/* Driver for Freecom USB/IDE adaptor
 *
 * $Id: freecom.c,v 1.19 2001/11/11 05:42:34 mdharm Exp $
 *
 * Freecom v0.1:
 *
 * First release
 *
 * Current development and maintenance by:
 *   (C) 2000 David Brown <usb-storage@davidb.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * This driver was developed with information provided in FREECOM's USB
 * Programmers Reference Guide.  For further information contact Freecom
 * (http://www.freecom.de/)
 */

#include <linux/config.h>
#include "transport.h"
#include "protocol.h"
#include "usb.h"
#include "debug.h"
#include "freecom.h"
#include "linux/hdreg.h"

#ifdef CONFIG_USB_STORAGE_DEBUG
static void pdump (void *, int);
#endif

struct freecom_udata {
        __u8    buffer[64];             /* Common command block. */
};
typedef struct freecom_udata *freecom_udata_t;

/* 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. */
        __u32   Count;                  /* Number of bytes to transfer. */
        __u8    Pad[58];
} __attribute__ ((packed));

struct freecom_ide_out {
        __u8    Type;                   /* Type + IDE register. */
        __u8    Pad;
        __u16   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;
        __u16   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

/*
 * Transfer an entire SCSI command's worth of data payload over the bulk
 * pipe.
 *
 * Note that this uses usb_stor_transfer_partial to achieve it's goals -- this
 * function simply determines if we're going to use scatter-gather or not,
 * and acts appropriately.  For now, it also re-interprets the error codes.
 */
static void us_transfer_freecom(Scsi_Cmnd *srb, struct us_data* us, int transfer_amount)
{
	int i;
	int result = -1;
	struct scatterlist *sg;
	unsigned int total_transferred = 0;

	/* was someone foolish enough to request more data than available
	 * buffer space? */
	if (transfer_amount > srb->request_bufflen)
		transfer_amount = srb->request_bufflen;

	/* are we scatter-gathering? */
	if (srb->use_sg) {

		/* loop over all the scatter gather structures and 
		 * make the appropriate requests for each, until done
		 */
		sg = (struct scatterlist *) srb->request_buffer;
		for (i = 0; i < srb->use_sg; i++) {

			US_DEBUGP("transfer_amount: %d and total_transferred: %d\n", transfer_amount, total_transferred);

			/* End this if we're done */
			if (transfer_amount == total_transferred)
				break;

			/* transfer the lesser of the next buffer or the
			 * remaining data */
			if (transfer_amount - total_transferred >= 
					sg[i].length) {
				result = usb_stor_transfer_partial(us,
						sg[i].address, sg[i].length);
				total_transferred += sg[i].length;
			} else {
				result = usb_stor_transfer_partial(us,
						sg[i].address,
						transfer_amount - total_transferred);
				total_transferred += transfer_amount - total_transferred;
			}

			/* if we get an error, end the loop here */
			if (result)
				break;
		}
	}
	else
		/* no scatter-gather, just make the request */
		result = usb_stor_transfer_partial(us, srb->request_buffer, 
					     transfer_amount);

	/* return the result in the data structure itself */
	srb->result = result;
}

#if 0
/* Write a value to an ide register. */
static int
freecom_ide_write (struct us_data *us, int reg, int value)
{
        freecom_udata_t extra = (freecom_udata_t) us->extra;
        struct freecom_ide_out *ideout =
                (struct freecom_ide_out *) extra->buffer;
        int opipe;
        int result, partial;

        US_DEBUGP("IDE out 0x%02x <- 0x%02x\n", reg, value);

