/*
 * Copyright (C) 2007-2011 Freescale Semiconductor, Inc.
 *
 * Author: Tony Li <tony.li@freescale.com>
 *         Jason Jin <Jason.jin@freescale.com>
 *
 * The hwirq alloc and free code reuse from sysdev/mpic_msi.c
 *
 * 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 <linux/pci.h>
#include <linux/slab.h>
#include <linux/of_platform.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <sysdev/fsl_soc.h>
#include <asm/prom.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>
#include <asm/mpic.h>
#include <asm/fsl_hcalls.h>

#include "fsl_msi.h"
#include "fsl_pci.h"

#define MSIIR_OFFSET_MASK       0xfffff
#define MSIIR_IBS_SHIFT         0
#define MSIIR_SRS_SHIFT         5
#define MSIIR1_IBS_SHIFT        4
#define MSIIR1_SRS_SHIFT        0
#define MSI_SRS_MASK            0xf
#define MSI_IBS_MASK            0x1f

#define msi_hwirq(msi, msir_index, intr_index) \
                ((msir_index) << (msi)->srs_shift | \
                 ((intr_index) << (msi)->ibs_shift))

static LIST_HEAD(msi_head);

struct fsl_msi_feature {
        u32 fsl_pic_ip;
        u32 msiir_offset; /* Offset of MSIIR, relative to start of MSIR bank */
};

struct fsl_msi_cascade_data {
        struct fsl_msi *msi_data;
        int index;
        int virq;
};

static inline u32 fsl_msi_read(u32 __iomem *base, unsigned int reg)
{
        return in_be32(base + (reg >> 2));
}

/*
 * We do not need this actually. The MSIR register has been read once
 * in the cascade interrupt. So, this MSI interrupt has been acked
*/
static void fsl_msi_end_irq(struct irq_data *d)
{
}

static void fsl_msi_print_chip(struct irq_data *irqd, struct seq_file *p)
{
        struct fsl_msi *msi_data = irqd->domain->host_data;
        irq_hw_number_t hwirq = irqd_to_hwirq(irqd);
        int cascade_virq, srs;

        srs = (hwirq >> msi_data->srs_shift) & MSI_SRS_MASK;
        cascade_virq = msi_data->cascade_array[srs]->virq;

        seq_printf(p, " fsl-msi-%d", cascade_virq);
}


static struct irq_chip fsl_msi_chip = {
        .irq_mask       = pci_msi_mask_irq,
        .irq_unmask     = pci_msi_unmask_irq,
        .irq_ack        = fsl_msi_end_irq,
        .irq_print_chip = fsl_msi_print_chip,
};

static int fsl_msi_host_map(struct irq_domain *h, unsigned int virq,
                                irq_hw_number_t hw)
{
        struct fsl_msi *msi_data = h->host_data;
        struct irq_chip *chip = &fsl_msi_chip;

        irq_set_status_flags(virq, IRQ_TYPE_EDGE_FALLING);

        irq_set_chip_data(virq, msi_data);
        irq_set_chip_and_handler(virq, chip, handle_edge_irq);

        return 0;
}

static const struct irq_domain_ops fsl_msi_host_ops = {
        .map = fsl_msi_host_map,
};

static int fsl_msi_init_allocator(struct fsl_msi *msi_data)
{
        int rc, hwirq;

        rc = msi_bitmap_alloc(&msi_data->bitmap, NR_MSI_IRQS_MAX,
                              irq_domain_get_of_node(msi_data->irqhost));
        if (rc)
                return rc;

        /*
         * Reserve all the hwirqs
         * The available hwirqs will be released in fsl_msi_setup_hwirq()
         */
        for (hwirq = 0; hwirq < NR_MSI_IRQS_MAX; hwirq++)
                msi_bitmap_reserve_hwirq(&msi_data->bitmap, hwirq);

        return 0;
}

static void fsl_teardown_msi_irqs(struct pci_dev *pdev)
{
        struct msi_desc *entry;
        struct fsl_msi *msi_data;
        irq_hw_number_t hwirq;

        for_each_pci_msi_entry(entry, pdev) {
                if (entry->irq == NO_IRQ)
                        continue;
                hwirq = virq_to_hw(entry->irq);
                msi_data = irq_get_chip_data(entry->irq);
                irq_set_msi_desc(entry->irq, NULL);
                irq_dispose_mapping(entry->irq);
                msi_bitmap_free_hwirqs(&msi_data->bitmap, hwirq, 1);
        }

        return;
}

static void fsl_compose_msi_msg(struct pci_dev *pdev, int hwirq,
                                struct msi_msg *msg,
                                struct fsl_msi *fsl_msi_data)
{
        struct fsl_msi *msi_data = fsl_msi_data;
        struct pci_controller *hose = pci_bus_to_host(pdev->bus);
        u64 address; /* Physical address of the MSIIR */
        int len;
        const __be64 *reg;

