// SPDX-License-Identifier: GPL-2.0-only
/*
 *  A low-level PATA driver to handle a Compact Flash connected on the
 *  Mikrotik's RouterBoard 532 board.
 *
 *  Copyright (C) 2007 Gabor Juhos <juhosg at openwrt.org>
 *  Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
 *
 *  This file was based on: drivers/ata/pata_ixp4xx_cf.c
 *      Copyright (C) 2006-07 Tower Technologies
 *      Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 *  Also was based on the driver for Linux 2.4.xx published by Mikrotik for
 *  their RouterBoard 1xx and 5xx series devices. The original Mikrotik code
 *  seems not to have a license.
 */

#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio/consumer.h>

#include <linux/libata.h>
#include <scsi/scsi_host.h>

#include <asm/mach-rc32434/rb.h>

#define DRV_NAME        "pata-rb532-cf"
#define DRV_VERSION     "0.1.0"
#define DRV_DESC        "PATA driver for RouterBOARD 532 Compact Flash"

#define RB500_CF_MAXPORTS       1
#define RB500_CF_IO_DELAY       400

#define RB500_CF_REG_BASE       0x0800
#define RB500_CF_REG_ERR        0x080D
#define RB500_CF_REG_CTRL       0x080E
/* 32bit buffered data register offset */
#define RB500_CF_REG_DBUF32     0x0C00

struct rb532_cf_info {
        void __iomem    *iobase;
        struct gpio_desc *gpio_line;
        unsigned int    irq;
};

/* ------------------------------------------------------------------------ */

static irqreturn_t rb532_pata_irq_handler(int irq, void *dev_instance)
{
        struct ata_host *ah = dev_instance;
        struct rb532_cf_info *info = ah->private_data;

        if (gpiod_get_value(info->gpio_line)) {
                irq_set_irq_type(info->irq, IRQ_TYPE_LEVEL_LOW);
                ata_sff_interrupt(info->irq, dev_instance);
        } else {
                irq_set_irq_type(info->irq, IRQ_TYPE_LEVEL_HIGH);
        }

        return IRQ_HANDLED;
}

static struct ata_port_operations rb532_pata_port_ops = {
        .inherits               = &ata_sff_port_ops,
        .sff_data_xfer          = ata_sff_data_xfer32,
};

/* ------------------------------------------------------------------------ */

static const struct scsi_host_template rb532_pata_sht = {
        ATA_PIO_SHT(DRV_NAME),
};

/* ------------------------------------------------------------------------ */

static void rb532_pata_setup_ports(struct ata_host *ah)
{
        struct rb532_cf_info *info = ah->private_data;
        struct ata_port *ap;

        ap = ah->ports[0];

        ap->ops         = &rb532_pata_port_ops;
        ap->pio_mask    = ATA_PIO4;

        ap->ioaddr.cmd_addr     = info->iobase + RB500_CF_REG_BASE;
        ap->ioaddr.ctl_addr     = info->iobase + RB500_CF_REG_CTRL;
        ap->ioaddr.altstatus_addr = info->iobase + RB500_CF_REG_CTRL;

        ata_sff_std_ports(&ap->ioaddr);

        ap->ioaddr.data_addr    = info->iobase + RB500_CF_REG_DBUF32;
        ap->ioaddr.error_addr   = info->iobase + RB500_CF_REG_ERR;
}

static int rb532_pata_driver_probe(struct platform_device *pdev)
{
        int irq;
        struct gpio_desc *gpiod;
        struct resource *res;
        struct ata_host *ah;
        struct rb532_cf_info *info;
        int ret;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&pdev->dev, "no IOMEM resource found\n");
                return -EINVAL;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;
        if (!irq)
                return -EINVAL;

        gpiod = devm_gpiod_get(&pdev->dev, NULL, GPIOD_IN);
        if (IS_ERR(gpiod)) {
                dev_err(&pdev->dev, "no GPIO found for irq%d\n", irq);
                return PTR_ERR(gpiod);
        }
        gpiod_set_consumer_name(gpiod, DRV_NAME);

        /* allocate host */
        ah = ata_host_alloc(&pdev->dev, RB500_CF_MAXPORTS);
        if (!ah)
                return -ENOMEM;

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

        ah->private_data = info;
        info->gpio_line = gpiod;
        info->irq = irq;

        info->iobase = devm_ioremap(&pdev->dev, res->start,
                                resource_size(res));
        if (!info->iobase)
                return -ENOMEM;

        rb532_pata_setup_ports(ah);

        ret = ata_host_activate(ah, irq, rb532_pata_irq_handler,
                                IRQF_TRIGGER_LOW, &rb532_pata_sht);
        if (ret)
                return ret;

        return 0;
}

static void rb532_pata_driver_remove(struct platform_device *pdev)
{
        struct ata_host *ah = platform_get_drvdata(pdev);

        ata_host_detach(ah);
}

static struct platform_driver rb532_pata_platform_driver = {
        .probe          = rb532_pata_driver_probe,
        .remove         = rb532_pata_driver_remove,
        .driver  = {
                .name   = DRV_NAME,
        },
};

#define DRV_INFO DRV_DESC " version " DRV_VERSION

module_platform_driver(rb532_pata_platform_driver);

MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION(DRV_DESC);
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);