        /* Get handles for both transports. */
        opipe = usb_sndbulkpipe (us->pusb_dev, us->ep_out);

        if (reg < 0 || reg > 8)
                return USB_STOR_TRANSPORT_ERROR;
        if (reg < 8)
                reg |= 0x20;
        else
                reg = 0x0e;

        ideout->Type = FCM_PACKET_IDE_WRITE | reg;
        ideout->Pad = 0;
        ideout->Value = cpu_to_le16 (value);
        memset (ideout->Pad2, 0, sizeof (ideout->Pad2));

        result = usb_stor_bulk_msg (us, ideout, opipe,
                        FCM_PACKET_LENGTH, &partial);
        if (result != 0) {
                if (result == -ENOENT)
                        return US_BULK_TRANSFER_ABORTED;
                else
                        return USB_STOR_TRANSPORT_ERROR;
        }

        return USB_STOR_TRANSPORT_GOOD;
}
#endif

#if 0 /* Unused at this time */
/* Read a value from an ide register. */
static int
freecom_ide_read (struct us_data *us, int reg, int *value)
{
        freecom_udata_t extra = (freecom_udata_t) us->extra;
        struct freecom_ide_in *idein =
                (struct freecom_ide_in *) extra->buffer;
        __u8 *buffer = extra->buffer;
        int ipipe, opipe;
        int result, partial;
        int desired_length;

        /* Get handles for both transports. */
        opipe = usb_sndbulkpipe (us->pusb_dev, us->ep_out);
        ipipe = usb_rcvbulkpipe (us->pusb_dev, us->ep_in);

        if (reg < 0 || reg > 8)
                return USB_STOR_TRANSPORT_ERROR;
        if (reg < 8)
                reg |= 0x10;
        else
                reg = 0x0e;

        US_DEBUGP("IDE in request for register 0x%02x\n", reg);

        idein->Type = FCM_PACKET_IDE_READ | reg;
        memset (idein->Pad, 0, sizeof (idein->Pad));

        result = usb_stor_bulk_msg (us, idein, opipe,
                        FCM_PACKET_LENGTH, &partial);
        if (result != 0) {
                if (result == -ENOENT)
                        return US_BULK_TRANSFER_ABORTED;
                else
                        return USB_STOR_TRANSPORT_ERROR;
        }

        desired_length = 1;
        if (reg == 0x10)
                desired_length = 2;

        result = usb_stor_bulk_msg (us, buffer, ipipe,
                        desired_length, &partial);
        if (result != 0) {
                if (result == -ENOENT)
                        return US_BULK_TRANSFER_ABORTED;
                else
                        return USB_STOR_TRANSPORT_ERROR;
        }
        US_DEBUGP("IDE in partial is %d\n", partial);

        if (desired_length == 1)
                *value = buffer[0];
        else
                *value = le16_to_cpu (*(__u16 *) buffer);

        US_DEBUGP("IDE in 0x%02x -> 0x%02x\n", reg, *value);

        return USB_STOR_TRANSPORT_GOOD;
}
#endif

static int
freecom_readdata (Scsi_Cmnd *srb, struct us_data *us,
                int ipipe, int opipe, int count)
{
        freecom_udata_t extra = (freecom_udata_t) us->extra;
        struct freecom_xfer_wrap *fxfr =
                (struct freecom_xfer_wrap *) extra->buffer;
        int result, partial;

        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));

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

        /* Issue the transfer command. */
        result = usb_stor_bulk_msg (us, fxfr, opipe,
                        FCM_PACKET_LENGTH, &partial);
        if (result != 0) {
                US_DEBUGP ("Freecom readdata xpot failure: r=%d, p=%d\n",
                                result, partial);

		/* -ENOENT -- we canceled this transfer */
		if (result == -ENOENT) {
			US_DEBUGP("freecom_readdata(): transfer aborted\n");
			return US_BULK_TRANSFER_ABORTED;
		}

                return USB_STOR_TRANSPORT_ERROR;
        }
        US_DEBUGP("Done issuing read request: %d %d\n", result, partial);

        /* Now transfer all of our blocks. */
	US_DEBUGP("Start of read\n");
	us_transfer_freecom(srb, us, count);
        US_DEBUGP("freecom_readdata done!\n");

        return USB_STOR_TRANSPORT_GOOD;
}

static int
freecom_writedata (Scsi_Cmnd *srb, struct us_data *us,
                int ipipe, int opipe, int count)
{
        freecom_udata_t extra = (freecom_udata_t) us->extra;
        struct freecom_xfer_wrap *fxfr =
                (struct freecom_xfer_wrap *) extra->buffer;
        int result, partial;

