path: root/arch/powerpc/platforms/pseries/xics.c

/*
 * arch/powerpc/platforms/pseries/xics.c
 *
 * Copyright 2000 IBM Corporation.
 *
 *  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; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/types.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/radix-tree.h>
#include <linux/cpu.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/percpu.h>

#include <asm/firmware.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/smp.h>
#include <asm/rtas.h>
#include <asm/hvcall.h>
#include <asm/machdep.h>

#include "xics.h"
#include "plpar_wrappers.h"

static struct irq_host *xics_host;

#define XICS_IPI		2
#define XICS_IRQ_SPURIOUS	0

/* Want a priority other than 0.  Various HW issues require this. */
#define	DEFAULT_PRIORITY	5

/*
 * Mark IPIs as higher priority so we can take them inside interrupts that
 * arent marked IRQF_DISABLED
 */
#define IPI_PRIORITY		4

/* The least favored priority */
#define LOWEST_PRIORITY		0xFF

/* The number of priorities defined above */
#define MAX_NUM_PRIORITIES	3

static unsigned int default_server = 0xFF;
static unsigned int default_distrib_server = 0;
static unsigned int interrupt_server_size = 8;

/* RTAS service tokens */
static int ibm_get_xive;
static int ibm_set_xive;
static int ibm_int_on;
static int ibm_int_off;

struct xics_cppr {
	unsigned char stack[MAX_NUM_PRIORITIES];
	int index;
};

static DEFINE_PER_CPU(struct xics_cppr, xics_cppr);

/* Direct hardware low level accessors */

/* The part of the interrupt presentation layer that we care about */
struct xics_ipl {
	union {
		u32 word;
		u8 bytes[4];
	} xirr_poll;
	union {
		u32 word;
		u8 bytes[4];
	} xirr;
	u32 dummy;
	union {
		u32 word;
		u8 bytes[4];
	} qirr;
};

static struct xics_ipl __iomem *xics_per_cpu[NR_CPUS];

static inline unsigned int direct_xirr_info_get(void)
{
	int cpu = smp_processor_id();

	return in_be32(&xics_per_cpu[cpu]->xirr.word);
}

static inline void direct_xirr_info_set(unsigned int value)
{
	int cpu = smp_processor_id();

	out_be32(&xics_per_cpu[cpu]->xirr.word, value);
}

static inline void direct_cppr_info(u8 value)
{
	int cpu = smp_processor_id();

	out_8(&xics_per_cpu[cpu]->xirr.bytes[0], value);
}

static inline void direct_qirr_info(int n_cpu, u8 value)
{
	out_8(&xics_per_cpu[n_cpu]->qirr.bytes[0], value);
}


/* LPAR low level accessors */

static inline unsigned int lpar_xirr_info_get(void)
{
	unsigned long lpar_rc;
	unsigned long return_value;

	lpar_rc = plpar_xirr(&return_value);
	if (lpar_rc != H_SUCCESS)
		panic(" bad return code xirr - rc = %lx \n", lpar_rc);
	return (unsigned int)return_value;
}

static inline void lpar_xirr_info_set(unsigned int value)
{
	unsigned long lpar_rc;

	lpar_rc = plpar_eoi(value);
	if (lpar_rc != H_SUCCESS)
		panic("bad return code EOI - rc = %ld, value=%x\n", lpar_rc,
		      value);
}

static inline void lpar_cppr_info(u8 value)
{
	unsigned long lpar_rc;

	lpar_rc = plpar_cppr(value);
	if (lpar_rc != H_SUCCESS)
		panic("bad return code cppr - rc = %lx\n", lpar_rc);
}

static inline void lpar_qirr_info(int n_cpu , u8 value)
{
	unsigned long lpar_rc;

	lpar_rc = plpar_ipi(get_hard_smp_processor_id(n_cpu), value);
	if (lpar_rc != H_SUCCESS)
		panic("bad return code qirr - rc = %lx\n", lpar_rc);
}


/* Interface to generic irq subsystem */

#ifdef CONFIG_SMP
static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
	int server;
	/* For the moment only implement delivery to all cpus or one cpu */
	cpumask_t cpumask;
	cpumask_t tmp = CPU_MASK_NONE;

	cpumask_copy(&cpumask, irq_to_desc(virq)->affinity);
	if (!distribute_irqs)
		return default_server;

	if (!cpus_equal(cpumask, CPU_MASK_ALL)) {
		cpus_and(tmp, cpu_online_map, cpumask);

		server = first_cpu(tmp);

		if (server < NR_CPUS)
			return get_hard_smp_processor_id(server);

		if (strict_check)
			return -1;
	}

	if (cpus_equal(cpu_online_map, cpu_present_map))
		return default_distrib_server;

	return default_server;
}
#else
static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
	return default_server;
}
#endif

static void xics_unmask_irq(unsigned int virq)
{
	unsigned int irq;
	int call_status;
	int</