// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  pata_rdc            -       Driver for later RDC PATA controllers
 *
 *  This is actually a driver for hardware meeting
 *  INCITS 370-2004 (1510D): ATA Host Adapter Standards
 *
 *  Based on ata_piix.
 */

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

#define DRV_NAME        "pata_rdc"
#define DRV_VERSION     "0.01"

struct rdc_host_priv {
        u32 saved_iocfg;
};

/**
 *      rdc_pata_cable_detect - Probe host controller cable detect info
 *      @ap: Port for which cable detect info is desired
 *
 *      Read 80c cable indicator from ATA PCI device's PCI config
 *      register.  This register is normally set by firmware (BIOS).
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static int rdc_pata_cable_detect(struct ata_port *ap)
{
        struct rdc_host_priv *hpriv = ap->host->private_data;
        u8 mask;

        /* check BIOS cable detect results */
        mask = 0x30 << (2 * ap->port_no);
        if ((hpriv->saved_iocfg & mask) == 0)
                return ATA_CBL_PATA40;
        return ATA_CBL_PATA80;
}

/**
 *      rdc_pata_prereset - prereset for PATA host controller
 *      @link: Target link
 *      @deadline: deadline jiffies for the operation
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static int rdc_pata_prereset(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 rdc_enable_bits[] = {
                { 0x41U, 1U, 0x80UL, 0x80UL },  /* port 0 */
                { 0x43U, 1U, 0x80UL, 0x80UL },  /* port 1 */
        };

        if (!pci_test_config_bits(pdev, &rdc_enable_bits[ap->port_no]))
                return -ENOENT;
        return ata_sff_prereset(link, deadline);
}

static DEFINE_SPINLOCK(rdc_lock);

/**
 *      rdc_set_piomode - Initialize host controller PATA PIO timings
 *      @ap: Port whose timings we are configuring
 *      @adev: um
 *
 *      Set PIO mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void rdc_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        unsigned int pio        = adev->pio_mode - XFER_PIO_0;
        struct pci_dev *dev     = to_pci_dev(ap->host->dev);
        unsigned long flags;
        unsigned int is_slave   = (adev->devno != 0);
        unsigned int master_port= ap->port_no ? 0x42 : 0x40;
        unsigned int slave_port = 0x44;
        u16 master_data;
        u8 slave_data;
        u8 udma_enable;
        int control = 0;

        static const     /* ISP  RTC */
        u8 timings[][2] = { { 0, 0 },
                            { 0, 0 },
                            { 1, 0 },
                            { 2, 1 },
                            { 2, 3 }, };

        if (pio >= 2)
                control |= 1;   /* TIME1 enable */
        if (ata_pio_need_iordy(adev))
                control |= 2;   /* IE enable */

        if (adev->class == ATA_DEV_ATA)
                control |= 4;   /* PPE enable */

        spin_lock_irqsave(&rdc_lock, flags);

        /* PIO configuration clears DTE unconditionally.  It will be
         * programmed in set_dmamode which is guaranteed to be called
         * after set_piomode if any DMA mode is available.
         */
        pci_read_config_word(dev, master_port, &master_data);
        if (is_slave) {
                /* clear TIME1|IE1|PPE1|DTE1 */
                master_data &= 0xff0f;
                /* Enable SITRE (separate slave timing register) */
                master_data |= 0x4000;
                /* enable PPE1, IE1 and TIME1 as needed */
                master_data |= (control << 4);
                pci_read_config_byte(dev, slave_port, &slave_data);
                slave_data &= (ap->port_no ? 0x0f : 0xf0);
                /* Load the timing nibble for this slave */
                slave_data |= ((timings[pio][0] << 2) | timings[pio][1])
                                                << (ap->port_no ? 4 : 0);
        } else {
                /* clear ISP|RCT|TIME0|IE0|PPE0|DTE0 */
                master_data &= 0xccf0;
                /* Enable PPE, IE and TIME as appropriate */
                master_data |= control;
                /* load ISP and RCT */
                master_data |=
                        (timings[pio][0] << 12) |
                        (timings[pio][1] << 8);
        }
        pci_write_config_word(dev, master_port, master_data);
        if (is_slave)
                pci_write_config_byte(dev, slave_port, slave_data);

