// SPDX-License-Identifier: GPL-2.0-only
/*
 * pata_optidma.c       - Opti DMA PATA for new ATA layer
 *                        (C) 2006 Red Hat Inc
 *
 *      The Opti DMA controllers are related to the older PIO PCI controllers
 *      and indeed the VLB ones. The main differences are that the timing
 *      numbers are now based off PCI clocks not VLB and differ, and that
 *      MWDMA is supported.
 *
 *      This driver should support Viper-N+, FireStar, FireStar Plus.
 *
 *      These devices support virtual DMA for read (aka the CS5520). Later
 *      chips support UDMA33, but only if the rest of the board logic does,
 *      so you have to get this right. We don't support the virtual DMA
 *      but we do handle UDMA.
 *
 *      Bits that are worth knowing
 *              Most control registers are shadowed into I/O registers
 *              0x1F5 bit 0 tells you if the PCI/VLB clock is 33 or 25Mhz
 *              Virtual DMA registers *move* between rev 0x02 and rev 0x10
 *              UDMA requires a 66MHz FSB
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>

#define DRV_NAME "pata_optidma"
#define DRV_VERSION "0.3.2"

enum {
        READ_REG        = 0,    /* index of Read cycle timing register */
        WRITE_REG       = 1,    /* index of Write cycle timing register */
        CNTRL_REG       = 3,    /* index of Control register */
        STRAP_REG       = 5,    /* index of Strap register */
        MISC_REG        = 6     /* index of Miscellaneous register */
};

static int pci_clock;   /* 0 = 33 1 = 25 */

/**
 *      optidma_pre_reset               -       probe begin
 *      @link: ATA link
 *      @deadline: deadline jiffies for the operation
 *
 *      Set up cable type and use generic probe init
 */

static int optidma_pre_reset(struct ata_link *link, unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        static const struct pci_bits optidma_enable_bits = {
                0x40, 1, 0x08, 0x00
        };

        if (ap->port_no && !pci_test_config_bits(pdev, &optidma_enable_bits))
                return -ENOENT;

        return ata_sff_prereset(link, deadline);
}

/**
 *      optidma_unlock          -       unlock control registers
 *      @ap: ATA port
 *
 *      Unlock the control register block for this adapter. Registers must not
 *      be unlocked in a situation where libata might look at them.
 */

static void optidma_unlock(struct ata_port *ap)
{
        void __iomem *regio = ap->ioaddr.cmd_addr;

        /* These 3 unlock the control register access */
        ioread16(regio + 1);
        ioread16(regio + 1);
        iowrite8(3, regio + 2);
}

/**
 *      optidma_lock            -       issue temporary relock
 *      @ap: ATA port
 *
 *      Re-lock the configuration register settings.
 */

static void optidma_lock(struct ata_port *ap)
{
        void __iomem *regio = ap->ioaddr.cmd_addr;

        /* Relock */
        iowrite8(0x83, regio + 2);
}

/**
 *      optidma_mode_setup      -       set mode data
 *      @ap: ATA interface
 *      @adev: ATA device
 *      @mode: Mode to set
 *
 *      Called to do the DMA or PIO mode setup. Timing numbers are all
 *      pre computed to keep the code clean. There are two tables depending
 *      on the hardware clock speed.
 *
 *      WARNING: While we do this the IDE registers vanish. If we take an
 *      IRQ here we depend on the host set locking to avoid catastrophe.
 */

static void optidma_mode_setup(struct ata_port *ap, struct ata_device *adev, u8 mode)
{
        struct ata_device *pair = ata_dev_pair(adev);
        int pio = adev->pio_mode - XFER_PIO_0;
        int dma = adev->dma_mode - XFER_MW_DMA_0;
        void __iomem *regio = ap->ioaddr.cmd_addr;
        u8 addr;

        /* Address table precomputed with a DCLK of 2 */
        static const u8 addr_timing[2][5] = {
                { 0x30, 0x20, 0x20, 0x10, 0x10 },
                { 0x20, 0x20, 0x10, 0x10, 0x10 }
        };
        static const u8 data_rec_timing[2][5] = {
                { 0x59, 0x46, 0x30, 0x20, 0x20 },
                { 0x46, 0x32, 0x20, 0x20, 0x10 }
        };
        static const u8 dma_data_rec_timing[2][3] = {
                { 0x76, 0x20, 0x20 },
                { 0x54, 0x20, 0x10 }
        };

        /* Switch from IDE to control mode */
        optidma_unlock(ap);


        /*
         *      As with many controllers the address setup time is shared
         *      and must suit both devices if present. FIXME: Check if we
         *      need to look at slowest of PIO/DMA mode of either device
         */

        if (mode >= XFER_MW_DMA_0)
                addr = 0;
        else
                addr = addr_timing[pci_clock][pio];

        if (pair) {
                u8 pair_addr;
                /* Hardware constraint */
                if (ata_dma_enabled(pair))
                        pair_addr = 0;
                else
                        pair_addr = addr_timing[pci_clock][pair->pio_mode - XFER_PIO_0];
                if (pair_addr > addr)
                        addr = pair_addr;
        }

