pata_at91.c

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/*
 * PATA driver for AT91SAM9260 Static Memory Controller
 * with CompactFlash interface in True IDE mode
 *
 * Copyright (C) 2009 Matyukevich Sergey
 *               2011 Igor Plyatov
 *
 * Based on:
 *      * generic platform driver by Paul Mundt: drivers/ata/pata_platform.c
 *      * pata_at32 driver by Kristoffer Nyborg Gregertsen
 *      * at91_ide driver by Stanislaw Gruszka
 *
 * 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/init.h>
#include <linux/blkdev.h>
#include <linux/gfp.h>
#include <scsi/scsi_host.h>
#include <linux/ata.h>
#include <linux/clk.h>
#include <linux/libata.h>
#include <linux/platform_device.h>
#include <linux/ata_platform.h>

#include <mach/at91sam9_smc.h>
#include <mach/board.h>
#include <asm/gpio.h>

#define DRV_NAME        "pata_at91"
#define DRV_VERSION     "0.3"

#define CF_IDE_OFFSET       0x00c00000
#define CF_ALT_IDE_OFFSET   0x00e00000
#define CF_IDE_RES_SIZE     0x08
#define CS_PULSE_MAXIMUM    319
#define ER_SMC_CALC     1
#define ER_SMC_RECALC       2

struct at91_ide_info {
    unsigned long mode;
    unsigned int cs;
    struct clk *mck;
    void __iomem *ide_addr;
    void __iomem *alt_addr;
};

struct smc_range {
    int min;
    int max;
};

static int adjust_smc_value(int *value, struct smc_range *range, int size)
{
    int maximum = (range + size - 1)->max;
    int remainder;

    do {
        if (*value < range->min) {
            remainder = range->min - *value;
            *value = range->min; /* nearest valid value */
            return remainder;
        } else if ((range->min <= *value) && (*value <= range->max))
            return 0;

        range++;
    } while (--size);
    *value = maximum;

    return -1; /* invalid value */
}

static int calc_smc_vals(struct device *dev,
        int *setup, int *pulse, int *cycle, int *cs_pulse)
{
    int ret_val;
    int err = 0;
    struct smc_range range_setup[] = {  /* SMC_SETUP valid values */
        {.min = 0,  .max = 31}, /* first  range */
        {.min = 128,    .max = 159} /* second range */
    };
    struct smc_range range_pulse[] = {  /* SMC_PULSE valid values */
        {.min = 0,  .max = 63}, /* first  range */
        {.min = 256,    .max = 319} /* second range */
    };
    struct smc_range range_cycle[] = {  /* SMC_CYCLE valid values */
        {.min = 0,  .max = 127},    /* first  range */
        {.min = 256,    .max = 383},    /* second range */
        {.min = 512,    .max = 639},    /* third  range */
        {.min = 768,    .max = 895} /* fourth range */
    };

    ret_val = adjust_smc_value(setup, range_setup, ARRAY_SIZE(range_setup));
    if (ret_val < 0)
        dev_warn(dev, "maximal SMC Setup value\n");
    else
        *cycle += ret_val;

    ret_val = adjust_smc_value(pulse, range_pulse, ARRAY_SIZE(range_pulse));
    if (ret_val < 0)
        dev_warn(dev, "maximal SMC Pulse value\n");
    else
        *cycle += ret_val;

    ret_val = adjust_smc_value(cycle, range_cycle, ARRAY_SIZE(range_cycle));
    if (ret_val < 0)
        dev_warn(dev, "maximal SMC Cycle value\n");

    *cs_pulse = *cycle;
    if (*cs_pulse > CS_PULSE_MAXIMUM) {
        dev_err(dev, "unable to calculate valid SMC settings\n");
        return -ER_SMC_CALC;
    }

    ret_val = adjust_smc_value(cs_pulse, range_pulse,
                    ARRAY_SIZE(range_pulse));
    if (ret_val < 0) {
        dev_warn(dev, "maximal SMC CS Pulse value\n");
    } else if (ret_val != 0) {
        *cycle = *cs_pulse;
        dev_warn(dev, "SMC Cycle extended\n");
        err = -ER_SMC_RECALC;
    }

    return err;
}

static void to_smc_format(int *setup, int *pulse, int *cycle, int *cs_pulse)
{
    *setup = (*setup & 0x1f) | ((*setup & 0x80) >> 2);
    *pulse = (*pulse & 0x3f) | ((*pulse & 0x100) >> 2);
    *cycle = (*cycle & 0x7f) | ((*cycle & 0x300) >> 1);
    *cs_pulse = (*cs_pulse & 0x3f) | ((*cs_pulse & 0x100) >> 2);
}

static unsigned long calc_mck_cycles(unsigned long ns, unsigned long mck_hz)
{
    unsigned long mul;