        /* Ensure the UDMA bit is off - it will be turned back on if
           UDMA is selected */

        pci_read_config_byte(dev, 0x48, &udma_enable);
        udma_enable &= ~(1 << (2 * ap->port_no + adev->devno));
        pci_write_config_byte(dev, 0x48, udma_enable);

        spin_unlock_irqrestore(&rdc_lock, flags);
}

/**
 *      rdc_set_dmamode - Initialize host controller PATA PIO timings
 *      @ap: Port whose timings we are configuring
 *      @adev: Drive in question
 *
 *      Set UDMA mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void rdc_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
        struct pci_dev *dev     = to_pci_dev(ap->host->dev);
        unsigned long flags;
        u8 master_port          = ap->port_no ? 0x42 : 0x40;
        u16 master_data;
        u8 speed                = adev->dma_mode;
        int devid               = adev->devno + 2 * ap->port_no;
        u8 udma_enable          = 0;

        static const     /* ISP  RTC */
        u8 timings[][2] = { { 0, 0 },
                            { 0, 0 },
                            { 1, 0 },
                            { 2, 1 },
                            { 2, 3 }, };

        spin_lock_irqsave(&rdc_lock, flags);

        pci_read_config_word(dev, master_port, &master_data);
        pci_read_config_byte(dev, 0x48, &udma_enable);

        if (speed >= XFER_UDMA_0) {
                unsigned int udma = adev->dma_mode - XFER_UDMA_0;
                u16 udma_timing;
                u16 ideconf;
                int u_clock, u_speed;

                /*
                 * UDMA is handled by a combination of clock switching and
                 * selection of dividers
                 *
                 * Handy rule: Odd modes are UDMATIMx 01, even are 02
                 *             except UDMA0 which is 00
                 */
                u_speed = min(2 - (udma & 1), udma);
                if (udma == 5)
                        u_clock = 0x1000;       /* 100Mhz */
                else if (udma > 2)
                        u_clock = 1;            /* 66Mhz */
                else
                        u_clock = 0;            /* 33Mhz */

                udma_enable |= (1 << devid);

                /* Load the CT/RP selection */
                pci_read_config_word(dev, 0x4A, &udma_timing);
                udma_timing &= ~(3 << (4 * devid));
                udma_timing |= u_speed << (4 * devid);
                pci_write_config_word(dev, 0x4A, udma_timing);

                /* Select a 33/66/100Mhz clock */
                pci_read_config_word(dev, 0x54, &ideconf);
                ideconf &= ~(0x1001 << devid);
                ideconf |= u_clock << devid;
                pci_write_config_word(dev, 0x54, ideconf);
        } else {
                /*
                 * MWDMA is driven by the PIO timings. We must also enable
                 * IORDY unconditionally along with TIME1. PPE has already
                 * been set when the PIO timing was set.
                 */
                unsigned int mwdma      = adev->dma_mode - XFER_MW_DMA_0;
                unsigned int control;
                u8 slave_data;
                const unsigned int needed_pio[3] = {
                        XFER_PIO_0, XFER_PIO_3, XFER_PIO_4
                };
                int pio = needed_pio[mwdma] - XFER_PIO_0;

                control = 3;    /* IORDY|TIME1 */

                /* If the drive MWDMA is faster than it can do PIO then
                   we must force PIO into PIO0 */

                if (adev->pio_mode < needed_pio[mwdma])
                        /* Enable DMA timing only */
                        control |= 8;   /* PIO cycles in PIO0 */

                if (adev->devno) {      /* Slave */
                        master_data &= 0xFF4F;  /* Mask out IORDY|TIME1|DMAONLY */
                        master_data |= control << 4;
                        pci_read_config_byte(dev, 0x44, &slave_data);
                        slave_data &= (ap->port_no ? 0x0f : 0xf0);
                        /* Load the matching timing */
                        slave_data |= ((timings[pio][0] << 2) | timings[pio][1]) << (ap->port_no ? 4 : 0);
                        pci_write_config_byte(dev, 0x44, slave_data);
                } else {        /* Master */
                        master_data &= 0xCCF4;  /* Mask out IORDY|TIME1|DMAONLY
                                                   and master timing bits */
                        master_data |= control;
                        master_data |=
                                (timings[pio][0] << 12) |
                                (timings[pio][1] << 8);
                }

