// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2002 Pavel Machek <pavel@ucw.cz>
 * Copyright (C) 2002-2005 by David Brownell
 */

// #define      DEBUG                   // error path messages, extra info
// #define      VERBOSE                 // more; success messages

#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/crc32.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <linux/usb/usbnet.h>


/*
 * All known Zaurii lie about their standards conformance.  At least
 * the earliest SA-1100 models lie by saying they support CDC Ethernet.
 * Some later models (especially PXA-25x and PXA-27x based ones) lie
 * and say they support CDC MDLM (for access to cell phone modems).
 *
 * There are non-Zaurus products that use these same protocols too.
 *
 * The annoying thing is that at the same time Sharp was developing
 * that annoying standards-breaking software, the Linux community had
 * a simple "CDC Subset" working reliably on the same SA-1100 hardware.
 * That is, the same functionality but not violating standards.
 *
 * The CDC Ethernet nonconformance points are troublesome to hosts
 * with a true CDC Ethernet implementation:
 *   - Framing appends a CRC, which the spec says drivers "must not" do;
 *   - Transfers data in altsetting zero, instead of altsetting 1;
 *   - All these peripherals use the same ethernet address.
 *
 * The CDC MDLM nonconformance is less immediately troublesome, since all
 * MDLM implementations are quasi-proprietary anyway.
 */

static struct sk_buff *
zaurus_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
        int                     padlen;
        struct sk_buff          *skb2;

        padlen = 2;
        if (!skb_cloned(skb)) {
                int     tailroom = skb_tailroom(skb);
                if ((padlen + 4) <= tailroom)
                        goto done;
        }
        skb2 = skb_copy_expand(skb, 0, 4 + padlen, flags);
        dev_kfree_skb_any(skb);
        skb = skb2;
        if (skb) {
                u32             fcs;
done:
                fcs = crc32_le(~0, skb->data, skb->len);
                fcs = ~fcs;

                skb_put_u8(skb, fcs & 0xff);
                skb_put_u8(skb, (fcs >> 8) & 0xff);
                skb_put_u8(skb, (fcs >> 16) & 0xff);
                skb_put_u8(skb, (fcs >> 24) & 0xff);
        }
        return skb;
}

static int zaurus_bind(struct usbnet *dev, struct usb_interface *intf)
{
        /* Belcarra's funky framing has other options; mostly
         * TRAILERS (!) with 4 bytes CRC, and maybe 2 pad bytes.
         */
        dev->net->hard_header_len += 6;
        dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
        return usbnet_generic_cdc_bind(dev, intf);
}

/* PDA style devices are always connected if present */
static int always_connected (struct usbnet *dev)
{
        return 0;
}

static const struct driver_info zaurus_sl5x00_info = {
        .description =  "Sharp Zaurus SL-5x00",
        .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_Z,
        .check_connect = always_connected,
        .bind =         zaurus_bind,
        .unbind =       usbnet_cdc_unbind,
        .tx_fixup =     zaurus_tx_fixup,
};
#define ZAURUS_STRONGARM_INFO   ((unsigned long)&zaurus_sl5x00_info)

static const struct driver_info zaurus_pxa_info = {
        .description =  "Sharp Zaurus, PXA-2xx based",
        .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_Z,
        .check_connect = always_connected,
        .bind =         zaurus_bind,
        .unbind =       usbnet_cdc_unbind,
        .tx_fixup =     zaurus_tx_fixup,
};
#define ZAURUS_PXA_INFO         ((unsigned long)&zaurus_pxa_info)

static const struct driver_info olympus_mxl_info = {
        .description =  "Olympus R1000",
        .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_Z,
        .check_connect = always_connected,
        .bind =         zaurus_bind,
        .unbind =       usbnet_cdc_unbind,
        .tx_fixup =     zaurus_tx_fixup,
};
#define OLYMPUS_MXL_INFO        ((unsigned long)&olympus_mxl_info)


/* Some more recent products using Lineo/Belcarra code will wrongly claim
 * CDC MDLM conformance.  They aren't conformant:  data endpoints live
 * in the control interface, there's no data interface, and it's not used
 * to talk to a cell phone radio.  But at least we can detect these two
 * pseudo-classes, rather than growing this product list with entries for
 * each new nonconformant product (sigh).
 */
static const u8 safe_guid[16] = {
        0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
        0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
};
static const u8 blan_guid[16] = {
        0x74, 0xf0, 0x3d, 0xbd, 0x1e, 0xc1, 0x44, 0x70,
        0xa3, 0x67, 0x71, 0x34, 0xc9, 0xf5, 0x54, 0x37,
};

static int blan_mdlm_bind(struct usbnet *dev, struct usb_interface *intf)
{
        u8                              *buf = intf->cur_altsetting->extra;
        int                             len = intf->cur_altsetting->extralen;
        struct usb_cdc_mdlm_desc        *desc = NULL;
        struct usb_cdc_mdlm_detail_desc *detail = NULL;

        while (len > 3) {
                if (buf [1] != USB_DT_CS_INTERFACE)
                        goto next_desc;

