// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for Option High Speed Mobile Devices.
 *
 *   (c) 2008 Dan Williams <dcbw@redhat.com>
 *
 * Inspiration taken from sierra_ms.c by Kevin Lloyd <klloyd@sierrawireless.com>
 */

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

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

#define ZCD_FORCE_MODEM                 0x01
#define ZCD_ALLOW_MS                    0x02

static unsigned int option_zero_cd = ZCD_FORCE_MODEM;
module_param(option_zero_cd, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
                 " 2=Allow CD-Rom");

#define RESPONSE_LEN 1024

static int option_rezero(struct us_data *us)
{
        static const unsigned char rezero_msg[] = {
          0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
          0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
        };
        char *buffer;
        int result;

        usb_stor_dbg(us, "Option MS: %s\n", "DEVICE MODE SWITCH");

        buffer = kzalloc(RESPONSE_LEN, GFP_KERNEL);
        if (buffer == NULL)
                return USB_STOR_TRANSPORT_ERROR;

        memcpy(buffer, rezero_msg, sizeof(rezero_msg));
        result = usb_stor_bulk_transfer_buf(us,
                        us->send_bulk_pipe,
                        buffer, sizeof(rezero_msg), NULL);
        if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_XFER_ERROR;
                goto out;
        }

        /*
         * Some of the devices need to be asked for a response, but we don't
         * care what that response is.
         */
        usb_stor_bulk_transfer_buf(us,
                        us->recv_bulk_pipe,
                        buffer, RESPONSE_LEN, NULL);

        /* Read the CSW */
        usb_stor_bulk_transfer_buf(us,
                        us->recv_bulk_pipe,
                        buffer, 13, NULL);

        result = USB_STOR_XFER_GOOD;

out:
        kfree(buffer);
        return result;
}

static int option_inquiry(struct us_data *us)
{
        static const unsigned char inquiry_msg[] = {
          0x55, 0x53, 0x42, 0x43, 0x12, 0x34, 0x56, 0x78,
          0x24, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x12,
          0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
        };
        char *buffer;
        int result;

        usb_stor_dbg(us, "Option MS: %s\n", "device inquiry for vendor name");

        buffer = kzalloc(0x24, GFP_KERNEL);
        if (buffer == NULL)
                return USB_STOR_TRANSPORT_ERROR;

        memcpy(buffer, inquiry_msg, sizeof(inquiry_msg));
        result = usb_stor_bulk_transfer_buf(us,
                        us->send_bulk_pipe,
                        buffer, sizeof(inquiry_msg), NULL);
        if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_XFER_ERROR;
                goto out;
        }

        result = usb_stor_bulk_transfer_buf(us,
                        us->recv_bulk_pipe,
                        buffer, 0x24, NULL);
        if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_XFER_ERROR;
                goto out;
        }

        result = memcmp(buffer+8, "Option", 6);

        if (result != 0)
                result = memcmp(buffer+8, "ZCOPTION", 8);

        /* Read the CSW */
        usb_stor_bulk_transfer_buf(us,
                        us->recv_bulk_pipe,
                        buffer, 13, NULL);

out:
        kfree(buffer);
        return result;
}


int option_ms_init(struct us_data *us)
{
        int result;

        usb_stor_dbg(us, "Option MS: %s\n", "option_ms_init called");

        /*
         * Additional test for vendor information via INQUIRY,
         * because some vendor/product IDs are ambiguous
         */
        result = option_inquiry(us);
        if (result != 0) {
                usb_stor_dbg(us, "Option MS: %s\n",
                             "vendor is not Option or not determinable, no action taken");
                return 0;
        } else
                usb_stor_dbg(us, "Option MS: %s\n",
                             "this is a genuine Option device, proceeding");

        /* Force Modem mode */
        if (option_zero_cd == ZCD_FORCE_MODEM) {
                usb_stor_dbg(us, "Option MS: %s\n", "Forcing Modem Mode");
                result = option_rezero(us);
                if (result != USB_STOR_XFER_GOOD)
                        usb_stor_dbg(us, "Option MS: %s\n",
                                     "Failed to switch to modem mode");
                return -EIO;
        } else if (option_zero_cd == ZCD_ALLOW_MS) {
                /* Allow Mass Storage mode (keep CD-Rom) */
                usb_stor_dbg(us, "Option MS: %s\n",
                             "Allowing Mass Storage Mode if device requests it");
        }

        return 0;
}