/*
 * This module supports the iSeries PCI bus interrupt handling
 * Copyright (C) 20yy  <Robert L Holtorf> <IBM Corp>
 * Copyright (C) 2004-2005 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.
 *
 * 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.,
 * 59 Temple Place, Suite 330,
 * Boston, MA  02111-1307  USA
 *
 * Change Activity:
 *   Created, December 13, 2000 by Wayne Holm
 * End Change Activity
 */
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/bootmem.h>
#include <linux/irq.h>
#include <linux/spinlock.h>

#include <asm/paca.h>
#include <asm/iseries/hv_types.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/hv_call_xm.h>
#include <asm/iseries/it_lp_queue.h>

#include "irq.h"
#include "pci.h"
#include "call_pci.h"
#include "smp.h"

#ifdef CONFIG_PCI

enum pci_event_type {
        pe_bus_created          = 0,    /* PHB has been created */
        pe_bus_error            = 1,    /* PHB has failed */
        pe_bus_failed           = 2,    /* Msg to Secondary, Primary failed bus */
        pe_node_failed          = 4,    /* Multi-adapter bridge has failed */
        pe_node_recovered       = 5,    /* Multi-adapter bridge has recovered */
        pe_bus_recovered        = 12,   /* PHB has been recovered */
        pe_unquiese_bus         = 18,   /* Secondary bus unqiescing */
        pe_bridge_error         = 21,   /* Bridge Error */
        pe_slot_interrupt       = 22    /* Slot interrupt */
};

struct pci_event {
        struct HvLpEvent event;
        union {
                u64 __align;            /* Align on an 8-byte boundary */
                struct {
                        u32             fisr;
                        HvBusNumber     bus_number;
                        HvSubBusNumber  sub_bus_number;
                        HvAgentId       dev_id;
                } slot;
                struct {
                        HvBusNumber     bus_number;
                        HvSubBusNumber  sub_bus_number;
                } bus;
                struct {
                        HvBusNumber     bus_number;
                        HvSubBusNumber  sub_bus_number;
                        HvAgentId       dev_id;
                } node;
        } data;
};

static DEFINE_SPINLOCK(pending_irqs_lock);
static int num_pending_irqs;
static int pending_irqs[NR_IRQS];

static void int_received(struct pci_event *event)
{
        int irq;

        switch (event->event.xSubtype) {
        case pe_slot_interrupt:
                irq = event->event.xCorrelationToken;
                if (irq < NR_IRQS) {
                        spin_lock(&pending_irqs_lock);
                        pending_irqs[irq]++;
                        num_pending_irqs++;
                        spin_unlock(&pending_irqs_lock);
                } else {
                        printk(KERN_WARNING "int_received: bad irq number %d\n",
                                        irq);
                        HvCallPci_eoi(event->data.slot.bus_number,
                                        event->data.slot.sub_bus_number,
                                        event->data.slot.dev_id);
                }
                break;
                /* Ignore error recovery events for now */
        case pe_bus_created:
                printk(KERN_INFO "int_received: system bus %d created\n",
                        event->data.bus.bus_number);
                break;
        case pe_bus_error:
        case pe_bus_failed:
                printk(KERN_INFO "int_received: system bus %d failed\n",
                        event->data.bus.bus_number);
                break;
        case pe_bus_recovered:
        case pe_unquiese_bus:
                printk(KERN_INFO "int_received: system bus %d recovered\n",
                        event->data.bus.bus_number);
                break;
        case pe_node_failed:
        case pe_bridge_error:
                printk(KERN_INFO
                        "int_received: multi-adapter bridge %d/%d/%d failed\n",
                        event->data.node.bus_number,
                        event->data.node.sub_bus_number,
                        event->data.node.dev_id);
                break;
        case pe_node_recovered:
                printk(KERN_INFO
                        "int_received: multi-adapter bridge %d/%d/%d recovered\n",
                        event->data.node.bus_number,
                        event->data.node.sub_bus_number,
                        event->data.node.dev_id);
                break;
        default:
                printk(KERN_ERR
                        "int_received: unrecognized event subtype 0x%x\n",
                        event->event.xSubtype);
                break;
        }
}

static void pci_event_handler(struct HvLpEvent *event)
{
        if (event && (event->xType == HvLpEvent_Type_PciIo)) {
                if (hvlpevent_is_int(event))
                        int_received((struct pci_event *)event);
                else
                        printk(KERN_ERR
                                "pci_event_handler: unexpected ack received\n");
        } else if (event)
                printk(KERN_ERR
                        "pci_event_handler: Unrecognized PCI event type 0x%x\n",
                        (int)event->xType);
        else
                printk(KERN_ERR "pci_event_handler: NULL event received\n");
}

