diff --git a/arch/mips/fw/cfe/cfe_api.c b/arch/mips/fw/cfe/cfe_api.c
index d06dc5a6b8d3..cf84f01931c5 100644
--- a/arch/mips/fw/cfe/cfe_api.c
+++ b/arch/mips/fw/cfe/cfe_api.c
@@ -406,12 +406,12 @@ int cfe_setenv(char *name, char *val)
 	return xiocb.xiocb_status;
 }
 
-int cfe_write(int handle, unsigned char *buffer, int length)
+int cfe_write(int handle, const char *buffer, int length)
 {
 	return cfe_writeblk(handle, 0, buffer, length);
 }
 
-int cfe_writeblk(int handle, s64 offset, unsigned char *buffer, int length)
+int cfe_writeblk(int handle, s64 offset, const char *buffer, int length)
 {
 	struct cfe_xiocb xiocb;
 
diff --git a/arch/mips/include/asm/fw/cfe/cfe_api.h b/arch/mips/include/asm/fw/cfe/cfe_api.h
index 17347551a1b2..a0ea69e91e2e 100644
--- a/arch/mips/include/asm/fw/cfe/cfe_api.h
+++ b/arch/mips/include/asm/fw/cfe/cfe_api.h
@@ -115,8 +115,8 @@ int cfe_read(int handle, unsigned char *buffer, int length);
 int cfe_readblk(int handle, int64_t offset, unsigned char *buffer,
 		int length);
 int cfe_setenv(char *name, char *val);
-int cfe_write(int handle, unsigned char *buffer, int length);
-int cfe_writeblk(int handle, int64_t offset, unsigned char *buffer,
+int cfe_write(int handle, const char *buffer, int length);
+int cfe_writeblk(int handle, int64_t offset, const char *buffer,
 		 int length);
 
 #endif				/* CFE_API_H */