[PATCH] ARM: OMAP3: Check for L2 cache enabled

[Dirk Behme <dirk.behme@googlemail.com>]

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Enabling L2 cache of Cortex-A8 based OMAP3 has to be done by 
bootloader. Check if this is done and warn if not.

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>

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Index: linux-beagle/arch/arm/mach-omap2/id.c
===================================================================
--- linux-beagle.orig/arch/arm/mach-omap2/id.c
+++ linux-beagle/arch/arm/mach-omap2/id.c
@@ -267,3 +267,26 @@ void __init omap2_check_revision(void)
 
 }
 
+#ifdef CONFIG_ARCH_OMAP3
+/*
+ * OMAP3 has L2 cache which has to be enabled by bootloader.
+ */
+static int __init omap3_check_l2cache(void)
+{
+	u32 val;
+
+	/* Get CP15 AUX register, bit 1 enabled indicates L2 cache is on */
+	asm volatile("mrc p15, 0, %0, c1, c0, 1":"=r" (val));
+
+	if ((val & 0x2) == 0) {
+		printk(KERN_WARNING "Warning: L2 cache not enabled. Check "
+		       "your bootloader. L2 off results in performance loss\n");
+	} else {
+		pr_info("OMAP3 L2 cache enabled");
+	}
+
+	return 0;
+}
+
+arch_initcall(omap3_check_l2cache_on);
+#endif /* CONFIG_ARCH_OMAP3 */