diff options
Diffstat (limited to 'arch/arm/mach-rpc/time.c')
| -rw-r--r-- | arch/arm/mach-rpc/time.c | 43 |
1 files changed, 26 insertions, 17 deletions
diff --git a/arch/arm/mach-rpc/time.c b/arch/arm/mach-rpc/time.c index 2689771c1d38..1d750152b160 100644 --- a/arch/arm/mach-rpc/time.c +++ b/arch/arm/mach-rpc/time.c @@ -1,19 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * linux/arch/arm/common/time-acorn.c * * Copyright (c) 1996-2000 Russell King. * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * Changelog: * 24-Sep-1996 RMK Created * 10-Oct-1996 RMK Brought up to date with arch-sa110eval * 04-Dec-1997 RMK Updated for new arch/arm/time.c * 13=Jun-2004 DS Moved to arch/arm/common b/c shared w/CLPS7500 */ -#include <linux/timex.h> +#include <linux/clocksource.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/irq.h> @@ -27,11 +24,15 @@ #define RPC_CLOCK_FREQ 2000000 #define RPC_LATCH DIV_ROUND_CLOSEST(RPC_CLOCK_FREQ, HZ) -static u32 ioc_timer_gettimeoffset(void) +static u32 ioc_time; + +static u64 ioc_timer_read(struct clocksource *cs) { unsigned int count1, count2, status; - long offset; + unsigned long flags; + u32 ticks; + local_irq_save(flags); ioc_writeb (0, IOC_T0LATCH); barrier (); count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); @@ -41,27 +42,34 @@ static u32 ioc_timer_gettimeoffset(void) ioc_writeb (0, IOC_T0LATCH); barrier (); count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); + ticks = ioc_time + RPC_LATCH - count2; + local_irq_restore(flags); - offset = count2; if (count2 < count1) { /* - * We have not had an interrupt between reading count1 - * and count2. + * The timer has not reloaded between reading count1 and + * count2, check whether an interrupt was actually pending. */ if (status & (1 << 5)) - offset -= RPC_LATCH; + ticks += RPC_LATCH; } else if (count2 > count1) { /* - * We have just had another interrupt between reading - * count1 and count2. + * The timer has reloaded, so count2 indicates the new + * count since the wrap. The interrupt would not have + * been processed, so add the missed ticks. */ - offset -= RPC_LATCH; + ticks += RPC_LATCH; } - offset = (RPC_LATCH - offset) * (tick_nsec / 1000); - return DIV_ROUND_CLOSEST(offset, RPC_LATCH) * 1000; + return ticks; } +static struct clocksource ioctime_clocksource = { + .read = ioc_timer_read, + .mask = CLOCKSOURCE_MASK(32), + .rating = 100, +}; + void __init ioctime_init(void) { ioc_writeb(RPC_LATCH & 255, IOC_T0LTCHL); @@ -72,6 +80,7 @@ void __init ioctime_init(void) static irqreturn_t ioc_timer_interrupt(int irq, void *dev_id) { + ioc_time += RPC_LATCH; timer_tick(); return IRQ_HANDLED; } @@ -86,7 +95,7 @@ static struct irqaction ioc_timer_irq = { */ void __init ioc_timer_init(void) { - arch_gettimeoffset = ioc_timer_gettimeoffset; + WARN_ON(clocksource_register_hz(&ioctime_clocksource, RPC_CLOCK_FREQ)); ioctime_init(); setup_irq(IRQ_TIMER0, &ioc_timer_irq); } |