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Subject[patch 21/36] Hexagon: Add SMP support
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>

---
arch/hexagon/include/asm/smp.h | 40 ++++
arch/hexagon/kernel/smp.c | 365 +++++++++++++++++++++++++++++++++++++++++
arch/hexagon/kernel/topology.c | 52 +++++
3 files changed, 457 insertions(+)
Index: linux-hexagon-kernel/arch/hexagon/include/asm/smp.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/include/asm/smp.h 2011-08-01 15:29:41.219060354 -0500
@@ -0,0 +1,40 @@
+/*
+ * SMP definitions for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. 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 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef __ASM_SMP_H
+#define __ASM_SMP_H
+
+#include <linux/cpumask.h>
+
+#define raw_smp_processor_id() (current_thread_info()->cpu)
+
+enum ipi_message_type {
+ IPI_RESCHEDULE,
+ IPI_CALL_FUNC,
+ IPI_CPU_STOP,
+ IPI_TIMER
+};
+
+extern void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg);
+extern void smp_start_cpus(void);
+
+void smp_vm_unmask_irq(void *info);
+
+#endif
Index: linux-hexagon-kernel/arch/hexagon/kernel/smp.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/smp.c 2011-08-01 15:31:33.739180622 -0500
@@ -0,0 +1,365 @@
+/*
+ * SMP support for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. 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 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+
+#include <asm/system.h> /* xchg */
+#include <asm/time.h> /* timer_interrupt */
+#include <asm/hexagon_vm.h>
+
+#define BASE_IPI_IRQ 26
+
+/*
+ * cpu_possible_map needs to be filled out prior to setup_per_cpu_areas
+ * (which is prior to any of our smp_prepare_cpu crap), in order to set
+ * up the... per_cpu areas.
+ */
+
+struct smp_call_struct {
+ void (*func) (void *info);
+ void *info;
+ long wait;
+ struct cpumask pending;
+ struct cpumask unfinished;
+};
+
+struct smp_call_struct *smp_call_function_data;
+
+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 inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi,
+ int cpu)
+{
+ do {
+ unsigned long msg = msg = ffz(~*ops);
+
+ *ops &= ~(1 << msg);
+
+ switch (msg) {
+ case IPI_TIMER:
+ ipi_timer();
+ break;
+ case IPI_CALL_FUNC:
+ {
+ struct smp_call_struct *data =
+ smp_call_function_data;
+ void (*func) (void *info) =
+ data->func;
+ void *info = data->info;
+ int wait = data->wait;
+
+ smp_mb();
+ cpumask_clear_cpu(cpu, &data->pending);
+
+ (*func)(info);
+
+ smp_mb();
+ if (wait)
+ cpumask_clear_cpu(cpu,
+ &data->unfinished);
+ break;
+ }
+ case IPI_CPU_STOP:
+ /*
+ * call vmstop()
+ */
+ __vmstop();
+ break;
+ case IPI_RESCHEDULE:
+ /*
+ * need to revisit our exit path; see comments for
+ * scheduler_ipi()
+ */
+ scheduler_ipi();
+ break;
+ }
+ } while (*ops);
+}
+
+/* Used for IPI call from other CPU's to unmask int */
+void smp_vm_unmask_irq(void *info)
+{
+ __vmintop_locen((long) info);
+}
+
+
+/*
+ * This is based on Alpha's IPI stuff.
+ * Supposed to take (int, void*) as args now.
+ * Specifically, first arg is irq, second is the irq_desc.
+ */
+
+irqreturn_t handle_ipi(int irq, void *desc)
+{
+ int cpu = smp_processor_id();
+ struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+ unsigned long ops;
+
+ while ((ops = xchg(&ipi->bits, 0)) != 0)
+ __handle_ipi(&ops, ipi, cpu);
+ return IRQ_HANDLED;
+}
+
+void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
+{
+ unsigned long flags;
+ unsigned long cpu;
+ unsigned long retval;
+
+ local_irq_save(flags);
+
+ for_each_cpu(cpu, cpumask) {
+ struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+
+ spin_lock(&ipi->lock);
+ ipi->bits |= 1 << msg; /* one bit per message */
+ spin_unlock(&ipi->lock);
+
+ retval = __vmintop_post(BASE_IPI_IRQ+cpu);
+ if (retval != 0) {
+ printk(KERN_ERR "interrupt %ld not configured?\n",
+ BASE_IPI_IRQ+cpu);
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+static struct irqaction ipi_intdesc = {
+ .handler = handle_ipi,
+ .flags = IRQF_DISABLED | IRQF_TRIGGER_RISING,
+ .name = "ipi_handler"
+};
+
+/*
+ * SMP call stuff
+ */
+static DEFINE_SPINLOCK(smp_call_function_lock);
+
+int smp_call_function_cpumask(const struct cpumask *cpumask,
+ void (*func) (void *info),
+ void *info, int wait)
+{
+ struct smp_call_struct data;
+
+ data.func = func;
+ data.info = info;
+ data.wait = wait;
+ cpumask_copy(&data.pending, cpumask);
+ cpumask_copy(&data.unfinished, cpumask);
+
+ spin_lock(&smp_call_function_lock);
+ smp_call_function_data = &data;
+ smp_mb();
+
+ send_ipi(cpumask, IPI_CALL_FUNC);
+
+ /* some archs implement a timeout here. */
+ while (!cpumask_empty(&data.pending))
+ barrier();
+
+ smp_call_function_data = NULL;
+ spin_unlock(&smp_call_function_lock);
+
+ if (wait) {
+ while (!cpumask_empty(&data.unfinished))
+ barrier();
+ }
+
+ return 0;
+}
+
+int smp_call_function_single(int cpu, void (*func) (void *info),
+ void *info, int wait)
+{
+ return smp_call_function_cpumask(cpumask_of(cpu), func, info,
+ wait);
+}
+
+/*
+ * smp_call_function(): Run a function on all other CPUs
+ * @mask: cpu mask of cpu's to run function on
+ * @func: the function to run; must be fast and non-blocking
+ * @info: arbitrary pointer to pass to the function
+ * @wait: if true, wait until function has completed on other CPUs
+ *
+ * Returns 0 on success, else a vague negative status code.
