From patchwork Wed Oct 24 04:04:36 2012
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Subject: [U-Boot,05/15] x86: Add basic cache operations
Date: Tue, 23 Oct 2012 18:04:36 -0000
From: Simon Glass <sjg@chromium.org>
X-Patchwork-Id: 193662
Message-Id: <1351051486-6980-6-git-send-email-sjg@chromium.org>
To: U-Boot Mailing List <u-boot@lists.denx.de>
Cc: Stefan Reinauer <reinauer@chromium.org>

From: Stefan Reinauer <reinauer@chromium.org>

Add functions to enable/disable the data cache.

Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

---
arch/x86/cpu/interrupts.c    |    8 +------
 arch/x86/include/asm/cache.h |   47 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/arch/x86/cpu/interrupts.c b/arch/x86/cpu/interrupts.c
index 43ec3f8..710b653 100644
--- a/arch/x86/cpu/interrupts.c
+++ b/arch/x86/cpu/interrupts.c
@@ -28,6 +28,7 @@
  */
 
 #include <common.h>
+#include <asm/cache.h>
 #include <asm/interrupt.h>
 #include <asm/io.h>
 #include <asm/processor-flags.h>
@@ -50,13 +51,6 @@
  */
 static unsigned long __force_order;
 
-static inline unsigned long read_cr0(void)
-{
-	unsigned long val;
-	asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order));
-	return val;
-}
-
 static inline unsigned long read_cr2(void)
 {
 	unsigned long val;
diff --git a/arch/x86/include/asm/cache.h b/arch/x86/include/asm/cache.h
index 87c9e0b..9836856 100644
--- a/arch/x86/include/asm/cache.h
+++ b/arch/x86/include/asm/cache.h
@@ -32,4 +32,51 @@
 #define ARCH_DMA_MINALIGN	64
 #endif
 
+/* The memory clobber prevents the GCC from reordering the read/write order
+ * of CR0
+ */
+static inline unsigned long read_cr0(void)
+{
+	unsigned long cr0;
+
+	asm volatile ("movl %%cr0, %0" : "=r" (cr0) : : "memory");
+	return cr0;
+}
+
+static inline void write_cr0(unsigned long cr0)
+{
+	asm volatile ("movl %0, %%cr0" : : "r" (cr0) : "memory");
+}
+
+static inline void wbinvd(void)
+{
+	asm volatile ("wbinvd" : : : "memory");
+}
+
+static inline void invd(void)
+{
+	asm volatile("invd" : : : "memory");
+}
+
+static inline void enable_cache(void)
+{
+	unsigned long cr0;
+
+	cr0 = read_cr0();
+	cr0 &= 0x9fffffff;
+	write_cr0(cr0);
+}
+
+static inline void disable_cache(void)
+{
+	/* Disable and write back the cache */
+	unsigned long cr0;
+
+	cr0 = read_cr0();
+	cr0 |= 0x40000000;
+	wbinvd();
+	write_cr0(cr0);
+	wbinvd();
+}
+
 #endif /* __X86_CACHE_H__ */