        /* If the msi-address-64 property exists, then use it */
        reg = of_get_property(hose->dn, "msi-address-64", &len);
        if (reg && (len == sizeof(u64)))
                address = be64_to_cpup(reg);
        else
                address = fsl_pci_immrbar_base(hose) + msi_data->msiir_offset;

        msg->address_lo = lower_32_bits(address);
        msg->address_hi = upper_32_bits(address);

        /*
         * MPIC version 2.0 has erratum PIC1. It causes
         * that neither MSI nor MSI-X can work fine.
         * This is a workaround to allow MSI-X to function
         * properly. It only works for MSI-X, we prevent
         * MSI on buggy chips in fsl_setup_msi_irqs().
         */
        if (msi_data->feature & MSI_HW_ERRATA_ENDIAN)
                msg->data = __swab32(hwirq);
        else
                msg->data = hwirq;

        pr_debug("%s: allocated srs: %d, ibs: %d\n", __func__,
                 (hwirq >> msi_data->srs_shift) & MSI_SRS_MASK,
                 (hwirq >> msi_data->ibs_shift) & MSI_IBS_MASK);
}

static int fsl_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
{
        struct pci_controller *hose = pci_bus_to_host(pdev->bus);
        struct device_node *np;
        phandle phandle = 0;
        int rc, hwirq = -ENOMEM;
        unsigned int virq;
        struct msi_desc *entry;
        struct msi_msg msg;
        struct fsl_msi *msi_data;

        if (type == PCI_CAP_ID_MSI) {
                /*
                 * MPIC version 2.0 has erratum PIC1. For now MSI
                 * could not work. So check to prevent MSI from
                 * being used on the board with this erratum.
                 */
                list_for_each_entry(msi_data, &msi_head, list)
                        if (msi_data->feature & MSI_HW_ERRATA_ENDIAN)
                                return -EINVAL;
        }

        /*
         * If the PCI node has an fsl,msi property, then we need to use it
         * to find the specific MSI.
         */
        np = of_parse_phandle(hose->dn, "fsl,msi", 0);
        if (np) {
                if (of_device_is_compatible(np, "fsl,mpic-msi") ||
                    of_device_is_compatible(np, "fsl,vmpic-msi") ||
                    of_device_is_compatible(np, "fsl,vmpic-msi-v4.3"))
                        phandle = np->phandle;
                else {
                        dev_err(&pdev->dev,
                                "node %s has an invalid fsl,msi phandle %u\n",
                                hose->dn->full_name, np->phandle);
                        return -EINVAL;
                }
        }

        for_each_pci_msi_entry(entry, pdev) {
                /*
                 * Loop over all the MSI devices until we find one that has an
                 * available interrupt.
                 */
                list_for_each_entry(msi_data, &msi_head, list) {
                        /*
                         * If the PCI node has an fsl,msi property, then we
                         * restrict our search to the corresponding MSI node.
                         * The simplest way is to skip over MSI nodes with the
                         * wrong phandle. Under the Freescale hypervisor, this
                         * has the additional benefit of skipping over MSI
                         * nodes that are not mapped in the PAMU.
                         */
                        if (phandle && (phandle != msi_data->phandle))
                                continue;

