MIPS: Add flush_dcache_range() and invalidate_dcache_range()

This patch adds flush_/invalidate_dcache_range() to the MIPS architecture.
Those functions are needed for the upcoming dcache support for the USB
EHCI driver. I chose this API because those cache handling functions are
already present in the PPC architecture.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>

cpu/mips/cpu.c

@@ -65,6 +65,34 @@ void flush_cache(ulong start_addr, ulong size)
 	}
 }
 
+void flush_dcache_range(ulong start_addr, ulong stop)
+{
+	unsigned long lsize = CONFIG_SYS_CACHELINE_SIZE;
+	unsigned long addr = start_addr & ~(lsize - 1);
+	unsigned long aend = (stop - 1) & ~(lsize - 1);
+
+	while (1) {
+		cache_op(Hit_Writeback_Inv_D, addr);
+		if (addr == aend)
+			break;
+		addr += lsize;
+	}
+}
+
+void invalidate_dcache_range(ulong start_addr, ulong stop)
+{
+	unsigned long lsize = CONFIG_SYS_CACHELINE_SIZE;
+	unsigned long addr = start_addr & ~(lsize - 1);
+	unsigned long aend = (stop - 1) & ~(lsize - 1);
+
+	while (1) {
+		cache_op(Hit_Invalidate_D, addr);
+		if (addr == aend)
+			break;
+		addr += lsize;
+	}
+}
+
 void write_one_tlb(int index, u32 pagemask, u32 hi, u32 low0, u32 low1)
 {
 	write_c0_entrylo0(low0);

include/common.h

@@ -597,6 +597,8 @@ ulong	video_setmem (ulong);
 
 /* lib_$(ARCH)/cache.c */
 void	flush_cache   (unsigned long, unsigned long);
+void	flush_dcache_range(unsigned long start, unsigned long stop);
+void	invalidate_dcache_range(unsigned long start, unsigned long stop);
 
 
 /* lib_$(ARCH)/ticks.S */