usb: dwc3: gadget: disable automatic calculation of ACK TP NUMP
authorFelipe Balbi <felipe.balbi@linux.intel.com>
Thu, 28 Apr 2016 07:56:28 +0000 (10:56 +0300)
committerFelipe Balbi <felipe.balbi@linux.intel.com>
Thu, 28 Apr 2016 07:56:28 +0000 (10:56 +0300)
Now that we calculate DCFG.NUMP, we can disable
dwc3's automatic calculation so we maximize our
chances of very high throughtput through the use of
bursts.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
drivers/usb/dwc3/core.h
drivers/usb/dwc3/gadget.c

index c5f576aa190307f182351fb651ada03c24fda0b0..186a8868829fe024c279e8b65c67696bf27eb259 100644 (file)
 #define DWC3_DESCFETCHQ                13
 #define DWC3_EVENTQ            15
 
+/* Global RX Threshold Configuration Register */
+#define DWC3_GRXTHRCFG_MAXRXBURSTSIZE(n) (((n) & 0x1f) << 19)
+#define DWC3_GRXTHRCFG_RXPKTCNT(n) (((n) & 0xf) << 24)
+#define DWC3_GRXTHRCFG_PKTCNTSEL (1 << 29)
+
 /* Global Configuration Register */
 #define DWC3_GCTL_PWRDNSCALE(n)        ((n) << 19)
 #define DWC3_GCTL_U2RSTECN     (1 << 16)
index 4b681b0d420f3f55c5a3435865659d5f28623db9..c3b0d01e1960b72390eb6d8ddfe40598037fc6fe 100644 (file)
@@ -1669,6 +1669,17 @@ static int dwc3_gadget_start(struct usb_gadget *g,
        }
        dwc3_writel(dwc->regs, DWC3_DCFG, reg);
 
+       /*
+        * We are telling dwc3 that we want to use DCFG.NUMP as ACK TP's NUMP
+        * field instead of letting dwc3 itself calculate that automatically.
+        *
+        * This way, we maximize the chances that we'll be able to get several
+        * bursts of data without going through any sort of endpoint throttling.
+        */
+       reg = dwc3_readl(dwc->regs, DWC3_GRXTHRCFG);
+       reg &= ~DWC3_GRXTHRCFG_PKTCNTSEL;
+       dwc3_writel(dwc->regs, DWC3_GRXTHRCFG, reg);
+
        /* Start with SuperSpeed Default */
        dwc3_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);