qiurui
/
rv1126-uboot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

UPSTREAM: usb: Only get 64 bytes device descriptor for full speed devices 

Full speed device endpoint 0 can have 8/16/32/64 bMaxPacketSize0.
Other speed devices report fixed value per USB spec. So it only
makes sense if we send a get device descriptor with 64 bytes to
full speed devices.

While we are here, update the comment block to be within 80 cols.

Change-Id: I035b83fb71ce4aa37f23fccba430d65814600a55
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
(cherry picked from commit c008faa77358bb5b313696dd1d5bb8afa03a6ca2)
This commit is contained in:
Bin Meng 2017-09-18 06:40:42 -07:00 committed by Kever Yang
parent 83e13f0fe7
commit a9cf383983
1 changed files with 15 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
common/usb.c
View File

@ -969,23 +969,24 @@ static int usb_setup_descriptor(struct usb_device *dev, bool do_read)
dev->epmaxpacketin[0] = dev->descriptor.bMaxPacketSize0;
dev->epmaxpacketout[0] = dev->descriptor.bMaxPacketSize0;
if (do_read) {
if (do_read && dev->speed == USB_SPEED_FULL) {
int err;
/*
* 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.
* 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.
* 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.
*/
err = get_descriptor_len(dev, 64, 8);
if (err)
@ -1008,7 +1009,7 @@ static int usb_setup_descriptor(struct usb_device *dev, bool do_read)
dev->maxpacketsize = PACKET_SIZE_64;
break;
default:
printf("usb_new_device: invalid max packet size\n");
printf("%s: invalid max packet size\n", __func__);
return -EIO;
}