target/linux/brcm2708/patches-4.19/950-0814-overlays-dwc2-Increase-RX-FIFO-size.patch

   1 From 389107911744588cce5e06c23a058c9cfb641f33 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 4 Feb 2020 13:03:21 +0000
   4 Subject: [PATCH] overlays: dwc2: Increase RX FIFO size
   5
   6 The previous version of the dwc2 overlay set the RX FIFO size to
   7 256 4-byte words. This sounds large enough for a 1024 byte packet (the
   8 largest isochronous high speed packet allowed), but it doesn't take
   9 into account some extra space needed by the hardware.
  10
  11 Minas Harutyunyan at Synopsys (the source of the DWC OTG design)
  12 came up with a more correct value, 301, but since there is spare packet
  13 RAM this can be increased to 558 to allow two packets per frame.
  14
  15 See: https://github.com/raspberrypi/linux/issues/3447
  16
  17 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  18 ---
  19  arch/arm/boot/dts/overlays/dwc2-overlay.dts | 2 +-
  20  1 file changed, 1 insertion(+), 1 deletion(-)
  21
  22 --- a/arch/arm/boot/dts/overlays/dwc2-overlay.dts
  23 +++ b/arch/arm/boot/dts/overlays/dwc2-overlay.dts
  24 @@ -12,7 +12,7 @@
  25                         compatible = "brcm,bcm2835-usb";
  26                         dr_mode = "otg";
  27                         g-np-tx-fifo-size = <32>;
  28 -                       g-rx-fifo-size = <256>;
  29 +                       g-rx-fifo-size = <558>;
  30                         g-tx-fifo-size = <512 512 512 512 512 256 256>;
  31                         status = "okay";
  32                 };