/*
 * Copyright 2007, Olof Johansson, PA Semi
 *
 * Based on arch/powerpc/sysdev/mpic_u3msi.c:
 *
 * Copyright 2006, Segher Boessenkool, IBM Corporation.
 * Copyright 2006-2007, Michael Ellerman, 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; version 2 of the
 * License.
 *
 */

#include <linux/irq.h>
#include <linux/msi.h>
#include <asm/mpic.h>
#include <asm/prom.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>
#include <asm/msi_bitmap.h>

#include <sysdev/mpic.h>

/* Allocate 16 interrupts per device, to give an alignment of 16,
 * since that's the size of the grouping w.r.t. affinity. If someone
 * needs more than 32 MSI's down the road we'll have to rethink this,
 * but it should be OK for now.
 */
#define ALLOC_CHUNK 16

#define PASEMI_MSI_ADDR 0xfc080000

/* A bit ugly, can we get this from the pci_dev somehow? */
static struct mpic *msi_mpic;


static void mpic_pasemi_msi_mask_irq(struct irq_data *data)
{
        pr_debug("mpic_pasemi_msi_mask_irq %d\n", data->irq);
        pci_msi_mask_irq(data);
        mpic_mask_irq(data);
}

static void mpic_pasemi_msi_unmask_irq(struct irq_data *data)
{
        pr_debug("mpic_pasemi_msi_unmask_irq %d\n", data->irq);
        mpic_unmask_irq(data);
        pci_msi_unmask_irq(data);
}

static struct irq_chip mpic_pasemi_msi_chip = {
        .irq_shutdown           = mpic_pasemi_msi_mask_irq,
        .irq_mask               = mpic_pasemi_msi_mask_irq,
        .irq_unmask             = mpic_pasemi_msi_unmask_irq,
        .irq_eoi                = mpic_end_irq,
        .irq_set_type           = mpic_set_irq_type,
        .irq_set_affinity       = mpic_set_affinity,
        .name                   = "PASEMI-MSI",
};

static void pasemi_msi_teardown_msi_irqs(struct pci_dev *pdev)
{
        struct msi_desc *entry;
        irq_hw_number_t hwirq;

        pr_debug("pasemi_msi_teardown_msi_irqs, pdev %p\n", pdev);

        for_each_pci_msi_entry(entry, pdev) {
                if (entry->irq == NO_IRQ)
                        continue;

                hwirq = virq_to_hw(entry->irq);
                irq_set_msi_desc(entry->irq, NULL);
                irq_dispose_mapping(entry->irq);
                msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, ALLOC_CHUNK);
        }

        return;
}

static int pasemi_msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
{
        unsigned int virq;
        struct msi_desc *entry;
        struct msi_msg msg;
        int hwirq;

        if (type == PCI_CAP_ID_MSIX)
                pr_debug("pasemi_msi: MSI-X untested, trying anyway\n");
        pr_debug("pasemi_msi_setup_msi_irqs, pdev %p nvec %d type %d\n",
                 pdev, nvec, type);

        msg.address_hi = 0;
        msg.address_lo = PASEMI_MSI_ADDR;

        for_each_pci_msi_entry(entry, pdev) {
                /* Allocate 16 interrupts for now, since that's the grouping for
                 * affinity. This can be changed later if it turns out 32 is too
                 * few MSIs for someone, but restrictions will apply to how the
                 * sources can be changed independently.
                 */
                hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap,
                                                ALLOC_CHUNK);
                if (hwirq < 0) {
                        pr_debug("pasemi_msi: failed allocating hwirq\n");
                        return hwirq;
                }

                virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
                if (virq == NO_IRQ) {
                        pr_debug("pasemi_msi: failed mapping hwirq 0x%x\n",
                                  hwirq);
                        msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq,
                                               ALLOC_CHUNK);
                        return -ENOSPC;
                }

                /* Vector on MSI is really an offset, the hardware adds
                 * it to the value written at the magic address. So set
                 * it to 0 to remain sane.
                 */
                mpic_set_vector(virq, 0);

                irq_set_msi_desc(virq, entry);
                irq_set_chip(virq, &mpic_pasemi_msi_chip);
                irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);

                pr_debug("pasemi_msi: allocated virq 0x%x (hw 0x%x) " \
                         "addr 0x%x\n", virq, hwirq, msg.address_lo);

                /* Likewise, the device writes [0...511] into the target
                 * register to generate MSI [512...1023]
                 */
                msg.data = hwirq-0x200;
                pci_write_msi_msg(virq, &msg);
        }

        return 0;
}

int mpic_pasemi_msi_init(struct mpic *mpic)
{
        int rc;
        struct pci_controller *phb;
        struct device_node *of_node;

        of_node = irq_domain_get_of_node(mpic->irqhost);
        if (!of_node ||
            !of_device_is_compatible(of_node,
                                     "pasemi,pwrficient-openpic"))
                return -ENODEV;

        rc = mpic_msi_init_allocator(mpic);
        if (rc) {
                pr_debug("pasemi_msi: Error allocating bitmap!\n");
                return rc;
        }

        pr_debug("pasemi_msi: Registering PA Semi MPIC MSI callbacks\n");

        msi_mpic = mpic;
        list_for_each_entry(phb, &hose_list, list_node) {
                WARN_ON(phb->controller_ops.setup_msi_irqs);
                phb->controller_ops.setup_msi_irqs = pasemi_msi_setup_msi_irqs;
                phb->controller_ops.teardown_msi_irqs = pasemi_msi_teardown_msi_irqs;
        }

        return 0;
}