// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for Freecom USB/IDE adaptor
 *
 * Freecom v0.1:
 *
 * First release
 *
 * Current development and maintenance by:
 *   (C) 2000 David Brown <usb-storage@davidb.org>
 *
 * This driver was developed with information provided in FREECOM's USB
 * Programmers Reference Guide.  For further information contact Freecom
 * (https://www.freecom.de/)
 */

#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include "usb.h"
#include "transport.h"
#include "protocol.h"
#include "debug.h"
#include "scsiglue.h"

#define DRV_NAME "ums-freecom"

MODULE_DESCRIPTION("Driver for Freecom USB/IDE adaptor");
MODULE_AUTHOR("David Brown <usb-storage@davidb.org>");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("USB_STORAGE");

#ifdef CONFIG_USB_STORAGE_DEBUG
static void pdump(struct us_data *us, void *ibuffer, int length);
#endif

/* Bits of HD_STATUS */
#define ERR_STAT                0x01
#define DRQ_STAT                0x08

/* All of the outgoing packets are 64 bytes long. */
struct freecom_cb_wrap {
        u8    Type;             /* Command type. */
        u8    Timeout;          /* Timeout in seconds. */
        u8    Atapi[12];        /* An ATAPI packet. */
        u8    Filler[50];       /* Padding Data. */
};

struct freecom_xfer_wrap {
        u8    Type;             /* Command type. */
        u8    Timeout;          /* Timeout in seconds. */
        __le32   Count;         /* Number of bytes to transfer. */
        u8    Pad[58];
} __attribute__ ((packed));

struct freecom_ide_out {
        u8    Type;             /* Type + IDE register. */
        u8    Pad;
        __le16   Value;         /* Value to write. */
        u8    Pad2[60];
};

struct freecom_ide_in {
        u8    Type;             /* Type | IDE register. */
        u8    Pad[63];
};

struct freecom_status {
        u8    Status;
        u8    Reason;
        __le16   Count;
        u8    Pad[60];
};

/*
 * Freecom stuffs the interrupt status in the INDEX_STAT bit of the ide
 * register.
 */
#define FCM_INT_STATUS          0x02 /* INDEX_STAT */
#define FCM_STATUS_BUSY         0x80

/*
 * These are the packet types.  The low bit indicates that this command
 * should wait for an interrupt.
 */
#define FCM_PACKET_ATAPI        0x21
#define FCM_PACKET_STATUS       0x20

/*
 * Receive data from the IDE interface.  The ATAPI packet has already
 * waited, so the data should be immediately available.
 */
#define FCM_PACKET_INPUT        0x81

/* Send data to the IDE interface. */
#define FCM_PACKET_OUTPUT       0x01

/*
 * Write a value to an ide register.  Or the ide register to write after
 * munging the address a bit.
 */
#define FCM_PACKET_IDE_WRITE    0x40
#define FCM_PACKET_IDE_READ     0xC0

/* All packets (except for status) are 64 bytes long. */
#define FCM_PACKET_LENGTH               64
#define FCM_STATUS_PACKET_LENGTH        4

static int init_freecom(struct us_data *us);


/*
 * The table of devices
 */
#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
                    vendorName, productName, useProtocol, useTransport, \
                    initFunction, flags) \
{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
  .driver_info = (flags) }

static const struct usb_device_id freecom_usb_ids[] = {
#       include "unusual_freecom.h"
        { }             /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, freecom_usb_ids);

#undef UNUSUAL_DEV

/*
 * The flags table
 */
#define UNUSUAL_DEV(idVendor, idProduct, bcdDeviceMin, bcdDeviceMax, \
                    vendor_name, product_name, use_protocol, use_transport, \
                    init_function, Flags) \
{ \
        .vendorName = vendor_name,      \
        .productName = product_name,    \
        .useProtocol = use_protocol,    \
        .useTransport = use_transport,  \
        .initFunction = init_function,  \
}

static const struct us_unusual_dev freecom_unusual_dev_list[] = {
#       include "unusual_freecom.h"
        { }             /* Terminating entry */
};

#undef UNUSUAL_DEV

static int
freecom_readdata (struct scsi_cmnd *srb, struct us_data *us,
                unsigned int ipipe, unsigned int opipe, int count)
{
        struct freecom_xfer_wrap *fxfr =
                (struct freecom_xfer_wrap *) us->iobuf;
        int result;

        fxfr->Type = FCM_PACKET_INPUT | 0x00;
        fxfr->Timeout = 0;    /* Short timeout for debugging. */
        fxfr->Count = cpu_to_le32 (count);
        memset (fxfr->Pad, 0, sizeof (fxfr->Pad));

        usb_stor_dbg(us, "Read data Freecom! (c=%d)\n", count);

