Commit 18a93cd3 authored Aug 30, 2019 by Benjamin Herrenschmidt Committed by Felipe Balbi Aug 30, 2019

usb: gadget: net2280: Add workaround for AB chip Errata 11

The errata description is:

Workaround for Default Duration of LFPS Handshake Signaling for
Device-Initiated U1 Exit is too short.

The default duration of the LFPS handshake generated by USB3380 for a device-initiated U1-exit may not be
long enough for certain SuperSpeed downstream ports (SuperSpeed hubs/hosts) to recognize. This could lead
to USB3380 entering the recovery state pre-maturely and ending up in the SS.Inactive state.

I have observed various enumeration failures, seemingly related to
lost transactions or SETUP status phases on modern hosts (typically
thunderbolt capable systems) without this workaround.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

parent ec8ca8a3

drivers/usb/gadget/udc/net2280.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -2269,6 +2269,16 @@ static void usb_reinit_338x(struct net2280 *dev)
		val \|= 0x3 << HOT_RX_RESET_TS2;
		writel(val, &dev->llregs->ll_tsn_counters_3);

		/*
		* AB errata. Errata 11. Workaround for Default Duration of LFPS
		* Handshake Signaling for Device-Initiated U1 Exit is too short.
		* Without this, various enumeration failures observed with
		* modern superspeed hosts.
		*/
		val = readl(&dev->llregs->ll_lfps_timers_2);
		writel((val & 0xffff0000) \| LFPS_TIMERS_2_WORKAROUND_VALUE,
		&dev->llregs->ll_lfps_timers_2);

		/*
		* Set Recovery Idle to Recover bit:
		* - On SS connections, setting Recovery Idle to Recover Fmw improves

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