From 490c3d87cb558a8cfe8ad4db9f39c9cb3df91d17 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sun, 22 Sep 2019 18:51:41 +0200
Subject: [PATCH] usbxhci: fix endpoint stall recovery, handle Ep.clrhalt flag

after issuing CR_RESETEP command, we have to invalidate
the endpoints output context buffer so that the halted/error
status reflects the new state. not doing so resulted in
the halted state to be stuck and we continued issuing
endpoint reset commands when we where already recovered.

handle the devusb Ep.clrhalt flag from devusb that userspace
uses to force a endpoint reset on the next transaction.
---
 sys/src/9/port/usbxhci.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/sys/src/9/port/usbxhci.c b/sys/src/9/port/usbxhci.c
index f1ce6d8ab..ab30aa040 100644
--- a/sys/src/9/port/usbxhci.c
+++ b/sys/src/9/port/usbxhci.c
@@ -1368,20 +1368,26 @@ isowrite(Ep *ep, uchar *p, long n)
 }
 
 static char*
-unstall(Ring *r)
+unstall(Ep *ep, Ring *r)
 {
 	char *err;
 
 	switch(r->ctx[0]&7){
 	case 2:	/* halted */
 	case 4:	/* error */
-		r->stopped = 1;
+		ep->clrhalt = 1;
+	}
+	if(ep->clrhalt){
+		ep->clrhalt = 0;
 		err = ctlrcmd(r->slot->ctlr, CR_RESETEP | (r->id<<16) | (r->slot->id<<24), 0, 0, nil);
+		dmaflush(0, r->ctx, 8*4 << r->slot->ctlr->csz);
 		if(err != nil)
 			return err;
+		r->stopped = 1;
 	}
 	if(r->stopped){
 		err = ctlrcmd(r->slot->ctlr, CR_SETTRDQP | (r->id<<16) | (r->slot->id<<24), 0, resetring(r), nil);
+		dmaflush(0, r->ctx, 8*4 << r->slot->ctlr->csz);
 		if(err != nil)
 			return err;
 		r->stopped = 0;
@@ -1444,7 +1450,7 @@ epread(Ep *ep, void *va, long n)
 		nexterror();
 	}
 
-	if((err = unstall(io->ring)) != nil)
+	if((err = unstall(ep, io->ring)) != nil)
 		error(err);
 
 	dmaflush(1, p, n);
@@ -1517,7 +1523,7 @@ epwrite(Ep *ep, void *va, long n)
 				io->b->wp += len;
 			}
 		}
-		if((err = unstall(ring)) != nil)
+		if((err = unstall(ep, ring)) != nil)
 			error(err);
 
 		if((ring->ctx[1]>>16) != ep->maxpkt){
@@ -1596,7 +1602,7 @@ epwrite(Ep *ep, void *va, long n)
 		nexterror();
 	}
 
-	if((err = unstall(io->ring)) != nil)
+	if((err = unstall(ep, io->ring)) != nil)
 		error(err);
 
 	dmaflush(1, p, n);