usb: dwc3: core: add fifo space helper

this helper will be used, initially, to dump space
of different queues and fifos in dwc3 to
debugfs. Later, it'll be used to issue remote wakeup
when we want to start a transfer and there's
something in a TX FIFO.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -60,6 +60,20 @@ void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
 	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
 }
 
+u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type)
+{
+	struct dwc3		*dwc = dep->dwc;
+	u32			reg;
+
+	dwc3_writel(dwc->regs, DWC3_GDBGFIFOSPACE,
+			DWC3_GDBGFIFOSPACE_NUM(dep->number) |
+			DWC3_GDBGFIFOSPACE_TYPE(type));
+
+	reg = dwc3_readl(dwc->regs, DWC3_GDBGFIFOSPACE);
+
+	return DWC3_GDBGFIFOSPACE_SPACE_AVAILABLE(reg);
+}
+
 /**
  * dwc3_core_soft_reset - Issues core soft reset and PHY reset
  * @dwc: pointer to our context structure

drivers/usb/dwc3/core.h

@@ -152,6 +152,19 @@
 
 /* Bit fields */
 
+/* Global Debug Queue/FIFO Space Available Register */
+#define DWC3_GDBGFIFOSPACE_NUM(n)	((n) & 0x1f)
+#define DWC3_GDBGFIFOSPACE_TYPE(n)	(((n) << 5) & 0x1e0)
+#define DWC3_GDBGFIFOSPACE_SPACE_AVAILABLE(n) (((n) >> 16) & 0xffff)
+
+#define DWC3_TXFIFOQ		1
+#define DWC3_RXFIFOQ		3
+#define DWC3_TXREQQ		5
+#define DWC3_RXREQQ		7
+#define DWC3_RXINFOQ		9
+#define DWC3_DESCFETCHQ		13
+#define DWC3_EVENTQ		15
+
 /* Global Configuration Register */
 #define DWC3_GCTL_PWRDNSCALE(n)	((n) << 19)
 #define DWC3_GCTL_U2RSTECN	(1 << 16)
@@ -1043,6 +1056,7 @@ struct dwc3_gadget_ep_cmd_params {
 
 /* prototypes */
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode);
+u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type);
 
 /* check whether we are on the DWC_usb31 core */
 static inline bool dwc3_is_usb31(struct dwc3 *dwc)