/*
 * Freescale iMX PATA driver
 *
 * Copyright (C) 2011 Arnaud Patard <arnaud.patard@rtp-net.org>
 *
 * Based on pata_platform - Copyright (C) 2006 - 2007  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * TODO:
 * - dmaengine support
 */

#include <linux/ata.h>
#include <linux/clk.h>
#include <linux/libata.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>

#define DRV_NAME "pata_imx"

#define PATA_IMX_ATA_TIME_OFF           0x00
#define PATA_IMX_ATA_TIME_ON            0x01
#define PATA_IMX_ATA_TIME_1             0x02
#define PATA_IMX_ATA_TIME_2W            0x03
#define PATA_IMX_ATA_TIME_2R            0x04
#define PATA_IMX_ATA_TIME_AX            0x05
#define PATA_IMX_ATA_TIME_PIO_RDX       0x06
#define PATA_IMX_ATA_TIME_4             0x07
#define PATA_IMX_ATA_TIME_9             0x08

#define PATA_IMX_ATA_CONTROL            0x24
#define PATA_IMX_ATA_CTRL_FIFO_RST_B    (1<<7)
#define PATA_IMX_ATA_CTRL_ATA_RST_B     (1<<6)
#define PATA_IMX_ATA_CTRL_IORDY_EN      (1<<0)
#define PATA_IMX_ATA_INT_EN             0x2C
#define PATA_IMX_ATA_INTR_ATA_INTRQ2    (1<<3)
#define PATA_IMX_DRIVE_DATA             0xA0
#define PATA_IMX_DRIVE_CONTROL          0xD8

static u32 pio_t4[] = { 30,  20,  15,  10,  10 };
static u32 pio_t9[] = { 20,  15,  10,  10,  10 };
static u32 pio_tA[] = { 35,  35,  35,  35,  35 };

struct pata_imx_priv {
        struct clk *clk;
        /* timings/interrupt/control regs */
        void __iomem *host_regs;
        u32 ata_ctl;
};

static void pata_imx_set_timing(struct ata_device *adev,
                                struct pata_imx_priv *priv)
{
        struct ata_timing timing;
        unsigned long clkrate;
        u32 T, mode;

        clkrate = clk_get_rate(priv->clk);

        if (adev->pio_mode < XFER_PIO_0 || adev->pio_mode > XFER_PIO_4 ||
            !clkrate)
                return;

        T = 1000000000 / clkrate;
        ata_timing_compute(adev, adev->pio_mode, &timing, T * 1000, 0);

        mode = adev->pio_mode - XFER_PIO_0;

        writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_OFF);
        writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_ON);
        writeb(timing.setup, priv->host_regs + PATA_IMX_ATA_TIME_1);
        writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2W);
        writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2R);
        writeb(1, priv->host_regs + PATA_IMX_ATA_TIME_PIO_RDX);

        writeb(pio_t4[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_4);
        writeb(pio_t9[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_9);
        writeb(pio_tA[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_AX);
}

static void pata_imx_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        struct pata_imx_priv *priv = ap->host->private_data;
        u32 val;

        pata_imx_set_timing(adev, priv);

        val = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
        if (ata_pio_need_iordy(adev))
                val |= PATA_IMX_ATA_CTRL_IORDY_EN;
        else
                val &= ~PATA_IMX_ATA_CTRL_IORDY_EN;
        __raw_writel(val, priv->host_regs + PATA_IMX_ATA_CONTROL);
}

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

static struct ata_port_operations pata_imx_port_ops = {
        .inherits               = &ata_sff_port_ops,
        .sff_data_xfer          = ata_sff_data_xfer32,
        .cable_detect           = ata_cable_unknown,
        .set_piomode            = pata_imx_set_piomode,
};

