usb: dwc2: gadget: Add descriptor DMA parameter

Add a parameter for descriptor DMA and set it based on hardware
capabilities. This won't actually be used by the gadget until later,
when the descriptor DMA code is in place.

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/core.h

@@ -419,6 +419,7 @@ enum dwc2_ep0_state {
  *			0 - No (default)
  *			1 - Yes
  * @g_dma:              Enables gadget dma usage (default: autodetect).
+ * @g_dma_desc:         Enables gadget descriptor DMA (default: autodetect).
  * @g_rx_fifo_size:	The periodic rx fifo size for the device, in
  *			DWORDS from 16-32768 (default: 2048 if
  *			possible, otherwise autodetect).
@@ -498,6 +499,7 @@ struct dwc2_core_params {
 
 	/* Gadget parameters */
 	bool g_dma;
+	bool g_dma_desc;
 	u16 g_rx_fifo_size;
 	u16 g_np_tx_fifo_size;
 	u32 g_tx_fifo_size[MAX_EPS_CHANNELS];

drivers/usb/dwc2/gadget.c

@@ -96,6 +96,17 @@ static inline bool using_dma(struct dwc2_hsotg *hsotg)
 	return hsotg->params.g_dma;
 }
 
+/*
+ * using_desc_dma - return the descriptor DMA status of the driver.
+ * @hsotg: The driver state.
+ *
+ * Return true if we're using descriptor DMA.
+ */
+static inline bool using_desc_dma(struct dwc2_hsotg *hsotg)
+{
+	return hsotg->params.g_dma_desc;
+}
+
 /**
  * dwc2_gadget_incr_frame_num - Increments the targeted frame number.
  * @hs_ep: The endpoint

drivers/usb/dwc2/params.c

@@ -1097,6 +1097,12 @@ static void dwc2_set_gadget_dma(struct dwc2_hsotg *hsotg)
 			    false, "gadget-dma",
 			    true, false,
 			    dma_capable);
+
+	/* DMA Descriptor */
+	dwc2_set_param_bool(hsotg, &p->g_dma_desc, false,
+			    "gadget-dma-desc",
+			    p->g_dma, false,
+			    !!hw->dma_desc_enable);
 }
 
 /**