// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for Future Domain TMC-16x0 and TMC-3260 SCSI host adapters
 * Copyright 2019 Ondrej Zary
 *
 * Original driver by
 * Rickard E. Faith, faith@cs.unc.edu
 *
 * Future Domain BIOS versions supported for autodetect:
 *    2.0, 3.0, 3.2, 3.4 (1.0), 3.5 (2.0), 3.6, 3.61
 * Chips supported:
 *    TMC-1800, TMC-18C50, TMC-18C30, TMC-36C70
 * Boards supported:
 *    Future Domain TMC-1650, TMC-1660, TMC-1670, TMC-1680, TMC-1610M/MER/MEX
 *    Future Domain TMC-3260 (PCI)
 *    Quantum ISA-200S, ISA-250MG
 *    Adaptec AHA-2920A (PCI) [BUT *NOT* AHA-2920C -- use aic7xxx instead]
 *    IBM ?
 *
 * NOTE:
 *
 * The Adaptec AHA-2920C has an Adaptec AIC-7850 chip on it.
 * Use the aic7xxx driver for this board.
 *
 * The Adaptec AHA-2920A has a Future Domain chip on it, so this is the right
 * driver for that card.  Unfortunately, the boxes will probably just say
 * "2920", so you'll have to look on the card for a Future Domain logo, or a
 * letter after the 2920.
 *
 * If you have a TMC-8xx or TMC-9xx board, then this is not the driver for
 * your board.
 *
 * DESCRIPTION:
 *
 * This is the Linux low-level SCSI driver for Future Domain TMC-1660/1680
 * TMC-1650/1670, and TMC-3260 SCSI host adapters.  The 1650 and 1670 have a
 * 25-pin external connector, whereas the 1660 and 1680 have a SCSI-2 50-pin
 * high-density external connector.  The 1670 and 1680 have floppy disk
 * controllers built in.  The TMC-3260 is a PCI bus card.
 *
 * Future Domain's older boards are based on the TMC-1800 chip, and this
 * driver was originally written for a TMC-1680 board with the TMC-1800 chip.
 * More recently, boards are being produced with the TMC-18C50 and TMC-18C30
 * chips.
 *
 * Please note that the drive ordering that Future Domain implemented in BIOS
 * versions 3.4 and 3.5 is the opposite of the order (currently) used by the
 * rest of the SCSI industry.
 *
 *
 * REFERENCES USED:
 *
 * "TMC-1800 SCSI Chip Specification (FDC-1800T)", Future Domain Corporation,
 * 1990.
 *
 * "Technical Reference Manual: 18C50 SCSI Host Adapter Chip", Future Domain
 * Corporation, January 1992.
 *
 * "LXT SCSI Products: Specifications and OEM Technical Manual (Revision
 * B/September 1991)", Maxtor Corporation, 1991.
 *
 * "7213S product Manual (Revision P3)", Maxtor Corporation, 1992.
 *
 * "Draft Proposed American National Standard: Small Computer System
 * Interface - 2 (SCSI-2)", Global Engineering Documents. (X3T9.2/86-109,
 * revision 10h, October 17, 1991)
 *
 * Private communications, Drew Eckhardt (drew@cs.colorado.edu) and Eric
 * Youngdale (ericy@cais.com), 1992.
 *
 * Private communication, Tuong Le (Future Domain Engineering department),
 * 1994. (Disk geometry computations for Future Domain BIOS version 3.4, and
 * TMC-18C30 detection.)
 *
 * Hogan, Thom. The Programmer's PC Sourcebook. Microsoft Press, 1988. Page
 * 60 (2.39: Disk Partition Table Layout).
 *
 * "18C30 Technical Reference Manual", Future Domain Corporation, 1993, page
 * 6-1.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/workqueue.h>
#include <scsi/scsicam.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include "fdomain.h"

