LXR linux/drivers/usb/storage/uas-detect.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#include <linux/usb.h>
   3#include <linux/usb/hcd.h>
   4#include "usb.h"
   5
   6static int uas_is_interface(struct usb_host_interface *intf)
   7{
   8        return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
   9                intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
  10                intf->desc.bInterfaceProtocol == USB_PR_UAS);
  11}
  12
  13static struct usb_host_interface *uas_find_uas_alt_setting(
  14                struct usb_interface *intf)
  15{
  16        int i;
  17
  18        for (i = 0; i < intf->num_altsetting; i++) {
  19                struct usb_host_interface *alt = &intf->altsetting[i];
  20
  21                if (uas_is_interface(alt))
  22                        return alt;
  23        }
  24
  25        return NULL;
  26}
  27
  28static int uas_find_endpoints(struct usb_host_interface *alt,
  29                              struct usb_host_endpoint *eps[])
  30{
  31        struct usb_host_endpoint *endpoint = alt->endpoint;
  32        unsigned i, n_endpoints = alt->desc.bNumEndpoints;
  33
  34        for (i = 0; i < n_endpoints; i++) {
  35                unsigned char *extra = endpoint[i].extra;
  36                int len = endpoint[i].extralen;
  37                while (len >= 3) {
  38                        if (extra[1] == USB_DT_PIPE_USAGE) {
  39                                unsigned pipe_id = extra[2];
  40                                if (pipe_id > 0 && pipe_id < 5)
  41                                        eps[pipe_id - 1] = &endpoint[i];
  42                                break;
  43                        }
  44                        len -= extra[0];
  45                        extra += extra[0];
  46                }
  47        }
  48
  49        if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
  50                return -ENODEV;
  51
  52        return 0;
  53}
  54
  55static int uas_use_uas_driver(struct usb_interface *intf,
  56                              const struct usb_device_id *id,
  57                              unsigned long *flags_ret)
  58{
  59        struct usb_host_endpoint *eps[4] = { };
  60        struct usb_device *udev = interface_to_usbdev(intf);
  61        struct usb_hcd *hcd = bus_to_hcd(udev->bus);
  62        unsigned long flags = id->driver_info;
  63        struct usb_host_interface *alt;
  64        int r;
  65
  66        alt = uas_find_uas_alt_setting(intf);
  67        if (!alt)
  68                return 0;
  69
  70        r = uas_find_endpoints(alt, eps);
  71        if (r < 0)
  72                return 0;
  73
  74        /*
  75         * ASMedia has a number of usb3 to sata bridge chips, at the time of
  76         * this writing the following versions exist:
  77         * ASM1051 - no uas support version
  78         * ASM1051 - with broken (*) uas support
  79         * ASM1053 - with working uas support, but problems with large xfers
  80         * ASM1153 - with working uas support
  81         *
  82         * Devices with these chips re-use a number of device-ids over the
  83         * entire line, so the device-id is useless to determine if we're
  84         * dealing with an ASM1051 (which we want to avoid).
  85         *
  86         * The ASM1153 can be identified by config.MaxPower == 0,
  87         * where as the ASM105x models have config.MaxPower == 36.
  88         *
  89         * Differentiating between the ASM1053 and ASM1051 is trickier, when
  90         * connected over USB-3 we can look at the number of streams supported,
  91         * ASM1051 supports 32 streams, where as early ASM1053 versions support
  92         * 16 streams, newer ASM1053-s also support 32 streams, but have a
  93         * different prod-id.
  94         *
  95         * (*) ASM1051 chips do work with UAS with some disks (with the
  96         *     US_FL_NO_REPORT_OPCODES quirk), but are broken with other disks
  97         */
  98        if (le16_to_cpu(udev->descriptor.idVendor) == 0x174c &&
  99                        (le16_to_cpu(udev->descriptor.idProduct) == 0x5106 ||
 100                         le16_to_cpu(udev->descriptor.idProduct) == 0x55aa)) {
 101                if (udev->actconfig->desc.bMaxPower == 0) {
 102                        /* ASM1153, do nothing */
 103                } else if (udev->speed < USB_SPEED_SUPER) {
 104                        /* No streams info, assume ASM1051 */
 105                        flags |= US_FL_IGNORE_UAS;
 106                } else if (usb_ss_max_streams(&eps[1]->ss_ep_comp) == 32) {
 107                        /* Possibly an ASM1051, disable uas */
 108                        flags |= US_FL_IGNORE_UAS;
 109                } else {
 110                        /* ASM1053, these have issues with large transfers */
 111                        flags |= US_FL_MAX_SECTORS_240;
 112                }
 113        }
 114
 115        usb_stor_adjust_quirks(udev, &flags);
 116
 117        if (flags & US_FL_IGNORE_UAS) {
 118                dev_warn(&udev->dev,
 119                        "UAS is blacklisted for this device, using usb-storage instead\n");
 120                return 0;
 121        }
 122
 123        if (udev->bus->sg_tablesize == 0) {
 124                dev_warn(&udev->dev,
 125                        "The driver for the USB controller %s does not support scatter-gather which is\n",
 126                        hcd->driver->description);
 127                dev_warn(&udev->dev,
 128                        "required by the UAS driver. Please try an other USB controller if you wish to use UAS.\n");
 129                return 0;
 130        }
 131
 132        if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams) {
 133                dev_warn(&udev->dev,
 134                        "USB controller %s does not support streams, which are required by the UAS driver.\n",
 135                        hcd_to_bus(hcd)->bus_name);
 136                dev_warn(&udev->dev,
 137                        "Please try an other USB controller if you wish to use UAS.\n");
 138                return 0;
 139        }
 140
 141        if (flags_ret)
 142                *flags_ret = flags;
 143
 144        return 1;
 145}
 146