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| author | Thinh Nguyen <Thinh.Nguyen@synopsys.com> | 2020-02-01 01:59:27 +0100 |
|---|---|---|
| committer | Felipe Balbi <balbi@kernel.org> | 2020-04-16 10:02:27 +0200 |
| commit | d94ea5319813658ad5861d161ae16a194c2abf88 (patch) | |
| tree | a13d292ff13e5e1c860e899c3f6119741cd89313 /Documentation | |
| parent | usb: dwc3: Fix GTXFIFOSIZ.TXFDEP macro name (diff) | |
| download | linux-d94ea5319813658ad5861d161ae16a194c2abf88.tar.xz linux-d94ea5319813658ad5861d161ae16a194c2abf88.zip | |
usb: dwc3: gadget: Properly set maxpacket limit
Currently the calculation of max packet size limit for IN endpoints is
too restrictive. This prevents a matching of a capable hardware endpoint
during configuration. Below is the minimum recommended HW configuration
to support a particular endpoint setup from the databook:
For OUT endpoints, the databook recommended the minimum RxFIFO size to
be at least 3x MaxPacketSize + 3x setup packets size (8 bytes each) +
clock crossing margin (16 bytes).
For IN endpoints, the databook recommended the minimum TxFIFO size to be
at least 3x MaxPacketSize for endpoints that support burst. If the
endpoint doesn't support burst or when the device is operating in USB
2.0 mode, a minimum TxFIFO size of 2x MaxPacketSize is recommended.
Base on these recommendations, we can calculate the MaxPacketSize limit
of each endpoint. This patch revises the IN endpoint MaxPacketSize limit
and also sets the MaxPacketSize limit for OUT endpoints.
Reference: Databook 3.30a section 3.2.2 and 3.2.3
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions