ARM: shmobile: r8a7740: add MERAM work-around

r8a7740 chip has lasting errata on MERAM buffer, and this patch adds
its work-around on setup-r8a7740.c
It solved CEU/VIO6C/2D-DMAC/VCP1/VPU5F/JPU/DISP memroy access error.

But MERAM driver can't control this issue,
since this work-around requires access to non-MERAM register address.
So, This it will be called as board specific code at this point.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Simon Horman <horms@verge.net.au>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/arch/arm/mach-shmobile/setup-r8a7740.c b/arch/arm/mach-shmobile/setup-r8a7740.c
index ec4eb49..366311b 100644
--- a/arch/arm/mach-shmobile/setup-r8a7740.c
+++ b/arch/arm/mach-shmobile/setup-r8a7740.c
@@ -324,6 +324,24 @@
 	&i2c1_device,
 };
 
+/*
+ * r8a7740 chip has lasting errata on MERAM buffer.
+ * this is work-around for it.
+ * see
+ *	"Media RAM (MERAM)" on r8a7740 documentation
+ */
+#define MEBUFCNTR	0xFE950098
+void r8a7740_meram_workaround(void)
+{
+	void __iomem *reg;
+
+	reg = ioremap_nocache(MEBUFCNTR, 4);
+	if (reg) {
+		iowrite32(0x01600164, reg);
+		iounmap(reg);
+	}
+}
+
 #define ICCR	0x0004
 #define ICSTART	0x0070