arch/tile: core support for Tilera 32-bit chips.

This change is the core kernel support for TILEPro and TILE64 chips.
No driver support (except the console driver) is included yet.

This includes the relevant Linux headers in asm/; the low-level
low-level "Tile architecture" headers in arch/, which are
shared with the hypervisor, etc., and are build-system agnostic;
and the relevant hypervisor headers in hv/.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>

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 00000000000..782c1bfa6df
--- /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);
+}