1 files changed, 575 insertions, 0 deletions
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
new file mode 100644
index 00000000000..4b6d1f14df3
--- /dev/null
+++ b/arch/metag/kernel/smp.c
@@ -0,0 +1,575 @@
+/*
+ *  Copyright (C) 2009,2010,2011 Imagination Technologies Ltd.
+ *
+ *  Copyright (C) 2002 ARM Limited, 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/atomic.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/cache.h>
+#include <linux/profile.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/err.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/seq_file.h>
+#include <linux/irq.h>
+#include <linux/bootmem.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cachepart.h>
+#include <asm/core_reg.h>
+#include <asm/cpu.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/processor.h>
+#include <asm/setup.h>
+#include <asm/tlbflush.h>
+#include <asm/hwthread.h>
+#include <asm/traps.h>
+
+DECLARE_PER_CPU(PTBI, pTBI);
+
+void *secondary_data_stack;
+
+/*
+ * structures for inter-processor calls
+ * - A collection of single bit ipi messages.
+ */
+struct ipi_data {
+	spinlock_t lock;
+	unsigned long ipi_count;
+	unsigned long bits;
+};
+
+static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
+	.lock	= __SPIN_LOCK_UNLOCKED(ipi_data.lock),
+};
+
+static DEFINE_SPINLOCK(boot_lock);
+
+/*
+ * "thread" is assumed to be a valid Meta hardware thread ID.
+ */
+int __cpuinit boot_secondary(unsigned int thread, struct task_struct *idle)
+{
+	u32 val;
+
+	/*
+	 * set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	spin_lock(&boot_lock);
+
+	core_reg_write(TXUPC_ID, 0, thread, (unsigned int)secondary_startup);
+	core_reg_write(TXUPC_ID, 1, thread, 0);
+
+	/*
+	 * Give the thread privilege (PSTAT) and clear potentially problematic
+	 * bits in the process (namely ISTAT, CBMarker, CBMarkerI, LSM_STEP).
+	 */
+	core_reg_write(TXUCT_ID, TXSTATUS_REGNUM, thread, TXSTATUS_PSTAT_BIT);
+
+	/* Clear the minim enable bit. */
+	val = core_reg_read(TXUCT_ID, TXPRIVEXT_REGNUM, thread);
+	core_reg_write(TXUCT_ID, TXPRIVEXT_REGNUM, thread, val & ~0x80);
+
+	/*
+	 * set the ThreadEnable bit (0x1) in the TXENABLE register
+	 * for the specified thread - off it goes!
+	 */
+	val = core_reg_read(TXUCT_ID, TXENABLE_REGNUM, thread);
+	core_reg_write(TXUCT_ID, TXENABLE_REGNUM, thread, val | 0x1);
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	spin_unlock(&boot_lock);
+
+	return 0;
+}
+
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
+{
+	unsigned int thread = cpu_2_hwthread_id[cpu];
+	int ret;
+
+	load_pgd(swapper_pg_dir, thread);
+
+	flush_tlb_all();
+
+	/*
+	 * Tell the secondary CPU where to find its idle thread's stack.
+	 */
+	secondary_data_stack = task_stack_page(idle);
+
+	wmb();
+
+	/*
+	 * Now bring the CPU into our world.
+	 */
+	ret = boot_secondary(thread, idle);
+	if (ret == 0) {
+		unsigned long timeout;
+
+		/*
+		 * CPU was successfully started, wait for it
+		 * to come online or time out.
+		 */
+		timeout = jiffies + HZ;
+		while (time_before(jiffies, timeout)) {
+			if (cpu_online(cpu))
+				break;
+
+			udelay(10);
+			barrier();
+		}
+
+		if (!cpu_online(cpu))
+			ret = -EIO;
+	}
+
+	secondary_data_stack = NULL;
+
+	if (ret) {
+		pr_crit("CPU%u: processor failed to boot\n", cpu);
+
+		/*
+		 * FIXME: We need to clean up the new idle thread. --rmk
+		 */
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static DECLARE_COMPLETION(cpu_killed);
+
+/*
+ * __cpu_disable runs on the processor to be shutdown.
+ */
+int __cpuexit __cpu_disable(void)
+{
+	unsigned int cpu = smp_processor_id();
+	struct task_struct *p;
+
+	/*
+	 * Take this CPU offline.  Once we clear this, we can't return,
+	 * and we must not schedule until we're ready to give up the cpu.
+	 */
+	set_cpu_online(cpu, false);
+
+	/*
+	 * OK - migrate IRQs away from this CPU
+	 */
+	migrate_irqs();
+
+	/*
+	 * Flush user cache and TLB mappings, and then remove this CPU
+	 * from the vm mask set of all processes.
+	 */
+	flush_cache_all();
+	local_flush_tlb_all();
+
+	read_lock(&tasklist_lock);
+	for_each_process(p) {
+		if (p->mm)
+			cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
+	}
+	read_unlock(&tasklist_lock);
+
+	return 0;
+}
+
+/*
+ * called on the thread which is asking for a CPU to be shutdown -
+ * waits until shutdown has completed, or it is timed out.
