Hexagon: Add SMP support

/*

 * 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_NOP = 0,

	IPI_RESCHEDULE = 1,

	IPI_CALL_FUNC,

	IPI_CALL_FUNC_SINGLE,

	IPI_CPU_STOP,

	IPI_TIMER,

};

extern void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg);

extern void smp_start_cpus(void);

extern void arch_send_call_function_single_ipi(int cpu);

extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);

extern void smp_vm_unmask_irq(void *info);

#endif

/*

 * 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 ipi_data {

	unsigned long bits;

};

static DEFINE_PER_CPU(struct ipi_data, ipi_data);

static inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi,

				int cpu)

{

	unsigned long msg = 0;

	do {

		msg = find_next_bit(ops, BITS_PER_LONG, msg+1);

		switch (msg) {

		case IPI_TIMER:

			ipi_timer();

			break;

		case IPI_CALL_FUNC:

			generic_smp_call_function_interrupt();

			break;

		case IPI_CALL_FUNC_SINGLE:

			generic_smp_call_function_single_interrupt();

			break;

		case IPI_CPU_STOP:

			/*

			 * call vmstop()

			 */

			__vmstop();

			break;

		case IPI_RESCHEDULE:

			scheduler_ipi();

			break;

		}

	} while (msg < BITS_PER_LONG);

}

/*  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);

		set_bit(msg, &ipi->bits);

		/*  Possible barrier here  */

		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_TRIGGER_RISING,

	.name = "ipi_handler"

};

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);

	set_cpu_online(cpu, true);

	while (!cpumask_test_cpu(cpu, cpu_active_mask))

		cpu_relax();

	local_irq_enable();

	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);

}

void arch_send_call_function_single_ipi(int cpu)

{

	send_ipi(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);

}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)

{

	send_ipi(mask, IPI_CALL_FUNC);

}

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);

}

/*

 * 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);