        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));

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

        /* Issue the transfer command. */
        result = usb_stor_bulk_msg (us, fxfr, opipe,
                        FCM_PACKET_LENGTH, &partial);
        if (result != 0) {
                US_DEBUGP ("Freecom writedata xpot failure: r=%d, p=%d\n",
                                result, partial);

		/* -ENOENT -- we canceled this transfer */
		if (result == -ENOENT) {
			US_DEBUGP("freecom_writedata(): transfer aborted\n");
			return US_BULK_TRANSFER_ABORTED;
		}

                return USB_STOR_TRANSPORT_ERROR;
        }
        US_DEBUGP("Done issuing write request: %d %d\n",
                        result, partial);

        /* Now transfer all of our blocks. */
	US_DEBUGP("Start of write\n");
	us_transfer_freecom(srb, us, count);

        US_DEBUGP("freecom_writedata done!\n");
        return USB_STOR_TRANSPORT_GOOD;
}

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

        extra = (freecom_udata_t) us->extra;

        fcb = (struct freecom_cb_wrap *) extra->buffer;
        fst = (struct freecom_status *) extra->buffer;

        US_DEBUGP("Freecom TRANSPORT STARTED\n");

        /* Get handles for both transports. */
        opipe = usb_sndbulkpipe (us->pusb_dev, us->ep_out);
        ipipe = usb_rcvbulkpipe (us->pusb_dev, us->ep_in);

        /* 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 (srb->cmnd, 12));

        /* Send it out. */
        result = usb_stor_bulk_msg (us, fcb, opipe,
                        FCM_PACKET_LENGTH, &partial);

        /* 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 != 0) {
                US_DEBUGP ("freecom xport failure: r=%d, p=%d\n",
                                result, partial);

		/* -ENOENT -- we canceled this transfer */
		if (result == -ENOENT) {
			US_DEBUGP("freecom_transport(): transfer aborted\n");
			return US_BULK_TRANSFER_ABORTED;
		}

                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_msg (us, fst, ipipe,
                        FCM_PACKET_LENGTH, &partial);
        US_DEBUGP("foo Status result %d %d\n", result, partial);
	/* -ENOENT -- we canceled this transfer */
	if (result == -ENOENT) {
		US_DEBUGP("freecom_transport(): transfer aborted\n");
		return US_BULK_TRANSFER_ABORTED;
	}

        US_DEBUG(pdump ((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) {
		US_DEBUGP("20 second USB/ATAPI bridge TIMEOUT occured!\n");
		US_DEBUGP("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->Filler));
		memset (fcb->Filler, 0, sizeof (fcb->Filler));

        	/* Send it out. */
		result = usb_stor_bulk_msg (us, fcb, opipe,
				FCM_PACKET_LENGTH, &partial);

		/* 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 != 0) {
			US_DEBUGP ("freecom xport failure: r=%d, p=%d\n",
					result, partial);

			/* -ENOENT -- we canceled this transfer */
			if (result == -ENOENT) {
				US_DEBUGP("freecom_transport(): transfer aborted\n");
				return US_BULK_TRANSFER_ABORTED;
			}

			return USB_STOR_TRANSPORT_ERROR;
		}

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

		US_DEBUGP("bar Status result %d %d\n", result, partial);

		/* -ENOENT -- we canceled this transfer */
		if (result == -ENOENT) {
			US_DEBUGP("freecom_transport(): transfer aborted\n");
			return US_BULK_TRANSFER_ABORTED;
		}

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

        if (partial != 4 || result != 0) {
                return USB_STOR_TRANSPORT_ERROR;
        }
        if ((fst->Status & 1) != 0) {
                US_DEBUGP("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. */
        US_DEBUGP("Device indicates that it has %d bytes available\n",
                        le16_to_cpu (fst->Count));