    /*
    * cycles = x [nsec] * f [Hz] / 10^9 [ns in sec] =
    *     x * (f / 1_000_000_000) =
    *     x * ((f * 65536) / 1_000_000_000) / 65536 =
    *     x * (((f / 10_000) * 65536) / 100_000) / 65536 =
    */

    mul = (mck_hz / 10000) << 16;
    mul /= 100000;

    return (ns * mul + 65536) >> 16;    /* rounding */
}

static void set_smc_timing(struct device *dev, struct ata_device *adev,
        struct at91_ide_info *info, const struct ata_timing *ata)
{
    int ret = 0;
    int use_iordy;
    struct sam9_smc_config smc;
    unsigned int t6z;         /* data tristate time in ns */
    unsigned int cycle;       /* SMC Cycle width in MCK ticks */
    unsigned int setup;       /* SMC Setup width in MCK ticks */
    unsigned int pulse;       /* CFIOR and CFIOW pulse width in MCK ticks */
    unsigned int cs_pulse;    /* CS4 or CS5 pulse width in MCK ticks*/
    unsigned int tdf_cycles;  /* SMC TDF MCK ticks */
    unsigned long mck_hz;     /* MCK frequency in Hz */

    t6z = (ata->mode < XFER_PIO_5) ? 30 : 20;
    mck_hz = clk_get_rate(info->mck);
    cycle = calc_mck_cycles(ata->cyc8b, mck_hz);
    setup = calc_mck_cycles(ata->setup, mck_hz);
    pulse = calc_mck_cycles(ata->act8b, mck_hz);
    tdf_cycles = calc_mck_cycles(t6z, mck_hz);

    do {
        ret = calc_smc_vals(dev, &setup, &pulse, &cycle, &cs_pulse);
    } while (ret == -ER_SMC_RECALC);

    if (ret == -ER_SMC_CALC)
        dev_err(dev, "Interface may not operate correctly\n");

    dev_dbg(dev, "SMC Setup=%u, Pulse=%u, Cycle=%u, CS Pulse=%u\n",
        setup, pulse, cycle, cs_pulse);
    to_smc_format(&setup, &pulse, &cycle, &cs_pulse);
    /* disable or enable waiting for IORDY signal */
    use_iordy = ata_pio_need_iordy(adev);
    if (use_iordy)
        info->mode |= AT91_SMC_EXNWMODE_READY;

    if (tdf_cycles > 15) {
        tdf_cycles = 15;
        dev_warn(dev, "maximal SMC TDF Cycles value\n");
    }

    dev_dbg(dev, "Use IORDY=%u, TDF Cycles=%u\n", use_iordy, tdf_cycles);

    /* SMC Setup Register */
    smc.nwe_setup = smc.nrd_setup = setup;
    smc.ncs_write_setup = smc.ncs_read_setup = 0;
    /* SMC Pulse Register */
    smc.nwe_pulse = smc.nrd_pulse = pulse;
    smc.ncs_write_pulse = smc.ncs_read_pulse = cs_pulse;
    /* SMC Cycle Register */
    smc.write_cycle = smc.read_cycle = cycle;
    /* SMC Mode Register*/
    smc.tdf_cycles = tdf_cycles;
    smc.mode = info->mode;

    sam9_smc_configure(0, info->cs, &smc);
}

static void pata_at91_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
    struct at91_ide_info *info = ap->host->private_data;
    struct ata_timing timing;
    int ret;

    /* Compute ATA timing and set it to SMC */
    ret = ata_timing_compute(adev, adev->pio_mode, &timing, 1000, 0);
    if (ret) {
        dev_warn(ap->dev, "Failed to compute ATA timing %d, "
             "set PIO_0 timing\n", ret);
        timing = *ata_timing_find_mode(XFER_PIO_0);
    }
    set_smc_timing(ap->dev, adev, info, &timing);
}

static unsigned int pata_at91_data_xfer_noirq(struct ata_device *dev,
        unsigned char *buf, unsigned int buflen, int rw)
{
    struct at91_ide_info *info = dev->link->ap->host->private_data;
    unsigned int consumed;
    unsigned long flags;
    struct sam9_smc_config smc;

    local_irq_save(flags);
    sam9_smc_read_mode(0, info->cs, &smc);

    /* set 16bit mode before writing data */
    smc.mode = (smc.mode & ~AT91_SMC_DBW) | AT91_SMC_DBW_16;
    sam9_smc_write_mode(0, info->cs, &smc);

    consumed = ata_sff_data_xfer(dev, buf, buflen, rw);

