// SPDX-License-Identifier: GPL-2.0-only
/*
 *    pata_it8213.c - iTE Tech. Inc.  IT8213 PATA driver
 *
 *    The IT8213 is a very Intel ICH like device for timing purposes, having
 *    a similar register layout and the same split clock arrangement. Cable
 *    detection is different, and it does not have slave channels or all the
 *    clutter of later ICH/SATA setups.
 */

#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 <scsi/scsi_host.h>
#include <linux/libata.h>
#include <linux/ata.h>

#define DRV_NAME        "pata_it8213"
#define DRV_VERSION     "0.0.3"

/**
 *      it8213_pre_reset        -       probe begin
 *      @link: link
 *      @deadline: deadline jiffies for the operation
 *
 *      Filter out ports by the enable bits before doing the normal reset
 *      and probe.
 */

static int it8213_pre_reset(struct ata_link *link, unsigned long deadline)
{
        static const struct pci_bits it8213_enable_bits[] = {
                { 0x41U, 1U, 0x80UL, 0x80UL },  /* port 0 */
        };
        struct ata_port *ap = link->ap;
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        if (!pci_test_config_bits(pdev, &it8213_enable_bits[ap->port_no]))
                return -ENOENT;

        return ata_sff_prereset(link, deadline);
}

/**
 *      it8213_cable_detect     -       check for 40/80 pin
 *      @ap: Port
 *
 *      Perform cable detection for the 8213 ATA interface. This is
 *      different to the PIIX arrangement
 */

static int it8213_cable_detect(struct ata_port *ap)
{
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        u8 tmp;
        pci_read_config_byte(pdev, 0x42, &tmp);
        if (tmp & 2)    /* The initial docs are incorrect */
                return ATA_CBL_PATA40;
        return ATA_CBL_PATA80;
}

/**
 *      it8213_set_piomode - Initialize host controller PATA PIO timings
 *      @ap: Port whose timings we are configuring
 *      @adev: Device whose timings we are configuring
 *
 *      Set PIO mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void it8213_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 int master_port = ap->port_no ? 0x42 : 0x40;
        u16 master_data;
        int control = 0;

        /*
         *      See Intel Document 298600-004 for the timing programming rules
         *      for PIIX/ICH. The 8213 is a clone so very similar
         */

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

        if (pio > 1)
                control |= 1;   /* TIME */
        if (ata_pio_need_iordy(adev))   /* PIO 3/4 require IORDY */
                control |= 2;   /* IE */
        /* Bit 2 is set for ATAPI on the IT8213 - reverse of ICH/PIIX */
        if (adev->class != ATA_DEV_ATA)
                control |= 4;   /* PPE */

        pci_read_config_word(dev, master_port, &master_data);

        /* Set PPE, IE, and TIME as appropriate */
        if (adev->devno == 0) {
                master_data &= 0xCCF0;
                master_data |= control;
                master_data |= (timings[pio][0] << 12) |
                        (timings[pio][1] << 8);
        } else {
                u8 slave_data;

                master_data &= 0xFF0F;
                master_data |= (control << 4);

                /* Slave timing in separate register */
                pci_read_config_byte(dev, 0x44, &slave_data);
                slave_data &= 0xF0;
                slave_data |= (timings[pio][0] << 2) | timings[pio][1];
                pci_write_config_byte(dev, 0x44, slave_data);
        }

        master_data |= 0x4000;  /* Ensure SITRE is set */
        pci_write_config_word(dev, master_port, master_data);
}

/**
 *      it8213_set_dmamode - Initialize host controller PATA DMA timings
 *      @ap: Port whose timings we are configuring
 *      @adev: Device to program
 *
 *      Set UDMA/MWDMA mode for device, in host controller PCI config space.
 *      This device is basically an ICH alike.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void it8213_set_dmamode (struct ata_port *ap, struct ata_device *adev)
{
        struct pci_dev *dev     = to_pci_dev(ap->host->dev);
        u16 master_data;
        u8 speed                = adev->dma_mode;
        int devid               = adev->devno;
        u8 udma_enable;

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

        pci_read_config_word(dev, 0x40, &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;

                /* Clocks follow the PIIX style */
                u_speed = min(2 - (udma & 1), udma);
                if (udma > 4)
                        u_clock = 0x1000;       /* 100Mhz */
                else if (udma > 2)
                        u_clock = 1;            /* 66Mhz */
                else
                        u_clock = 0;            /* 33Mhz */

                udma_enable |= (1 << devid);

                /* Load the UDMA cycle time */
                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);

                /* Load the clock selection */
                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;
                static 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 (devid) {    /* Slave */
                        master_data &= 0xFF4F;  /* Mask out IORDY|TIME1|DMAONLY */
                        master_data |= control << 4;
                        pci_read_config_byte(dev, 0x44, &slave_data);
                        slave_data &= 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, 0x40, master_data);
        }
        pci_write_config_byte(dev, 0x48, udma_enable);
}

static const struct scsi_host_template it8213_sht = {
        ATA_BMDMA_SHT(DRV_NAME),
};


static struct ata_port_operations it8213_ops = {
        .inherits               = &ata_bmdma_port_ops,
        .cable_detect           = it8213_cable_detect,
        .set_piomode            = it8213_set_piomode,
        .set_dmamode            = it8213_set_dmamode,
        .reset.prereset         = it8213_pre_reset,
};


/**
 *      it8213_init_one - Register 8213 ATA PCI device with kernel services
 *      @pdev: PCI device to register
 *      @ent: Entry in it8213_pci_tbl matching with @pdev
 *
 *      Called from kernel PCI layer.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 *
 *      RETURNS:
 *      Zero on success, or -ERRNO value.
 */

static int it8213_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static const struct ata_port_info info = {
                .flags          = ATA_FLAG_SLAVE_POSS,
                .pio_mask       = ATA_PIO4,
                .mwdma_mask     = ATA_MWDMA12_ONLY,
                .udma_mask      = ATA_UDMA6,
                .port_ops       = &it8213_ops,
        };
        /* Current IT8213 stuff is single port */
        const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };

        ata_print_version_once(&pdev->dev, DRV_VERSION);

        return ata_pci_bmdma_init_one(pdev, ppi, &it8213_sht, NULL, 0);
}

static const struct pci_device_id it8213_pci_tbl[] = {
        { PCI_VDEVICE(ITE, PCI_DEVICE_ID_ITE_8213), },

        { }     /* terminate list */
};

static struct pci_driver it8213_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = it8213_pci_tbl,
        .probe                  = it8213_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(it8213_pci_driver);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("SCSI low-level driver for the ITE 8213");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, it8213_pci_tbl);
MODULE_VERSION(DRV_VERSION);