        /* Issue the transfer command. */
        result = usb_stor_bulk_transfer_buf (us, opipe, fxfr,
                        FCM_PACKET_LENGTH, NULL);
        if (result != USB_STOR_XFER_GOOD) {
                usb_stor_dbg(us, "Freecom readdata transport error\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        /* Now transfer all of our blocks. */
        usb_stor_dbg(us, "Start of read\n");
        result = usb_stor_bulk_srb(us, ipipe, srb);
        usb_stor_dbg(us, "freecom_readdata done!\n");

        if (result > USB_STOR_XFER_SHORT)
                return USB_STOR_TRANSPORT_ERROR;
        return USB_STOR_TRANSPORT_GOOD;
}

static int
freecom_writedata (struct scsi_cmnd *srb, struct us_data *us,
                int unsigned ipipe, unsigned int opipe, int count)
{
        struct freecom_xfer_wrap *fxfr =
                (struct freecom_xfer_wrap *) us->iobuf;
        int result;

        fxfr->Type = FCM_PACKET_OUTPUT | 0x00;
        fxfr->Timeout = 0;    /* Short timeout for debugging. */
        fxfr->Count = cpu_to_le32 (count);
        memset (fxfr->Pad, 0, sizeof (fxfr->Pad));

        usb_stor_dbg(us, "Write data Freecom! (c=%d)\n", count);

        /* Issue the transfer command. */
        result = usb_stor_bulk_transfer_buf (us, opipe, fxfr,
                        FCM_PACKET_LENGTH, NULL);
        if (result != USB_STOR_XFER_GOOD) {
                usb_stor_dbg(us, "Freecom writedata transport error\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        /* Now transfer all of our blocks. */
        usb_stor_dbg(us, "Start of write\n");
        result = usb_stor_bulk_srb(us, opipe, srb);

        usb_stor_dbg(us, "freecom_writedata done!\n");
        if (result > USB_STOR_XFER_SHORT)
                return USB_STOR_TRANSPORT_ERROR;
        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Transport for the Freecom USB/IDE adaptor.
 *
 */
static int freecom_transport(struct scsi_cmnd *srb, struct us_data *us)
{
        struct freecom_cb_wrap *fcb;
        struct freecom_status  *fst;
        unsigned int ipipe, opipe;              /* We need both pipes. */
        int result;
        unsigned int partial;
        int length;

        fcb = (struct freecom_cb_wrap *) us->iobuf;
        fst = (struct freecom_status *) us->iobuf;

        usb_stor_dbg(us, "Freecom TRANSPORT STARTED\n");

        /* Get handles for both transports. */
        opipe = us->send_bulk_pipe;
        ipipe = us->recv_bulk_pipe;

        /* The ATAPI Command always goes out first. */
        fcb->Type = FCM_PACKET_ATAPI | 0x00;
        fcb->Timeout = 0;
        memcpy (fcb->Atapi, srb->cmnd, 12);
        memset (fcb->Filler, 0, sizeof (fcb->Filler));

        US_DEBUG(pdump(us, srb->cmnd, 12));

        /* Send it out. */
        result = usb_stor_bulk_transfer_buf (us, opipe, fcb,
                        FCM_PACKET_LENGTH, NULL);

        /*
         * The Freecom device will only fail if there is something wrong in
         * USB land.  It returns the status in its own registers, which
         * come back in the bulk pipe.
         */
        if (result != USB_STOR_XFER_GOOD) {
                usb_stor_dbg(us, "freecom transport error\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        /*
         * There are times we can optimize out this status read, but it
         * doesn't hurt us to always do it now.
         */
        result = usb_stor_bulk_transfer_buf (us, ipipe, fst,
                        FCM_STATUS_PACKET_LENGTH, &partial);
        usb_stor_dbg(us, "foo Status result %d %u\n", result, partial);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUG(pdump(us, (void *)fst, partial));

        /*
         * The firmware will time-out commands after 20 seconds. Some commands
         * can legitimately take longer than this, so we use a different
         * command that only waits for the interrupt and then sends status,
         * without having to send a new ATAPI command to the device.
         *
         * NOTE: There is some indication that a data transfer after a timeout
         * may not work, but that is a condition that should never happen.
         */
        while (fst->Status & FCM_STATUS_BUSY) {
                usb_stor_dbg(us, "20 second USB/ATAPI bridge TIMEOUT occurred!\n");
                usb_stor_dbg(us, "fst->Status is %x\n", fst->Status);

                /* Get the status again */
                fcb->Type = FCM_PACKET_STATUS;
                fcb->Timeout = 0;
                memset (fcb->Atapi, 0, sizeof(fcb->Atapi));
                memset (fcb->Filler, 0, sizeof (fcb->Filler));

