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f79a60b878
- For Control Read transfer, the ACK handshake on an IN transaction
may be corrupted, so the device may not receive the ACK for data
stage, the complete irq will not occur at this situation.
Therefore, we need to move prime status stage from complete irq
routine to the place where the data stage has just primed, or the
host will never get ACK for status stage.
The above issue has been described at USB2.0 spec chapter 8.5.3.3.
- After adding prime status stage just after prime the data stage,
there is a potential problem when the status dTD is added before the data stage
has primed by hardware. The reason is the device's dTD descriptor has NO direction bit,
if data stage (IN) prime hasn't finished, the status stage(OUT)
dTD will be added at data stage dTD's Next dTD Pointer, so when the data stage
transfer has finished, the status dTD will be primed as IN by hardware,
then the host will never receive ACK from the device side for status stage.
- Delete below code at fsl_ep_queue:
/* Update ep0 state */
if ((ep_index(ep) == 0))
udc->ep0_state = DATA_STATE_XMIT;
the udc->ep0_state will be updated again after udc->driver->setup
finishes.
It is tested at i.mx51 bbg board with g_mass_storage, g_ether, g_serial.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
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| core | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| renesas_usbhs | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-common.c | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.