+ *
+ * "Does not return until remote CPUs are nearly ready to execute <func> or
+ * are or have executed." Translation: don't count on it.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ *
+ */
+
+int smp_call_function(void (*func) (void *info), void *info, int wait)
+{
+ struct cpumask targets;
+
+ cpumask_copy(&targets, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), &targets);
+ return smp_call_function_cpumask(&targets, func, info, wait);
+}
+
+
+void __init smp_prepare_boot_cpu(void)
+{
+}
+
+/*
+ * interrupts should already be disabled from the VM
+ * SP should already be correct; need to set THREADINFO_REG
+ * to point to current thread info
+ */
+
+void __cpuinit start_secondary(void)
+{
+ unsigned int cpu;
+ unsigned long thread_ptr;
+
+ /* Calculate thread_info pointer from stack pointer */
+ __asm__ __volatile__(
+ "%0 = SP;\n"
+ : "=r" (thread_ptr)
+ );
+
+ thread_ptr = thread_ptr & ~(THREAD_SIZE-1);
+
+ __asm__ __volatile__(
+ QUOTED_THREADINFO_REG " = %0;\n"
+ :
+ : "r" (thread_ptr)
+ );
+
+ /* Set the memory struct */
+ atomic_inc(&init_mm.mm_count);
+ current->active_mm = &init_mm;
+
+ cpu = smp_processor_id();
+
+ setup_irq(BASE_IPI_IRQ + cpu, &ipi_intdesc);
+
+ /* Register the clock_event dummy */
+ setup_percpu_clockdev();
+
+ printk(KERN_INFO "%s cpu %d\n", __func__, current_thread_info()->cpu);
+
+ local_irq_enable();
+ set_cpu_online(cpu, true);
+ cpu_idle();
+}
+
+
+/*
+ * called once for each present cpu
+ * apparently starts up the CPU and then
+ * maintains control until "cpu_online(cpu)" is set.
+ */
+
+int __cpuinit __cpu_up(unsigned int cpu)
+{
+ struct task_struct *idle;
+ struct thread_info *thread;
+ void *stack_start;
+
+ /* Create new init task for the CPU */
+ idle = fork_idle(cpu);
+ if (IS_ERR(idle))
+ panic(KERN_ERR "fork_idle failed\n");
+
+ thread = (struct thread_info *)idle->stack;
+ thread->cpu = cpu;
+
+ /* Boot to the head. */
+ stack_start = ((void *) thread) + THREAD_SIZE;
+ __vmstart(start_secondary, stack_start);
+
+ while (!cpu_isset(cpu, cpu_online_map))
+ barrier();
+
+ return 0;
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+ int i;
+
+ /*
+ * should eventually have some sort of machine
+ * descriptor that has this stuff
+ */
+
+ /* Right now, let's just fake it. */
+ for (i = 0; i < max_cpus; i++)
+ cpu_set(i, cpu_present_map);
+
+ /* Also need to register the interrupts for IPI */
+ if (max_cpus > 1)
+ setup_irq(BASE_IPI_IRQ, &ipi_intdesc);
+}
+
+void smp_send_reschedule(int cpu)
+{
+ send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
+}
+
+void smp_send_stop(void)
+{
+ struct cpumask targets;
+ cpumask_copy(&targets, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), &targets);
+ send_ipi(&targets, IPI_CPU_STOP);
+}
+
+
+int setup_profiling_timer(unsigned int multiplier)
+{
+ return -EINVAL;
+}
+
+void smp_start_cpus(void)
+{
+ int i;
+
+ for (i = 0; i < NR_CPUS; i++)
+ cpu_set(i, cpu_possible_map);
+}
Index: linux-hexagon-kernel/arch/hexagon/kernel/topology.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/topology.c 2011-08-01 15:29:41.219060354 -0500
@@ -0,0 +1,52 @@
+/*
+ * CPU topology for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. 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 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/node.h>
+#include <linux/nodemask.h>
+#include <linux/percpu.h>
+
+/* Swiped from MIPS. */
+
+static DEFINE_PER_CPU(struct cpu, cpu_devices);
+
+static int __init topology_init(void)
+{
+ int i, ret;
+
+ for_each_present_cpu(i) {
+
+ /*
+ * register_cpu takes a per_cpu pointer and
+ * just points it at another per_cpu struct...
+ */
+
+ ret = register_cpu(&per_cpu(cpu_devices, i), i);
+ if (ret)
+ printk(KERN_WARNING "topology_init: register_cpu %d "
+ "failed (%d)\n", i, ret);
+ }
+
+ return 0;
+}
+
+subsys_initcall(topology_init);
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.



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