dt-bindings: usb: dwc3: Add DWC_usb3 TX/RX threshold configurable
authorStanley Chang <stanley_chang@realtek.com>
Tue, 12 Sep 2023 04:19:03 +0000 (12:19 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 2 Oct 2023 12:05:53 +0000 (14:05 +0200)
commit6591e278f05c13f2525e0adb805e18174eda7024
tree286ff3365dc2bc766c6a31f58043c8c2151632e2
parente72fc8d6a12af7ae8dd1b52cf68ed68569d29f80
dt-bindings: usb: dwc3: Add DWC_usb3 TX/RX threshold configurable

In Synopsys's dwc3 data book:
To avoid underrun and overrun during the burst, in a high-latency bus
system (like USB), threshold and burst size control is provided through
GTXTHRCFG and GRXTHRCFG registers.
By default, USB TX and RX threshold are not enabled. To enable
TX or RX threshold, both packet threshold count and max burst size
properties must be set to a valid non-zero value.

In Realtek DHC SoC, DWC3 USB 3.0 uses AHB system bus. When dwc3 is
connected with USB 2.5G Ethernet, there will be overrun problem.
Therefore, setting TX/RX thresholds can avoid this issue.

Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230912041904.30721-2-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/devicetree/bindings/usb/snps,dwc3.yaml