gsc.c

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/*
 * Interrupt management for most GSC and related devices.
 *
 * (c) Copyright 1999 Alex deVries for The Puffin Group
 * (c) Copyright 1999 Grant Grundler for Hewlett-Packard
 * (c) Copyright 1999 Matthew Wilcox
 * (c) Copyright 2000 Helge Deller
 * (c) Copyright 2001 Matthew Wilcox for Hewlett-Packard
 *
 *  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/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/types.h>

#include <asm/hardware.h>
#include <asm/io.h>

#include "gsc.h"

#undef DEBUG

#ifdef DEBUG
#define DEBPRINTK printk
#else
#define DEBPRINTK(x,...)
#endif

int gsc_alloc_irq(struct gsc_irq *i)
{
    int irq = txn_alloc_irq(GSC_EIM_WIDTH);
    if (irq < 0) {
        printk("cannot get irq\n");
        return irq;
    }

    i->txn_addr = txn_alloc_addr(irq);
    i->txn_data = txn_alloc_data(irq);
    i->irq = irq;

    return irq;
}

int gsc_claim_irq(struct gsc_irq *i, int irq)
{
    int c = irq;

    irq += CPU_IRQ_BASE; /* virtualize the IRQ first */

    irq = txn_claim_irq(irq);
    if (irq < 0) {
        printk("cannot claim irq %d\n", c);
        return irq;
    }

    i->txn_addr = txn_alloc_addr(irq);
    i->txn_data = txn_alloc_data(irq);
    i->irq = irq;

    return irq;
}

EXPORT_SYMBOL(gsc_alloc_irq);
EXPORT_SYMBOL(gsc_claim_irq);

/* Common interrupt demultiplexer used by Asp, Lasi & Wax.  */
irqreturn_t gsc_asic_intr(int gsc_asic_irq, void *dev)
{
    unsigned long irr;
    struct gsc_asic *gsc_asic = dev;

    irr = gsc_readl(gsc_asic->hpa + OFFSET_IRR);
    if (irr == 0)
        return IRQ_NONE;

    DEBPRINTK("%s intr, mask=0x%x\n", gsc_asic->name, irr);

    do {
        int local_irq = __ffs(irr);
        unsigned int irq = gsc_asic->global_irq[local_irq];
        generic_handle_irq(irq);
        irr &= ~(1 << local_irq);
    } while (irr);

    return IRQ_HANDLED;
}

int gsc_find_local_irq(unsigned int irq, int *global_irqs, int limit)
{
    int local_irq;

    for (local_irq = 0; local_irq < limit; local_irq++) {
        if (global_irqs[local_irq] == irq)
            return local_irq;
    }

    return NO_IRQ;
}

static void gsc_asic_mask_irq(struct irq_data *d)
{
    struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
    int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
    u32 imr;

    DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x\n", __func__, d->irq,
            irq_dev->name, imr);

    /* Disable the IRQ line by clearing the bit in the IMR */
    imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
    imr &= ~(1 << local_irq);
    gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
}

static void gsc_asic_unmask_irq(struct irq_data *d)
{
    struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
    int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
    u32 imr;

    DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x\n", __func__, d->irq,
            irq_dev->name, imr);

    /* Enable the IRQ line by setting the bit in the IMR */
    imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
    imr |= 1 << local_irq;
    gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
    /*
     * FIXME: read IPR to make sure the IRQ isn't already pending.
     *   If so, we need to read IRR and manually call do_irq().
     */
}

static struct irq_chip gsc_asic_interrupt_type = {
    .name       =   "GSC-ASIC",
    .irq_unmask =   gsc_asic_unmask_irq,
    .irq_mask   =   gsc_asic_mask_irq,
};

int gsc_assign_irq(struct irq_chip *type, void *data)
{
    static int irq = GSC_IRQ_BASE;

    if (irq > GSC_IRQ_MAX)
        return NO_IRQ;

    irq_set_chip_and_handler(irq, type, handle_simple_irq);
    irq_set_chip_data(irq, data);

    return irq++;
}

void gsc_asic_assign_irq(struct gsc_asic *asic, int local_irq, int *irqp)
{
    int irq = asic->global_irq[local_irq];
    
    if (irq <= 0) {
        irq = gsc_assign_irq(&gsc_asic_interrupt_type, asic);
        if (irq == NO_IRQ)
            return;

        asic->global_irq[local_irq] = irq;
    }
    *irqp = irq;
}

struct gsc_fixup_struct {
    void (*choose_irq)(struct parisc_device *, void *);
    void *ctrl;
};

static int gsc_fixup_irqs_callback(struct device *dev, void *data)
{
    struct parisc_device *padev = to_parisc_device(dev);
    struct gsc_fixup_struct *gf = data;

    /* work-around for 715/64 and others which have parent
       at path [5] and children at path [5/0/x] */
    if (padev->id.hw_type == HPHW_FAULTY)
        gsc_fixup_irqs(padev, gf->ctrl, gf->choose_irq);
    gf->choose_irq(padev, gf->ctrl);

    return 0;
}

void gsc_fixup_irqs(struct parisc_device *parent, void *ctrl,
            void (*choose_irq)(struct parisc_device *, void *))
{
    struct gsc_fixup_struct data = {
        .choose_irq = choose_irq,
        .ctrl       = ctrl,
    };

    device_for_each_child(&parent->dev, &data, gsc_fixup_irqs_callback);
}

int gsc_common_setup(struct parisc_device *parent, struct gsc_asic *gsc_asic)
{
    struct resource *res;
    int i;

    gsc_asic->gsc = parent;

    /* Initialise local irq -> global irq mapping */
    for (i = 0; i < 32; i++) {
        gsc_asic->global_irq[i] = NO_IRQ;
    }

    /* allocate resource region */
    res = request_mem_region(gsc_asic->hpa, 0x100000, gsc_asic->name);
    if (res) {
        res->flags = IORESOURCE_MEM;    /* do not mark it busy ! */
    }

#if 0
    printk(KERN_WARNING "%s IRQ %d EIM 0x%x", gsc_asic->name,
            parent->irq, gsc_asic->eim);
    if (gsc_readl(gsc_asic->hpa + OFFSET_IMR))
        printk("  IMR is non-zero! (0x%x)",
                gsc_readl(gsc_asic->hpa + OFFSET_IMR));
    printk("\n");
#endif

    return 0;
}

extern struct parisc_driver lasi_driver;
extern struct parisc_driver asp_driver;
extern struct parisc_driver wax_driver;

void __init gsc_init(void)
{
#ifdef CONFIG_GSC_LASI
    register_parisc_driver(&lasi_driver);
    register_parisc_driver(&asp_driver);
#endif
#ifdef CONFIG_GSC_WAX
    register_parisc_driver(&wax_driver);
#endif
}