From 05735f0854e1e2fc0dd266cc6f583fc79dfdd5d8 Mon Sep 17 00:00:00 2001 From: Piyush Mehta Date: Mon, 13 Sep 2021 19:30:05 +0530 Subject: usb: chipidea: udc: make controller hardware endpoint primed Root-cause: There is an issue like endpoint is not recognized as primed, when bus have more pressure and 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. This issue observed with the Windows10 host machine. Workaround: The software must implement a periodic cycle, and check for each dTD, 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]. Link: https://lore.kernel.org/linux-usb/SJ0PR02MB8644CBBA848A0F68323F1AA5D4D99@SJ0PR02MB8644.namprd02.prod.outlook.com/ Acked-by: Peter Chen Signed-off-by: Piyush Mehta Link: https://lore.kernel.org/r/20210913140005.955699-1-piyush.mehta@xilinx.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/chipidea/udc.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/usb/chipidea') diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c index 8834ca613721..f9ca5010f65b 100644 --- a/drivers/usb/chipidea/udc.c +++ b/drivers/usb/chipidea/udc.c @@ -49,6 +49,8 @@ ctrl_endpt_in_desc = { .wMaxPacketSize = cpu_to_le16(CTRL_PAYLOAD_MAX), }; +static int reprime_dtd(struct ci_hdrc *ci, struct ci_hw_ep *hwep, + struct td_node *node); /** * hw_ep_bit: calculates the bit number * @num: endpoint number @@ -599,6 +601,12 @@ static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq) prevlastnode->ptr->next = cpu_to_le32(next); wmb(); + + if (ci->rev == CI_REVISION_22) { + if (!hw_read(ci, OP_ENDPTSTAT, BIT(n))) + reprime_dtd(ci, hwep, prevlastnode); + } + if (hw_read(ci, OP_ENDPTPRIME, BIT(n))) goto done; do { -- cgit v1.2.3