1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/usb.h>
3 #include <linux/usb/hcd.h>
4 #include "usb.h"
5 
uas_is_interface(struct usb_host_interface * intf)6 static 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 
uas_find_uas_alt_setting(struct usb_interface * intf)13 static 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 
uas_find_endpoints(struct usb_host_interface * alt,struct usb_host_endpoint * eps[])28 static 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 
uas_use_uas_driver(struct usb_interface * intf,const struct usb_device_id * id,unsigned long * flags_ret)55 static 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 	/* All Seagate disk enclosures have broken ATA pass-through support */
116 	if (le16_to_cpu(udev->descriptor.idVendor) == 0x0bc2)
117 		flags |= US_FL_NO_ATA_1X;
118 
119 	usb_stor_adjust_quirks(udev, &flags);
120 
121 	if (flags & US_FL_IGNORE_UAS) {
122 		dev_warn(&udev->dev,
123 			"UAS is ignored for this device, using usb-storage instead\n");
124 		return 0;
125 	}
126 
127 	if (udev->bus->sg_tablesize == 0) {
128 		dev_warn(&udev->dev,
129 			"The driver for the USB controller %s does not support scatter-gather which is\n",
130 			hcd->driver->description);
131 		dev_warn(&udev->dev,
132 			"required by the UAS driver. Please try an other USB controller if you wish to use UAS.\n");
133 		return 0;
134 	}
135 
136 	if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams) {
137 		dev_warn(&udev->dev,
138 			"USB controller %s does not support streams, which are required by the UAS driver.\n",
139 			hcd_to_bus(hcd)->bus_name);
140 		dev_warn(&udev->dev,
141 			"Please try an other USB controller if you wish to use UAS.\n");
142 		return 0;
143 	}
144 
145 	if (flags_ret)
146 		*flags_ret = flags;
147 
148 	return 1;
149 }
150