From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Felipe Balbi <balbi@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org
Cc: John Youn <John.Youn@synopsys.com>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Subject: [PATCH 2/3] usb: dwc3: gadget: Ignore Update Transfer cmd params
Date: Mon, 29 Nov 2021 18:53:16 -0800 [thread overview]
Message-ID: <997d9ebf38c6bba920d4ee77bd8c77bf81978a55.1638240306.git.Thinh.Nguyen@synopsys.com> (raw)
In-Reply-To: <cover.1638240306.git.Thinh.Nguyen@synopsys.com>
The controller doesn't check for Update Transfer command parameters
DEPCMDPAR{0,1,2}. Writing to these registers is unnecessary. Ignoring
this improves performance slightly by removing the register write
delay.
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
drivers/usb/dwc3/gadget.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 00b3f19c4d3e..f66baaef8a40 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -331,9 +331,17 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
}
}
- dwc3_writel(dep->regs, DWC3_DEPCMDPAR0, params->param0);
- dwc3_writel(dep->regs, DWC3_DEPCMDPAR1, params->param1);
- dwc3_writel(dep->regs, DWC3_DEPCMDPAR2, params->param2);
+ /*
+ * For some commands such as Update Transfer command, DEPCMDPARn
+ * registers are reserved. Since the driver often sends Update Transfer
+ * command, don't write to DEPCMDPARn to avoid register write delays and
+ * improve performance.
+ */
+ if (DWC3_DEPCMD_CMD(cmd) != DWC3_DEPCMD_UPDATETRANSFER) {
+ dwc3_writel(dep->regs, DWC3_DEPCMDPAR0, params->param0);
+ dwc3_writel(dep->regs, DWC3_DEPCMDPAR1, params->param1);
+ dwc3_writel(dep->regs, DWC3_DEPCMDPAR2, params->param2);
+ }
/*
* Synopsys Databook 2.60a states in section 6.3.2.5.6 of that if we're
--
2.28.0
next prev parent reply other threads:[~2021-11-30 2:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-30 2:53 [PATCH 0/3] usb: dwc3: gadget: Reduce register read/write operations Thinh Nguyen
2021-11-30 2:53 ` [PATCH 1/3] usb: dwc3: gadget: Skip checking Update Transfer status Thinh Nguyen
2021-11-30 2:53 ` Thinh Nguyen [this message]
2021-11-30 2:53 ` [PATCH 3/3] usb: dwc3: gadget: Skip reading GEVNTSIZn Thinh Nguyen
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=997d9ebf38c6bba920d4ee77bd8c77bf81978a55.1638240306.git.Thinh.Nguyen@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.