                /* use bDescriptorSubType, and just verify that we get a
                 * "BLAN" (or "SAFE") descriptor.
                 */
                switch (buf [2]) {
                case USB_CDC_MDLM_TYPE:
                        if (desc) {
                                dev_dbg(&intf->dev, "extra MDLM\n");
                                goto bad_desc;
                        }
                        desc = (void *) buf;
                        if (desc->bLength != sizeof *desc) {
                                dev_dbg(&intf->dev, "MDLM len %u\n",
                                        desc->bLength);
                                goto bad_desc;
                        }
                        /* expect bcdVersion 1.0, ignore */
                        if (memcmp(&desc->bGUID, blan_guid, 16) &&
                            memcmp(&desc->bGUID, safe_guid, 16)) {
                                /* hey, this one might _really_ be MDLM! */
                                dev_dbg(&intf->dev, "MDLM guid\n");
                                goto bad_desc;
                        }
                        break;
                case USB_CDC_MDLM_DETAIL_TYPE:
                        if (detail) {
                                dev_dbg(&intf->dev, "extra MDLM detail\n");
                                goto bad_desc;
                        }
                        detail = (void *) buf;
                        switch (detail->bGuidDescriptorType) {
                        case 0:                 /* "SAFE" */
                                if (detail->bLength != (sizeof *detail + 2))
                                        goto bad_detail;
                                break;
                        case 1:                 /* "BLAN" */
                                if (detail->bLength != (sizeof *detail + 3))
                                        goto bad_detail;
                                break;
                        default:
                                goto bad_detail;
                        }

                        /* assuming we either noticed BLAN already, or will
                         * find it soon, there are some data bytes here:
                         *  - bmNetworkCapabilities (unused)
                         *  - bmDataCapabilities (bits, see below)
                         *  - bPad (ignored, for PADAFTER -- BLAN-only)
                         * bits are:
                         *  - 0x01 -- Zaurus framing (add CRC)
                         *  - 0x02 -- PADBEFORE (CRC includes some padding)
                         *  - 0x04 -- PADAFTER (some padding after CRC)
                         *  - 0x08 -- "fermat" packet mangling (for hw bugs)
                         * the PADBEFORE appears not to matter; we interop
                         * with devices that use it and those that don't.
                         */
                        if ((detail->bDetailData[1] & ~0x02) != 0x01) {
                                /* bmDataCapabilities == 0 would be fine too,
                                 * but framing is minidriver-coupled for now.
                                 */
bad_detail:
                                dev_dbg(&intf->dev,
                                                "bad MDLM detail, %d %d %d\n",
                                                detail->bLength,
                                                detail->bDetailData[0],
                                                detail->bDetailData[2]);
                                goto bad_desc;
                        }

                        /* same extra framing as for non-BLAN mode */
                        dev->net->hard_header_len += 6;
                        dev->rx_urb_size = dev->net->hard_header_len
                                        + dev->net->mtu;
                        break;
                }
next_desc:
                len -= buf [0]; /* bLength */
                buf += buf [0];
        }

        if (!desc || !detail) {
                dev_dbg(&intf->dev, "missing cdc mdlm %s%sdescriptor\n",
                        desc ? "" : "func ",
                        detail ? "" : "detail ");
                goto bad_desc;
        }

        /* There's probably a CDC Ethernet descriptor there, but we can't
         * rely on the Ethernet address it provides since not all vendors
         * bother to make it unique.  Likewise there's no point in tracking
         * of the CDC event notifications.
         */
        return usbnet_get_endpoints(dev, intf);

bad_desc:
        dev_info(&dev->udev->dev, "unsupported MDLM descriptors\n");
        return -ENODEV;
}

static const struct driver_info bogus_mdlm_info = {
        .description =  "pseudo-MDLM (BLAN) device",
        .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_Z,
        .check_connect = always_connected,
        .tx_fixup =     zaurus_tx_fixup,
        .bind =         blan_mdlm_bind,
};

static const struct usb_device_id       products [] = {
#define ZAURUS_MASTER_INTERFACE \
        .bInterfaceClass        = USB_CLASS_COMM, \
        .bInterfaceSubClass     = USB_CDC_SUBCLASS_ETHERNET, \
        .bInterfaceProtocol     = USB_CDC_PROTO_NONE

