dm: usb: Move descriptor setup code into its own function

usb_new_device() is far too long and does far too much. As a first step, move
the code that does initial setup and reads a descriptor into its own function
called usb_setup_descriptor().

For XHCI the init order is different - we set up the device but don't
actually read the descriptor until after we set an address. Support this
option as a parameter to usb_setup_descriptor().

Avoid changing this torturous code more than necessary to make it easy to
review.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>

diff --git a/common/usb.c b/common/usb.c
index 8a3bb114ec5da55aeee4dc6557ce70456a4acc91..5a49502f8e04ff4d231ac26953ed15c6c9292fc7 100644 (file)
--- a/common/usb.c
+++ b/common/usb.c
@@ -897,34 +897,11 @@ int usb_legacy_port_reset(struct usb_device *hub, int portnr)
        return 0;
 }
 
-/*
- * By the time we get here, the device has gotten a new device ID
- * and is in the default state. We need to identify the thing and
- * get the ball rolling..
- *
- * Returns 0 for success, != 0 for error.
- */
-int usb_new_device(struct usb_device *dev)
+static int usb_setup_descriptor(struct usb_device *dev, bool do_read)
 {
-       int addr, err;
-       int tmp;
+       __maybe_unused struct usb_device_descriptor *desc;
        ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, USB_BUFSIZ);
 
-       /*
-        * Allocate usb 3.0 device context.
-        * USB 3.0 (xHCI) protocol tries to allocate device slot
-        * and related data structures first. This call does that.
-        * Refer to sec 4.3.2 in xHCI spec rev1.0
-        */
-       if (usb_alloc_device(dev)) {
-               printf("Cannot allocate device context to get SLOT_ID\n");
-               return -EINVAL;
-       }
-
-       /* We still haven't set the Address yet */
-       addr = dev->devnum;
-       dev->devnum = 0;
-
        /*
         * This is a Windows scheme of initialization sequence, with double
         * reset of the device (Linux uses the same sequence)
@@ -940,55 +917,46 @@ int usb_new_device(struct usb_device *dev)
         * the maxpacket size is 8 or 16 the device may be waiting to transmit
         * some more, or keeps on retransmitting the 8 byte header. */
 
+       desc = (struct usb_device_descriptor *)tmpbuf;
        dev->descriptor.bMaxPacketSize0 = 64;       /* Start off at 64 bytes  */
        /* Default to 64 byte max packet size */
        dev->maxpacketsize = PACKET_SIZE_64;
        dev->epmaxpacketin[0] = 64;
        dev->epmaxpacketout[0] = 64;
 
-       /*
-        * XHCI needs to issue a Address device command to setup
-        * proper device context structures, before it can interact
-        * with the device. So a get_descriptor will fail before any
-        * of that is done for XHCI unlike EHCI.
-        */
-#ifndef CONFIG_USB_XHCI
-       struct usb_device_descriptor *desc;
+       if (do_read) {
+               int err;
 
-       desc = (struct usb_device_descriptor *)tmpbuf;
-       err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
-       /*
-        * Validate we've received only at least 8 bytes, not that we've
-        * received the entire descriptor. The reasoning is:
-        * - The code only uses fields in the first 8 bytes, so that's all we
-        *   need to have fetched at this stage.
-        * - The smallest maxpacket size is 8 bytes. Before we know the actual
-        *   maxpacket the device uses, the USB controller may only accept a
-        *   single packet. Consequently we are only guaranteed to receive 1
-        *   packet (at least 8 bytes) even in a non-error case.
-        *
-        * At least the DWC2 controller needs to be programmed with the number
-        * of packets in addition to the number of bytes. A request for 64
-        * bytes of data with the maxpacket guessed as 64 (above) yields a
-        * request for 1 packet.
-        */
-       if (err < 8) {
-               debug("usb_new_device: usb_get_descriptor() failed\n");
-               return -EIO;
+               err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
+               /*
+                * Validate we've received only at least 8 bytes, not that we've
+                * received the entire descriptor. The reasoning is:
+                * - The code only uses fields in the first 8 bytes, so that's all we
+                *   need to have fetched at this stage.
+                * - The smallest maxpacket size is 8 bytes. Before we know the actual
+                *   maxpacket the device uses, the USB controller may only accept a
+                *   single packet. Consequently we are only guaranteed to receive 1
+                *   packet (at least 8 bytes) even in a non-error case.
+                *
+                * At least the DWC2 controller needs to be programmed with the number
+                * of packets in addition to the number of bytes. A request for 64
+                * bytes of data with the maxpacket guessed as 64 (above) yields a
+                * request for 1 packet.
+                */
+               if (err < 8) {
+                       if (err < 0) {
+                               printf("unable to get device descriptor (error=%d)\n",
+                                      err);
+                               return err;
+                       } else {
+                               printf("USB device descriptor short read (expected %i, got %i)\n",
+                                      (int)sizeof(dev->descriptor), err);
+                               return -EIO;
+                       }
+               }
+               memcpy(&dev->descriptor, tmpbuf, sizeof(dev->descriptor));
        }
 
-       dev->descriptor.bMaxPacketSize0 = desc->bMaxPacketSize0;
-       /*
-        * Fetch the device class, driver can use this info
-        * to differentiate between HUB and DEVICE.
-        */
-       dev->descriptor.bDeviceClass = desc->bDeviceClass;
-#endif
-
-       err = usb_legacy_port_reset(dev->parent, dev->portnr);
-       if (err)
-               return err;
-
        dev->epmaxpacketin[0] = dev->descriptor.bMaxPacketSize0;
        dev->epmaxpacketout[0] = dev->descriptor.bMaxPacketSize0;
        switch (dev->descriptor.bMaxPacketSize0) {
@@ -1008,6 +976,55 @@ int usb_new_device(struct usb_device *dev)
                printf("usb_new_device: invalid max packet size\n");
                return -EIO;
        }
+
+       return 0;
+}
+
+/*
+ * By the time we get here, the device has gotten a new device ID
+ * and is in the default state. We need to identify the thing and
+ * get the ball rolling..
+ *
+ * Returns 0 for success, != 0 for error.
+ */
+int usb_new_device(struct usb_device *dev)
+{
+       bool do_read = true;
+       int addr, err;
+       int tmp;
+       ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, USB_BUFSIZ);
+
+       /*
+        * Allocate usb 3.0 device context.
+        * USB 3.0 (xHCI) protocol tries to allocate device slot
+        * and related data structures first. This call does that.
+        * Refer to sec 4.3.2 in xHCI spec rev1.0
+        */
+       if (usb_alloc_device(dev)) {
+               printf("Cannot allocate device context to get SLOT_ID\n");
+               return -1;
+       }
+
+       /* We still haven't set the Address yet */
+       addr = dev->devnum;
+       dev->devnum = 0;
+
+       /*
+        * XHCI needs to issue a Address device command to setup
+        * proper device context structures, before it can interact
+        * with the device. So a get_descriptor will fail before any
+        * of that is done for XHCI unlike EHCI.
+        */
+#ifdef CONFIG_USB_XHCI
+       do_read = false;
+#endif
+       err = usb_setup_descriptor(dev, do_read);
+       if (err)
+               return err;
+       err = usb_legacy_port_reset(dev->parent, dev->portnr);
+       if (err)
+               return err;
+
        dev->devnum = addr;
 
        err = usb_set_address(dev); /* set address */