usb: dwc3: gadget: add a pointer to endpoint registers

By adding a pointer to endpoint registers' base
address, we can avoid using our controller-wide
struct dwc3 pointer for everything. At some point
this will allow us to have per-endpoint locks which
will, in turn, let us queue requests to separate
endpoints in parallel.

Because of this change our debugfs interface and io
accessors need to be changed accordingly.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 27afe14..02990ab 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -138,10 +138,12 @@
 #define DWC3_DGCMDPAR		0xc710
 #define DWC3_DGCMD		0xc714
 #define DWC3_DALEPENA		0xc720
-#define DWC3_DEPCMDPAR2(n)	(0xc800 + (n * 0x10))
-#define DWC3_DEPCMDPAR1(n)	(0xc804 + (n * 0x10))
-#define DWC3_DEPCMDPAR0(n)	(0xc808 + (n * 0x10))
-#define DWC3_DEPCMD(n)		(0xc80c + (n * 0x10))
+
+#define DWC3_DEP_BASE(n)	(0xc800 + (n * 0x10))
+#define DWC3_DEPCMDPAR2		0x00
+#define DWC3_DEPCMDPAR1		0x04
+#define DWC3_DEPCMDPAR0		0x08
+#define DWC3_DEPCMD		0x0c
 
 /* OTG Registers */
 #define DWC3_OCFG		0xcc00
@@ -480,6 +482,7 @@
  * @endpoint: usb endpoint
  * @pending_list: list of pending requests for this endpoint
  * @started_list: list of started requests on this endpoint
+ * @regs: pointer to first endpoint register
  * @trb_pool: array of transaction buffers
  * @trb_pool_dma: dma address of @trb_pool
  * @trb_enqueue: enqueue 'pointer' into TRB array
@@ -501,6 +504,8 @@
 	struct list_head	pending_list;
 	struct list_head	started_list;
 
+	void __iomem		*regs;
+
 	struct dwc3_trb		*trb_pool;
 	dma_addr_t		trb_pool_dma;
 	const struct usb_ss_ep_comp_descriptor *comp_desc;