_core_count(void) +{ + unsigned int ncores; + + ncores = __raw_readl(IO_ADDRESS(REALVIEW_MPCORE_SCU_BASE) + SCU_CONFIG); + + return (ncores & 0x03) + 1; +} + +static DEFINE_SPINLOCK(boot_lock); + +void __cpuinit platform_secondary_init(unsigned int cpu) +{ + /* + * the primary core may have used a "cross call" soft interrupt + * to get this processor out of WFI in the BootMonitor - make + * sure that we are no longer being sent this soft interrupt + */ + smp_cross_call_done(cpumask_of_cpu(cpu)); + + /* + * 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(__io_address(REALVIEW_GIC_CPU_BASE)); + + /* + * let the primary processor know we're out of the + * pen, then head off into the C entry point + */ + pen_release = -1; + + /* + * 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); + + /* + * 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; + flush_cache_all(); + + /* + * XXX + * + * This is a later addition to the booting protocol: the + * bootMonitor now puts secondary cores into WFI, so + * poke_milo() no longer gets the cores moving; we need + * to send a soft interrupt to wake the secondary core. + * Use smp_cross_call() for this, since there's little + * point duplicating the code here + */ + smp_cross_call(cpumask_of_cpu(cpu)); + + timeout = jiffies + (1 * HZ); + while (time_before(jiffies, timeout)) { + 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 poke_milo(void) +{ + extern void secondary_startup(void); + + /* nobody is to be released from the pen yet */ + pen_release = -1; + + /* + * write the address of secondary startup into the system-wide + * flags register, then clear the bottom two bits, which is what + * BootMonitor is waiting for + */ +#if 1 +#define REALVIEW_SYS_FLAGSS_OFFSET 0x30 + __raw_writel(virt_to_phys(realview_secondary_startup), + (IO_ADDRESS(REALVIEW_SYS_BASE) + + REALVIEW_SYS_FLAGSS_OFFSET)); +#define REALVIEW_SYS_FLAGSC_OFFSET 0x34 + __raw_writel(3, + (IO_ADDRESS(REALVIEW_SYS_BASE) + + REALVIEW_SYS_FLAGSC_OFFSET)); +#endif + + mb(); +} + +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 + "Realview: strange CM count of 0? Default to 1\n"); + + ncores = 1; + } + + if (ncores > NR_CPUS) { + printk(KERN_WARNING + "Realview: 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 possible/present maps. + * cpu_possible_map describes the set of CPUs which may be present + * cpu_present_map describes the set of CPUs populated + */ + for (i = 0; i < max_cpus; i++) { + cpu_set(i, cpu_possible_map); + cpu_set(i, cpu_present_map); + } + + /* + * Do we need any more CPUs? If so, then let them know where + * to start. Note that, on modern versions of MILO, the "poke" + * doesn't actually do anything until each individual core is + * sent a soft interrupt to get it out of WFI + */ + if (max_cpus > 1) + poke_milo(); +} |
