97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
#include <linux/usb.h>
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#include <linux/usb/hcd.h>
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#include "usb.h"
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static int uas_is_interface(struct usb_host_interface *intf)
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{
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return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
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intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
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intf->desc.bInterfaceProtocol == USB_PR_UAS);
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}
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static int uas_isnt_supported(struct usb_device *udev)
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{
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struct usb_hcd *hcd = bus_to_hcd(udev->bus);
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dev_warn(&udev->dev, "The driver for the USB controller %s does not "
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"support scatter-gather which is\n",
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hcd->driver->description);
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dev_warn(&udev->dev, "required by the UAS driver. Please try an"
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"alternative USB controller if you wish to use UAS.\n");
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return -ENODEV;
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}
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static int uas_find_uas_alt_setting(struct usb_interface *intf)
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{
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int i;
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struct usb_device *udev = interface_to_usbdev(intf);
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int sg_supported = udev->bus->sg_tablesize != 0;
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for (i = 0; i < intf->num_altsetting; i++) {
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struct usb_host_interface *alt = &intf->altsetting[i];
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if (uas_is_interface(alt)) {
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if (!sg_supported)
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return uas_isnt_supported(udev);
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return alt->desc.bAlternateSetting;
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}
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}
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return -ENODEV;
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}
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static int uas_find_endpoints(struct usb_host_interface *alt,
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struct usb_host_endpoint *eps[])
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{
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struct usb_host_endpoint *endpoint = alt->endpoint;
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unsigned i, n_endpoints = alt->desc.bNumEndpoints;
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for (i = 0; i < n_endpoints; i++) {
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unsigned char *extra = endpoint[i].extra;
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int len = endpoint[i].extralen;
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while (len >= 3) {
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if (extra[1] == USB_DT_PIPE_USAGE) {
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unsigned pipe_id = extra[2];
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if (pipe_id > 0 && pipe_id < 5)
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eps[pipe_id - 1] = &endpoint[i];
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break;
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}
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len -= extra[0];
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extra += extra[0];
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}
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}
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if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
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return -ENODEV;
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return 0;
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}
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static int uas_use_uas_driver(struct usb_interface *intf,
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const struct usb_device_id *id)
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{
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struct usb_host_endpoint *eps[4] = { };
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struct usb_device *udev = interface_to_usbdev(intf);
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struct usb_hcd *hcd = bus_to_hcd(udev->bus);
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unsigned long flags = id->driver_info;
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int r, alt;
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usb_stor_adjust_quirks(udev, &flags);
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if (flags & US_FL_IGNORE_UAS)
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return 0;
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if (udev->speed >= USB_SPEED_SUPER && !hcd->can_do_streams)
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return 0;
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alt = uas_find_uas_alt_setting(intf);
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if (alt < 0)
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return 0;
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r = uas_find_endpoints(&intf->altsetting[alt], eps);
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if (r < 0)
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return 0;
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return 1;
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}
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