diff options
Diffstat (limited to 'arch/arm/mach-realview/platsmp.c')
| -rw-r--r-- | arch/arm/mach-realview/platsmp.c | 114 |
1 files changed, 36 insertions, 78 deletions
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 6da8a2e53c4..a22bf67f2f7 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -19,7 +19,6 @@ #include <asm/cacheflush.h> #include <mach/hardware.h> #include <asm/mach-types.h> -#include <asm/localtimer.h> #include <asm/unified.h> #include <mach/board-eb.h> @@ -37,6 +36,19 @@ extern void realview_secondary_startup(void); */ volatile int __cpuinitdata 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 (machine_is_realview_eb_mp()) @@ -50,20 +62,10 @@ static void __iomem *scu_base_addr(void) return (void __iomem *)0; } -static inline unsigned int get_core_count(void) -{ - void __iomem *scu_base = scu_base_addr(); - 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 @@ -75,8 +77,7 @@ void __cpuinit platform_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(); + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -103,20 +104,14 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * Note that "pen_release" is the hardware CPU ID, whereas * "cpu" is Linux's internal ID. */ - pen_release = cpu; - flush_cache_all(); + write_pen_release(cpu); /* - * 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 + * Send the secondary CPU a soft interrupt, thereby causing + * the boot monitor to read the system wide flags register, + * and branch to the address found there. */ - smp_cross_call(cpumask_of(cpu)); + smp_cross_call(cpumask_of(cpu), 1); timeout = jiffies + (1 * HZ); while (time_before(jiffies, timeout)) { @@ -136,48 +131,18 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) return pen_release != -1 ? -ENOSYS : 0; } -static void __init poke_milo(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. The BootMonitor waits for this register to become - * non-zero. - */ - __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), - __io_address(REALVIEW_SYS_FLAGSSET)); - - 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(); + void __iomem *scu_base = scu_base_addr(); + unsigned int i, ncores; - 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; + ncores = scu_base ? scu_get_core_count(scu_base) : 1; /* 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 " @@ -186,13 +151,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus) ncores = NR_CPUS; } - smp_store_cpu_info(cpu); + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); +} - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; +void __init platform_smp_prepare_cpus(unsigned int max_cpus) +{ + int i; /* * Initialise the present map, which describes the set of CPUs @@ -201,21 +166,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); + scu_enable(scu_base_addr()); + /* - * Initialise the SCU if there are more than one CPU and 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 + * Write the address of secondary startup into the + * system-wide flags register. The BootMonitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. */ - 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(); - - scu_enable(scu_base_addr()); - poke_milo(); - } + __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), + __io_address(REALVIEW_SYS_FLAGSSET)); } |