1 files changed, 202 insertions, 0 deletions
diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c
new file mode 100644
index 0000000..782c1bf
--- /dev/null
+++ b/arch/tile/kernel/smp.c
@@ -0,0 +1,202 @@
+/*
+ * Copyright 2010 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * TILE SMP support routines.
+ */
+
+#include <linux/smp.h>
+#include <linux/irq.h>
+#include <asm/cacheflush.h>
+
+HV_Topology smp_topology __write_once;
+
+
+/*
+ * Top-level send_IPI*() functions to send messages to other cpus.
+ */
+
+/* Set by smp_send_stop() to avoid recursive panics. */
+static int stopping_cpus;
+
+void send_IPI_single(int cpu, int tag)
+{
+	HV_Recipient recip = {
+		.y = cpu / smp_width,
+		.x = cpu % smp_width,
+		.state = HV_TO_BE_SENT
+	};
+	int rc = hv_send_message(&recip, 1, (HV_VirtAddr)&tag, sizeof(tag));
+	BUG_ON(rc <= 0);
+}
+
+void send_IPI_many(const struct cpumask *mask, int tag)
+{
+	HV_Recipient recip[NR_CPUS];
+	int cpu, sent;
+	int nrecip = 0;
+	int my_cpu = smp_processor_id();
+	for_each_cpu(cpu, mask) {
+		HV_Recipient *r;
+		BUG_ON(cpu == my_cpu);
+		r = &recip[nrecip++];
+		r->y = cpu / smp_width;
+		r->x = cpu % smp_width;
+		r->state = HV_TO_BE_SENT;
+	}
+	sent = 0;
+	while (sent < nrecip) {
+		int rc = hv_send_message(recip, nrecip,
+					 (HV_VirtAddr)&tag, sizeof(tag));
+		if (rc <= 0) {
+			if (!stopping_cpus)  /* avoid recursive panic */
+				panic("hv_send_message returned %d", rc);
+			break;
+		}
+		sent += rc;
+	}
+}
+
+void send_IPI_allbutself(int tag)
+{
+	struct cpumask mask;
+	cpumask_copy(&mask, cpu_online_mask);
+	cpumask_clear_cpu(smp_processor_id(), &mask);
+	send_IPI_many(&mask, tag);
+}
+
+
+/*
+ * Provide smp_call_function_mask, but also run function locally
+ * if specified in the mask.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *),
+		      void *info, bool wait)
+{
+	int cpu = get_cpu();
+	smp_call_function_many(mask, func, info, wait);
+	if (cpumask_test_cpu(cpu, mask)) {
+		local_irq_disable();
+		func(info);
+		local_irq_enable();
+	}
+	put_cpu();
+}
+
+
+/*
+ * Functions related to starting/stopping cpus.
+ */
+
+/* Handler to start the current cpu. */
+static void smp_start_cpu_interrupt(void)
+{
+	extern unsigned long start_cpu_function_addr;
+	get_irq_regs()->pc = start_cpu_function_addr;
+}
+
+/* Handler to stop the current cpu. */
+static void smp_stop_cpu_interrupt(void)
+{
+	set_cpu_online(smp_processor_id(), 0);
+	raw_local_irq_disable_all();
+	for (;;)
+		asm("nap");
+}
+
+/* This function calls the 'stop' function on all other CPUs in the system. */
+void smp_send_stop(void)
+{
+	stopping_cpus = 1;
+	send_IPI_allbutself(MSG_TAG_STOP_CPU);
+}
+
+
+/*
+ * Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
+ */
+void evaluate_message(int tag)
+{
+	switch (tag) {
+	case MSG_TAG_START_CPU: /* Start up a cpu */
+		smp_start_cpu_interrupt();
+		break;
+
+	case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
+		smp_stop_cpu_interrupt();
+		break;
+
+	case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
+		generic_smp_call_function_interrupt();
+		break;
+
+	case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
+		generic_smp_call_function_single_interrupt();
+		break;
+
+	default:
+		panic("Unknown IPI message tag %d", tag);
+		break;
+	}
+}
+
+
+/*
+ * flush_icache_range() code uses smp_call_function().
+ */
+
+struct ipi_flush {
+	unsigned long start;
+	unsigned long end;
+};
+
+static void ipi_flush_icache_range(void *info)
+{
+	struct ipi_flush *flush = (struct ipi_flush *) info;
+	__flush_icache_range(flush->start, flush->end);
+}
+
+void flush_icache_range(unsigned long start, unsigned long end)
+{
+	struct ipi_flush flush = { start, end };
+	preempt_disable();
+	on_each_cpu(ipi_flush_icache_range, &flush, 1);
+	preempt_enable();
+}
+
+
+/*
+ * The smp_send_reschedule() path does not use the hv_message_intr()
+ * path but instead the faster tile_dev_intr() path for interrupts.
+ */
+
+irqreturn_t handle_reschedule_ipi(int irq, void *token)
+{
+	/*
+	 * Nothing to do here; when we return from interrupt, the
+	 * rescheduling will occur there. But do bump the interrupt
+	 * profiler count in the meantime.
+	 */
+	__get_cpu_var(irq_stat).irq_resched_count++;
+
+	return IRQ_HANDLED;
+}
+
+void smp_send_reschedule(int cpu)
+{
+	HV_Coord coord;
+
+	WARN_ON(cpu_is_offline(cpu));
+	coord.y = cpu / smp_width;
+	coord.x = cpu % smp_width;
+	hv_trigger_ipi(coord, IRQ_RESCHEDULE);
+}