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Diffstat (limited to 'arch/mips/alchemy/common/time.c')
| -rw-r--r-- | arch/mips/alchemy/common/time.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/arch/mips/alchemy/common/time.c b/arch/mips/alchemy/common/time.c new file mode 100644 index 000000000..d794ffb67 --- /dev/null +++ b/arch/mips/alchemy/common/time.c @@ -0,0 +1,155 @@ +// 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 */ +} |