ARM: dts: bcm283x: increase dwc2's RX FIFO size

The previous version of the dwc2 overlay set the RX FIFO size to
256 4-byte words. This is not enough for 1024 bytes of the largest
isochronous high speed packet allowed, because it doesn't take into
account extra space needed by dwc2.

RX FIFO's size is calculated based on the following (in 4byte words):
- 13 locations for SETUP packets
  5*n + 8 for Slave and Buffer DMA mode where n is number of control
  endpoints which is 1 on the bcm283x core

- 1 location for Global OUT NAK

- 2 * 257 locations for status information and the received packet.
  Typically two spaces are recommended so that when the previous packet
  is being transferred to AHB, the USB can receive the subsequent
  packet.

- 10 * 1 location for transfer complete status for last packet of each
  endpoint. The bcm283x core has 5 IN and 5 OUT EPs

- 10 * 1 additional location for EPDisable status for each endpoint

- 5 * 2 additional locations are recommended for each OUT endpoint

Total is 558 locations.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/e9e7d070-593c-122f-3a5c-2435bb147ab2@ivitera.com/

diff --git a/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi b/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi
index e2fd961..20322de 100644 (file)
--- a/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi
+++ b/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 &usb {
        dr_mode = "otg";
-       g-rx-fifo-size = <256>;
+       g-rx-fifo-size = <558>;
        g-np-tx-fifo-size = <32>;
        /*
         * According to dwc2 the sum of all device EP

diff --git a/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi b/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi
index 0ff0e9e..1409d1b 100644 (file)
--- a/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi
+++ b/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 &usb {
        dr_mode = "peripheral";
-       g-rx-fifo-size = <256>;
+       g-rx-fifo-size = <558>;
        g-np-tx-fifo-size = <32>;
        g-tx-fifo-size = <256 256 512 512 512 768 768>;
 };