static void pata_imx_setup_port(struct ata_ioports *ioaddr)
{
        /* Fixup the port shift for platforms that need it */
        ioaddr->data_addr       = ioaddr->cmd_addr + (ATA_REG_DATA    << 2);
        ioaddr->error_addr      = ioaddr->cmd_addr + (ATA_REG_ERR     << 2);
        ioaddr->feature_addr    = ioaddr->cmd_addr + (ATA_REG_FEATURE << 2);
        ioaddr->nsect_addr      = ioaddr->cmd_addr + (ATA_REG_NSECT   << 2);
        ioaddr->lbal_addr       = ioaddr->cmd_addr + (ATA_REG_LBAL    << 2);
        ioaddr->lbam_addr       = ioaddr->cmd_addr + (ATA_REG_LBAM    << 2);
        ioaddr->lbah_addr       = ioaddr->cmd_addr + (ATA_REG_LBAH    << 2);
        ioaddr->device_addr     = ioaddr->cmd_addr + (ATA_REG_DEVICE  << 2);
        ioaddr->status_addr     = ioaddr->cmd_addr + (ATA_REG_STATUS  << 2);
        ioaddr->command_addr    = ioaddr->cmd_addr + (ATA_REG_CMD     << 2);
}

static int pata_imx_probe(struct platform_device *pdev)
{
        struct ata_host *host;
        struct ata_port *ap;
        struct pata_imx_priv *priv;
        int irq = 0;
        struct resource *io_res;
        int ret;

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

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

        priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
        if (IS_ERR(priv->clk)) {
                dev_err(&pdev->dev, "Failed to get and enable clock\n");
                return PTR_ERR(priv->clk);
        }

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

        host->private_data = priv;
        ap = host->ports[0];

        ap->ops = &pata_imx_port_ops;
        ap->pio_mask = ATA_PIO4;
        ap->flags |= ATA_FLAG_SLAVE_POSS;

        priv->host_regs = devm_platform_get_and_ioremap_resource(pdev, 0, &io_res);
        if (IS_ERR(priv->host_regs))
                return PTR_ERR(priv->host_regs);

        ap->ioaddr.cmd_addr = priv->host_regs + PATA_IMX_DRIVE_DATA;
        ap->ioaddr.ctl_addr = priv->host_regs + PATA_IMX_DRIVE_CONTROL;

        ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;

        pata_imx_setup_port(&ap->ioaddr);

        ata_port_desc(ap, "cmd 0x%llx ctl 0x%llx",
                (unsigned long long)io_res->start + PATA_IMX_DRIVE_DATA,
                (unsigned long long)io_res->start + PATA_IMX_DRIVE_CONTROL);

        /* deassert resets */
        __raw_writel(PATA_IMX_ATA_CTRL_FIFO_RST_B |
                        PATA_IMX_ATA_CTRL_ATA_RST_B,
                        priv->host_regs + PATA_IMX_ATA_CONTROL);
        /* enable interrupts */
        __raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
                        priv->host_regs + PATA_IMX_ATA_INT_EN);

        /* activate */
        ret = ata_host_activate(host, irq, ata_sff_interrupt, 0,
                                &pata_imx_sht);

        if (ret)
                return ret;

        return 0;
}

static void pata_imx_remove(struct platform_device *pdev)
{
        struct ata_host *host = platform_get_drvdata(pdev);
        struct pata_imx_priv *priv = host->private_data;

        ata_host_detach(host);

        __raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
}

#ifdef CONFIG_PM_SLEEP
static int pata_imx_suspend(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct pata_imx_priv *priv = host->private_data;

        ata_host_suspend(host, PMSG_SUSPEND);

        __raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
        priv->ata_ctl = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
        clk_disable_unprepare(priv->clk);

        return 0;
}

static int pata_imx_resume(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct pata_imx_priv *priv = host->private_data;

        int ret = clk_prepare_enable(priv->clk);
        if (ret)
                return ret;

        __raw_writel(priv->ata_ctl, priv->host_regs + PATA_IMX_ATA_CONTROL);

        __raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
                        priv->host_regs + PATA_IMX_ATA_INT_EN);

        ata_host_resume(host);

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(pata_imx_pm_ops, pata_imx_suspend, pata_imx_resume);

static const struct of_device_id imx_pata_dt_ids[] = {
        {
                .compatible = "fsl,imx27-pata",
        }, {
                /* sentinel */
        }
};
MODULE_DEVICE_TABLE(of, imx_pata_dt_ids);

static struct platform_driver pata_imx_driver = {
        .probe          = pata_imx_probe,
        .remove         = pata_imx_remove,
        .driver = {
                .name           = DRV_NAME,
                .of_match_table = imx_pata_dt_ids,
                .pm             = &pata_imx_pm_ops,
        },
};

module_platform_driver(pata_imx_driver);

MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>");
MODULE_DESCRIPTION("low-level driver for iMX PATA");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);