openwrt-xburst/target/linux/brcm63xx/patches-2.6.25/100-bcm963xx_add_new_timer_code.patch

From 7d6656dc127b54e53e507e8f264bb7e14e620cad Mon Sep 17 00:00:00 2001
From: Axel Gembe <ago@bastart.eu.org>
Date: Sat, 17 May 2008 15:02:39 +0200
Subject: [PATCH] bcm963xx: add new timer code

This basically selects the new generic MIPS timer code for BCM963xx and
simplifies the timer setup code.

Signed-off-by: Axel Gembe <ago@bastart.eu.org>
---
 arch/mips/Kconfig         |    2 +
 arch/mips/bcm963xx/time.c |   64 ++++++++++++++++++++------------------------
 2 files changed, 31 insertions(+), 35 deletions(-)

Index: linux-2.6.25.4/arch/mips/Kconfig
===================================================================
--- linux-2.6.25.4.orig/arch/mips/Kconfig
+++ linux-2.6.25.4/arch/mips/Kconfig
@@ -67,6 +67,8 @@ config BCM963XX
        select HW_HAS_PCI
        select DMA_NONCOHERENT
        select IRQ_CPU
+       select CEVT_R4K
+       select CSRC_R4K
        help
          This is a fmaily of boards based on the Broadcom MIPS32
 
Index: linux-2.6.25.4/arch/mips/bcm963xx/time.c
===================================================================
--- linux-2.6.25.4.orig/arch/mips/bcm963xx/time.c
+++ linux-2.6.25.4/arch/mips/bcm963xx/time.c
@@ -1,6 +1,7 @@
 /*
 <:copyright-gpl
  Copyright 2004 Broadcom Corp. All Rights Reserved.
+ Copyright (C) 2008 Axel Gembe <ago@bastart.eu.org>
 
  This program is free software; you can distribute it and/or modify it
  under the terms of the GNU General Public License (Version 2) as
@@ -40,50 +41,43 @@
 #include <bcm_map_part.h>
 #include <bcm_intr.h>
 
-static unsigned long r4k_offset;	/* Amount to increment compare reg each time */
-static unsigned long r4k_cur;		/* What counter should be at next timer irq */
-
-/*  *********************************************************************
-    *  calculateCpuSpeed()
-    *      Calculate the BCM6348 CPU speed by reading the PLL strap register
-    *      and applying the following formula:
-    *      cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
-    *  Input parameters:
-    *      none
-    *  Return value:
-    *      none
-    ********************************************************************* */
-
+/*
+ * calculateCpuSpeed()
+ *
+ * Calculate the BCM6348 CPU speed by reading the PLL strap register and applying
+ * the following formula:
+ *
+ * cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
+ */
 static inline unsigned long __init calculateCpuSpeed(void)
 {
-    u32 pllStrap = PERF->PllStrap;
-    int n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
-    int n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
-    int m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
+	u32 pllStrap;
+	int n1, n2, m1cpu;
+
+	pllStrap = PERF->PllStrap;
+	n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
+	n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
+	m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
 
 	return (16 * (n1 + 1) * (n2 + 2) / (m1cpu + 1)) * 1000000;
 }
 
 
-static inline unsigned long __init cal_r4koff(void)
-{   
-	mips_hpt_frequency = calculateCpuSpeed() / 2;
-	return (mips_hpt_frequency / HZ);
-}
-
 void __init plat_time_init(void)
 {
-	unsigned int est_freq, flags;
-	local_irq_save(flags);
+	unsigned long cpu_clock;
+
+	cpu_clock = calculateCpuSpeed();
+
+	printk("CPU frequency %lu.%02lu MHz\n", cpu_clock / 1000000,
+		(cpu_clock % 1000000) * 100 / 1000000);
+
+	mips_hpt_frequency = cpu_clock / 2;
 
-	printk("calculating r4koff... ");
-	r4k_offset = cal_r4koff();
-	printk("%08lx(%d)\n", r4k_offset, (int)r4k_offset);
-
-	est_freq = 2 * r4k_offset * HZ;
-	est_freq += 5000;   /* round */
-	est_freq -= est_freq % 10000;
-	printk("CPU frequency %d.%02d MHz\n", est_freq / 1000000,
-		   (est_freq % 1000000) * 100 / 1000000);
-	local_irq_restore(flags);
+	/*
+	 * Use deterministic values for initial counter interrupt
+	 * so that calibrate delay avoids encountering a counter wrap.
+	 */
+	write_c0_count(0);
+	write_c0_compare(0xffff);
 }