x86: Add basic cache operations

Add functions to enable/disable the data cache.

Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index fabfbd1..315e87a 100644
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -34,6 +34,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <asm/control_regs.h>
 #include <asm/processor.h>
 #include <asm/processor-flags.h>
 #include <asm/interrupt.h>
@@ -147,16 +148,27 @@
 
 void x86_enable_caches(void)
 {
-	const u32 nw_cd_rst = ~(X86_CR0_NW | X86_CR0_CD);
+	unsigned long cr0;
 
-	/* turn on the cache and disable write through */
-	asm("movl	%%cr0, %%eax\n"
-	    "andl	%0, %%eax\n"
-	    "movl	%%eax, %%cr0\n"
-	    "wbinvd\n" : : "i" (nw_cd_rst) : "eax");
+	cr0 = read_cr0();
+	cr0 &= ~(X86_CR0_NW | X86_CR0_CD);
+	write_cr0(cr0);
+	wbinvd();
 }
 void enable_caches(void) __attribute__((weak, alias("x86_enable_caches")));
 
+void x86_disable_caches(void)
+{
+	unsigned long cr0;
+
+	cr0 = read_cr0();
+	cr0 |= X86_CR0_NW | X86_CR0_CD;
+	wbinvd();
+	write_cr0(cr0);
+	wbinvd();
+}
+void disable_caches(void) __attribute__((weak, alias("x86_disable_caches")));
+
 int x86_init_cache(void)
 {
 	enable_caches();
@@ -200,3 +212,17 @@
 	generate_gpf();			/* start the show */
 }
 void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));
+
+int dcache_status(void)
+{
+	return !(read_cr0() & 0x40000000);
+}
+
+/* Define these functions to allow ehch-hcd to function */
+void flush_dcache_range(unsigned long start, unsigned long stop)
+{
+}
+
+void invalidate_dcache_range(unsigned long start, unsigned long stop)
+{
+}