/*
 * FIFO_COUNT: The host adapter has an 8K cache (host adapters based on the
 * 18C30 chip have a 2k cache).  When this many 512 byte blocks are filled by
 * the SCSI device, an interrupt will be raised.  Therefore, this could be as
 * low as 0, or as high as 16.  Note, however, that values which are too high
 * or too low seem to prevent any interrupts from occurring, and thereby lock
 * up the machine.
 */
#define FIFO_COUNT      2       /* Number of 512 byte blocks before INTR */
#define PARITY_MASK     ACTL_PAREN      /* Parity enabled, 0 = disabled */

enum chip_type {
        unknown         = 0x00,
        tmc1800         = 0x01,
        tmc18c50        = 0x02,
        tmc18c30        = 0x03,
};

struct fdomain {
        int base;
        struct scsi_cmnd *cur_cmd;
        enum chip_type chip;
        struct work_struct work;
};

static struct scsi_pointer *fdomain_scsi_pointer(struct scsi_cmnd *cmd)
{
        return scsi_cmd_priv(cmd);
}

static inline void fdomain_make_bus_idle(struct fdomain *fd)
{
        outb(0, fd->base + REG_BCTL);
        outb(0, fd->base + REG_MCTL);
        if (fd->chip == tmc18c50 || fd->chip == tmc18c30)
                /* Clear forced intr. */
                outb(ACTL_RESET | ACTL_CLRFIRQ | PARITY_MASK,
                     fd->base + REG_ACTL);
        else
                outb(ACTL_RESET | PARITY_MASK, fd->base + REG_ACTL);
}

static enum chip_type fdomain_identify(int port)
{
        u16 id = inb(port + REG_ID_LSB) | inb(port + REG_ID_MSB) << 8;

        switch (id) {
        case 0x6127:
                return tmc1800;
        case 0x60e9: /* 18c50 or 18c30 */
                break;
        default:
                return unknown;
        }

        /* Try to toggle 32-bit mode. This only works on an 18c30 chip. */
        outb(CFG2_32BIT, port + REG_CFG2);
        if ((inb(port + REG_CFG2) & CFG2_32BIT)) {
                outb(0, port + REG_CFG2);
                if ((inb(port + REG_CFG2) & CFG2_32BIT) == 0)
                        return tmc18c30;
        }
        /* If that failed, we are an 18c50. */
        return tmc18c50;
}

static int fdomain_test_loopback(int base)
{
        int i;

        for (i = 0; i < 255; i++) {
                outb(i, base + REG_LOOPBACK);
                if (inb(base + REG_LOOPBACK) != i)
                        return 1;
        }

        return 0;
}

static void fdomain_reset(int base)
{
        outb(BCTL_RST, base + REG_BCTL);
        mdelay(20);
        outb(0, base + REG_BCTL);
        mdelay(1150);
        outb(0, base + REG_MCTL);
        outb(PARITY_MASK, base + REG_ACTL);
}

static int fdomain_select(struct Scsi_Host *sh, int target)
{
        int status;
        unsigned long timeout;
        struct fdomain *fd = shost_priv(sh);

        outb(BCTL_BUSEN | BCTL_SEL, fd->base + REG_BCTL);
        outb(BIT(sh->this_id) | BIT(target), fd->base + REG_SCSI_DATA_NOACK);

        /* Stop arbitration and enable parity */
        outb(PARITY_MASK, fd->base + REG_ACTL);

        timeout = 350;  /* 350 msec */

        do {
                status = inb(fd->base + REG_BSTAT);
                if (status & BSTAT_BSY) {
                        /* Enable SCSI Bus */
                        /* (on error, should make bus idle with 0) */
                        outb(BCTL_BUSEN, fd->base + REG_BCTL);
                        return 0;
                }
                mdelay(1);
        } while (--timeout);
        fdomain_make_bus_idle(fd);
        return 1;
}

