// SPDX-License-Identifier: GPL-2.0-only
/*
 *  cb710/core.c
 *
 *  Copyright by Michał Mirosław, 2008-2009
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <linux/cb710.h>
#include <linux/gfp.h>

static DEFINE_IDA(cb710_ida);

void cb710_pci_update_config_reg(struct pci_dev *pdev,
        int reg, uint32_t mask, uint32_t xor)
{
        u32 rval;

        pci_read_config_dword(pdev, reg, &rval);
        rval = (rval & mask) ^ xor;
        pci_write_config_dword(pdev, reg, rval);
}
EXPORT_SYMBOL_GPL(cb710_pci_update_config_reg);

/* Some magic writes based on Windows driver init code */
static int cb710_pci_configure(struct pci_dev *pdev)
{
        unsigned int devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
        struct pci_dev *pdev0;
        u32 val;

        cb710_pci_update_config_reg(pdev, 0x48,
                ~0x000000FF, 0x0000003F);

        pci_read_config_dword(pdev, 0x48, &val);
        if (val & 0x80000000)
                return 0;

        pdev0 = pci_get_slot(pdev->bus, devfn);
        if (!pdev0)
                return -ENODEV;

        if (pdev0->vendor == PCI_VENDOR_ID_ENE
            && pdev0->device == PCI_DEVICE_ID_ENE_720) {
                cb710_pci_update_config_reg(pdev0, 0x8C,
                        ~0x00F00000, 0x00100000);
                cb710_pci_update_config_reg(pdev0, 0xB0,
                        ~0x08000000, 0x08000000);
        }

        cb710_pci_update_config_reg(pdev0, 0x8C,
                ~0x00000F00, 0x00000200);
        cb710_pci_update_config_reg(pdev0, 0x90,
                ~0x00060000, 0x00040000);

        pci_dev_put(pdev0);

        return 0;
}

static irqreturn_t cb710_irq_handler(int irq, void *data)
{
        struct cb710_chip *chip = data;
        struct cb710_slot *slot = &chip->slot[0];
        irqreturn_t handled = IRQ_NONE;
        unsigned nr;

        spin_lock(&chip->irq_lock); /* incl. smp_rmb() */

        for (nr = chip->slots; nr; ++slot, --nr) {
                cb710_irq_handler_t handler_func = slot->irq_handler;
                if (handler_func && handler_func(slot))
                        handled = IRQ_HANDLED;
        }

        spin_unlock(&chip->irq_lock);

        return handled;
}

static void cb710_release_slot(struct device *dev)
{
#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
        struct cb710_slot *slot = cb710_pdev_to_slot(to_platform_device(dev));
        struct cb710_chip *chip = cb710_slot_to_chip(slot);

        /* slot struct can be freed now */
        atomic_dec(&chip->slot_refs_count);
#endif
}

static int cb710_register_slot(struct cb710_chip *chip,
        unsigned slot_mask, unsigned io_offset, const char *name)
{
        int nr = chip->slots;
        struct cb710_slot *slot = &chip->slot[nr];
        int err;

        dev_dbg(cb710_chip_dev(chip),
                "register: %s.%d; slot %d; mask %d; IO offset: 0x%02X\n",
                name, chip->platform_id, nr, slot_mask, io_offset);

        /* slot->irq_handler == NULL here; this needs to be
         * seen before platform_device_register() */
        ++chip->slots;
        smp_wmb();

        slot->iobase = chip->iobase + io_offset;
        slot->pdev.name = name;
        slot->pdev.id = chip->platform_id;
        slot->pdev.dev.parent = &chip->pdev->dev;
        slot->pdev.dev.release = cb710_release_slot;

        err = platform_device_register(&slot->pdev);

#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
        atomic_inc(&chip->slot_refs_count);
#endif

        if (err) {
                /* device_initialize() called from platform_device_register()
                 * wants this on error path */
                platform_device_put(&slot->pdev);

                /* slot->irq_handler == NULL here anyway, so no lock needed */
                --chip->slots;
                return err;
        }

        chip->slot_mask |= slot_mask;

        return 0;
}

static void cb710_unregister_slot(struct cb710_chip *chip,
        unsigned slot_mask)
{
        int nr = chip->slots - 1;

        if (!(chip->slot_mask & slot_mask))
                return;

        platform_device_unregister(&chip->slot[nr].pdev);

        /* complementary to spin_unlock() in cb710_set_irq_handler() */
        smp_rmb();
        BUG_ON(chip->slot[nr].irq_handler != NULL);

