usb: dwc2: gadget: Enable descriptor DMA mode

Add DCFG register field macro for descriptor DMA mode and update core
initialization routine to set that bit accordingly.

Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/gadget.c

@@ -2888,15 +2888,21 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 
 	dwc2_writel(intmsk, hsotg->regs + GINTMSK);
 
-	if (using_dma(hsotg))
+	if (using_dma(hsotg)) {
 		dwc2_writel(GAHBCFG_GLBL_INTR_EN | GAHBCFG_DMA_EN |
 			    (GAHBCFG_HBSTLEN_INCR4 << GAHBCFG_HBSTLEN_SHIFT),
 			    hsotg->regs + GAHBCFG);
-	else
+
+		/* Set DDMA mode support in the core if needed */
+		if (using_desc_dma(hsotg))
+			__orr32(hsotg->regs + DCFG, DCFG_DESCDMA_EN);
+
+	} else {
 		dwc2_writel(((hsotg->dedicated_fifos) ?
 						(GAHBCFG_NP_TXF_EMP_LVL |
 						 GAHBCFG_P_TXF_EMP_LVL) : 0) |
 			    GAHBCFG_GLBL_INTR_EN, hsotg->regs + GAHBCFG);
+	}
 
 	/*
 	 * If INTknTXFEmpMsk is enabled, it's important to disable ep interrupts

drivers/usb/dwc2/hw.h

@@ -412,6 +412,7 @@
 /* Device mode registers */
 
 #define DCFG				HSOTG_REG(0x800)
+#define DCFG_DESCDMA_EN			(1 << 23)
 #define DCFG_EPMISCNT_MASK		(0x1f << 18)
 #define DCFG_EPMISCNT_SHIFT		18
 #define DCFG_EPMISCNT_LIMIT		0x1f