/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include "usb.h"

static int uas_is_interface(struct usb_host_interface *intf)
{
        return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
                intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
                intf->desc.bInterfaceProtocol == USB_PR_UAS);
}

static struct usb_host_interface *uas_find_uas_alt_setting(
                struct usb_interface *intf)
{
        int i;

        for (i = 0; i < intf->num_altsetting; i++) {
                struct usb_host_interface *alt = &intf->altsetting[i];

                if (uas_is_interface(alt))
                        return alt;
        }

        return NULL;
}

static int uas_find_endpoints(struct usb_host_interface *alt,
                              struct usb_host_endpoint *eps[])
{
        struct usb_host_endpoint *endpoint = alt->endpoint;
        unsigned i, n_endpoints = alt->desc.bNumEndpoints;

        for (i = 0; i < n_endpoints; i++) {
                unsigned char *extra = endpoint[i].extra;
                int len = endpoint[i].extralen;
                while (len >= 3) {
                        if (extra[1] == USB_DT_PIPE_USAGE) {
                                unsigned pipe_id = extra[2];
                                if (pipe_id > 0 && pipe_id < 5)
                                        eps[pipe_id - 1] = &endpoint[i];
                                break;
                        }
                        len -= extra[0];
                        extra += extra[0];
                }
        }

        if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
                return -ENODEV;

        return 0;
}

static int uas_use_uas_driver(struct usb_interface *intf,
                              const struct usb_device_id *id,
                              u64 *flags_ret)
{
        struct usb_host_endpoint *eps[4] = { };
        struct usb_device *udev = interface_to_usbdev(intf);
        struct usb_hcd *hcd = bus_to_hcd(udev->bus);
        u64 flags = id->driver_info;
        struct usb_host_interface *alt;
        int r;

        alt = uas_find_uas_alt_setting(intf);
        if (!alt)
                return 0;

        r = uas_find_endpoints(alt, eps);
        if (r < 0)
                return 0;

        /*
         * ASMedia has a number of usb3 to sata bridge chips, at the time of
         * this writing the following versions exist:
         * ASM1051 - no uas support version
         * ASM1051 - with broken (*) uas support
         * ASM1053 - with working uas support, but problems with large xfers
         * ASM1153 - with working uas support
         *
         * Devices with these chips re-use a number of device-ids over the
         * entire line, so the device-id is useless to determine if we're
         * dealing with an ASM1051 (which we want to avoid).
         *
         * The ASM1153 can be identified by config.MaxPower == 0,
         * where as the ASM105x models have config.MaxPower == 36.
         *
         * Differentiating between the ASM1053 and ASM1051 is trickier, when
         * connected over USB-3 we can look at the number of streams supported,
         * ASM1051 supports 32 streams, where as early ASM1053 versions support
         * 16 streams, newer ASM1053-s also support 32 streams, but have a
         * different prod-id.
         *
         * (*) ASM1051 chips do work with UAS with some disks (with the
         *     US_FL_NO_REPORT_OPCODES quirk), but are broken with other disks
         */
        if (le16_to_cpu(udev->descriptor.idVendor) == 0x174c &&
                        (le16_to_cpu(udev->descriptor.idProduct) == 0x5106 ||
                         le16_to_cpu(udev->descriptor.idProduct) == 0x55aa)) {
                if (udev->actconfig->desc.bMaxPower == 0) {
                        /* ASM1153, do nothing */
                } else if (udev->speed < USB_SPEED_SUPER) {
                        /* No streams info, assume ASM1051 */
                        flags |= US_FL_IGNORE_UAS;
                } else if (usb_ss_max_streams(&eps[1]->ss_ep_comp) == 32) {
                        /* Possibly an ASM1051, disable uas */
                        flags |= US_FL_IGNORE_UAS;
                } else {
                        /* ASM1053, these have issues with large transfers */
                        flags |= US_FL_MAX_SECTORS_240;
                }
        }

        /* All Seagate disk enclosures have broken ATA pass-through support */
        if (le16_to_cpu(udev->descriptor.idVendor) == 0x0bc2)
                flags |= US_FL_NO_ATA_1X;

        /*
         * RTL9210-based enclosure from HIKSEMI, MD202 reportedly have issues
         * with UAS.  This isn't distinguishable with just idVendor and
         * idProduct, use manufacturer and product too.
         *
         * Reported-by: Hongling Zeng <zenghongling@kylinos.cn>
         */
        if (le16_to_cpu(udev->descriptor.idVendor) == 0x0bda &&
                        le16_to_cpu(udev->descriptor.idProduct) == 0x9210 &&
                        (udev->manufacturer && !strcmp(udev->manufacturer, "HIKSEMI")) &&
                        (udev->product && !strcmp(udev->product, "MD202")))
                flags |= US_FL_IGNORE_UAS;

        usb_stor_adjust_quirks(udev, &flags);

        if (flags & US_FL_IGNORE_UAS) {
                dev_warn(&udev->dev,
                        "UAS is ignored for this device, using usb-storage instead\n");
                return 0;
        }

        if (udev->bus->sg_tablesize == 0) {
                dev_warn(&udev->dev,
                        "The driver for the USB controller %s does not support scatter-gather which is\n",
                        hcd->driver->description);
                dev_warn(&udev->dev,
                        "required by the UAS driver. Please try an other USB controller if you wish to use UAS.\n");
                return 0;
        }

        if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams) {
                dev_warn(&udev->dev,
                        "USB controller %s does not support streams, which are required by the UAS driver.\n",
                        hcd_to_bus(hcd)->bus_name);
                dev_warn(&udev->dev,
                        "Please try an other USB controller if you wish to use UAS.\n");
                return 0;
        }

        if (flags_ret)
                *flags_ret = flags;

        return 1;
}