                udma_enable &= ~(1 << devid);
                pci_write_config_word(dev, master_port, master_data);
        }
        pci_write_config_byte(dev, 0x48, udma_enable);

        spin_unlock_irqrestore(&rdc_lock, flags);
}

static struct ata_port_operations rdc_pata_ops = {
        .inherits               = &ata_bmdma32_port_ops,
        .cable_detect           = rdc_pata_cable_detect,
        .set_piomode            = rdc_set_piomode,
        .set_dmamode            = rdc_set_dmamode,
        .reset.prereset         = rdc_pata_prereset,
};

static const struct ata_port_info rdc_port_info = {

        .flags          = ATA_FLAG_SLAVE_POSS,
        .pio_mask       = ATA_PIO4,
        .mwdma_mask     = ATA_MWDMA12_ONLY,
        .udma_mask      = ATA_UDMA5,
        .port_ops       = &rdc_pata_ops,
};

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

/**
 *      rdc_init_one - Register PIIX ATA PCI device with kernel services
 *      @pdev: PCI device to register
 *      @ent: Entry in rdc_pci_tbl matching with @pdev
 *
 *      Called from kernel PCI layer.  We probe for combined mode (sigh),
 *      and then hand over control to libata, for it to do the rest.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 *
 *      RETURNS:
 *      Zero on success, or -ERRNO value.
 */

static int rdc_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        struct device *dev = &pdev->dev;
        struct ata_port_info port_info[2];
        const struct ata_port_info *ppi[] = { &port_info[0], &port_info[1] };
        struct ata_host *host;
        struct rdc_host_priv *hpriv;
        int rc;

        ata_print_version_once(&pdev->dev, DRV_VERSION);

        port_info[0] = rdc_port_info;
        port_info[1] = rdc_port_info;

        /* enable device and prepare host */
        rc = pcim_enable_device(pdev);
        if (rc)
                return rc;

        hpriv = devm_kzalloc(dev, sizeof(*hpriv), GFP_KERNEL);
        if (!hpriv)
                return -ENOMEM;

        /* Save IOCFG, this will be used for cable detection, quirk
         * detection and restoration on detach.
         */
        pci_read_config_dword(pdev, 0x54, &hpriv->saved_iocfg);

        rc = ata_pci_bmdma_prepare_host(pdev, ppi, &host);
        if (rc)
                return rc;
        host->private_data = hpriv;

        pcim_intx(pdev, 1);

        host->flags |= ATA_HOST_PARALLEL_SCAN;

        pci_set_master(pdev);
        return ata_pci_sff_activate_host(host, ata_bmdma_interrupt, &rdc_sht);
}

static void rdc_remove_one(struct pci_dev *pdev)
{
        struct ata_host *host = pci_get_drvdata(pdev);
        struct rdc_host_priv *hpriv = host->private_data;

        pci_write_config_dword(pdev, 0x54, hpriv->saved_iocfg);

        ata_pci_remove_one(pdev);
}

static const struct pci_device_id rdc_pci_tbl[] = {
        { PCI_VDEVICE(RDC, 0x1011) },
        { PCI_VDEVICE(RDC, 0x1012) },
        { }     /* terminate list */
};

static struct pci_driver rdc_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = rdc_pci_tbl,
        .probe                  = rdc_init_one,
        .remove                 = rdc_remove_one,
#ifdef CONFIG_PM_SLEEP
        .suspend                = ata_pci_device_suspend,
        .resume                 = ata_pci_device_resume,
#endif
};


module_pci_driver(rdc_pci_driver);

MODULE_AUTHOR("Alan Cox (based on ata_piix)");
MODULE_DESCRIPTION("SCSI low-level driver for RDC PATA controllers");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, rdc_pci_tbl);
MODULE_VERSION(DRV_VERSION);