/*
 * AVR32 SMC/CFC PATA Driver
 *
 * Copyright (C) 2007 Atmel Norway
 *
 * 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.
 */

#define DEBUG

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <scsi/scsi_host.h>
#include <linux/ata.h>
#include <linux/libata.h>
#include <linux/err.h>
#include <linux/io.h>

#include <mach/board.h>
#include <mach/smc.h>

#define DRV_NAME "pata_at32"
#define DRV_VERSION "0.0.3"

/*
 * CompactFlash controller memory layout relative to the base address:
 *
 *      Attribute memory:  0000 0000 -> 003f ffff
 *      Common memory:     0040 0000 -> 007f ffff
 *      I/O memory:        0080 0000 -> 00bf ffff
 *      True IDE Mode:     00c0 0000 -> 00df ffff
 *      Alt IDE Mode:      00e0 0000 -> 00ff ffff
 *
 * Only True IDE and Alt True IDE mode are needed for this driver.
 *
 *      True IDE mode     => CS0 = 0, CS1 = 1 (cmd, error, stat, etc)
 *      Alt True IDE mode => CS0 = 1, CS1 = 0 (ctl, alt_stat)
 */
#define CF_IDE_OFFSET     0x00c00000
#define CF_ALT_IDE_OFFSET 0x00e00000
#define CF_RES_SIZE       2048

/*
 * Define DEBUG_BUS if you are doing debugging of your own EBI -> PATA
 * adaptor with a logic analyzer or similar.
 */
#undef DEBUG_BUS

/*
 * ATA PIO modes
 *
 *      Name    | Mb/s  | Min cycle time | Mask
 *      --------+-------+----------------+--------
 *      Mode 0  | 3.3   | 600 ns         | 0x01
 *      Mode 1  | 5.2   | 383 ns         | 0x03
 *      Mode 2  | 8.3   | 240 ns         | 0x07
 *      Mode 3  | 11.1  | 180 ns         | 0x0f
 *      Mode 4  | 16.7  | 120 ns         | 0x1f
 *
 * Alter PIO_MASK below according to table to set maximal PIO mode.
 */
enum {
  PIO_MASK = ATA_PIO4,
};

/*
 * Struct containing private information about device.
 */
struct at32_ide_info {
        unsigned int            irq;
        struct resource         res_ide;
        struct resource         res_alt;
        void __iomem            *ide_addr;
        void __iomem            *alt_addr;
        unsigned int            cs;
        struct smc_config       smc;
};

/*
 * Setup SMC for the given ATA timing.
 */
static int pata_at32_setup_timing(struct device *dev,
                                  struct at32_ide_info *info,
                                  const struct ata_timing *ata)
{
        struct smc_config *smc = &info->smc;
        struct smc_timing timing;

        int active;
        int recover;

        memset(&timing, 0, sizeof(struct smc_timing));

        /* Total cycle time */
        timing.read_cycle  = ata->cyc8b;

        /* DIOR <= CFIOR timings */
        timing.nrd_setup   = ata->setup;
        timing.nrd_pulse   = ata->act8b;
        timing.nrd_recover = ata->rec8b;

        /* Convert nanosecond timing to clock cycles */
        smc_set_timing(smc, &timing);

        /* Add one extra cycle setup due to signal ring */
        smc->nrd_setup = smc->nrd_setup + 1;

        active  = smc->nrd_setup + smc->nrd_pulse;
        recover = smc->read_cycle - active;

        /* Need at least two cycles recovery */
        if (recover < 2)
          smc->read_cycle = active + 2;

        /* (CS0, CS1, DIR, OE) <= (CFCE1, CFCE2, CFRNW, NCSX) timings */
        smc->ncs_read_setup = 1;
        smc->ncs_read_pulse = smc->read_cycle - 2;

        /* Write timings same as read timings */
        smc->write_cycle = smc->read_cycle;
        smc->nwe_setup = smc->nrd_setup;
        smc->nwe_pulse = smc->nrd_pulse;
        smc->ncs_write_setup = smc->ncs_read_setup;
        smc->ncs_write_pulse = smc->ncs_read_pulse;

