[U-Boot] [PATCH v3 1/3] dm: usb: Move descriptor setup code into its own function

Simon Glass
2015-04-14T03:19:02Z

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>
---

Changes in v3:
- Fix polarity of CONFIG_XHCI check (which broke USB keyboards)

common/usb.c | 117 ++++++++++++++++++++++++++++++++++-------------------------
1 file changed, 67 insertions(+), 50 deletions(-)

diff --git a/common/usb.c b/common/usb.c
index 4ab2213..e5df98f 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -891,35 +891,12 @@ 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 -1;
- }
-
- /* 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)
* Some equipment is said to work only with such init sequence; this
@@ -934,40 +911,31 @@ 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);
- if (err < 0) {
- debug("usb_new_device: usb_get_descriptor() failed\n");
- return 1;
+ err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
+ if (err < sizeof(dev->descriptor)) {
+ 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) {
@@ -984,6 +952,55 @@ int usb_new_device(struct usb_device *dev)
dev->maxpacketsize = PACKET_SIZE_64;
break;
}
+
+ 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 */
--
2.2.0.rc0.207.ga3a616c