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[4/4] usb: renesas_usbhs: set quirk_avoids_skb_reserve if USB-DMAC is used

Message ID 1471855708-10897-5-git-send-email-yoshihiro.shimoda.uh@renesas.com (mailing list archive)
State Accepted
Delegated to: Geert Uytterhoeven
Headers show

Commit Message

Yoshihiro Shimoda Aug. 22, 2016, 8:48 a.m. UTC 
This patch sets the quirk_avoids_skb_reserve flag to improve performance
of a network gadget driver (e.g. f_ncm.c) if USB-DMAC is used.

For example (on r8a7795 board + f_ncm.c + iperf udp mode / receiving):
  - without this patch:  90.3 Mbits/sec
  - with    this patch: 273   Mbits/sec

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
---
 drivers/usb/renesas_usbhs/mod_gadget.c | 2 ++
 1 file changed, 2 insertions(+)
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Patch

diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c b/drivers/usb/renesas_usbhs/mod_gadget.c
index 92bc83b..b4e9e6f 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -1106,6 +1106,8 @@  int usbhs_mod_gadget_probe(struct usbhs_priv *priv)
 	gpriv->gadget.name		= "renesas_usbhs_udc";
 	gpriv->gadget.ops		= &usbhsg_gadget_ops;
 	gpriv->gadget.max_speed		= USB_SPEED_HIGH;
+	gpriv->gadget.quirk_avoids_skb_reserve = usbhs_get_dparam(priv,
+								has_usb_dmac);
 
 	INIT_LIST_HEAD(&gpriv->gadget.ep_list);