Re: [PATCH] ARM: dts: bcm283x: increase dwc2's RX FIFO size
From: Stefan Wahren <hidden>
Date: 2021-05-26 17:12:32
Also in:
linux-devicetree
Hi Pavel, Am 13.11.20 um 08:18 schrieb Pavel Hofman:
quoted hunk ↗ jump to hunk
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 <redacted> Signed-off-by: Pavel Hofman <redacted> --- arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi | 2 +- arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsib/arch/arm/boot/dts/bcm283x-rpi-usb-otg.dtsi index e2fd961..20322de 100644--- 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 EPdiff --git a/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsib/arch/arm/boot/dts/bcm283x-rpi-usb-peripheral.dtsi index 0ff0e9e..1409d1b 100644--- 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>;
sorry for being late at the party, but this change introduce a regression on Raspberry Pi 4 B: dwc2 fe980000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g-tx-fifo-size, setting to default average I known you didn't change the tx fifo size, but there are complex constrains regarding the total fifo size. Are you able to test this with a mainline kernel (not Raspberry Pi kernel) and send a fix for this?
g-np-tx-fifo-size = <32>; g-tx-fifo-size = <256 256 512 512 512 768 768>; };