+ */
+void __cpuexit __cpu_die(unsigned int cpu)
+{
+	if (!wait_for_completion_timeout(&cpu_killed, msecs_to_jiffies(1)))
+		pr_err("CPU%u: unable to kill\n", cpu);
+}
+
+/*
+ * Called from the idle thread for the CPU which has been shutdown.
+ *
+ * Note that we do not return from this function. If this cpu is
+ * brought online again it will need to run secondary_startup().
+ */
+void __cpuexit cpu_die(void)
+{
+	local_irq_disable();
+	idle_task_exit();
+
+	complete(&cpu_killed);
+
+	asm ("XOR	TXENABLE, D0Re0,D0Re0\n");
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/*
+ * Called by both boot and secondaries to move global data into
+ * per-processor storage.
+ */
+void __cpuinit smp_store_cpu_info(unsigned int cpuid)
+{
+	struct cpuinfo_metag *cpu_info = &per_cpu(cpu_data, cpuid);
+
+	cpu_info->loops_per_jiffy = loops_per_jiffy;
+}
+
+/*
+ * This is the secondary CPU boot entry.  We're using this CPUs
+ * idle thread stack and the global page tables.
+ */
+asmlinkage void secondary_start_kernel(void)
+{
+	struct mm_struct *mm = &init_mm;
+	unsigned int cpu = smp_processor_id();
+
+	/*
+	 * All kernel threads share the same mm context; grab a
+	 * reference and switch to it.
+	 */
+	atomic_inc(&mm->mm_users);
+	atomic_inc(&mm->mm_count);
+	current->active_mm = mm;
+	cpumask_set_cpu(cpu, mm_cpumask(mm));
+	enter_lazy_tlb(mm, current);
+	local_flush_tlb_all();
+
+	/*
+	 * TODO: Some day it might be useful for each Linux CPU to
+	 * have its own TBI structure. That would allow each Linux CPU
+	 * to run different interrupt handlers for the same IRQ
+	 * number.
+	 *
+	 * For now, simply copying the pointer to the boot CPU's TBI
+	 * structure is sufficient because we always want to run the
+	 * same interrupt handler whatever CPU takes the interrupt.
+	 */
+	per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
+
+	if (!per_cpu(pTBI, cpu))
+		panic("No TBI found!");
+
+	per_cpu_trap_init(cpu);
+
+	preempt_disable();
+
+	setup_priv();
+
+	/*
+	 * Enable local interrupts.
+	 */
+	tbi_startup_interrupt(TBID_SIGNUM_TRT);
+	notify_cpu_starting(cpu);
+	local_irq_enable();
+
+	pr_info("CPU%u (thread %u): Booted secondary processor\n",
+		cpu, cpu_2_hwthread_id[cpu]);
+
+	calibrate_delay();
+	smp_store_cpu_info(cpu);
+
+	/*
+	 * OK, now it's safe to let the boot CPU continue
+	 */
+	set_cpu_online(cpu, true);
+
+	/*
+	 * Check for cache aliasing.
+	 * Preemption is disabled
+	 */
+	check_for_cache_aliasing(cpu);
+
+	/*
+	 * OK, it's off to the idle thread for us
+	 */
+	cpu_idle();
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+	int cpu;
+	unsigned long bogosum = 0;
+
+	for_each_online_cpu(cpu)
+		bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
+
+	pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
+		num_online_cpus(),
+		bogosum / (500000/HZ),
+		(bogosum / (5000/HZ)) % 100);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned int cpu = smp_processor_id();
+
+	init_new_context(current, &init_mm);
+	current_thread_info()->cpu = cpu;
+
+	smp_store_cpu_info(cpu);
+	init_cpu_present(cpu_possible_mask);
+}
+
+void __init smp_prepare_boot_cpu(void)
+{
+	unsigned int cpu = smp_processor_id();
+
+	per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
+
+	if (!per_cpu(pTBI, cpu))
+		panic("No TBI found!");
+}
+
+static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg);
+
+static void send_ipi_message(const struct cpumask *mask, enum ipi_msg_type msg)
+{
+	unsigned long flags;
+	unsigned int cpu;
+	cpumask_t map;
+
+	cpumask_clear(&map);
+	local_irq_save(flags);
+
+	for_each_cpu(cpu, mask) {
+		struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+
+		spin_lock(&ipi->lock);
+
+		/*
+		 * KICK interrupts are queued in hardware so we'll get
+		 * multiple interrupts if we call smp_cross_call()
+		 * multiple times for one msg. The problem is that we
+		 * only have one bit for each message - we can't queue
+		 * them in software.
+		 *
+		 * The first time through ipi_handler() we'll clear
+		 * the msg bit, having done all the work. But when we
+		 * return we'll get _another_ interrupt (and another,
+		 * and another until we've handled all the queued
+		 * KICKs). Running ipi_handler() when there's no work
+		 * to do is bad because that's how kick handler
+		 * chaining detects who the KICK was intended for.
+		 * See arch/metag/kernel/kick.c for more details.
+		 *
+		 * So only add 'cpu' to 'map' if we haven't already
+		 * queued a KICK interrupt for 'msg'.
