pq2ads-pci-pic.c

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/*
 * PQ2 ADS-style PCI interrupt controller
 *
 * Copyright 2007 Freescale Semiconductor, Inc.
 * Author: Scott Wood <[email protected]>
 *
 * Loosely based on mpc82xx ADS support by Vitaly Bordug <[email protected]>
 * Copyright (c) 2006 MontaVista Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/types.h>
#include <linux/bootmem.h>
#include <linux/slab.h>

#include <asm/io.h>
#include <asm/prom.h>
#include <asm/cpm2.h>

#include "pq2.h"

static DEFINE_RAW_SPINLOCK(pci_pic_lock);

struct pq2ads_pci_pic {
    struct device_node *node;
    struct irq_domain *host;

    struct {
        u32 stat;
        u32 mask;
    } __iomem *regs;
};

#define NUM_IRQS 32

static void pq2ads_pci_mask_irq(struct irq_data *d)
{
    struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
    int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;

    if (irq != -1) {
        unsigned long flags;
        raw_spin_lock_irqsave(&pci_pic_lock, flags);

        setbits32(&priv->regs->mask, 1 << irq);
        mb();

        raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
    }
}

static void pq2ads_pci_unmask_irq(struct irq_data *d)
{
    struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
    int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;

    if (irq != -1) {
        unsigned long flags;

        raw_spin_lock_irqsave(&pci_pic_lock, flags);
        clrbits32(&priv->regs->mask, 1 << irq);
        raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
    }
}

static struct irq_chip pq2ads_pci_ic = {
    .name = "PQ2 ADS PCI",
    .irq_mask = pq2ads_pci_mask_irq,
    .irq_mask_ack = pq2ads_pci_mask_irq,
    .irq_ack = pq2ads_pci_mask_irq,
    .irq_unmask = pq2ads_pci_unmask_irq,
    .irq_enable = pq2ads_pci_unmask_irq,
    .irq_disable = pq2ads_pci_mask_irq
};

static void pq2ads_pci_irq_demux(unsigned int irq, struct irq_desc *desc)
{
    struct pq2ads_pci_pic *priv = irq_desc_get_handler_data(desc);
    u32 stat, mask, pend;
    int bit;

    for (;;) {
        stat = in_be32(&priv->regs->stat);
        mask = in_be32(&priv->regs->mask);

        pend = stat & ~mask;

        if (!pend)
            break;

        for (bit = 0; pend != 0; ++bit, pend <<= 1) {
            if (pend & 0x80000000) {
                int virq = irq_linear_revmap(priv->host, bit);
                generic_handle_irq(virq);
            }
        }
    }
}

static int pci_pic_host_map(struct irq_domain *h, unsigned int virq,
                irq_hw_number_t hw)
{
    irq_set_status_flags(virq, IRQ_LEVEL);
    irq_set_chip_data(virq, h->host_data);
    irq_set_chip_and_handler(virq, &pq2ads_pci_ic, handle_level_irq);
    return 0;
}

static const struct irq_domain_ops pci_pic_host_ops = {
    .map = pci_pic_host_map,
};

int __init pq2ads_pci_init_irq(void)
{
    struct pq2ads_pci_pic *priv;
    struct irq_domain *host;
    struct device_node *np;
    int ret = -ENODEV;
    int irq;

    np = of_find_compatible_node(NULL, NULL, "fsl,pq2ads-pci-pic");
    if (!np) {
        printk(KERN_ERR "No pci pic node in device tree.\n");
        of_node_put(np);
        goto out;
    }

    irq = irq_of_parse_and_map(np, 0);
    if (irq == NO_IRQ) {
        printk(KERN_ERR "No interrupt in pci pic node.\n");
        of_node_put(np);
        goto out;
    }

    priv = kzalloc(sizeof(*priv), GFP_KERNEL);
    if (!priv) {
        of_node_put(np);
        ret = -ENOMEM;
        goto out_unmap_irq;
    }

    /* PCI interrupt controller registers: status and mask */
    priv->regs = of_iomap(np, 0);
    if (!priv->regs) {
        printk(KERN_ERR "Cannot map PCI PIC registers.\n");
        goto out_free_bootmem;
    }

    /* mask all PCI interrupts */
    out_be32(&priv->regs->mask, ~0);
    mb();

    host = irq_domain_add_linear(np, NUM_IRQS, &pci_pic_host_ops, priv);
    if (!host) {
        ret = -ENOMEM;
        goto out_unmap_regs;
    }

    priv->host = host;
    irq_set_handler_data(irq, priv);
    irq_set_chained_handler(irq, pq2ads_pci_irq_demux);

    of_node_put(np);
    return 0;

out_unmap_regs:
    iounmap(priv->regs);
out_free_bootmem:
    free_bootmem((unsigned long)priv,
                 sizeof(struct pq2ads_pci_pic));
    of_node_put(np);
out_unmap_irq:
    irq_dispose_mapping(irq);
out:
    return ret;
}