        /* Do some debugging output of ATA and SMC timings */
        dev_dbg(dev, "ATA: C=%d S=%d P=%d R=%d\n",
                ata->cyc8b, ata->setup, ata->act8b, ata->rec8b);

        dev_dbg(dev, "SMC: C=%d S=%d P=%d NS=%d NP=%d\n",
                smc->read_cycle, smc->nrd_setup, smc->nrd_pulse,
                smc->ncs_read_setup, smc->ncs_read_pulse);

        /* Finally, configure the SMC */
        return smc_set_configuration(info->cs, smc);
}

/*
 * Procedures for libATA.
 */
static void pata_at32_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        struct ata_timing timing;
        struct at32_ide_info *info = ap->host->private_data;

        int ret;

        /* Compute ATA timing */
        ret = ata_timing_compute(adev, adev->pio_mode, &timing, 1000, 0);
        if (ret) {
                dev_warn(ap->dev, "Failed to compute ATA timing %d\n", ret);
                return;
        }

        /* Setup SMC to ATA timing */
        ret = pata_at32_setup_timing(ap->dev, info, &timing);
        if (ret) {
                dev_warn(ap->dev, "Failed to setup ATA timing %d\n", ret);
                return;
        }
}

static struct scsi_host_template at32_sht = {
        ATA_PIO_SHT(DRV_NAME),
};

static struct ata_port_operations at32_port_ops = {
        .inherits               = &ata_sff_port_ops,
        .cable_detect           = ata_cable_40wire,
        .set_piomode            = pata_at32_set_piomode,
};

static int __init pata_at32_init_one(struct device *dev,
                                     struct at32_ide_info *info)
{
        struct ata_host *host;
        struct ata_port *ap;

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

        ap = host->ports[0];

        /* Setup ATA bindings */
        ap->ops      = &at32_port_ops;
        ap->pio_mask = PIO_MASK;
        ap->flags   |= ATA_FLAG_SLAVE_POSS;

        /*
         * Since all 8-bit taskfile transfers has to go on the lower
         * byte of the data bus and there is a bug in the SMC that
         * makes it impossible to alter the bus width during runtime,
         * we need to hardwire the address signals as follows:
         *
         *      A_IDE(2:0) <= A_EBI(3:1)
         *
         * This makes all addresses on the EBI even, thus all data
         * will be on the lower byte of the data bus.  All addresses
         * used by libATA need to be altered according to this.
         */
        ap->ioaddr.altstatus_addr = info->alt_addr + (0x06 << 1);
        ap->ioaddr.ctl_addr       = info->alt_addr + (0x06 << 1);

        ap->ioaddr.data_addr      = info->ide_addr + (ATA_REG_DATA << 1);
        ap->ioaddr.error_addr     = info->ide_addr + (ATA_REG_ERR << 1);
        ap->ioaddr.feature_addr   = info->ide_addr + (ATA_REG_FEATURE << 1);
        ap->ioaddr.nsect_addr     = info->ide_addr + (ATA_REG_NSECT << 1);
        ap->ioaddr.lbal_addr      = info->ide_addr + (ATA_REG_LBAL << 1);
        ap->ioaddr.lbam_addr      = info->ide_addr + (ATA_REG_LBAM << 1);
        ap->ioaddr.lbah_addr      = info->ide_addr + (ATA_REG_LBAH << 1);
        ap->ioaddr.device_addr    = info->ide_addr + (ATA_REG_DEVICE << 1);
        ap->ioaddr.status_addr    = info->ide_addr + (ATA_REG_STATUS << 1);
        ap->ioaddr.command_addr   = info->ide_addr + (ATA_REG_CMD << 1);

        /* Set info as private data of ATA host */
        host->private_data = info;

        /* Register ATA device and return */
        return ata_host_activate(host, info->irq, ata_sff_interrupt,
                                 IRQF_SHARED | IRQF_TRIGGER_RISING,
                                 &at32_sht);
}

/*
 * This function may come in handy for people analyzing their own
 * EBI -> PATA adaptors.
 */
#ifdef DEBUG_BUS

static void __init pata_at32_debug_bus(struct device *dev,
                                       struct at32_ide_info *info)
{
        const int d1 = 0xff;
        const int d2 = 0x00;

        int i;

        /* Write 8-bit values (registers) */
        iowrite8(d1, info->alt_addr + (0x06 << 1));
        iowrite8(d2, info->alt_addr + (0x06 << 1));

        for (i = 0; i < 8; i++) {
                iowrite8(d1, info->ide_addr + (i << 1));
                iowrite8(d2, info->ide_addr + (i << 1));
        }

