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From: Manish Narani <manish.narani@xilinx.com>
To: <peter.chen@kernel.org>, <gregkh@linuxfoundation.org>,
	<michal.simek@xilinx.com>
Cc: <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<git@xilinx.com>, Piyush Mehta <piyush.mehta@xilinx.com>,
	Manish Narani <manish.narani@xilinx.com>
Subject: [PATCH 6/6] usb: chipidea: udc: Add xilinx revision support
Date: Tue, 24 Aug 2021 22:46:18 +0530	[thread overview]
Message-ID: <1629825378-8089-7-git-send-email-manish.narani@xilinx.com> (raw)
In-Reply-To: <1629825378-8089-1-git-send-email-manish.narani@xilinx.com>

From: Piyush Mehta <piyush.mehta@xilinx.com>

Issue: Adding a dTD to a Primed Endpoint May Not Get Recognized with
revision 2.20a.

There is an issue with the add dTD tripwire semaphore (ATDTW bit in
USBCMD register) that can cause the controller to ignore a dTD that is
added to a primed endpoint. When this happens, the software can read
the tripwire bit and the status bit at '1' even though the endpoint is
unprimed.
This issue observed with the Windows host machine.

Workaround:
The software must implement a periodic cycle, and check for each dTD
pending on execution (Active = 1), if the endpoint is primed. It can do
this by reading the corresponding bits in the ENDPTPRIME and ENDPTSTAT
registers. If these bits are read at 0, the software needs to re-prime
the endpoint by writing 1 to the corresponding bit in the ENDPTPRIME
register.

Added conditional revision check of 2.20[CI_REVISION_22] along with 2.40.

Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com>
Signed-off-by: Manish Narani <manish.narani@xilinx.com>
---
 drivers/usb/chipidea/udc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 8834ca6..b440205 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -680,7 +680,8 @@ static int _hardware_dequeue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 		if ((TD_STATUS_ACTIVE & tmptoken) != 0) {
 			int n = hw_ep_bit(hwep->num, hwep->dir);
 
-			if (ci->rev == CI_REVISION_24)
+			if (ci->rev == CI_REVISION_24 ||
+			    ci->rev == CI_REVISION_22)
 				if (!hw_read(ci, OP_ENDPTSTAT, BIT(n)))
 					reprime_dtd(ci, hwep, node);
 			hwreq->req.status = -EALREADY;
-- 
2.1.1


  parent reply	other threads:[~2021-08-24 17:19 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 17:16 [PATCH 0/6] Chipidea USB driver Enhancements and Bug Fixes Manish Narani
2021-08-24 17:16 ` [PATCH 1/6] usb: chipidea: Add support for VBUS control with PHY Manish Narani
2021-10-07  4:44   ` Peter Chen
2021-10-08  4:59   ` Jun Li
2021-08-24 17:16 ` [PATCH 2/6] usb: chipidea: Use usb2 phy for Zynq platform Manish Narani
2021-10-07  4:52   ` Peter Chen
2021-08-24 17:16 ` [PATCH 3/6] usb: chipidea: Check usb_phy exists before using it Manish Narani
2021-10-07  4:54   ` Peter Chen
2021-08-24 17:16 ` [PATCH 4/6] usb: chipidea: Fix return value handling Manish Narani
2021-08-24 17:16 ` [PATCH 5/6] usb: chipidea: core: Add return value function check Manish Narani
2021-10-07  5:00   ` Peter Chen
2021-08-24 17:16 ` Manish Narani [this message]
2021-10-07  5:02   ` [PATCH 6/6] usb: chipidea: udc: Add xilinx revision support Peter Chen
2021-10-07  5:03   ` Peter Chen
2021-10-07  5:12 ` [PATCH 0/6] Chipidea USB driver Enhancements and Bug Fixes Peter Chen

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