+		 */
+		if (!(ipi->bits & (1 << msg))) {
+			ipi->bits |= 1 << msg;
+			cpumask_set_cpu(cpu, &map);
+		}
+
+		spin_unlock(&ipi->lock);
+	}
+
+	/*
+	 * Call the platform specific cross-CPU call function.
+	 */
+	smp_cross_call(map, msg);
+
+	local_irq_restore(flags);
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	send_ipi_message(mask, IPI_CALL_FUNC);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+}
+
+void show_ipi_list(struct seq_file *p)
+{
+	unsigned int cpu;
+
+	seq_puts(p, "IPI:");
+
+	for_each_present_cpu(cpu)
+		seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
+
+	seq_putc(p, '\n');
+}
+
+static DEFINE_SPINLOCK(stop_lock);
+
+/*
+ * Main handler for inter-processor interrupts
+ *
+ * For Meta, the ipimask now only identifies a single
+ * category of IPI (Bit 1 IPIs have been replaced by a
+ * different mechanism):
+ *
+ *  Bit 0 - Inter-processor function call
+ */
+static int do_IPI(struct pt_regs *regs)
+{
+	unsigned int cpu = smp_processor_id();
+	struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	unsigned long msgs, nextmsg;
+	int handled = 0;
+
+	ipi->ipi_count++;
+
+	spin_lock(&ipi->lock);
+	msgs = ipi->bits;
+	nextmsg = msgs & -msgs;
+	ipi->bits &= ~nextmsg;
+	spin_unlock(&ipi->lock);
+
+	if (nextmsg) {
+		handled = 1;
+
+		nextmsg = ffz(~nextmsg);
+		switch (nextmsg) {
+		case IPI_RESCHEDULE:
+			scheduler_ipi();
+			break;
+
+		case IPI_CALL_FUNC:
+			generic_smp_call_function_interrupt();
+			break;
+
+		case IPI_CALL_FUNC_SINGLE:
+			generic_smp_call_function_single_interrupt();
+			break;
+
+		default:
+			pr_crit("CPU%u: Unknown IPI message 0x%lx\n",
+				cpu, nextmsg);
+			break;
+		}
+	}
+
+	set_irq_regs(old_regs);
+
+	return handled;
+}
+
+void smp_send_reschedule(int cpu)
+{
+	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
+}
+
+static void stop_this_cpu(void *data)
+{
+	unsigned int cpu = smp_processor_id();
+
+	if (system_state == SYSTEM_BOOTING ||
+	    system_state == SYSTEM_RUNNING) {
+		spin_lock(&stop_lock);
+		pr_crit("CPU%u: stopping\n", cpu);
+		dump_stack();
+		spin_unlock(&stop_lock);
+	}
+
+	set_cpu_online(cpu, false);
+
+	local_irq_disable();
+
+	hard_processor_halt(HALT_OK);
+}
+
+void smp_send_stop(void)
+{
+	smp_call_function(stop_this_cpu, NULL, 0);
+}
+
+/*
+ * not supported here
+ */
+int setup_profiling_timer(unsigned int multiplier)
+{
+	return -EINVAL;
+}
+
+/*
+ * We use KICKs for inter-processor interrupts.
+ *
+ * For every CPU in "callmap" the IPI data must already have been
+ * stored in that CPU's "ipi_data" member prior to calling this
+ * function.
+ */
+static void kick_raise_softirq(cpumask_t callmap, unsigned int irq)
+{
+	int cpu;
+
+	for_each_cpu(cpu, &callmap) {
+		unsigned int thread;
+
+		thread = cpu_2_hwthread_id[cpu];
+
+		BUG_ON(thread == BAD_HWTHREAD_ID);
+
+		metag_out32(1, T0KICKI + (thread * TnXKICK_STRIDE));
+	}
+}
+
+static TBIRES ipi_handler(TBIRES State, int SigNum, int Triggers,
+		   int Inst, PTBI pTBI, int *handled)
+{
+	*handled = do_IPI((struct pt_regs *)State.Sig.pCtx);
+
+	return State;
+}
+
+static struct kick_irq_handler ipi_irq = {
+	.func = ipi_handler,
+};
+
+static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg)
+{
+	kick_raise_softirq(callmap, 1);
+}
+
+static inline unsigned int get_core_count(void)
+{
+	int i;
+	unsigned int ret = 0;
+
+	for (i = 0; i < CONFIG_NR_CPUS; i++) {
+		if (core_reg_read(TXUCT_ID, TXENABLE_REGNUM, i))
+			ret++;
+	}
+
+	return ret;
+}
+
+/*
+ * 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();
+
+	/* If no hwthread_map early param was set use default mapping */
+	for (i = 0; i < NR_CPUS; i++)
+		if (cpu_2_hwthread_id[i] == BAD_HWTHREAD_ID) {
+			cpu_2_hwthread_id[i] = i;
+			hwthread_id_2_cpu[i] = i;
+		}
+
+	for (i = 0; i < ncores; i++)
+		set_cpu_possible(i, true);
+
+	kick_register_func(&ipi_irq);
+}