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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008-2009 Manuel Lauss <manuel.lauss@gmail.com>
*
* Previous incarnations were:
* Copyright (C) 2001, 2006, 2008 MontaVista Software, <source@mvista.com>
* Copied and modified Carsten Langgaard's time.c
*
* Carsten Langgaard, carstenl@mips.com
* Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
*
* ########################################################################
*
* ########################################################################
*
* Clocksource/event using the 32.768kHz-clocked Counter1 ('RTC' in the
* databooks). Firmware/Board init code must enable the counters in the
* counter control register, otherwise the CP0 counter clocksource/event
* will be installed instead (and use of 'wait' instruction is prohibited).
*/
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <asm/idle.h>
#include <asm/processor.h>
#include <asm/time.h>
#include <asm/mach-au1x00/au1000.h>
/* 32kHz clock enabled and detected */
#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
static u64 au1x_counter1_read(struct clocksource *cs)
{
return alchemy_rdsys(AU1000_SYS_RTCREAD);
}
static struct clocksource au1x_counter1_clocksource = {
.name = "alchemy-counter1",
.read = au1x_counter1_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.rating = 1500,
};
static int au1x_rtcmatch2_set_next_event(unsigned long delta,
struct clock_event_device *cd)
{
delta += alchemy_rdsys(AU1000_SYS_RTCREAD);
/* wait for register access */
while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_M21)
;
alchemy_wrsys(delta, AU1000_SYS_RTCMATCH2);
return 0;
}
static irqreturn_t au1x_rtcmatch2_irq(int irq, void *dev_id)
{
struct clock_event_device *cd = dev_id;
cd->event_handler(cd);
return IRQ_HANDLED;
}
static struct clock_event_device au1x_rtcmatch2_clockdev = {
.name = "rtcmatch2",
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 1500,
.set_next_event = au1x_rtcmatch2_set_next_event,
.cpumask = cpu_possible_mask,
};
static int __init alchemy_time_init(unsigned int m2int)
{
struct clock_event_device *cd = &au1x_rtcmatch2_clockdev;
unsigned long t;
au1x_rtcmatch2_clockdev.irq = m2int;
/* Check if firmware (YAMON, ...) has enabled 32kHz and clock
* has been detected. If so install the rtcmatch2 clocksource,
* otherwise don't bother. Note that both bits being set is by
* no means a definite guarantee that the counters actually work
* (the 32S bit seems to be stuck set to 1 once a single clock-
* edge is detected, hence the timeouts).
*/
if (CNTR_OK != (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & CNTR_OK))
goto cntr_err;
/*
* setup counter 1 (RTC) to tick at full speed
*/
t = 0xffffff;
while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T1S) && --t)
asm volatile ("nop");
if (!t)
goto cntr_err;
alchemy_wrsys(0, AU1000_SYS_RTCTRIM); /* 32.768 kHz */
t = 0xffffff;
while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C1S) && --t)
asm volatile ("nop");
if (!t)
goto cntr_err;
alchemy_wrsys(0, AU1000_SYS_RTCWRITE);
t = 0xffffff;
while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C1S) && --t)
asm volatile ("nop");
if (!t)
goto cntr_err;
/* register counter1 clocksource and event device */
clocksource_register_hz(&au1x_counter1_clocksource, 32768);
cd->shift = 32;
cd->mult = div_sc(32768, NSEC_PER_SEC, cd->shift);
cd->max_delta_ns = clockevent_delta2ns(0xffffffff, cd);
cd->max_delta_ticks = 0xffffffff;
cd->min_delta_ns = clockevent_delta2ns(9, cd);
cd->min_delta_ticks = 9; /* ~0.28ms */
clockevents_register_device(cd);
if (request_irq(m2int, au1x_rtcmatch2_irq, IRQF_TIMER, "timer",
&au1x_rtcmatch2_clockdev))
pr_err("Failed to register timer interrupt\n");
printk(KERN_INFO "Alchemy clocksource installed\n");
return 0;
cntr_err:
return -1;
}
static int alchemy_m2inttab[] __initdata = {
AU1000_RTC_MATCH2_INT,
AU1500_RTC_MATCH2_INT,
AU1100_RTC_MATCH2_INT,
AU1550_RTC_MATCH2_INT,
AU1200_RTC_MATCH2_INT,
AU1300_RTC_MATCH2_INT,
};
void __init plat_time_init(void)
{
int t;
t = alchemy_get_cputype();
if (t == ALCHEMY_CPU_UNKNOWN ||
alchemy_time_init(alchemy_m2inttab[t]))
cpu_wait = NULL; /* wait doesn't work with r4k timer */
}
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