/*
 * ixp4xx PATA/Compact Flash driver
 * Copyright (C) 2006-07 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * An ATA driver to handle a Compact Flash connected
 * to the ixp4xx expansion bus in TrueIDE mode. The CF
 * must have it chip selects connected to two CS lines
 * on the ixp4xx. In the irq is not available, you might
 * want to modify both this driver and libata to run in
 * polling mode.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/libata.h>
#include <linux/irq.h>
#include <linux/platform_device.h>
#include <scsi/scsi_host.h>

#define DRV_NAME        "pata_ixp4xx_cf"
#define DRV_VERSION     "0.2"

static int ixp4xx_set_mode(struct ata_link *link, struct ata_device **error)
{
        struct ata_device *dev;

        ata_for_each_dev(dev, link, ENABLED) {
                ata_dev_info(dev, "configured for PIO0\n");
                dev->pio_mode = XFER_PIO_0;
                dev->xfer_mode = XFER_PIO_0;
                dev->xfer_shift = ATA_SHIFT_PIO;
                dev->flags |= ATA_DFLAG_PIO;
        }
        return 0;
}

static unsigned int ixp4xx_mmio_data_xfer(struct ata_device *dev,
                                unsigned char *buf, unsigned int buflen, int rw)
{
        unsigned int i;
        unsigned int words = buflen >> 1;
        u16 *buf16 = (u16 *) buf;
        struct ata_port *ap = dev->link->ap;
        void __iomem *mmio = ap->ioaddr.data_addr;
        struct ixp4xx_pata_data *data = dev_get_platdata(ap->host->dev);

        /* set the expansion bus in 16bit mode and restore
         * 8 bit mode after the transaction.
         */
        *data->cs0_cfg &= ~(0x01);
        udelay(100);

        /* Transfer multiple of 2 bytes */
        if (rw == READ)
                for (i = 0; i < words; i++)
                        buf16[i] = readw(mmio);
        else
                for (i = 0; i < words; i++)
                        writew(buf16[i], mmio);

        /* Transfer trailing 1 byte, if any. */
        if (unlikely(buflen & 0x01)) {
                u16 align_buf[1] = { 0 };
                unsigned char *trailing_buf = buf + buflen - 1;

                if (rw == READ) {
                        align_buf[0] = readw(mmio);
                        memcpy(trailing_buf, align_buf, 1);
                } else {
                        memcpy(align_buf, trailing_buf, 1);
                        writew(align_buf[0], mmio);
                }
                words++;
        }

        udelay(100);
        *data->cs0_cfg |= 0x01;

        return words << 1;
}

static struct scsi_host_template ixp4xx_sht = {
        ATA_PIO_SHT(DRV_NAME),
};

static struct ata_port_operations ixp4xx_port_ops = {
        .inherits               = &ata_sff_port_ops,
        .sff_data_xfer          = ixp4xx_mmio_data_xfer,
        .cable_detect           = ata_cable_40wire,
        .set_mode               = ixp4xx_set_mode,
};

static void ixp4xx_setup_port(struct ata_port *ap,
                              struct ixp4xx_pata_data *data,
                              unsigned long raw_cs0, unsigned long raw_cs1)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        unsigned long raw_cmd = raw_cs0;
        unsigned long raw_ctl = raw_cs1 + 0x06;

        ioaddr->cmd_addr        = data->cs0;
        ioaddr->altstatus_addr  = data->cs1 + 0x06;
        ioaddr->ctl_addr        = data->cs1 + 0x06;

        ata_sff_std_ports(ioaddr);

#ifndef __ARMEB__

        /* adjust the addresses to handle the address swizzling of the
         * ixp4xx in little endian mode.
         */

        *(unsigned long *)&ioaddr->data_addr            ^= 0x02;
        *(unsigned long *)&ioaddr->cmd_addr             ^= 0x03;
        *(unsigned long *)&ioaddr->altstatus_addr       ^= 0x03;
        *(unsigned long *)&ioaddr->ctl_addr             ^= 0x03;
        *(unsigned long *)&ioaddr->error_addr           ^= 0x03;
        *(unsigned long *)&ioaddr->feature_addr         ^= 0x03;
        *(unsigned long *)&ioaddr->nsect_addr           ^= 0x03;
        *(unsigned long *)&ioaddr->lbal_addr            ^= 0x03;
        *(unsigned long *)&ioaddr->lbam_addr            ^= 0x03;
        *(unsigned long *)&ioaddr->lbah_addr            ^= 0x03;
        *(unsigned long *)&ioaddr->device_addr          ^= 0x03;
        *(unsigned long *)&ioaddr->status_addr          ^= 0x03;
        *(unsigned long *)&ioaddr->command_addr         ^= 0x03;

        raw_cmd ^= 0x03;
        raw_ctl ^= 0x03;
#endif

        ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", raw_cmd, raw_ctl);
}

static int ixp4xx_pata_probe(struct platform_device *pdev)
{
        unsigned int irq;
        struct resource *cs0, *cs1;
        struct ata_host *host;
        struct ata_port *ap;
        struct ixp4xx_pata_data *data = dev_get_platdata(&pdev->dev);
        int ret;

        cs0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        cs1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);

        if (!cs0 || !cs1)
                return -EINVAL;

        /* allocate host */
        host = ata_host_alloc(&pdev->dev, 1);
        if (!host)
                return -ENOMEM;

        /* acquire resources and fill host */
        ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        data->cs0 = devm_ioremap(&pdev->dev, cs0->start, 0x1000);
        data->cs1 = devm_ioremap(&pdev->dev, cs1->start, 0x1000);

        if (!data->cs0 || !data->cs1)
                return -ENOMEM;

        irq = platform_get_irq(pdev, 0);
        if (irq)
                irq_set_irq_type(irq, IRQ_TYPE_EDGE_RISING);

        /* Setup expansion bus chip selects */
        *data->cs0_cfg = data->cs0_bits;
        *data->cs1_cfg = data->cs1_bits;

        ap = host->ports[0];

        ap->ops = &ixp4xx_port_ops;
        ap->pio_mask = ATA_PIO4;
        ap->flags |= ATA_FLAG_NO_ATAPI;

        ixp4xx_setup_port(ap, data, cs0->start, cs1->start);

        ata_print_version_once(&pdev->dev, DRV_VERSION);

        /* activate host */
        return ata_host_activate(host, irq, ata_sff_interrupt, 0, &ixp4xx_sht);
}

static struct platform_driver ixp4xx_pata_platform_driver = {
        .driver  = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
        .probe          = ixp4xx_pata_probe,
        .remove         = ata_platform_remove_one,
};

module_platform_driver(ixp4xx_pata_platform_driver);

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("low-level driver for ixp4xx Compact Flash PATA");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:" DRV_NAME);