#define REAL_IRQ_TO_SUBBUS(irq) (((irq) >> 14) & 0xff)
#define REAL_IRQ_TO_BUS(irq)    ((((irq) >> 6) & 0xff) + 1)
#define REAL_IRQ_TO_IDSEL(irq)  ((((irq) >> 3) & 7) + 1)
#define REAL_IRQ_TO_FUNC(irq)   ((irq) & 7)

/*
 * This will be called by device drivers (via enable_IRQ)
 * to enable INTA in the bridge interrupt status register.
 */
static void iseries_enable_IRQ(unsigned int irq)
{
        u32 bus, dev_id, function, mask;
        const u32 sub_bus = 0;
        unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

        /* The IRQ has already been locked by the caller */
        bus = REAL_IRQ_TO_BUS(rirq);
        function = REAL_IRQ_TO_FUNC(rirq);
        dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

        /* Unmask secondary INTA */
        mask = 0x80000000;
        HvCallPci_unmaskInterrupts(bus, sub_bus, dev_id, mask);
}

/* This is called by iseries_activate_IRQs */
static unsigned int iseries_startup_IRQ(unsigned int irq)
{
        u32 bus, dev_id, function, mask;
        const u32 sub_bus = 0;
        unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

        bus = REAL_IRQ_TO_BUS(rirq);
        function = REAL_IRQ_TO_FUNC(rirq);
        dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

        /* Link the IRQ number to the bridge */
        HvCallXm_connectBusUnit(bus, sub_bus, dev_id, irq);

        /* Unmask bridge interrupts in the FISR */
        mask = 0x01010000 << function;
        HvCallPci_unmaskFisr(bus, sub_bus, dev_id, mask);
        iseries_enable_IRQ(irq);
        return 0;
}

/*
 * This is called out of iSeries_fixup to activate interrupt
 * generation for usable slots
 */
void __init iSeries_activate_IRQs()
{
        int irq;
        unsigned long flags;

        for_each_irq (irq) {
                struct irq_desc *desc = get_irq_desc(irq);

                if (desc && desc->chip && desc->chip->startup) {
                        spin_lock_irqsave(&desc->lock, flags);
                        desc->chip->startup(irq);
                        spin_unlock_irqrestore(&desc->lock, flags);
                }
        }
}

/*  this is not called anywhere currently */
static void iseries_shutdown_IRQ(unsigned int irq)
{
        u32 bus, dev_id, function, mask;
        const u32 sub_bus = 0;
        unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

        /* irq should be locked by the caller */
        bus = REAL_IRQ_TO_BUS(rirq);
        function = REAL_IRQ_TO_FUNC(rirq);
        dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

        /* Invalidate the IRQ number in the bridge */
        HvCallXm_connectBusUnit(bus, sub_bus, dev_id, 0);

        /* Mask bridge interrupts in the FISR */
        mask = 0x01010000 << function;
        HvCallPci_maskFisr(bus, sub_bus, dev_id, mask);
}

/*
 * This will be called by device drivers (via disable_IRQ)
 * to disable INTA in the bridge interrupt status register.
 */
static void iseries_disable_IRQ(unsigned int irq)
{
        u32 bus, dev_id, function, mask;
        const u32 sub_bus = 0;
        unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

        /* The IRQ has already been locked by the caller */
        bus = REAL_IRQ_TO_BUS(rirq);
        function = REAL_IRQ_TO_FUNC(rirq);
        dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

