Allow the data cache to be turned off on MPC8260 systems.

Due to HW bugs on older systems the data-cache must be turned off on these
systems.  From Wolfgang Denk <wd@denx.de>.

arch/ppc/8260_io/Config.help

@@ -22,3 +22,6 @@ CONFIG_SCC1_ENET
 CONFIG_SCC2_ENET
   Use MPC8xx serial communications controller 2 to drive Ethernet.
 
+CONFIG_DCACHE_DISABLE
+  This option allows you to run the kernel with data cache disabled.
+  Say Y if you experience CPM lock-ups.

arch/ppc/8260_io/Config.in

@@ -2,7 +2,7 @@
 # MPC8260 Communication options
 #
 mainmenu_option next_comment
-comment 'MPC8260 Communication Options'
+comment 'MPC8260 CPM Options'
 bool 'Enable SCC Console' CONFIG_SCC_CONSOLE
 if [ "$CONFIG_NET_ETHERNET" = "y" ]; then
   mainmenu_option next_comment
@@ -32,4 +32,7 @@ if [ "$CONFIG_NET_ETHERNET" = "y" ]; then
       fi
   fi
 fi
+
+comment 'Generic MPC8260 Options'
+bool 'Disable data cache' CONFIG_DCACHE_DISABLE
 endmenu

arch/ppc/configs/est8260_defconfig

@@ -421,6 +421,7 @@ CONFIG_PARTITION_ADVANCED=y
 CONFIG_SCC_ENET=y
 CONFIG_SCC1_ENET=y
 # CONFIG_FEC_ENET is not set
+# CONFIG_DCACHE_DISABLE is not set
 
 #
 # USB support

arch/ppc/kernel/head.S

@@ -1272,7 +1272,11 @@ _GLOBAL(__setup_cpu_generic)
 setup_common_caches:
 	mfspr	r11,HID0
 	andi.	r0,r11,HID0_DCE
+#ifdef CONFIG_DCACHE_DISABLE
+	ori	r11,r11,HID0_ICE
+#else
 	ori	r11,r11,HID0_ICE|HID0_DCE
+#endif
 	ori	r8,r11,HID0_ICFI
 	bne	1f			/* don't invalidate the D-cache */
 	ori	r8,r8,HID0_DCI		/* unless it wasn't enabled */