usb: dwc2: host: Set host_rx_fifo_size to 525 for rk3066
authorDouglas Anderson <dianders@chromium.org>
Fri, 29 Jan 2016 02:19:54 +0000 (18:19 -0800)
committerFelipe Balbi <balbi@kernel.org>
Fri, 4 Mar 2016 13:14:39 +0000 (15:14 +0200)
commit098c1ef8fe6bcdfed7905cea1debdd3a0ff9a16f
tree7c8a9f104ef735faa7aec03bfe894eac64dfe234
parent3bc04e28a030a8b7dfa2227a7eaf748ada5e2c94
usb: dwc2: host: Set host_rx_fifo_size to 525 for rk3066

As documented in dwc2_calculate_dynamic_fifo(), host_rx_fifo_size should
really be:
 2 * ((Largest Packet size / 4) + 1 + 1) + n
 with n = number of host channel.

We have 9 host channels, so
 2 * ((1024/4) + 2) + 9 = 516 + 9 = 525

We've got 960 / 972 total_fifo_size on rk3288 (and presumably on
rk3066) and 525 + 128 + 256 = 909 so we're still under on both ports
even when we increment by 5.

In the future, it would be nice if dwc2_calculate_dynamic_fifo() could
handle the "too small" FIFO case and come up with something more
dynamically.  When we do that we can figure out how to allocate the
extra 48 / 60 bytes of FIFO that we're currently wasting.

NOTE: no known bugs are fixed by this patch, but it seems like a simple
fix and ought to fix someone.

Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
drivers/usb/dwc2/platform.c