        /* Find the length we desire to read. */
        length = usb_stor_transfer_length (srb);
        US_DEBUGP("SCSI requested %d\n", length);

	/* verify that this amount is legal */
	if (length > srb->request_bufflen) {
		length = srb->request_bufflen;
		US_DEBUGP("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 SCSI_DATA_READ:
                /* Make sure that the status indicates that the device
                 * wants data as well. */
                if ((fst->Status & DRQ_STAT) == 0 || (fst->Reason & 3) != 2) {
                        US_DEBUGP("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;

                US_DEBUGP("FCM: Waiting for status\n");
                result = usb_stor_bulk_msg (us, fst, ipipe,
                                FCM_PACKET_LENGTH, &partial);
		US_DEBUG(pdump ((void *) fst, partial));
                if (result == -ENOENT) {
                        US_DEBUGP ("freecom_transport: transfer aborted\n");
                        return US_BULK_TRANSFER_ABORTED;
                }
                if (partial != 4 || result != 0)
                        return USB_STOR_TRANSPORT_ERROR;
                if ((fst->Status & ERR_STAT) != 0) {
                        US_DEBUGP("operation failed\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                if ((fst->Reason & 3) != 3) {
                        US_DEBUGP("Drive seems still hungry\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                US_DEBUGP("Transfer happy\n");
                break;

        case SCSI_DATA_WRITE:
                /* 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;

                US_DEBUGP("FCM: Waiting for status\n");
                result = usb_stor_bulk_msg (us, fst, ipipe,
                                FCM_PACKET_LENGTH, &partial);
                if (result == -ENOENT) {
                        US_DEBUGP ("freecom_transport: transfer aborted\n");
                        return US_BULK_TRANSFER_ABORTED;
                }
                if (partial != 4 || result != 0)
                        return USB_STOR_TRANSPORT_ERROR;
                if ((fst->Status & ERR_STAT) != 0) {
                        US_DEBUGP("operation failed\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }
                if ((fst->Reason & 3) != 3) {
                        US_DEBUGP("Drive seems still hungry\n");
                        return USB_STOR_TRANSPORT_FAILED;
                }

                US_DEBUGP("Transfer happy\n");
                break;


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

        default:
                US_DEBUGP ("freecom unimplemented direction: %d\n",
                                us->srb->sc_data_direction);
                // Return fail, SCSI seems to handle this better.
                return USB_STOR_TRANSPORT_FAILED;
                break;
        }

        return USB_STOR_TRANSPORT_GOOD;

        US_DEBUGP("Freecom: transfer_length = %d\n",
			usb_stor_transfer_length (srb));

        US_DEBUGP("Freecom: direction = %d\n", srb->sc_data_direction);

        return USB_STOR_TRANSPORT_ERROR;
}

int
freecom_init (struct us_data *us)
{
        int result;
	char buffer[33];

        /* Allocate a buffer for us.  The upper usb transport code will
         * free this for us when cleaning up. */
        if (us->extra == NULL) {
                us->extra = kmalloc (sizeof (struct freecom_udata),
                                GFP_KERNEL);
                if (us->extra == NULL) {
                        US_DEBUGP("Out of memory\n");
                        return USB_STOR_TRANSPORT_ERROR;
                }
        }

	result = usb_control_msg(us->pusb_dev,
			usb_rcvctrlpipe(us->pusb_dev, 0),
			0x4c, 0xc0, 0x4346, 0x0, buffer, 0x20, 3*HZ);
	buffer[32] = '\0';
	US_DEBUGP("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_control_msg(us->pusb_dev,
			usb_sndctrlpipe(us->pusb_dev, 0),
			0x4d, 0x40, 0x24d8, 0x0, NULL, 0x0, 3*HZ);
	US_DEBUGP("result from activate reset is %d\n", result);

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

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

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

        return USB_STOR_TRANSPORT_GOOD;
}

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 (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;
				US_DEBUGP("%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;
	US_DEBUGP("%s\n", line);
	offset = 0;
}
#endif