        /* Mask secondary INTA   */
        mask = 0x80000000;
        HvCallPci_maskInterrupts(bus, sub_bus, dev_id, mask);
}

static void iseries_end_IRQ(unsigned int irq)
{
        unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

        HvCallPci_eoi(REAL_IRQ_TO_BUS(rirq), REAL_IRQ_TO_SUBBUS(rirq),
                (REAL_IRQ_TO_IDSEL(rirq) << 4) + REAL_IRQ_TO_FUNC(rirq));
}

static struct irq_chip iseries_pic = {
        .typename       = "iSeries irq controller",
        .startup        = iseries_startup_IRQ,
        .shutdown       = iseries_shutdown_IRQ,
        .unmask         = iseries_enable_IRQ,
        .mask           = iseries_disable_IRQ,
        .eoi            = iseries_end_IRQ
};

/*
 * This is called out of iSeries_scan_slot to allocate an IRQ for an EADS slot
 * It calculates the irq value for the slot.
 * Note that sub_bus is always 0 (at the moment at least).
 */
int __init iSeries_allocate_IRQ(HvBusNumber bus,
                HvSubBusNumber sub_bus, u32 bsubbus)
{
        unsigned int realirq;
        u8 idsel = ISERIES_GET_DEVICE_FROM_SUBBUS(bsubbus);
        u8 function = ISERIES_GET_FUNCTION_FROM_SUBBUS(bsubbus);

        realirq = (((((sub_bus << 8) + (bus - 1)) << 3) + (idsel - 1)) << 3)
                + function;

        return irq_create_mapping(NULL, realirq);
}

#endif /* CONFIG_PCI */

/*
 * Get the next pending IRQ.
 */
unsigned int iSeries_get_irq(void)
{
        int irq = NO_IRQ_IGNORE;

#ifdef CONFIG_SMP
        if (get_lppaca()->int_dword.fields.ipi_cnt) {
                get_lppaca()->int_dword.fields.ipi_cnt = 0;
                iSeries_smp_message_recv();
        }
#endif /* CONFIG_SMP */
        if (hvlpevent_is_pending())
                process_hvlpevents();

#ifdef CONFIG_PCI
        if (num_pending_irqs) {
                spin_lock(&pending_irqs_lock);
                for (irq = 0; irq < NR_IRQS; irq++) {
                        if (pending_irqs[irq]) {
                                pending_irqs[irq]--;
                                num_pending_irqs--;
                                break;
                        }
                }
                spin_unlock(&pending_irqs_lock);
                if (irq >= NR_IRQS)
                        irq = NO_IRQ_IGNORE;
        }
#endif

        return irq;
}

#ifdef CONFIG_PCI

static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
                                irq_hw_number_t hw)
{
        set_irq_chip_and_handler(virq, &iseries_pic, handle_fasteoi_irq);

        return 0;
}

static int iseries_irq_host_match(struct irq_host *h, struct device_node *np)
{
        /* Match all */
        return 1;
}

static struct irq_host_ops iseries_irq_host_ops = {
        .map = iseries_irq_host_map,
        .match = iseries_irq_host_match,
};

/*
 * This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c
 * It must be called before the bus walk.
 */
void __init iSeries_init_IRQ(void)
{
        /* Register PCI event handler and open an event path */
        struct irq_host *host;
        int ret;

        /*
         * The Hypervisor only allows us up to 256 interrupt
         * sources (the irq number is passed in a u8).
         */
        irq_set_virq_count(256);

        /* Create irq host. No need for a revmap since HV will give us
         * back our virtual irq number
         */
        host = irq_alloc_host(NULL, IRQ_HOST_MAP_NOMAP, 0,
                              &iseries_irq_host_ops, 0);
        BUG_ON(host == NULL);
        irq_set_default_host(host);

        ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
                        &pci_event_handler);
        if (ret == 0) {
                ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
                if (ret != 0)
                        printk(KERN_ERR "iseries_init_IRQ: open event path "
                                        "failed with rc 0x%x\n", ret);
        } else
                printk(KERN_ERR "iseries_init_IRQ: register handler "
                                "failed with rc 0x%x\n", ret);
}

#endif  /* CONFIG_PCI */