// SPDX-License-Identifier: GPL-2.0-only
/*
 * uio_aec.c -- simple driver for Adrienne Electronics Corp time code PCI device
 *
 * Copyright (C) 2008 Brandon Philips <brandon@ifup.org>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/uio_driver.h>
#include <linux/slab.h>

#define PCI_VENDOR_ID_AEC 0xaecb
#define PCI_DEVICE_ID_AEC_VITCLTC 0x6250

#define INT_ENABLE_ADDR         0xFC
#define INT_ENABLE              0x10
#define INT_DISABLE             0x0

#define INT_MASK_ADDR           0x2E
#define INT_MASK_ALL            0x3F

#define INTA_DRVR_ADDR          0xFE
#define INTA_ENABLED_FLAG       0x08
#define INTA_FLAG               0x01

#define MAILBOX                 0x0F

static const struct pci_device_id ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_AEC, PCI_DEVICE_ID_AEC_VITCLTC), },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, ids);

static irqreturn_t aectc_irq(int irq, struct uio_info *dev_info)
{
        void __iomem *int_flag = dev_info->priv + INTA_DRVR_ADDR;
        unsigned char status = ioread8(int_flag);


        if ((status & INTA_ENABLED_FLAG) && (status & INTA_FLAG)) {
                /* application writes 0x00 to 0x2F to get next interrupt */
                status = ioread8(dev_info->priv + MAILBOX);
                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

static void print_board_data(struct pci_dev *pdev, struct uio_info *i)
{
        dev_info(&pdev->dev, "PCI-TC board vendor: %x%x number: %x%x"
                " revision: %c%c\n",
                ioread8(i->priv + 0x01),
                ioread8(i->priv + 0x00),
                ioread8(i->priv + 0x03),
                ioread8(i->priv + 0x02),
                ioread8(i->priv + 0x06),
                ioread8(i->priv + 0x07));
}

static int probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct uio_info *info;
        int ret;

        info = devm_kzalloc(&pdev->dev, sizeof(struct uio_info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        if (pci_enable_device(pdev))
                return -ENODEV;

        if (pci_request_regions(pdev, "aectc"))
                goto out_disable;

        info->name = "aectc";
        info->port[0].start = pci_resource_start(pdev, 0);
        if (!info->port[0].start)
                goto out_release;
        info->priv = pci_iomap(pdev, 0, 0);
        if (!info->priv)
                goto out_release;
        info->port[0].size = pci_resource_len(pdev, 0);
        info->port[0].porttype = UIO_PORT_GPIO;

        info->version = "0.0.1";
        info->irq = pdev->irq;
        info->irq_flags = IRQF_SHARED;
        info->handler = aectc_irq;

        print_board_data(pdev, info);
        ret = uio_register_device(&pdev->dev, info);
        if (ret)
                goto out_unmap;

        iowrite32(INT_ENABLE, info->priv + INT_ENABLE_ADDR);
        iowrite8(INT_MASK_ALL, info->priv + INT_MASK_ADDR);
        if (!(ioread8(info->priv + INTA_DRVR_ADDR)
                        & INTA_ENABLED_FLAG))
                dev_err(&pdev->dev, "aectc: interrupts not enabled\n");

        pci_set_drvdata(pdev, info);

        return 0;

out_unmap:
        pci_iounmap(pdev, info->priv);
out_release:
        pci_release_regions(pdev);
out_disable:
        pci_disable_device(pdev);
        return -ENODEV;
}

static void remove(struct pci_dev *pdev)
{
        struct uio_info *info = pci_get_drvdata(pdev);

        /* disable interrupts */
        iowrite8(INT_DISABLE, info->priv + INT_MASK_ADDR);
        iowrite32(INT_DISABLE, info->priv + INT_ENABLE_ADDR);
        /* read mailbox to ensure board drops irq */
        ioread8(info->priv + MAILBOX);

        uio_unregister_device(info);
        pci_release_regions(pdev);
        pci_disable_device(pdev);
        pci_iounmap(pdev, info->priv);
}

static struct pci_driver pci_driver = {
        .name = "aectc",
        .id_table = ids,
        .probe = probe,
        .remove = remove,
};

module_pci_driver(pci_driver);
MODULE_DESCRIPTION("Adrienne Electronics Corp time code PCI device");
MODULE_LICENSE("GPL");