From 61d58242f634642de42d6a4098913b7254a65053 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Mon, 29 Aug 2011 16:46:38 +0200 Subject: [PATCH] usb: dwc3: gadget: replace mdelay with udelay in the busy loop There are two spots where we wait until the HW finishes processing a certain command. Initially we had a few problems and we used 500ms as a limit to be on a the safe side. Paul Zimmerman mentioned this is little too much. After a debugging session, we noticed that we hardly ever go over 20us and didn't pass 30usec so far. Using mdelay() seems way overloaded. Giving the current numbers 500usec as the upper limit is more than enough. Should it ever timeout then something is definitely wrong. While here, also replace the type with u32 since long does not really fit here. Cc: Paul Zimmerman Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/gadget.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 7c014e9c1277..b5d95f8329f2 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -153,7 +153,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep, unsigned cmd, struct dwc3_gadget_ep_cmd_params *params) { struct dwc3_ep *dep = dwc->eps[ep]; - unsigned long timeout = 500; + u32 timeout = 500; u32 reg; dev_vdbg(dwc->dev, "%s: cmd '%s' params %08x %08x %08x\n", @@ -175,7 +175,6 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep, } /* - * XXX Figure out a sane timeout here. 500ms is way too much. * We can't sleep here, because it is also called from * interrupt context. */ @@ -183,7 +182,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep, if (!timeout) return -ETIMEDOUT; - mdelay(1); + udelay(1); } while (1); } @@ -1066,7 +1065,7 @@ static int dwc3_gadget_set_selfpowered(struct usb_gadget *g, static void dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on) { u32 reg; - unsigned long timeout = 500; + u32 timeout = 500; reg = dwc3_readl(dwc->regs, DWC3_DCTL); if (is_on) @@ -1085,13 +1084,10 @@ static void dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on) if (reg & DWC3_DSTS_DEVCTRLHLT) break; } - /* - * XXX reduce the 500ms delay - */ timeout--; if (!timeout) break; - mdelay(1); + udelay(1); } while (1); dev_vdbg(dwc->dev, "gadget %s data soft-%s\n", -- 2.11.0