        /* Commence primary programming sequence */
        /* First we load the device number into the timing select */
        iowrite8(adev->devno, regio + MISC_REG);
        /* Now we load the data timings into read data/write data */
        if (mode < XFER_MW_DMA_0) {
                iowrite8(data_rec_timing[pci_clock][pio], regio + READ_REG);
                iowrite8(data_rec_timing[pci_clock][pio], regio + WRITE_REG);
        } else if (mode < XFER_UDMA_0) {
                iowrite8(dma_data_rec_timing[pci_clock][dma], regio + READ_REG);
                iowrite8(dma_data_rec_timing[pci_clock][dma], regio + WRITE_REG);
        }
        /* Finally we load the address setup into the misc register */
        iowrite8(addr | adev->devno, regio + MISC_REG);

        /* Programming sequence complete, timing 0 dev 0, timing 1 dev 1 */
        iowrite8(0x85, regio + CNTRL_REG);

        /* Switch back to IDE mode */
        optidma_lock(ap);

        /* Note: at this point our programming is incomplete. We are
           not supposed to program PCI 0x43 "things we hacked onto the chip"
           until we've done both sets of PIO/DMA timings */
}

/**
 *      optiplus_mode_setup     -       DMA setup for Firestar Plus
 *      @ap: ATA port
 *      @adev: device
 *      @mode: desired mode
 *
 *      The Firestar plus has additional UDMA functionality for UDMA0-2 and
 *      requires we do some additional work. Because the base work we must do
 *      is mostly shared we wrap the Firestar setup functionality in this
 *      one
 */

static void optiplus_mode_setup(struct ata_port *ap, struct ata_device *adev, u8 mode)
{
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        u8 udcfg;
        u8 udslave;
        int dev2 = 2 * adev->devno;
        int unit = 2 * ap->port_no + adev->devno;
        int udma = mode - XFER_UDMA_0;

        pci_read_config_byte(pdev, 0x44, &udcfg);
        if (mode <= XFER_UDMA_0) {
                udcfg &= ~(1 << unit);
                optidma_mode_setup(ap, adev, adev->dma_mode);
        } else {
                udcfg |=  (1 << unit);
                if (ap->port_no) {
                        pci_read_config_byte(pdev, 0x45, &udslave);
                        udslave &= ~(0x03 << dev2);
                        udslave |= (udma << dev2);
                        pci_write_config_byte(pdev, 0x45, udslave);
                } else {
                        udcfg &= ~(0x30 << dev2);
                        udcfg |= (udma << dev2);
                }
        }
        pci_write_config_byte(pdev, 0x44, udcfg);
}

/**
 *      optidma_set_pio_mode    -       PIO setup callback
 *      @ap: ATA port
 *      @adev: Device
 *
 *      The libata core provides separate functions for handling PIO and
 *      DMA programming. The architecture of the Firestar makes it easier
 *      for us to have a common function so we provide wrappers
 */

static void optidma_set_pio_mode(struct ata_port *ap, struct ata_device *adev)
{
        optidma_mode_setup(ap, adev, adev->pio_mode);
}

/**
 *      optidma_set_dma_mode    -       DMA setup callback
 *      @ap: ATA port
 *      @adev: Device
 *
 *      The libata core provides separate functions for handling PIO and
 *      DMA programming. The architecture of the Firestar makes it easier
 *      for us to have a common function so we provide wrappers
 */

static void optidma_set_dma_mode(struct ata_port *ap, struct ata_device *adev)
{
        optidma_mode_setup(ap, adev, adev->dma_mode);
}

/**
 *      optiplus_set_pio_mode   -       PIO setup callback
 *      @ap: ATA port
 *      @adev: Device
 *
 *      The libata core provides separate functions for handling PIO and
 *      DMA programming. The architecture of the Firestar makes it easier
 *      for us to have a common function so we provide wrappers
 */

static void optiplus_set_pio_mode(struct ata_port *ap, struct ata_device *adev)
{
        optiplus_mode_setup(ap, adev, adev->pio_mode);
}

/**
 *      optiplus_set_dma_mode   -       DMA setup callback
 *      @ap: ATA port
 *      @adev: Device
 *
 *      The libata core provides separate functions for handling PIO and
 *      DMA programming. The architecture of the Firestar makes it easier
 *      for us to have a common function so we provide wrappers
 */

static void optiplus_set_dma_mode(struct ata_port *ap, struct ata_device *adev)
{
        optiplus_mode_setup(ap, adev, adev->dma_mode);
}

/**
 *      optidma_make_bits43     -       PCI setup helper
 *      @adev: ATA device
 *
 *      Turn the ATA device setup into PCI configuration bits
 *      for register 0x43 and return the two bits needed.
 */

static u8 optidma_make_bits43(struct ata_device *adev)
{
        static const u8 bits43[5] = {
                0, 0, 0, 1, 2
        };
        if (!ata_dev_enabled(adev))
                return 0;
        if (ata_dma_enabled(adev))
                return adev->dma_mode - XFER_MW_DMA_0;
        return bits43[adev->pio_mode - XFER_PIO_0];
}

