[Linux-mips-commits]CVS: linux/arch/mips/vr41xx/vr4122/common bcu.c,1.1,1.2

[Paul M. <le...@us...>]

Update of /cvsroot/linux-mips/linux/arch/mips/vr41xx/vr4122/common
In directory usw-pr-cvs1:/tmp/cvs-serv32523/arch/mips/vr41xx/vr4122/common

Modified Files:
	bcu.c 
Log Message:
Implement workaround to calculate mips_counter_frequency properly on revs 2.0
and 2.1 of the Vr4131.



Index: bcu.c
===================================================================
RCS file: /cvsroot/linux-mips/linux/arch/mips/vr41xx/vr4122/common/bcu.c,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -d -r1.1 -r1.2
--- bcu.c	7 Mar 2002 03:16:54 -0000	1.1
+++ bcu.c	10 Mar 2002 08:17:40 -0000	1.2
@@ -32,6 +32,9 @@
  */
 /*
  * Changes:
+ *  Paul Mundt <le...@ch...>
+ *  - Calculate mips_counter_frequency properly on VR4131.
+ *
  *  MontaVista Software Inc. <yy...@mv...> or <so...@mv...>
  *  - New creation, NEC VR4122 and VR4131 are supported.
  */
@@ -76,5 +79,26 @@
 	tclock = calc_tclock(clksp, vr41xx_vtclock);
 	printk(KERN_INFO "TClock: %ldHz\n", tclock);
 
-	mips_counter_frequency = tclock / 4;
+	/*
+	 * The base clock divisor varies depending on which revision of the
+	 * Vr4131 we happen to be dealing with ..
+	 */
+#ifdef CONFIG_VR4131
+	{
+		int prid = read_32bit_cp0_register(CP0_PRID);
+
+		/*
+		 * Revisions 2.0 and 2.1 use a value of (tclock / 2).
+		 */
+		if (prid == 0x0c81 || prid == 0x0c82)
+			mips_counter_frequency = tclock / 2;
+	}
+#endif
+
+	/*
+	 * All other revisions of the Vr4131, as well as the Vr4122 use a
+	 * value of (tclock / 4).
+	 */
+	if (!mips_counter_frequency)
+		mips_counter_frequency = tclock / 4;
 }