diff options
Diffstat (limited to 'arch/arm/mach-ux500/platsmp.c')
| -rw-r--r-- | arch/arm/mach-ux500/platsmp.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c new file mode 100644 index 00000000..eff5842f --- /dev/null +++ b/arch/arm/mach-ux500/platsmp.c @@ -0,0 +1,177 @@ +/* + * Copyright (C) 2002 ARM Ltd. + * Copyright (C) 2008 STMicroelctronics. + * Copyright (C) 2009 ST-Ericsson. + * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> + * + * This file is based on arm realview platform + * + * 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 <linux/io.h> + +#include <asm/cacheflush.h> +#include <asm/hardware/gic.h> +#include <asm/smp_plat.h> +#include <asm/smp_scu.h> +#include <mach/hardware.h> +#include <mach/setup.h> + +/* This is called from headsmp.S to wakeup the secondary core */ +extern void u8500_secondary_startup(void); + +/* + * control for which core is the next to come out of the secondary + * boot "holding pen" + */ +volatile int pen_release = -1; + +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + +static void __iomem *scu_base_addr(void) +{ + if (cpu_is_u5500()) + return __io_address(U5500_SCU_BASE); + else if (cpu_is_u8500()) + return __io_address(U8500_SCU_BASE); + else + ux500_unknown_soc(); + + return NULL; +} + +static DEFINE_SPINLOCK(boot_lock); + +void __cpuinit platform_secondary_init(unsigned int 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_secondary_init(0); + + /* + * let the primary processor know we're out of the + * pen, then head off into the C entry point + */ + write_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. + */ + write_pen_release(cpu_logical_map(cpu)); + + smp_send_reschedule(cpu); + + timeout = jiffies + (1 * HZ); + while (time_before(jiffies, timeout)) { + if (pen_release == -1) + break; + } + + /* + * 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 wakeup_secondary(void) +{ + void __iomem *backupram; + + if (cpu_is_u5500()) + backupram = __io_address(U5500_BACKUPRAM0_BASE); + else if (cpu_is_u8500()) + backupram = __io_address(U8500_BACKUPRAM0_BASE); + else + ux500_unknown_soc(); + + /* + * write the address of secondary startup into the backup ram register + * at offset 0x1FF4, then write the magic number 0xA1FEED01 to the + * backup ram register at offset 0x1FF0, which is what boot rom code + * is waiting for. This would wake up the secondary core from WFE + */ +#define UX500_CPU1_JUMPADDR_OFFSET 0x1FF4 + __raw_writel(virt_to_phys(u8500_secondary_startup), + backupram + UX500_CPU1_JUMPADDR_OFFSET); + +#define UX500_CPU1_WAKEMAGIC_OFFSET 0x1FF0 + __raw_writel(0xA1FEED01, + backupram + UX500_CPU1_WAKEMAGIC_OFFSET); + + /* make sure write buffer is drained */ + 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) +{ + void __iomem *scu_base = scu_base_addr(); + unsigned int i, ncores; + + ncores = scu_base ? scu_get_core_count(scu_base) : 1; + + /* sanity check */ + if (ncores > nr_cpu_ids) { + pr_warn("SMP: %u cores greater than maximum (%u), clipping\n", + ncores, nr_cpu_ids); + ncores = nr_cpu_ids; + } + + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); + + set_smp_cross_call(gic_raise_softirq); +} + +void __init platform_smp_prepare_cpus(unsigned int max_cpus) +{ + + scu_enable(scu_base_addr()); + wakeup_secondary(); +} |