                        hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
                        if (hwirq >= 0)
                                break;
                }

                if (hwirq < 0) {
                        rc = hwirq;
                        dev_err(&pdev->dev, "could not allocate MSI interrupt\n");
                        goto out_free;
                }

                virq = irq_create_mapping(msi_data->irqhost, hwirq);

                if (virq == NO_IRQ) {
                        dev_err(&pdev->dev, "fail mapping hwirq %i\n", hwirq);
                        msi_bitmap_free_hwirqs(&msi_data->bitmap, hwirq, 1);
                        rc = -ENOSPC;
                        goto out_free;
                }
                /* chip_data is msi_data via host->hostdata in host->map() */
                irq_set_msi_desc(virq, entry);

                fsl_compose_msi_msg(pdev, hwirq, &msg, msi_data);
                pci_write_msi_msg(virq, &msg);
        }
        return 0;

out_free:
        /* free by the caller of this function */
        return rc;
}

static irqreturn_t fsl_msi_cascade(int irq, void *data)
{
        unsigned int cascade_irq;
        struct fsl_msi *msi_data;
        int msir_index = -1;
        u32 msir_value = 0;
        u32 intr_index;
        u32 have_shift = 0;
        struct fsl_msi_cascade_data *cascade_data = data;
        irqreturn_t ret = IRQ_NONE;

        msi_data = cascade_data->msi_data;

        msir_index = cascade_data->index;

        if (msir_index >= NR_MSI_REG_MAX)
                cascade_irq = NO_IRQ;

        switch (msi_data->feature & FSL_PIC_IP_MASK) {
        case FSL_PIC_IP_MPIC:
                msir_value = fsl_msi_read(msi_data->msi_regs,
                        msir_index * 0x10);
                break;
        case FSL_PIC_IP_IPIC:
                msir_value = fsl_msi_read(msi_data->msi_regs, msir_index * 0x4);
                break;
#ifdef CONFIG_EPAPR_PARAVIRT
        case FSL_PIC_IP_VMPIC: {
                unsigned int ret;
                ret = fh_vmpic_get_msir(virq_to_hw(irq), &msir_value);
                if (ret) {
                        pr_err("fsl-msi: fh_vmpic_get_msir() failed for "
                               "irq %u (ret=%u)\n", irq, ret);
                        msir_value = 0;
                }
                break;
        }
#endif
        }

        while (msir_value) {
                intr_index = ffs(msir_value) - 1;

                cascade_irq = irq_linear_revmap(msi_data->irqhost,
                                msi_hwirq(msi_data, msir_index,
                                          intr_index + have_shift));
                if (cascade_irq != NO_IRQ) {
                        generic_handle_irq(cascade_irq);
                        ret = IRQ_HANDLED;
                }
                have_shift += intr_index + 1;
                msir_value = msir_value >> (intr_index + 1);
        }

        return ret;
}

static int fsl_of_msi_remove(struct platform_device *ofdev)
{
        struct fsl_msi *msi = platform_get_drvdata(ofdev);
        int virq, i;

        if (msi->list.prev != NULL)
                list_del(&msi->list);
        for (i = 0; i < NR_MSI_REG_MAX; i++) {
                if (msi->cascade_array[i]) {
                        virq = msi->cascade_array[i]->virq;

                        BUG_ON(virq == NO_IRQ);

                        free_irq(virq, msi->cascade_array[i]);
                        kfree(msi->cascade_array[i]);
                        irq_dispose_mapping(virq);
                }
        }
        if (msi->bitmap.bitmap)
                msi_bitmap_free(&msi->bitmap);
        if ((msi->feature & FSL_PIC_IP_MASK) != FSL_PIC_IP_VMPIC)
                iounmap(msi->msi_regs);
        kfree(msi);

        return 0;
}

static struct lock_class_key fsl_msi_irq_class;

static int fsl_msi_setup_hwirq(struct fsl_msi *msi, struct platform_device *dev,
                               int offset, int irq_index)
{
        struct fsl_msi_cascade_data *cascade_data = NULL;
        int virt_msir, i, ret;

        virt_msir = irq_of_parse_and_map(dev->dev.of_node, irq_index);
        if (virt_msir == NO_IRQ) {
                dev_err(&dev->dev, "%s: Cannot translate IRQ index %d\n",
                        __func__, irq_index);
                return 0;
        }

        cascade_data = kzalloc(sizeof(struct fsl_msi_cascade_data), GFP_KERNEL);
        if (!cascade_data) {
                dev_err(&dev->dev, "No memory for MSI cascade data\n");
                return -ENOMEM;
        }
        irq_set_lockdep_class(virt_msir, &fsl_msi_irq_class);
        cascade_data->index = offset;
        cascade_data->msi_data = msi;
        cascade_data->virq = virt_msir;
        msi->cascade_array[irq_index] = cascade_data;

        ret = request_irq(virt_msir, fsl_msi_cascade, IRQF_NO_THREAD,
                          "fsl-msi-cascade", cascade_data);
        if (ret) {
                dev_err(&dev->dev, "failed to request_irq(%d), ret = %d\n",
                        virt_msir, ret);
                return ret;
        }

