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