                /* Send it out. */
                result = usb_stor_bulk_transfer_buf (us, opipe, fcb,
                                FCM_PACKET_LENGTH, NULL);

                /*
                 * The Freecom device will only fail if there is something
                 * wrong in USB land.  It returns the status in its own
                 * registers, which come back in the bulk pipe.
                 */
                if (result != USB_STOR_XFER_GOOD) {
                        usb_stor_dbg(us, "freecom transport error\n");
                        return USB_STOR_TRANSPORT_ERROR;
                }

                /* get the data */
                result = usb_stor_bulk_transfer_buf (us, ipipe, fst,
                                FCM_STATUS_PACKET_LENGTH, &partial);

                usb_stor_dbg(us, "bar Status result %d %u\n", result, partial);
                if (result != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                US_DEBUG(pdump(us, (void *)fst, partial));
        }

        if (partial != 4)
                return USB_STOR_TRANSPORT_ERROR;
        if ((fst->Status & 1) != 0) {
                usb_stor_dbg(us, "operation failed\n");
                return USB_STOR_TRANSPORT_FAILED;
        }

        /*
         * The device might not have as much data available as we
         * requested.  If you ask for more than the device has, this reads
         * and such will hang.
         */
        usb_stor_dbg(us, "Device indicates that it has %d bytes available\n",
                     le16_to_cpu(fst->Count));
        usb_stor_dbg(us, "SCSI requested %d\n", scsi_bufflen(srb));

        /* Find the length we desire to read. */
        switch (srb->cmnd[0]) {
        case INQUIRY:
        case REQUEST_SENSE:     /* 16 or 18 bytes? spec says 18, lots of devices only have 16 */
        case MODE_SENSE:
        case MODE_SENSE_10:
                length = le16_to_cpu(fst->Count);
                break;
        default:
                length = scsi_bufflen(srb);
        }

        /* verify that this amount is legal */
        if (length > scsi_bufflen(srb)) {
                length = scsi_bufflen(srb);
                usb_stor_dbg(us, "Truncating request to match buffer length: %d\n",
                             length);
        }

        /*
         * What we do now depends on what direction the data is supposed to
         * move in.
         */

        switch (us->srb->sc_data_direction) {
        case DMA_FROM_DEVICE:
                /* catch bogus "read 0 length" case */
                if (!length)
                        break;
                /*
                 * Make sure that the status indicates that the device
                 * wants data as well.
                 */
                if ((fst->Status & DRQ_STAT) == 0 || (fst->Reason & 3) != 2) {
                        usb_stor_dbg(us, "SCSI wants data, drive doesn't have any\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                result = freecom_readdata (srb, us, ipipe, opipe, length);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        return result;

                usb_stor_dbg(us, "Waiting for status\n");
                result = usb_stor_bulk_transfer_buf (us, ipipe, fst,
                                FCM_PACKET_LENGTH, &partial);
                US_DEBUG(pdump(us, (void *)fst, partial));

                if (partial != 4 || result > USB_STOR_XFER_SHORT)
                        return USB_STOR_TRANSPORT_ERROR;
                if ((fst->Status & ERR_STAT) != 0) {
                        usb_stor_dbg(us, "operation failed\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                if ((fst->Reason & 3) != 3) {
                        usb_stor_dbg(us, "Drive seems still hungry\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                usb_stor_dbg(us, "Transfer happy\n");
                break;

        case DMA_TO_DEVICE:
                /* catch bogus "write 0 length" case */
                if (!length)
                        break;
                /*
                 * Make sure the status indicates that the device wants to
                 * send us data.
                 */
                /* !!IMPLEMENT!! */
                result = freecom_writedata (srb, us, ipipe, opipe, length);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        return result;

                usb_stor_dbg(us, "Waiting for status\n");
                result = usb_stor_bulk_transfer_buf (us, ipipe, fst,
                                FCM_PACKET_LENGTH, &partial);

                if (partial != 4 || result > USB_STOR_XFER_SHORT)
                        return USB_STOR_TRANSPORT_ERROR;
                if ((fst->Status & ERR_STAT) != 0) {
                        usb_stor_dbg(us, "operation failed\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                if ((fst->Reason & 3) != 3) {
                        usb_stor_dbg(us, "Drive seems still hungry\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }

                usb_stor_dbg(us, "Transfer happy\n");
                break;


        case DMA_NONE:
                /* Easy, do nothing. */
                break;

        default:
                /* should never hit here -- filtered in usb.c */
                usb_stor_dbg(us, "freecom unimplemented direction: %d\n",
                             us->srb->sc_data_direction);
                /* Return fail, SCSI seems to handle this better. */
                return USB_STOR_TRANSPORT_FAILED;
        }

        return USB_STOR_TRANSPORT_GOOD;
}

static int init_freecom(struct us_data *us)
{
        int result;
        char *buffer = us->iobuf;

