From 7d6656dc127b54e53e507e8f264bb7e14e620cad Mon Sep 17 00:00:00 2001 From: Axel Gembe 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 --- 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 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 #include -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); }