From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Felipe Balbi <balbi@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
linux-usb@vger.kernel.org
Cc: John Youn <John.Youn@synopsys.com>
Subject: [PATCH v2 3/3] usb: dwc3: gadget: Remove END_TRANSFER delay
Date: Wed, 18 Dec 2019 18:14:56 -0800 [thread overview]
Message-ID: <ba66a4882a861749b29b7c80db33d686080dab09.1576715470.git.thinhn@synopsys.com> (raw)
In-Reply-To: <cover.1576715470.git.thinhn@synopsys.com>
We had a 100us delay to synchronize the END_TRANSFER command completion
before giving back requests to the function drivers. Now, the controller
driver can handle cancelled TRBs with the requests' cancelled_list and
it can also wait until the END_TRANSFER completion before starting new
transfers. Synchronization can simply base on the controller's command
completion interrupt. The 100us delay is no longer needed. Remove this
arbitrary delay.
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
---
Changes in v2:
- Remove unused variable
drivers/usb/dwc3/gadget.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 61b7bef98cf9..05dbeae1308a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2686,7 +2686,6 @@ static void dwc3_reset_gadget(struct dwc3 *dwc)
static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
bool interrupt)
{
- struct dwc3 *dwc = dep->dwc;
struct dwc3_gadget_ep_cmd_params params;
u32 cmd;
int ret;
@@ -2702,16 +2701,13 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
* much trouble synchronizing between us and gadget driver.
*
* We have discussed this with the IP Provider and it was
- * suggested to giveback all requests here, but give HW some
- * extra time to synchronize with the interconnect. We're using
- * an arbitrary 100us delay for that.
+ * suggested to giveback all requests here.
*
* Note also that a similar handling was tested by Synopsys
* (thanks a lot Paul) and nothing bad has come out of it.
- * In short, what we're doing is:
- *
- * - Issue EndTransfer WITH CMDIOC bit set
- * - Wait 100us
+ * In short, what we're doing is issuing EndTransfer with
+ * CMDIOC bit set and delay kicking transfer until the
+ * EndTransfer command had completed.
*
* As of IP version 3.10a of the DWC_usb3 IP, the controller
* supports a mode to work around the above limitation. The
@@ -2720,8 +2716,7 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
* by writing GUCTL2[14]. This polling is already done in the
* dwc3_send_gadget_ep_cmd() function so if the mode is
* enabled, the EndTransfer command will have completed upon
- * returning from this function and we don't need to delay for
- * 100us.
+ * returning from this function.
*
* This mode is NOT available on the DWC_usb31 IP.
*/
@@ -2739,9 +2734,6 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
else
dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
-
- if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A)
- udelay(100);
}
static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
--
2.11.0
next prev parent reply other threads:[~2019-12-19 2:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 2:14 [PATCH v2 0/3] usb: dwc3: gadget: Improve END_TRANSFER handling Thinh Nguyen
2019-12-19 2:14 ` [PATCH v2 1/3] usb: dwc3: gadget: Check END_TRANSFER completion Thinh Nguyen
2019-12-19 2:14 ` [PATCH v2 2/3] usb: dwc3: gadget: Delay starting transfer Thinh Nguyen
2019-12-19 2:14 ` Thinh Nguyen [this message]
2020-01-09 11:30 ` [PATCH v2 0/3] usb: dwc3: gadget: Improve END_TRANSFER handling Felipe Balbi
2020-01-09 19:31 ` Thinh Nguyen
2020-01-15 8:52 ` Felipe Balbi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ba66a4882a861749b29b7c80db33d686080dab09.1576715470.git.thinhn@synopsys.com \
--to=thinh.nguyen@synopsys.com \
--cc=John.Youn@synopsys.com \
--cc=balbi@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=linux-usb@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).