static void fdomain_finish_cmd(struct fdomain *fd)
{
        outb(0, fd->base + REG_ICTL);
        fdomain_make_bus_idle(fd);
        scsi_done(fd->cur_cmd);
        fd->cur_cmd = NULL;
}

static void fdomain_read_data(struct scsi_cmnd *cmd)
{
        struct fdomain *fd = shost_priv(cmd->device->host);
        unsigned char *virt, *ptr;
        size_t offset, len;

        while ((len = inw(fd->base + REG_FIFO_COUNT)) > 0) {
                offset = scsi_bufflen(cmd) - scsi_get_resid(cmd);
                virt = scsi_kmap_atomic_sg(scsi_sglist(cmd), scsi_sg_count(cmd),
                                           &offset, &len);
                ptr = virt + offset;
                if (len & 1)
                        *ptr++ = inb(fd->base + REG_FIFO);
                if (len > 1)
                        insw(fd->base + REG_FIFO, ptr, len >> 1);
                scsi_set_resid(cmd, scsi_get_resid(cmd) - len);
                scsi_kunmap_atomic_sg(virt);
        }
}

static void fdomain_write_data(struct scsi_cmnd *cmd)
{
        struct fdomain *fd = shost_priv(cmd->device->host);
        /* 8k FIFO for pre-tmc18c30 chips, 2k FIFO for tmc18c30 */
        int FIFO_Size = fd->chip == tmc18c30 ? 0x800 : 0x2000;
        unsigned char *virt, *ptr;
        size_t offset, len;

        while ((len = FIFO_Size - inw(fd->base + REG_FIFO_COUNT)) > 512) {
                offset = scsi_bufflen(cmd) - scsi_get_resid(cmd);
                if (len + offset > scsi_bufflen(cmd)) {
                        len = scsi_bufflen(cmd) - offset;
                        if (len == 0)
                                break;
                }
                virt = scsi_kmap_atomic_sg(scsi_sglist(cmd), scsi_sg_count(cmd),
                                           &offset, &len);
                ptr = virt + offset;
                if (len & 1)
                        outb(*ptr++, fd->base + REG_FIFO);
                if (len > 1)
                        outsw(fd->base + REG_FIFO, ptr, len >> 1);
                scsi_set_resid(cmd, scsi_get_resid(cmd) - len);
                scsi_kunmap_atomic_sg(virt);
        }
}

static void fdomain_work(struct work_struct *work)
{
        struct fdomain *fd = container_of(work, struct fdomain, work);
        struct Scsi_Host *sh = container_of((void *)fd, struct Scsi_Host,
                                            hostdata);
        struct scsi_cmnd *cmd = fd->cur_cmd;
        struct scsi_pointer *scsi_pointer = fdomain_scsi_pointer(cmd);
        unsigned long flags;
        int status;
        int done = 0;

        spin_lock_irqsave(sh->host_lock, flags);

        if (scsi_pointer->phase & in_arbitration) {
                status = inb(fd->base + REG_ASTAT);
                if (!(status & ASTAT_ARB)) {
                        set_host_byte(cmd, DID_BUS_BUSY);
                        fdomain_finish_cmd(fd);
                        goto out;
                }
                scsi_pointer->phase = in_selection;

                outb(ICTL_SEL | FIFO_COUNT, fd->base + REG_ICTL);
                outb(BCTL_BUSEN | BCTL_SEL, fd->base + REG_BCTL);
                outb(BIT(cmd->device->host->this_id) | BIT(scmd_id(cmd)),
                     fd->base + REG_SCSI_DATA_NOACK);
                /* Stop arbitration and enable parity */
                outb(ACTL_IRQEN | PARITY_MASK, fd->base + REG_ACTL);
                goto out;
        } else if (scsi_pointer->phase & in_selection) {
                status = inb(fd->base + REG_BSTAT);
                if (!(status & BSTAT_BSY)) {
                        /* Try again, for slow devices */
                        if (fdomain_select(cmd->device->host, scmd_id(cmd))) {
                                set_host_byte(cmd, DID_NO_CONNECT);
                                fdomain_finish_cmd(fd);
                                goto out;
                        }
                        /* Stop arbitration and enable parity */
                        outb(ACTL_IRQEN | PARITY_MASK, fd->base + REG_ACTL);
                }
                scsi_pointer->phase = in_other;
                outb(ICTL_FIFO | ICTL_REQ | FIFO_COUNT, fd->base + REG_ICTL);
                outb(BCTL_BUSEN, fd->base + REG_BCTL);
                goto out;
        }

