usb: dwc3: Enable undefined length INCR burst type

Enable the undefined length INCR burst type and set INCRx.
Different platform may has the different burst size type.
In order to get best performance, we need to tune the burst
size to one special value, instead of the default value.

Signed-off-by: Changming Huang <jerry.huang@nxp.com>
Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Signed-off-by: Pengbo Mu <pengbo.mu@nxp.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -778,6 +778,98 @@ static void dwc3_core_setup_global_control(struct dwc3 *dwc)
 static int dwc3_core_get_phy(struct dwc3 *dwc);
 static int dwc3_core_ulpi_init(struct dwc3 *dwc);
 
+/* set global incr burst type configuration registers */
+static void dwc3_set_incr_burst_type(struct dwc3 *dwc)
+{
+	struct device *dev = dwc->dev;
+	/* incrx_mode : for INCR burst type. */
+	bool incrx_mode;
+	/* incrx_size : for size of INCRX burst. */
+	u32 incrx_size;
+	u32 *vals;
+	u32 cfg;
+	int ntype;
+	int ret;
+	int i;
+
+	cfg = dwc3_readl(dwc->regs, DWC3_GSBUSCFG0);
+
+	/*
+	 * Handle property "snps,incr-burst-type-adjustment".
+	 * Get the number of value from this property:
+	 * result <= 0, means this property is not supported.
+	 * result = 1, means INCRx burst mode supported.
+	 * result > 1, means undefined length burst mode supported.
+	 */
+	ntype = device_property_read_u32_array(dev,
+			"snps,incr-burst-type-adjustment", NULL, 0);
+	if (ntype <= 0)
+		return;
+
+	vals = kcalloc(ntype, sizeof(u32), GFP_KERNEL);
+	if (!vals) {
+		dev_err(dev, "Error to get memory\n");
+		return;
+	}
+
+	/* Get INCR burst type, and parse it */
+	ret = device_property_read_u32_array(dev,
+			"snps,incr-burst-type-adjustment", vals, ntype);
+	if (ret) {
+		dev_err(dev, "Error to get property\n");
+		return;
+	}
+
+	incrx_size = *vals;
+
+	if (ntype > 1) {
+		/* INCRX (undefined length) burst mode */
+		incrx_mode = INCRX_UNDEF_LENGTH_BURST_MODE;
+		for (i = 1; i < ntype; i++) {
+			if (vals[i] > incrx_size)
+				incrx_size = vals[i];
+		}
+	} else {
+		/* INCRX burst mode */
+		incrx_mode = INCRX_BURST_MODE;
+	}
+
+	/* Enable Undefined Length INCR Burst and Enable INCRx Burst */
+	cfg &= ~DWC3_GSBUSCFG0_INCRBRST_MASK;
+	if (incrx_mode)
+		cfg |= DWC3_GSBUSCFG0_INCRBRSTENA;
+	switch (incrx_size) {
+	case 256:
+		cfg |= DWC3_GSBUSCFG0_INCR256BRSTENA;
+		break;
+	case 128:
+		cfg |= DWC3_GSBUSCFG0_INCR128BRSTENA;
+		break;
+	case 64:
+		cfg |= DWC3_GSBUSCFG0_INCR64BRSTENA;
+		break;
+	case 32:
+		cfg |= DWC3_GSBUSCFG0_INCR32BRSTENA;
+		break;
+	case 16:
+		cfg |= DWC3_GSBUSCFG0_INCR16BRSTENA;
+		break;
+	case 8:
+		cfg |= DWC3_GSBUSCFG0_INCR8BRSTENA;
+		break;
+	case 4:
+		cfg |= DWC3_GSBUSCFG0_INCR4BRSTENA;
+		break;
+	case 1:
+		break;
+	default:
+		dev_err(dev, "Invalid property\n");
+		break;
+	}
+
+	dwc3_writel(dwc->regs, DWC3_GSBUSCFG0, cfg);
+}
+
 /**
  * dwc3_core_init - Low-level initialization of DWC3 Core
  * @dwc: Pointer to our controller context structure
@@ -840,6 +932,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
 	/* Adjust Frame Length */
 	dwc3_frame_length_adjustment(dwc);
 
+	dwc3_set_incr_burst_type(dwc);
+
 	usb_phy_set_suspend(dwc->usb2_phy, 0);
 	usb_phy_set_suspend(dwc->usb3_phy, 0);
 	ret = phy_power_on(dwc->usb2_generic_phy);

drivers/usb/dwc3/core.h

@@ -1168,6 +1168,9 @@ struct dwc3 {
 	u16			imod_interval;
 };
 
+#define INCRX_BURST_MODE 0
+#define INCRX_UNDEF_LENGTH_BURST_MODE 1
+
 #define work_to_dwc(w)		(container_of((w), struct dwc3, drd_work))
 
 /* -------------------------------------------------------------------------- */