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>

diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index ecaa3d2..bc3f2a4 100644 (file)
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -126,7 +126,7 @@ static const struct dwc2_core_params params_rk3066 = {
        .speed                          = -1,
        .enable_dynamic_fifo            = 1,
        .en_multiple_tx_fifo            = -1,
-       .host_rx_fifo_size              = 520,  /* 520 DWORDs */
+       .host_rx_fifo_size              = 525,  /* 525 DWORDs */
        .host_nperio_tx_fifo_size       = 128,  /* 128 DWORDs */
        .host_perio_tx_fifo_size        = 256,  /* 256 DWORDs */
        .max_transfer_size              = -1,