#define ZAURUS_FAKE_INTERFACE \
        .bInterfaceClass        = USB_CLASS_COMM, \
        .bInterfaceSubClass     = USB_CDC_SUBCLASS_MDLM, \
        .bInterfaceProtocol     = USB_CDC_PROTO_NONE

/* SA-1100 based Sharp Zaurus ("collie"), or compatible. */
{
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8004,
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_STRONGARM_INFO,
},

/* PXA-2xx based models are also lying-about-cdc.  If you add any
 * more devices that claim to be CDC Ethernet, make sure they get
 * added to the blacklist in cdc_ether too.
 *
 * NOTE:  OpenZaurus versions with 2.6 kernels won't use these entries,
 * unlike the older ones with 2.4 "embedix" kernels.
 */
{
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8005,       /* A-300 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8005,       /* A-300 */
        ZAURUS_FAKE_INTERFACE,
        .driver_info = (unsigned long)&bogus_mdlm_info,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8006,       /* B-500/SL-5600 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8006,       /* B-500/SL-5600 */
        ZAURUS_FAKE_INTERFACE,
        .driver_info = (unsigned long)&bogus_mdlm_info,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                  | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8007,       /* C-700 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                          | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x8007,       /* C-700 */
        ZAURUS_FAKE_INTERFACE,
        .driver_info = (unsigned long)&bogus_mdlm_info,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                 | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x9031,       /* C-750 C-760 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
}, {
        /* C-750/C-760/C-860/SL-C3000 PDA in MDLM mode */
        USB_DEVICE_AND_INTERFACE_INFO(0x04DD, 0x9031, USB_CLASS_COMM,
                        USB_CDC_SUBCLASS_MDLM, USB_CDC_PROTO_NONE),
        .driver_info = (unsigned long) &bogus_mdlm_info,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                 | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x9032,       /* SL-6000 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                            | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        .idProduct              = 0x9032,       /* SL-6000 */
        ZAURUS_FAKE_INTERFACE,
        .driver_info = (unsigned long)&bogus_mdlm_info,
}, {
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                 | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x04DD,
        /* reported with some C860 units */
        .idProduct              = 0x9050,       /* C-860 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = ZAURUS_PXA_INFO,
},
{
        /* Motorola Rokr E6 */
        USB_DEVICE_AND_INTERFACE_INFO(0x22b8, 0x6027, USB_CLASS_COMM,
                        USB_CDC_SUBCLASS_MDLM, USB_CDC_PROTO_NONE),
        .driver_info = (unsigned long) &bogus_mdlm_info,
}, {
        /* Motorola MOTOMAGX phones */
        USB_DEVICE_AND_INTERFACE_INFO(0x22b8, 0x6425, USB_CLASS_COMM,
                        USB_CDC_SUBCLASS_MDLM, USB_CDC_PROTO_NONE),
        .driver_info = (unsigned long) &bogus_mdlm_info,
},

/* Olympus has some models with a Zaurus-compatible option.
 * R-1000 uses a FreeScale i.MXL cpu (ARMv4T)
 */
{
        .match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
                 | USB_DEVICE_ID_MATCH_DEVICE,
        .idVendor               = 0x07B4,
        .idProduct              = 0x0F02,       /* R-1000 */
        ZAURUS_MASTER_INTERFACE,
        .driver_info = OLYMPUS_MXL_INFO,
},

/* Logitech Harmony 900 - uses the pseudo-MDLM (BLAN) driver */
{
        USB_DEVICE_AND_INTERFACE_INFO(0x046d, 0xc11f, USB_CLASS_COMM,
                        USB_CDC_SUBCLASS_MDLM, USB_CDC_PROTO_NONE),
        .driver_info = (unsigned long) &bogus_mdlm_info,
},
        { },            // END
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver zaurus_driver = {
        .name =         "zaurus",
        .id_table =     products,
        .probe =        usbnet_probe,
        .disconnect =   usbnet_disconnect,
        .suspend =      usbnet_suspend,
        .resume =       usbnet_resume,
        .disable_hub_initiated_lpm = 1,
};

module_usb_driver(zaurus_driver);

MODULE_AUTHOR("Pavel Machek, David Brownell");
MODULE_DESCRIPTION("Sharp Zaurus PDA, and compatible products");
MODULE_LICENSE("GPL");