FiiO M3K/X1000: add USB support

This only required a minor patch to the usb-designware driver due
to DMA requiring physical addresses -- on the X1000, these differ
from virtual addresses so we have to do the usual conversion.

Both the mass storage and HID drivers work, but there are a few
issues so this can't be considered 100% stable yet.

- Mass storage might not be detected properly on insertion,
  and USB has to be replugged before it shows up
- HID driver may occasionally panic or hang the machine

Change-Id: Ia3ce7591d5928ec7cbca7953abfef01bdbd873ef

firmware/drivers/usb-designware.c

@@ -53,6 +53,15 @@
 #define COMMIT_DCACHE_RANGE(b,s)    commit_dcache_range(b,s)
 #endif
 
+/* On some platforms, virtual addresses must be mangled to
+ * get a physical address for DMA
+ */
+#if CONFIG_CPU == X1000
+# define DMA_ADDR2PHYS(x) PHYSADDR(x)
+#else
+# define DMA_ADDR2PHYS(x) x
+#endif
+
 #ifndef USB_DW_TOUTCAL
 #define USB_DW_TOUTCAL 0
 #endif
@@ -449,7 +458,7 @@ static void usb_dw_nptx_unqueue(int epnum)
             dw_ep->addr -= (bytesinfifo + 3) >> 2;
 #else
             (void) bytesinfifo;
-            DWC_DIEPDMA(ep) = (uint32_t)(dw_ep->addr) + sentbytes;
+            DWC_DIEPDMA(ep) = DMA_ADDR2PHYS((uint32_t)(dw_ep->addr) + sentbytes);
 #endif
             DWC_DIEPTSIZ(ep) = PKTCNT(packetsleft) | (dw_ep->size - sentbytes);
 
@@ -676,7 +685,7 @@ static void usb_dw_start_xfer(int epnum,
     /* Set up data source */
     dw_ep->addr = (uint32_t*)buf;
 #ifndef USB_DW_ARCH_SLAVE
-    DWC_EPDMA(epnum, epdir) = (uint32_t)buf;
+    DWC_EPDMA(epnum, epdir) = DMA_ADDR2PHYS((uint32_t)buf);
 #endif
 
     if (epdir == USB_DW_EPDIR_IN)