        /* fdomain_scsi_pointer(cur_cmd)->phase == in_other: this is the body of the routine */
        status = inb(fd->base + REG_BSTAT);

        if (status & BSTAT_REQ) {
                switch (status & (BSTAT_MSG | BSTAT_CMD | BSTAT_IO)) {
                case BSTAT_CMD: /* COMMAND OUT */
                        outb(cmd->cmnd[scsi_pointer->sent_command++],
                             fd->base + REG_SCSI_DATA);
                        break;
                case 0: /* DATA OUT -- tmc18c50/tmc18c30 only */
                        if (fd->chip != tmc1800 && !scsi_pointer->have_data_in) {
                                scsi_pointer->have_data_in = -1;
                                outb(ACTL_IRQEN | ACTL_FIFOWR | ACTL_FIFOEN |
                                     PARITY_MASK, fd->base + REG_ACTL);
                        }
                        break;
                case BSTAT_IO:  /* DATA IN -- tmc18c50/tmc18c30 only */
                        if (fd->chip != tmc1800 && !scsi_pointer->have_data_in) {
                                scsi_pointer->have_data_in = 1;
                                outb(ACTL_IRQEN | ACTL_FIFOEN | PARITY_MASK,
                                     fd->base + REG_ACTL);
                        }
                        break;
                case BSTAT_CMD | BSTAT_IO:      /* STATUS IN */
                        scsi_pointer->Status = inb(fd->base + REG_SCSI_DATA);
                        break;
                case BSTAT_MSG | BSTAT_CMD:     /* MESSAGE OUT */
                        outb(MESSAGE_REJECT, fd->base + REG_SCSI_DATA);
                        break;
                case BSTAT_MSG | BSTAT_CMD | BSTAT_IO:  /* MESSAGE IN */
                        scsi_pointer->Message = inb(fd->base + REG_SCSI_DATA);
                        if (scsi_pointer->Message == COMMAND_COMPLETE)
                                ++done;
                        break;
                }
        }

        if (fd->chip == tmc1800 && !scsi_pointer->have_data_in &&
            scsi_pointer->sent_command >= cmd->cmd_len) {
                if (cmd->sc_data_direction == DMA_TO_DEVICE) {
                        scsi_pointer->have_data_in = -1;
                        outb(ACTL_IRQEN | ACTL_FIFOWR | ACTL_FIFOEN |
                             PARITY_MASK, fd->base + REG_ACTL);
                } else {
                        scsi_pointer->have_data_in = 1;
                        outb(ACTL_IRQEN | ACTL_FIFOEN | PARITY_MASK,
                             fd->base + REG_ACTL);
                }
        }

        if (scsi_pointer->have_data_in == -1) /* DATA OUT */
                fdomain_write_data(cmd);

        if (scsi_pointer->have_data_in == 1) /* DATA IN */
                fdomain_read_data(cmd);

        if (done) {
                set_status_byte(cmd, scsi_pointer->Status);
                set_host_byte(cmd, DID_OK);
                scsi_msg_to_host_byte(cmd, scsi_pointer->Message);
                fdomain_finish_cmd(fd);
        } else {
                if (scsi_pointer->phase & disconnect) {
                        outb(ICTL_FIFO | ICTL_SEL | ICTL_REQ | FIFO_COUNT,
                             fd->base + REG_ICTL);
                        outb(0, fd->base + REG_BCTL);
                } else
                        outb(ICTL_FIFO | ICTL_REQ | FIFO_COUNT,
                             fd->base + REG_ICTL);
        }
out:
        spin_unlock_irqrestore(sh->host_lock, flags);
}

static irqreturn_t fdomain_irq(int irq, void *dev_id)
{
        struct fdomain *fd = dev_id;

