/* Driver for Rio Karma
 *
 *   (c) 2006 Bob Copeland <me@bobcopeland.com>
 *   (c) 2006 Keith Bennett <keith@mcs.st-and.ac.uk>
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/slab.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>

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

MODULE_DESCRIPTION("Driver for Rio Karma");
MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>, Keith Bennett <keith@mcs.st-and.ac.uk>");
MODULE_LICENSE("GPL");

#define RIO_PREFIX "RIOP\x00"
#define RIO_PREFIX_LEN 5
#define RIO_SEND_LEN 40
#define RIO_RECV_LEN 0x200

#define RIO_ENTER_STORAGE 0x1
#define RIO_LEAVE_STORAGE 0x2
#define RIO_RESET 0xC

struct karma_data {
        int in_storage;
        char *recv;
};

static int rio_karma_init(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)|(USB_US_TYPE_STOR<<24) }

struct usb_device_id karma_usb_ids[] = {
#       include "unusual_karma.h"
        { }             /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, karma_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 struct us_unusual_dev karma_unusual_dev_list[] = {
#       include "unusual_karma.h"
        { }             /* Terminating entry */
};

#undef UNUSUAL_DEV


/*
 * Send commands to Rio Karma.
 *
 * For each command we send 40 bytes starting 'RIOP\0' followed by
 * the command number and a sequence number, which the device will ack
 * with a 512-byte packet with the high four bits set and everything
 * else null.  Then we send 'RIOP\x80' followed by a zero and the
 * sequence number, until byte 5 in the response repeats the sequence
 * number.
 */
static int rio_karma_send_command(char cmd, struct us_data *us)
{
        int result, partial;
        unsigned long timeout;
        static unsigned char seq = 1;
        struct karma_data *data = (struct karma_data *) us->extra;

        US_DEBUGP("karma: sending command %04x\n", cmd);
        memset(us->iobuf, 0, RIO_SEND_LEN);
        memcpy(us->iobuf, RIO_PREFIX, RIO_PREFIX_LEN);
        us->iobuf[5] = cmd;
        us->iobuf[6] = seq;

        timeout = jiffies + msecs_to_jiffies(6000);
        for (;;) {
                result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
                        us->iobuf, RIO_SEND_LEN, &partial);
                if (result != USB_STOR_XFER_GOOD)
                        goto err;

                result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
                        data->recv, RIO_RECV_LEN, &partial);
                if (result != USB_STOR_XFER_GOOD)
                        goto err;

                if (data->recv[5] == seq)
                        break;

                if (time_after(jiffies, timeout))
                        goto err;

                us->iobuf[4] = 0x80;
                us->iobuf[5] = 0;
                msleep(50);
        }

        seq++;
        if (seq == 0)
                seq = 1;

        US_DEBUGP("karma: sent command %04x\n", cmd);
        return 0;
err:
        US_DEBUGP("karma: command %04x failed\n", cmd);
        return USB_STOR_TRANSPORT_FAILED;
}

/*
 * Trap START_STOP and READ_10 to leave/re-enter storage mode.
 * Everything else is propagated to the normal bulk layer.
 */
static int rio_karma_transport(struct scsi_cmnd *srb, struct us_data *us)
{
        int ret;
        struct karma_data *data = (struct karma_data *) us->extra;

        if (srb->cmnd[0] == READ_10 && !data->in_storage) {
                ret = rio_karma_send_command(RIO_ENTER_STORAGE, us);
                if (ret)
                        return ret;

                data->in_storage = 1;
                return usb_stor_Bulk_transport(srb, us);
        } else if (srb->cmnd[0] == START_STOP) {
                ret = rio_karma_send_command(RIO_LEAVE_STORAGE, us);
                if (ret)
                        return ret;

                data->in_storage = 0;
                return rio_karma_send_command(RIO_RESET, us);
        }
        return usb_stor_Bulk_transport(srb, us);
}

static void rio_karma_destructor(void *extra)
{
        struct karma_data *data = (struct karma_data *) extra;
        kfree(data->recv);
}

static int rio_karma_init(struct us_data *us)
{
        int ret = 0;
        struct karma_data *data = kzalloc(sizeof(struct karma_data), GFP_NOIO);
        if (!data)
                goto out;

        data->recv = kmalloc(RIO_RECV_LEN, GFP_NOIO);
        if (!data->recv) {
                kfree(data);
                goto out;
        }

        us->extra = data;
        us->extra_destructor = rio_karma_destructor;
        ret = rio_karma_send_command(RIO_ENTER_STORAGE, us);
        data->in_storage = (ret == 0);
out:
        return ret;
}

static int karma_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 - karma_usb_ids) + karma_unusual_dev_list);
        if (result)
                return result;

        us->transport_name = "Rio Karma/Bulk";
        us->transport = rio_karma_transport;
        us->transport_reset = usb_stor_Bulk_reset;

        result = usb_stor_probe2(us);
        return result;
}

static struct usb_driver karma_driver = {
        .name =         "ums-karma",
        .probe =        karma_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 =     karma_usb_ids,
        .soft_unbind =  1,
};

static int __init karma_init(void)
{
        return usb_register(&karma_driver);
}

static void __exit karma_exit(void)
{
        usb_deregister(&karma_driver);
}

module_init(karma_init);
module_exit(karma_exit);