Linux-libre 4.6.5-gnupck-4.6.5-gnu

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 3c58d633c..dec0b21fc 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -64,6 +64,17 @@
 	DWC2_TRACE_SCHEDULER_VB(pr_fmt("%s: SCH: " fmt),		\
 				dev_name(hsotg->dev), ##__VA_ARGS__)
 
+#ifdef CONFIG_MIPS
+/*
+ * There are some MIPS machines that can run in either big-endian
+ * or little-endian mode and that use the dwc2 register without
+ * a byteswap in both ways.
+ * Unlike other architectures, MIPS apparently does not require a
+ * barrier before the __raw_writel() to synchronize with DMA but does
+ * require the barrier after the __raw_writel() to serialize a set of
+ * writes. This set of operations was added specifically for MIPS and
+ * should only be used there.
+ */
 static inline u32 dwc2_readl(const void __iomem *addr)
 {
 	u32 value = __raw_readl(addr);
@@ -90,6 +101,22 @@ static inline void dwc2_writel(u32 value, void __iomem *addr)
 	pr_info("INFO:: wrote %08x to %p\n", value, addr);
 #endif
 }
+#else
+/* Normal architectures just use readl/write */
+static inline u32 dwc2_readl(const void __iomem *addr)
+{
+	return readl(addr);
+}
+
+static inline void dwc2_writel(u32 value, void __iomem *addr)
+{
+	writel(value, addr);
+
+#ifdef DWC2_LOG_WRITES
+	pr_info("info:: wrote %08x to %p\n", value, addr);
+#endif
+}
+#endif
 
 /* Maximum number of Endpoints/HostChannels */
 #define MAX_EPS_CHANNELS	16