Hi Doug,
On 01/23/2016 02:18 AM, Douglas Anderson wrote:
> 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.
>
> Since we have space, Kever Yang suggests bumping by 8. He says this
> will meet INCR16 access and next fifo type can start with a aligned
> address.
I have double check this feature, the INCR16 is actually a burst 16
on to the bus, the aligned problem only happen on the DRAM
access, and it's OK for internal RAM access via internal DMA.
Bump to 8 looks much better when we check the FIFO setting if we
have enough memory, right? :)
rk3066/rk3188/rk3288 have the same hw config for dwc2 controller,
so this patch should works on those files.
Reviewed-by: Kever Yang <kever.yang at rock-chips.com>
>
> ...so let's bump up by 8. 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.
>
> Signed-off-by: Douglas Anderson <dianders at chromium.org>
> ---
> Changes in v5: None
> Changes in v4:
> - Set host_rx_fifo_size to 528 for rk3066 new for v4.
>
> Changes in v3: None
> Changes in v2: None
>
> drivers/usb/dwc2/platform.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index 5008a467ce06..b6d7666e715c 100644
> --- 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 = 528, /* 528 DWORDs */
> .host_nperio_tx_fifo_size = 128, /* 128 DWORDs */
> .host_perio_tx_fifo_size = 256, /* 256 DWORDs */
> .max_transfer_size = -1,