        /* Write 16 bit values (data) */
        iowrite16(d1,      info->ide_addr);
        iowrite16(d1 << 8, info->ide_addr);

        iowrite16(d1,      info->ide_addr);
        iowrite16(d1 << 8, info->ide_addr);
}

#endif

static int __init pata_at32_probe(struct platform_device *pdev)
{
        const struct ata_timing initial_timing =
                {XFER_PIO_0, 70, 290, 240, 600, 165, 150, 600, 0};

        struct device            *dev = &pdev->dev;
        struct at32_ide_info     *info;
        struct ide_platform_data *board = pdev->dev.platform_data;
        struct resource          *res;

        int irq;
        int ret;

        if (!board)
                return -ENXIO;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENXIO;

        /* Retrive IRQ */
        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        /* Setup struct containing private information */
        info = kzalloc(sizeof(struct at32_ide_info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->irq = irq;
        info->cs  = board->cs;

        /* Request memory resources */
        info->res_ide.start = res->start + CF_IDE_OFFSET;
        info->res_ide.end   = info->res_ide.start + CF_RES_SIZE - 1;
        info->res_ide.name  = "ide";
        info->res_ide.flags = IORESOURCE_MEM;

        ret = request_resource(res, &info->res_ide);
        if (ret)
                goto err_req_res_ide;

        info->res_alt.start = res->start + CF_ALT_IDE_OFFSET;
        info->res_alt.end   = info->res_alt.start + CF_RES_SIZE - 1;
        info->res_alt.name  = "alt";
        info->res_alt.flags = IORESOURCE_MEM;

        ret = request_resource(res, &info->res_alt);
        if (ret)
                goto err_req_res_alt;

        /* Setup non-timing elements of SMC */
        info->smc.bus_width      = 2; /* 16 bit data bus */
        info->smc.nrd_controlled = 1; /* Sample data on rising edge of NRD */
        info->smc.nwe_controlled = 0; /* Drive data on falling edge of NCS */
        info->smc.nwait_mode     = 3; /* NWAIT is in READY mode */
        info->smc.byte_write     = 0; /* Byte select access type */
        info->smc.tdf_mode       = 0; /* TDF optimization disabled */
        info->smc.tdf_cycles     = 0; /* No TDF wait cycles */

        /* Setup SMC to ATA timing */
        ret = pata_at32_setup_timing(dev, info, &initial_timing);
        if (ret)
                goto err_setup_timing;

        /* Map ATA address space */
        ret = -ENOMEM;
        info->ide_addr = devm_ioremap(dev, info->res_ide.start, 16);
        info->alt_addr = devm_ioremap(dev, info->res_alt.start, 16);
        if (!info->ide_addr || !info->alt_addr)
                goto err_ioremap;

#ifdef DEBUG_BUS
        pata_at32_debug_bus(dev, info);
#endif

        /* Setup and register ATA device */
        ret = pata_at32_init_one(dev, info);
        if (ret)
                goto err_ata_device;

        return 0;

 err_ata_device:
 err_ioremap:
 err_setup_timing:
        release_resource(&info->res_alt);
 err_req_res_alt:
        release_resource(&info->res_ide);
 err_req_res_ide:
        kfree(info);

        return ret;
}

static int __exit pata_at32_remove(struct platform_device *pdev)
{
        struct ata_host *host = platform_get_drvdata(pdev);
        struct at32_ide_info *info;

        if (!host)
                return 0;

        info = host->private_data;
        ata_host_detach(host);

        if (!info)
                return 0;

        release_resource(&info->res_ide);
        release_resource(&info->res_alt);

        kfree(info);

        return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:at32_ide");

static struct platform_driver pata_at32_driver = {
        .remove        = __exit_p(pata_at32_remove),
        .driver        = {
                .name  = "at32_ide",
                .owner = THIS_MODULE,
        },
};

module_platform_driver_probe(pata_at32_driver, pata_at32_probe);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AVR32 SMC/CFC PATA Driver");
MODULE_AUTHOR("Kristoffer Nyborg Gregertsen <kngregertsen@norway.atmel.com>");
MODULE_VERSION(DRV_VERSION);