    /* restore 8bit mode after data is written */
    smc.mode = (smc.mode & ~AT91_SMC_DBW) | AT91_SMC_DBW_8;
    sam9_smc_write_mode(0, info->cs, &smc);

    local_irq_restore(flags);
    return consumed;
}

static struct scsi_host_template pata_at91_sht = {
    ATA_PIO_SHT(DRV_NAME),
};

static struct ata_port_operations pata_at91_port_ops = {
    .inherits   = &ata_sff_port_ops,

    .sff_data_xfer  = pata_at91_data_xfer_noirq,
    .set_piomode    = pata_at91_set_piomode,
    .cable_detect   = ata_cable_40wire,
};

static int __devinit pata_at91_probe(struct platform_device *pdev)
{
    struct at91_cf_data *board = pdev->dev.platform_data;
    struct device *dev = &pdev->dev;
    struct at91_ide_info *info;
    struct resource *mem_res;
    struct ata_host *host;
    struct ata_port *ap;

    int irq_flags = 0;
    int irq = 0;
    int ret;

    /*  get platform resources: IO/CTL memories and irq/rst pins */

    if (pdev->num_resources != 1) {
        dev_err(&pdev->dev, "invalid number of resources\n");
        return -EINVAL;
    }

    mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

    if (!mem_res) {
        dev_err(dev, "failed to get mem resource\n");
        return -EINVAL;
    }

    irq = board->irq_pin;

    /* init ata host */

    host = ata_host_alloc(dev, 1);

    if (!host)
        return -ENOMEM;

    ap = host->ports[0];
    ap->ops = &pata_at91_port_ops;
    ap->flags |= ATA_FLAG_SLAVE_POSS;
    ap->pio_mask = ATA_PIO4;

    if (!gpio_is_valid(irq)) {
        ap->flags |= ATA_FLAG_PIO_POLLING;
        ata_port_desc(ap, "no IRQ, using PIO polling");
    }

    info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);

    if (!info) {
        dev_err(dev, "failed to allocate memory for private data\n");
        return -ENOMEM;
    }

    info->mck = clk_get(NULL, "mck");

    if (IS_ERR(info->mck)) {
        dev_err(dev, "failed to get access to mck clock\n");
        return -ENODEV;
    }

    info->cs    = board->chipselect;
    info->mode  = AT91_SMC_READMODE | AT91_SMC_WRITEMODE |
        AT91_SMC_EXNWMODE_READY | AT91_SMC_BAT_SELECT |
        AT91_SMC_DBW_8 | AT91_SMC_TDF_(0);

    info->ide_addr = devm_ioremap(dev,
            mem_res->start + CF_IDE_OFFSET, CF_IDE_RES_SIZE);

    if (!info->ide_addr) {
        dev_err(dev, "failed to map IO base\n");
        ret = -ENOMEM;
        goto err_put;
    }

    info->alt_addr = devm_ioremap(dev,
            mem_res->start + CF_ALT_IDE_OFFSET, CF_IDE_RES_SIZE);

    if (!info->alt_addr) {
        dev_err(dev, "failed to map CTL base\n");
        ret = -ENOMEM;
        goto err_put;
    }

    ap->ioaddr.cmd_addr = info->ide_addr;
    ap->ioaddr.ctl_addr = info->alt_addr + 0x06;
    ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;

    ata_sff_std_ports(&ap->ioaddr);

    ata_port_desc(ap, "mmio cmd 0x%llx ctl 0x%llx",
            (unsigned long long)mem_res->start + CF_IDE_OFFSET,
            (unsigned long long)mem_res->start + CF_ALT_IDE_OFFSET);

    host->private_data = info;

    return ata_host_activate(host, gpio_is_valid(irq) ? gpio_to_irq(irq) : 0,
            gpio_is_valid(irq) ? ata_sff_interrupt : NULL,
            irq_flags, &pata_at91_sht);

    if (!ret)
        return 0;

err_put:
    clk_put(info->mck);
    return ret;
}

static int __devexit pata_at91_remove(struct platform_device *pdev)
{
    struct ata_host *host = dev_get_drvdata(&pdev->dev);
    struct at91_ide_info *info;

    if (!host)
        return 0;
    info = host->private_data;

    ata_host_detach(host);

    if (!info)
        return 0;

    clk_put(info->mck);

    return 0;
}

static struct platform_driver pata_at91_driver = {
    .probe      = pata_at91_probe,
    .remove     = __devexit_p(pata_at91_remove),
    .driver     = {
        .name       = DRV_NAME,
        .owner      = THIS_MODULE,
    },
};

module_platform_driver(pata_at91_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for CF in True IDE mode on AT91SAM9260 SoC");
MODULE_AUTHOR("Matyukevich Sergey");
MODULE_VERSION(DRV_VERSION);