[U-Boot] [PATCH v4 8/8] riscv: cache: use CCTL to flush d-cache

[Andes]

From: Rick Chen <rick at andestech.com>

Use CCTL command to do d-cache write back
and invalidate instead of fence.

Signed-off-by: Rick Chen <rick at andestech.com>
Cc: KC Lin <kclin at andestech.com>
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
---
 arch/riscv/cpu/ax25/cache.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/cpu/ax25/cache.c b/arch/riscv/cpu/ax25/cache.c
index 8f5455e..41de30c 100644
--- a/arch/riscv/cpu/ax25/cache.c
+++ b/arch/riscv/cpu/ax25/cache.c
@@ -8,17 +8,21 @@
 #include <dm.h>
 #include <dm/uclass-internal.h>
 #include <cache.h>
+#include <asm/csr.h>
+
+#ifdef CONFIG_RISCV_NDS_CACHE
+/* mcctlcommand */
+#define CCTL_REG_MCCTLCOMMAND_NUM	0x7cc
+
+/* D-cache operation */
+#define CCTL_L1D_WBINVAL_ALL	6
+#endif
 
 void flush_dcache_all(void)
 {
-	/*
-	 * Andes' AX25 does not have a coherence agent. U-Boot must use data
-	 * cache flush and invalidate functions to keep data in the system
-	 * coherent.
-	 * The implementation of the fence instruction in the AX25 flushes the
-	 * data cache and is used for this purpose.
-	 */
-	asm volatile ("fence" ::: "memory");
+#ifdef CONFIG_RISCV_NDS_CACHE
+	csr_write(CCTL_REG_MCCTLCOMMAND_NUM, CCTL_L1D_WBINVAL_ALL);
+#endif
 }
 
 void flush_dcache_range(unsigned long start, unsigned long end)
@@ -84,8 +88,8 @@ void dcache_disable(void)
 #ifdef CONFIG_RISCV_NDS_CACHE
 	struct udevice *dev = NULL;
 
+	csr_write(CCTL_REG_MCCTLCOMMAND_NUM, CCTL_L1D_WBINVAL_ALL);
 	asm volatile (
-		"fence\n\t"
 		"csrr t1, mcache_ctl\n\t"
 		"andi t0, t1, ~0x2\n\t"
 		"csrw mcache_ctl, t0\n\t"
-- 
2.7.4