/**
 *      optidma_set_mode        -       mode setup
 *      @link: link to set up
 *      @r_failed: out parameter for failed device
 *
 *      Use the standard setup to tune the chipset and then finalise the
 *      configuration by writing the nibble of extra bits of data into
 *      the chip.
 */

static int optidma_set_mode(struct ata_link *link, struct ata_device **r_failed)
{
        struct ata_port *ap = link->ap;
        u8 r;
        int nybble = 4 * ap->port_no;
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        int rc;

        rc = ata_set_mode(link, r_failed);
        if (rc == 0) {
                pci_read_config_byte(pdev, 0x43, &r);

                r &= (0x0F << nybble);
                r |= (optidma_make_bits43(&link->device[0]) +
                     (optidma_make_bits43(&link->device[0]) << 2)) << nybble;
                pci_write_config_byte(pdev, 0x43, r);
        }
        return rc;
}

static const struct scsi_host_template optidma_sht = {
        ATA_BMDMA_SHT(DRV_NAME),
};

static struct ata_port_operations optidma_port_ops = {
        .inherits       = &ata_bmdma_port_ops,
        .cable_detect   = ata_cable_40wire,
        .set_piomode    = optidma_set_pio_mode,
        .set_dmamode    = optidma_set_dma_mode,
        .set_mode       = optidma_set_mode,
        .reset.prereset = optidma_pre_reset,
};

static struct ata_port_operations optiplus_port_ops = {
        .inherits       = &optidma_port_ops,
        .set_piomode    = optiplus_set_pio_mode,
        .set_dmamode    = optiplus_set_dma_mode,
};

/**
 *      optiplus_with_udma      -       Look for UDMA capable setup
 *      @pdev: ATA controller
 */

static int optiplus_with_udma(struct pci_dev *pdev)
{
        u8 r;
        int ret = 0;
        int ioport = 0x22;
        struct pci_dev *dev1;

        /* Find function 1 */
        dev1 = pci_get_device(0x1045, 0xC701, NULL);
        if (dev1 == NULL)
                return 0;

        /* Rev must be >= 0x10 */
        pci_read_config_byte(dev1, 0x08, &r);
        if (r < 0x10)
                goto done_nomsg;
        /* Read the chipset system configuration to check our mode */
        pci_read_config_byte(dev1, 0x5F, &r);
        ioport |= (r << 8);
        outb(0x10, ioport);
        /* Must be 66Mhz sync */
        if ((inb(ioport + 2) & 1) == 0)
                goto done;

        /* Check the ATA arbitration/timing is suitable */
        pci_read_config_byte(pdev, 0x42, &r);
        if ((r & 0x36) != 0x36)
                goto done;
        pci_read_config_byte(dev1, 0x52, &r);
        if (r & 0x80)   /* IDEDIR disabled */
                ret = 1;
done:
        printk(KERN_WARNING "UDMA not supported in this configuration.\n");
done_nomsg:             /* Wrong chip revision */
        pci_dev_put(dev1);
        return ret;
}

static int optidma_init_one(struct pci_dev *dev, const struct pci_device_id *id)
{
        static const struct ata_port_info info_82c700 = {
                .flags = ATA_FLAG_SLAVE_POSS,
                .pio_mask = ATA_PIO4,
                .mwdma_mask = ATA_MWDMA2,
                .port_ops = &optidma_port_ops
        };
        static const struct ata_port_info info_82c700_udma = {
                .flags = ATA_FLAG_SLAVE_POSS,
                .pio_mask = ATA_PIO4,
                .mwdma_mask = ATA_MWDMA2,
                .udma_mask = ATA_UDMA2,
                .port_ops = &optiplus_port_ops
        };
        const struct ata_port_info *ppi[] = { &info_82c700, NULL };
        int rc;

        ata_print_version_once(&dev->dev, DRV_VERSION);

        rc = pcim_enable_device(dev);
        if (rc)
                return rc;

        /* Fixed location chipset magic */
        inw(0x1F1);
        inw(0x1F1);
        pci_clock = inb(0x1F5) & 1;             /* 0 = 33Mhz, 1 = 25Mhz */

        if (optiplus_with_udma(dev))
                ppi[0] = &info_82c700_udma;

        return ata_pci_bmdma_init_one(dev, ppi, &optidma_sht, NULL, 0);
}

static const struct pci_device_id optidma[] = {
        { PCI_VDEVICE(OPTI, 0xD568), },         /* Opti 82C700 */

        { },
};

static struct pci_driver optidma_pci_driver = {
        .name           = DRV_NAME,
        .id_table       = optidma,
        .probe          = optidma_init_one,
        .remove         = ata_pci_remove_one,
#ifdef CONFIG_PM_SLEEP
        .suspend        = ata_pci_device_suspend,
        .resume         = ata_pci_device_resume,
#endif
};

module_pci_driver(optidma_pci_driver);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("low-level driver for Opti Firestar/Firestar Plus");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, optidma);
MODULE_VERSION(DRV_VERSION);