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usb: chipidea: udc: make controller hardware endpoint primed

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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 <peter.chen@kernel.org>
Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com>
Link: https://lore.kernel.org/r/20210913140005.955699-1-piyush.mehta@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Piyush Mehta 2021-09-13 19:30:05 +05:30 committed by Greg Kroah-Hartman
parent 2c52ad743f
commit 05735f0854
1 changed files with 8 additions and 0 deletions
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8
drivers/usb/chipidea/udc.c
View file

@ -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 {