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patch "usb: cdnsp: fix lack of ZLP for ep0" added to usb-testing

PATCH [email protected] 1 participant 1 message Nov 28, 2022

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Stable branch USB Cadence usbssp DRD IP driver
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This is a note to let you know that I've just added the patch titled

usb: cdnsp: fix lack of ZLP for ep0

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the usb-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From c4069289acc0ffd3b52cfb8a756ae8774a195bfd Mon Sep 17 00:00:00 2001
From: Pawel Laszczak <[email protected]>
Date: Tue, 22 Nov 2022 03:51:38 -0500
Subject: usb: cdnsp: fix lack of ZLP for ep0

Patch implements the handling of ZLP for control transfer. To send the ZLP driver must prepare the extra TRB in TD with length set to zero and TRB type to TRB_NORMAL.
The first TRB must have set TRB_CHAIN flag, TD_SIZE = 1 and TRB type to TRB_DATA.

Fixes 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
cc <[email protected]>
Reviewed-by Peter Chen <[email protected]>
Signed-off-by Pawel Laszczak <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/usb/cdns3/cdnsp-ring.c | 42 ++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 10 deletions(-)
drivers/usb/cdns3/cdnsp-ring.c +32 -10
index 2f29431f612e..b23e543b3a3d 100644
@@ -2006,10 +2006,11 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 
 int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 {
-	u32 field, length_field, remainder;
+	u32 field, length_field, zlp = 0;
 	struct cdnsp_ep *pep = preq->pep;
 	struct cdnsp_ring *ep_ring;
 	int num_trbs;
+	u32 maxp;
 	int ret;
 
 	ep_ring = cdnsp_request_to_transfer_ring(pdev, preq);

@@ -2019,26 +2020,33 @@ int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 	/* 1 TRB for data, 1 for status */
 	num_trbs = (pdev->three_stage_setup) ? 2 : 1;
 
+	maxp = usb_endpoint_maxp(pep->endpoint.desc);
+
+	if (preq->request.zero && preq->request.length &&
+	    (preq->request.length % maxp == 0)) {
+		num_trbs++;
+		zlp = 1;
+	}
+
 	ret = cdnsp_prepare_transfer(pdev, preq, num_trbs);
 	if (ret)
 		return ret;
 
 	/* If there's data, queue data TRBs */
-	if (pdev->ep0_expect_in)
-		field = TRB_TYPE(TRB_DATA) | TRB_IOC;
-	else
-		field = TRB_ISP | TRB_TYPE(TRB_DATA) | TRB_IOC;
-
 	if (preq->request.length > 0) {
-		remainder = cdnsp_td_remainder(pdev, 0, preq->request.length,
-					       preq->request.length, preq, 1, 0);
+		field = TRB_TYPE(TRB_DATA);
 
-		length_field = TRB_LEN(preq->request.length) |
-				TRB_TD_SIZE(remainder) | TRB_INTR_TARGET(0);
+		if (zlp)
+			field |= TRB_CHAIN;
+		else
+			field |= TRB_IOC | (pdev->ep0_expect_in ? 0 : TRB_ISP);
 
 		if (pdev->ep0_expect_in)
 			field |= TRB_DIR_IN;
 
+		length_field = TRB_LEN(preq->request.length) |
+			       TRB_TD_SIZE(zlp) | TRB_INTR_TARGET(0);
+
 		cdnsp_queue_trb(pdev, ep_ring, true,
 				lower_32_bits(preq->request.dma),
 				upper_32_bits(preq->request.dma), length_field,

@@ -2046,6 +2054,20 @@ int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 				TRB_SETUPID(pdev->setup_id) |
 				pdev->setup_speed);
 
+		if (zlp) {
+			field = TRB_TYPE(TRB_NORMAL) | TRB_IOC;
+
+			if (!pdev->ep0_expect_in)
+				field = TRB_ISP;
+
+			cdnsp_queue_trb(pdev, ep_ring, true,
+					lower_32_bits(preq->request.dma),
+					upper_32_bits(preq->request.dma), 0,
+					field | ep_ring->cycle_state |
+					TRB_SETUPID(pdev->setup_id) |
+					pdev->setup_speed);
+		}
+
 		pdev->ep0_stage = CDNSP_DATA_STAGE;
 	}
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