        /* Is it our IRQ? */
        if ((inb(fd->base + REG_ASTAT) & ASTAT_IRQ) == 0)
                return IRQ_NONE;

        outb(0, fd->base + REG_ICTL);

        /* We usually have one spurious interrupt after each command. */
        if (!fd->cur_cmd)       /* Spurious interrupt */
                return IRQ_NONE;

        schedule_work(&fd->work);

        return IRQ_HANDLED;
}

static enum scsi_qc_status fdomain_queue(struct Scsi_Host *sh,
                                         struct scsi_cmnd *cmd)
{
        struct scsi_pointer *scsi_pointer = fdomain_scsi_pointer(cmd);
        struct fdomain *fd = shost_priv(cmd->device->host);
        unsigned long flags;

        scsi_pointer->Status            = 0;
        scsi_pointer->Message           = 0;
        scsi_pointer->have_data_in      = 0;
        scsi_pointer->sent_command      = 0;
        scsi_pointer->phase             = in_arbitration;
        scsi_set_resid(cmd, scsi_bufflen(cmd));

        spin_lock_irqsave(sh->host_lock, flags);

        fd->cur_cmd = cmd;

        fdomain_make_bus_idle(fd);

        /* Start arbitration */
        outb(0, fd->base + REG_ICTL);
        outb(0, fd->base + REG_BCTL);   /* Disable data drivers */
        /* Set our id bit */
        outb(BIT(cmd->device->host->this_id), fd->base + REG_SCSI_DATA_NOACK);
        outb(ICTL_ARB, fd->base + REG_ICTL);
        /* Start arbitration */
        outb(ACTL_ARB | ACTL_IRQEN | PARITY_MASK, fd->base + REG_ACTL);

        spin_unlock_irqrestore(sh->host_lock, flags);

        return 0;
}

static int fdomain_abort(struct scsi_cmnd *cmd)
{
        struct Scsi_Host *sh = cmd->device->host;
        struct fdomain *fd = shost_priv(sh);
        unsigned long flags;

        if (!fd->cur_cmd)
                return FAILED;

        spin_lock_irqsave(sh->host_lock, flags);

        fdomain_make_bus_idle(fd);
        fdomain_scsi_pointer(fd->cur_cmd)->phase |= aborted;

        /* Aborts are not done well. . . */
        set_host_byte(fd->cur_cmd, DID_ABORT);
        fdomain_finish_cmd(fd);
        spin_unlock_irqrestore(sh->host_lock, flags);
        return SUCCESS;
}

static int fdomain_host_reset(struct scsi_cmnd *cmd)
{
        struct Scsi_Host *sh = cmd->device->host;
        struct fdomain *fd = shost_priv(sh);
        unsigned long flags;

        spin_lock_irqsave(sh->host_lock, flags);
        fdomain_reset(fd->base);
        spin_unlock_irqrestore(sh->host_lock, flags);
        return SUCCESS;
}

static int fdomain_biosparam(struct scsi_device *sdev,
                             struct gendisk *disk, sector_t capacity,
                             int geom[])
{
        unsigned char *p = scsi_bios_ptable(disk);

        if (p && p[65] == 0xaa && p[64] == 0x55 /* Partition table valid */
            && p[4]) {   /* Partition type */
                geom[0] = p[5] + 1;     /* heads */
                geom[1] = p[6] & 0x3f;  /* sectors */
        } else {
                if (capacity >= 0x7e0000) {
                        geom[0] = 255;  /* heads */
                        geom[1] = 63;   /* sectors */
                } else if (capacity >= 0x200000) {
                        geom[0] = 128;  /* heads */
                        geom[1] = 63;   /* sectors */
                } else {
                        geom[0] = 64;   /* heads */
                        geom[1] = 32;   /* sectors */
                }
        }
        geom[2] = sector_div(capacity, geom[0] * geom[1]);
        kfree(p);