        /* slot->irq_handler == NULL here, so no lock needed */
        --chip->slots;
        chip->slot_mask &= ~slot_mask;
}

void cb710_set_irq_handler(struct cb710_slot *slot,
        cb710_irq_handler_t handler)
{
        struct cb710_chip *chip = cb710_slot_to_chip(slot);
        unsigned long flags;

        spin_lock_irqsave(&chip->irq_lock, flags);
        slot->irq_handler = handler;
        spin_unlock_irqrestore(&chip->irq_lock, flags);
}
EXPORT_SYMBOL_GPL(cb710_set_irq_handler);

static int __maybe_unused cb710_suspend(struct device *dev_d)
{
        struct pci_dev *pdev = to_pci_dev(dev_d);
        struct cb710_chip *chip = pci_get_drvdata(pdev);

        devm_free_irq(&pdev->dev, pdev->irq, chip);
        return 0;
}

static int __maybe_unused cb710_resume(struct device *dev_d)
{
        struct pci_dev *pdev = to_pci_dev(dev_d);
        struct cb710_chip *chip = pci_get_drvdata(pdev);

        return devm_request_irq(&pdev->dev, pdev->irq,
                cb710_irq_handler, IRQF_SHARED, KBUILD_MODNAME, chip);
}

static int cb710_probe(struct pci_dev *pdev,
        const struct pci_device_id *ent)
{
        struct cb710_chip *chip;
        u32 val;
        int err;
        int n = 0;

        err = cb710_pci_configure(pdev);
        if (err)
                return err;

        /* this is actually magic... */
        pci_read_config_dword(pdev, 0x48, &val);
        if (!(val & 0x80000000)) {
                pci_write_config_dword(pdev, 0x48, val|0x71000000);
                pci_read_config_dword(pdev, 0x48, &val);
        }

        dev_dbg(&pdev->dev, "PCI config[0x48] = 0x%08X\n", val);
        if (!(val & 0x70000000))
                return -ENODEV;
        val = (val >> 28) & 7;
        if (val & CB710_SLOT_MMC)
                ++n;
        if (val & CB710_SLOT_MS)
                ++n;
        if (val & CB710_SLOT_SM)
                ++n;

        chip = devm_kzalloc(&pdev->dev, struct_size(chip, slot, n),
                            GFP_KERNEL);
        if (!chip)
                return -ENOMEM;

        err = pcim_enable_device(pdev);
        if (err)
                return err;

        spin_lock_init(&chip->irq_lock);
        chip->pdev = pdev;
        chip->iobase = pcim_iomap_region(pdev, 0, KBUILD_MODNAME);
        if (IS_ERR(chip->iobase))
                return PTR_ERR(chip->iobase);

        pci_set_drvdata(pdev, chip);

        err = devm_request_irq(&pdev->dev, pdev->irq,
                cb710_irq_handler, IRQF_SHARED, KBUILD_MODNAME, chip);
        if (err)
                return err;

        err = ida_alloc(&cb710_ida, GFP_KERNEL);
        if (err < 0)
                return err;
        chip->platform_id = err;

        dev_info(&pdev->dev, "id %d, IO 0x%p, IRQ %d\n",
                chip->platform_id, chip->iobase, pdev->irq);

        if (val & CB710_SLOT_MMC) {     /* MMC/SD slot */
                err = cb710_register_slot(chip,
                        CB710_SLOT_MMC, 0x00, "cb710-mmc");
                if (err)
                        return err;
        }

        if (val & CB710_SLOT_MS) {      /* MemoryStick slot */
                err = cb710_register_slot(chip,
                        CB710_SLOT_MS, 0x40, "cb710-ms");
                if (err)
                        goto unreg_mmc;
        }

        if (val & CB710_SLOT_SM) {      /* SmartMedia slot */
                err = cb710_register_slot(chip,
                        CB710_SLOT_SM, 0x60, "cb710-sm");
                if (err)
                        goto unreg_ms;
        }

        return 0;
unreg_ms:
        cb710_unregister_slot(chip, CB710_SLOT_MS);
unreg_mmc:
        cb710_unregister_slot(chip, CB710_SLOT_MMC);

#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
        BUG_ON(atomic_read(&chip->slot_refs_count) != 0);
#endif
        return err;
}

static void cb710_remove_one(struct pci_dev *pdev)
{
        struct cb710_chip *chip = pci_get_drvdata(pdev);

        cb710_unregister_slot(chip, CB710_SLOT_SM);
        cb710_unregister_slot(chip, CB710_SLOT_MS);
        cb710_unregister_slot(chip, CB710_SLOT_MMC);
#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
        BUG_ON(atomic_read(&chip->slot_refs_count) != 0);
#endif

        ida_free(&cb710_ida, chip->platform_id);
}

static const struct pci_device_id cb710_pci_tbl[] = {
        { PCI_VENDOR_ID_ENE, PCI_DEVICE_ID_ENE_CB710_FLASH,
                PCI_ANY_ID, PCI_ANY_ID, },
        { 0, }
};

static SIMPLE_DEV_PM_OPS(cb710_pm_ops, cb710_suspend, cb710_resume);

static struct pci_driver cb710_driver = {
        .name = KBUILD_MODNAME,
        .id_table = cb710_pci_tbl,
        .probe = cb710_probe,
        .remove = cb710_remove_one,
        .driver.pm = &cb710_pm_ops,
};

static int __init cb710_init_module(void)
{
        return pci_register_driver(&cb710_driver);
}

static void __exit cb710_cleanup_module(void)
{
        pci_unregister_driver(&cb710_driver);
        ida_destroy(&cb710_ida);
}

module_init(cb710_init_module);
module_exit(cb710_cleanup_module);

MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
MODULE_DESCRIPTION("ENE CB710 memory card reader driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, cb710_pci_tbl);