        /*
         * The DMA-mapped I/O buffer is 64 bytes long, just right for
         * all our packets.  No need to allocate any extra buffer space.
         */

        result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
                        0x4c, 0xc0, 0x4346, 0x0, buffer, 0x20, 3*HZ);
        buffer[32] = '\0';
        usb_stor_dbg(us, "String returned from FC init is: %s\n", buffer);

        /*
         * Special thanks to the people at Freecom for providing me with
         * this "magic sequence", which they use in their Windows and MacOS
         * drivers to make sure that all the attached perhiperals are
         * properly reset.
         */

        /* send reset */
        result = usb_stor_control_msg(us, us->send_ctrl_pipe,
                        0x4d, 0x40, 0x24d8, 0x0, NULL, 0x0, 3*HZ);
        usb_stor_dbg(us, "result from activate reset is %d\n", result);

        /* wait 250ms */
        msleep(250);

        /* clear reset */
        result = usb_stor_control_msg(us, us->send_ctrl_pipe,
                        0x4d, 0x40, 0x24f8, 0x0, NULL, 0x0, 3*HZ);
        usb_stor_dbg(us, "result from clear reset is %d\n", result);

        /* wait 3 seconds */
        msleep(3 * 1000);

        return USB_STOR_TRANSPORT_GOOD;
}

static int usb_stor_freecom_reset(struct us_data *us)
{
        printk (KERN_CRIT "freecom reset called\n");

        /* We don't really have this feature. */
        return FAILED;
}

#ifdef CONFIG_USB_STORAGE_DEBUG
static void pdump(struct us_data *us, void *ibuffer, int length)
{
        static char line[80];
        int offset = 0;
        unsigned char *buffer = (unsigned char *) ibuffer;
        int i, j;
        int from, base;

        offset = 0;
        for (i = 0; i < length; i++) {
                if ((i & 15) == 0) {
                        if (i > 0) {
                                offset += sprintf (line+offset, " - ");
                                for (j = i - 16; j < i; j++) {
                                        if (buffer[j] >= 32 && buffer[j] <= 126)
                                                line[offset++] = buffer[j];
                                        else
                                                line[offset++] = '.';
                                }
                                line[offset] = 0;
                                usb_stor_dbg(us, "%s\n", line);
                                offset = 0;
                        }
                        offset += sprintf (line+offset, "%08x:", i);
                } else if ((i & 7) == 0) {
                        offset += sprintf (line+offset, " -");
                }
                offset += sprintf (line+offset, " %02x", buffer[i] & 0xff);
        }

        /* Add the last "chunk" of data. */
        from = (length - 1) % 16;
        base = ((length - 1) / 16) * 16;

        for (i = from + 1; i < 16; i++)
                offset += sprintf (line+offset, "   ");
        if (from < 8)
                offset += sprintf (line+offset, "  ");
        offset += sprintf (line+offset, " - ");

        for (i = 0; i <= from; i++) {
                if (buffer[base+i] >= 32 && buffer[base+i] <= 126)
                        line[offset++] = buffer[base+i];
                else
                        line[offset++] = '.';
        }
        line[offset] = 0;
        usb_stor_dbg(us, "%s\n", line);
}
#endif

static struct scsi_host_template freecom_host_template;

static int freecom_probe(struct usb_interface *intf,
                         const struct usb_device_id *id)
{
        struct us_data *us;
        int result;

        result = usb_stor_probe1(&us, intf, id,
                        (id - freecom_usb_ids) + freecom_unusual_dev_list,
                        &freecom_host_template);
        if (result)
                return result;

        us->transport_name = "Freecom";
        us->transport = freecom_transport;
        us->transport_reset = usb_stor_freecom_reset;
        us->max_lun = 0;

        result = usb_stor_probe2(us);
        return result;
}

static struct usb_driver freecom_driver = {
        .name =         DRV_NAME,
        .probe =        freecom_probe,
        .disconnect =   usb_stor_disconnect,
        .suspend =      usb_stor_suspend,
        .resume =       usb_stor_resume,
        .reset_resume = usb_stor_reset_resume,
        .pre_reset =    usb_stor_pre_reset,
        .post_reset =   usb_stor_post_reset,
        .id_table =     freecom_usb_ids,
        .soft_unbind =  1,
        .no_dynamic_id = 1,
};

module_usb_stor_driver(freecom_driver, freecom_host_template, DRV_NAME);