        return 0;
}

static const struct scsi_host_template fdomain_template = {
        .module                 = THIS_MODULE,
        .name                   = "Future Domain TMC-16x0",
        .proc_name              = "fdomain",
        .queuecommand           = fdomain_queue,
        .eh_abort_handler       = fdomain_abort,
        .eh_host_reset_handler  = fdomain_host_reset,
        .bios_param             = fdomain_biosparam,
        .can_queue              = 1,
        .this_id                = 7,
        .sg_tablesize           = 64,
        .dma_boundary           = PAGE_SIZE - 1,
        .cmd_size               = sizeof(struct scsi_pointer),
};

struct Scsi_Host *fdomain_create(int base, int irq, int this_id,
                                 struct device *dev)
{
        struct Scsi_Host *sh;
        struct fdomain *fd;
        enum chip_type chip;
        static const char * const chip_names[] = {
                "Unknown", "TMC-1800", "TMC-18C50", "TMC-18C30"
        };
        unsigned long irq_flags = 0;

        chip = fdomain_identify(base);
        if (!chip)
                return NULL;

        fdomain_reset(base);

        if (fdomain_test_loopback(base))
                return NULL;

        if (!irq) {
                dev_err(dev, "card has no IRQ assigned");
                return NULL;
        }

        sh = scsi_host_alloc(&fdomain_template, sizeof(struct fdomain));
        if (!sh)
                return NULL;

        if (this_id)
                sh->this_id = this_id & 0x07;

        sh->irq = irq;
        sh->io_port = base;
        sh->n_io_port = FDOMAIN_REGION_SIZE;

        fd = shost_priv(sh);
        fd->base = base;
        fd->chip = chip;
        INIT_WORK(&fd->work, fdomain_work);

        if (dev_is_pci(dev) || !strcmp(dev->bus->name, "pcmcia"))
                irq_flags = IRQF_SHARED;

        if (request_irq(irq, fdomain_irq, irq_flags, "fdomain", fd))
                goto fail_put;

        shost_printk(KERN_INFO, sh, "%s chip at 0x%x irq %d SCSI ID %d\n",
                     dev_is_pci(dev) ? "TMC-36C70 (PCI bus)" : chip_names[chip],
                     base, irq, sh->this_id);

        if (scsi_add_host(sh, dev))
                goto fail_free_irq;

        scsi_scan_host(sh);

        return sh;

fail_free_irq:
        free_irq(irq, fd);
fail_put:
        scsi_host_put(sh);
        return NULL;
}
EXPORT_SYMBOL_GPL(fdomain_create);

int fdomain_destroy(struct Scsi_Host *sh)
{
        struct fdomain *fd = shost_priv(sh);

        cancel_work_sync(&fd->work);
        scsi_remove_host(sh);
        if (sh->irq)
                free_irq(sh->irq, fd);
        scsi_host_put(sh);
        return 0;
}
EXPORT_SYMBOL_GPL(fdomain_destroy);

#ifdef CONFIG_PM_SLEEP
static int fdomain_resume(struct device *dev)
{
        struct fdomain *fd = shost_priv(dev_get_drvdata(dev));

        fdomain_reset(fd->base);
        return 0;
}

static SIMPLE_DEV_PM_OPS(fdomain_pm_ops, NULL, fdomain_resume);
#endif /* CONFIG_PM_SLEEP */

MODULE_AUTHOR("Ondrej Zary, Rickard E. Faith");
MODULE_DESCRIPTION("Future Domain TMC-16x0/TMC-3260 SCSI driver");
MODULE_LICENSE("GPL");