        /* Release the hwirqs corresponding to this MSI register */
        for (i = 0; i < IRQS_PER_MSI_REG; i++)
                msi_bitmap_free_hwirqs(&msi->bitmap,
                                       msi_hwirq(msi, offset, i), 1);

        return 0;
}

static const struct of_device_id fsl_of_msi_ids[];
static int fsl_of_msi_probe(struct platform_device *dev)
{
        const struct of_device_id *match;
        struct fsl_msi *msi;
        struct resource res, msiir;
        int err, i, j, irq_index, count;
        const u32 *p;
        const struct fsl_msi_feature *features;
        int len;
        u32 offset;
        struct pci_controller *phb;

        match = of_match_device(fsl_of_msi_ids, &dev->dev);
        if (!match)
                return -EINVAL;
        features = match->data;

        printk(KERN_DEBUG "Setting up Freescale MSI support\n");

        msi = kzalloc(sizeof(struct fsl_msi), GFP_KERNEL);
        if (!msi) {
                dev_err(&dev->dev, "No memory for MSI structure\n");
                return -ENOMEM;
        }
        platform_set_drvdata(dev, msi);

        msi->irqhost = irq_domain_add_linear(dev->dev.of_node,
                                      NR_MSI_IRQS_MAX, &fsl_msi_host_ops, msi);

        if (msi->irqhost == NULL) {
                dev_err(&dev->dev, "No memory for MSI irqhost\n");
                err = -ENOMEM;
                goto error_out;
        }

        /*
         * Under the Freescale hypervisor, the msi nodes don't have a 'reg'
         * property.  Instead, we use hypercalls to access the MSI.
         */
        if ((features->fsl_pic_ip & FSL_PIC_IP_MASK) != FSL_PIC_IP_VMPIC) {
                err = of_address_to_resource(dev->dev.of_node, 0, &res);
                if (err) {
                        dev_err(&dev->dev, "invalid resource for node %s\n",
                                dev->dev.of_node->full_name);
                        goto error_out;
                }

                msi->msi_regs = ioremap(res.start, resource_size(&res));
                if (!msi->msi_regs) {
                        err = -ENOMEM;
                        dev_err(&dev->dev, "could not map node %s\n",
                                dev->dev.of_node->full_name);
                        goto error_out;
                }
                msi->msiir_offset =
                        features->msiir_offset + (res.start & 0xfffff);

                /*
                 * First read the MSIIR/MSIIR1 offset from dts
                 * On failure use the hardcode MSIIR offset
                 */
                if (of_address_to_resource(dev->dev.of_node, 1, &msiir))
                        msi->msiir_offset = features->msiir_offset +
                                            (res.start & MSIIR_OFFSET_MASK);
                else
                        msi->msiir_offset = msiir.start & MSIIR_OFFSET_MASK;
        }

        msi->feature = features->fsl_pic_ip;

        /* For erratum PIC1 on MPIC version 2.0*/
        if ((features->fsl_pic_ip & FSL_PIC_IP_MASK) == FSL_PIC_IP_MPIC
                        && (fsl_mpic_primary_get_version() == 0x0200))
                msi->feature |= MSI_HW_ERRATA_ENDIAN;

        /*
         * Remember the phandle, so that we can match with any PCI nodes
         * that have an "fsl,msi" property.
         */
        msi->phandle = dev->dev.of_node->phandle;

        err = fsl_msi_init_allocator(msi);
        if (err) {
                dev_err(&dev->dev, "Error allocating MSI bitmap\n");
                goto error_out;
        }

        p = of_get_property(dev->dev.of_node, "msi-available-ranges", &len);

        if (of_device_is_compatible(dev->dev.of_node, "fsl,mpic-msi-v4.3") ||
            of_device_is_compatible(dev->dev.of_node, "fsl,vmpic-msi-v4.3")) {
                msi->srs_shift = MSIIR1_SRS_SHIFT;
                msi->ibs_shift = MSIIR1_IBS_SHIFT;
                if (p)
                        dev_warn(&dev->dev, "%s: dose not support msi-available-ranges property\n",
                                __func__);

