usb: Assimilate usb_get_descriptor() to linux

Before this commit, usb_get_descriptor() failed for some flakey USB
devices. We hereby adopt the more robust linux implementation [1].

For instance, for the "Alcor Micro Corp. Flash Drive" (VID 0x058f, PID
0x6387), the following behavior occurs from time to time:

=> usb start
starting USB...
Bus xhci_pci: Register 10000840 NbrPorts 16
Starting the controller
USB XHCI 1.20
scanning bus xhci_pci for devices... usb_new_device: Cannot read configuration, skipping device 058f:6387

Signed-off-by: Philip Oberfichtner <pro@denx.de>
Reviewed-by: Marek Vasut <marex@denx.de>
[1] From a38297e3fb012 (Linux 6.9), see
    https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/usb/core/message.c?h=v6.9#n781

diff --git a/common/usb.c b/common/usb.c
index 84b10f5c7d8c2b5993827e2aa8c84482684b4a0d..f5b21c883f32eb92fc8ff017fc31327eb0ab6fea 100644 (file)
--- a/common/usb.c
+++ b/common/usb.c
@@ -214,8 +214,9 @@ int usb_int_msg(struct usb_device *dev, unsigned long pipe,
  * clear keyboards LEDs). For data transfers, (storage transfers) we don't
  * allow control messages with 0 timeout, by previousely resetting the flag
  * asynch_allowed (usb_disable_asynch(1)).
- * returns the transferred length if OK or -1 if error. The transferred length
- * and the current status are stored in the dev->act_len and dev->status.
+ * returns the transferred length if OK, otherwise a negative error code. The
+ * transferred length and the current status are stored in the dev->act_len and
+ * dev->status.
  */
 int usb_control_msg(struct usb_device *dev, unsigned int pipe,
                        unsigned char request, unsigned char requesttype,
@@ -257,11 +258,14 @@ int usb_control_msg(struct usb_device *dev, unsigned int pipe,
                        break;
                mdelay(1);
        }
+
+       if (timeout == 0)
+               return -ETIMEDOUT;
+
        if (dev->status)
                return -1;
 
        return dev->act_len;
-
 }
 
 /*-------------------------------------------------------------------
@@ -562,10 +566,29 @@ int usb_clear_halt(struct usb_device *dev, int pipe)
 static int usb_get_descriptor(struct usb_device *dev, unsigned char type,
                        unsigned char index, void *buf, int size)
 {
-       return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
-                              USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
-                              (type << 8) + index, 0, buf, size,
-                              USB_CNTL_TIMEOUT);
+       int i;
+       int result;
+
+       if (size <= 0)          /* No point in asking for no data */
+               return -EINVAL;
+
+       memset(buf, 0, size);   /* Make sure we parse really received data */
+
+       for (i = 0; i < 3; ++i) {
+               /* retry on length 0 or error; some devices are flakey */
+               result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+                                        USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+                                        (type << 8) + index, 0, buf, size,
+                                        USB_CNTL_TIMEOUT);
+               if (result <= 0 && result != -ETIMEDOUT)
+                       continue;
+               if (result > 1 && ((u8 *)buf)[1] != type) {
+                       result = -ENODATA;
+                       continue;
+               }
+               break;
+       }
+       return result;
 }
 
 /**********************************************************************