                for (irq_index = 0; irq_index < NR_MSI_REG_MSIIR1;
                     irq_index++) {
                        err = fsl_msi_setup_hwirq(msi, dev,
                                                  irq_index, irq_index);
                        if (err)
                                goto error_out;
                }
        } else {
                static const u32 all_avail[] =
                        { 0, NR_MSI_REG_MSIIR * IRQS_PER_MSI_REG };

                msi->srs_shift = MSIIR_SRS_SHIFT;
                msi->ibs_shift = MSIIR_IBS_SHIFT;

                if (p && len % (2 * sizeof(u32)) != 0) {
                        dev_err(&dev->dev, "%s: Malformed msi-available-ranges property\n",
                                __func__);
                        err = -EINVAL;
                        goto error_out;
                }

                if (!p) {
                        p = all_avail;
                        len = sizeof(all_avail);
                }

                for (irq_index = 0, i = 0; i < len / (2 * sizeof(u32)); i++) {
                        if (p[i * 2] % IRQS_PER_MSI_REG ||
                            p[i * 2 + 1] % IRQS_PER_MSI_REG) {
                                pr_warn("%s: %s: msi available range of %u at %u is not IRQ-aligned\n",
                                       __func__, dev->dev.of_node->full_name,
                                       p[i * 2 + 1], p[i * 2]);
                                err = -EINVAL;
                                goto error_out;
                        }

                        offset = p[i * 2] / IRQS_PER_MSI_REG;
                        count = p[i * 2 + 1] / IRQS_PER_MSI_REG;

                        for (j = 0; j < count; j++, irq_index++) {
                                err = fsl_msi_setup_hwirq(msi, dev, offset + j,
                                                          irq_index);
                                if (err)
                                        goto error_out;
                        }
                }
        }

        list_add_tail(&msi->list, &msi_head);

        /*
         * Apply the MSI ops to all the controllers.
         * It doesn't hurt to reassign the same ops,
         * but bail out if we find another MSI driver.
         */
        list_for_each_entry(phb, &hose_list, list_node) {
                if (!phb->controller_ops.setup_msi_irqs) {
                        phb->controller_ops.setup_msi_irqs = fsl_setup_msi_irqs;
                        phb->controller_ops.teardown_msi_irqs = fsl_teardown_msi_irqs;
                } else if (phb->controller_ops.setup_msi_irqs != fsl_setup_msi_irqs) {
                        dev_err(&dev->dev, "Different MSI driver already installed!\n");
                        err = -ENODEV;
                        goto error_out;
                }
        }
        return 0;
error_out:
        fsl_of_msi_remove(dev);
        return err;
}

static const struct fsl_msi_feature mpic_msi_feature = {
        .fsl_pic_ip = FSL_PIC_IP_MPIC,
        .msiir_offset = 0x140,
};

static const struct fsl_msi_feature ipic_msi_feature = {
        .fsl_pic_ip = FSL_PIC_IP_IPIC,
        .msiir_offset = 0x38,
};

static const struct fsl_msi_feature vmpic_msi_feature = {
        .fsl_pic_ip = FSL_PIC_IP_VMPIC,
        .msiir_offset = 0,
};

static const struct of_device_id fsl_of_msi_ids[] = {
        {
                .compatible = "fsl,mpic-msi",
                .data = &mpic_msi_feature,
        },
        {
                .compatible = "fsl,mpic-msi-v4.3",
                .data = &mpic_msi_feature,
        },
        {
                .compatible = "fsl,ipic-msi",
                .data = &ipic_msi_feature,
        },
#ifdef CONFIG_EPAPR_PARAVIRT
        {
                .compatible = "fsl,vmpic-msi",
                .data = &vmpic_msi_feature,
        },
        {
                .compatible = "fsl,vmpic-msi-v4.3",
                .data = &vmpic_msi_feature,
        },
#endif
        {}
};

static struct platform_driver fsl_of_msi_driver = {
        .driver = {
                .name = "fsl-msi",
                .of_match_table = fsl_of_msi_ids,
        },
        .probe = fsl_of_msi_probe,
        .remove = fsl_of_msi_remove,
};

static __init int fsl_of_msi_init(void)
{
        return platform_driver_register(&fsl_of_msi_driver);
}

subsys_initcall(fsl_of_msi_init);