diff options
Diffstat (limited to 'arch/mips/mti-malta/malta-time.c')
| -rw-r--r-- | arch/mips/mti-malta/malta-time.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/arch/mips/mti-malta/malta-time.c b/arch/mips/mti-malta/malta-time.c new file mode 100644 index 000000000..2cb708cdf --- /dev/null +++ b/arch/mips/mti-malta/malta-time.c @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Carsten Langgaard, carstenl@mips.com + * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. + * + * Setting up the clock on the MIPS boards. + */ +#include <linux/types.h> +#include <linux/i8253.h> +#include <linux/init.h> +#include <linux/kernel_stat.h> +#include <linux/libfdt.h> +#include <linux/math64.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/timex.h> +#include <linux/mc146818rtc.h> + +#include <asm/cpu.h> +#include <asm/mipsregs.h> +#include <asm/mipsmtregs.h> +#include <asm/hardirq.h> +#include <asm/irq.h> +#include <asm/div64.h> +#include <asm/setup.h> +#include <asm/time.h> +#include <asm/mc146818-time.h> +#include <asm/msc01_ic.h> +#include <asm/mips-cps.h> + +#include <asm/mips-boards/generic.h> +#include <asm/mips-boards/maltaint.h> + +static int mips_cpu_timer_irq; +static int mips_cpu_perf_irq; +extern int cp0_perfcount_irq; + +static unsigned int gic_frequency; + +static void mips_timer_dispatch(void) +{ + do_IRQ(mips_cpu_timer_irq); +} + +static void mips_perf_dispatch(void) +{ + do_IRQ(mips_cpu_perf_irq); +} + +static unsigned int freqround(unsigned int freq, unsigned int amount) +{ + freq += amount; + freq -= freq % (amount*2); + return freq; +} + +/* + * Estimate CPU and GIC frequencies. + */ +static void __init estimate_frequencies(void) +{ + unsigned long flags; + unsigned int count, start; + unsigned char secs1, secs2, ctrl; + int secs; + u64 giccount = 0, gicstart = 0; + + local_irq_save(flags); + + if (mips_gic_present()) + clear_gic_config(GIC_CONFIG_COUNTSTOP); + + /* + * Read counters exactly on rising edge of update flag. + * This helps get an accurate reading under virtualisation. + */ + while (CMOS_READ(RTC_REG_A) & RTC_UIP); + while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); + start = read_c0_count(); + if (mips_gic_present()) + gicstart = read_gic_counter(); + + /* Wait for falling edge before reading RTC. */ + while (CMOS_READ(RTC_REG_A) & RTC_UIP); + secs1 = CMOS_READ(RTC_SECONDS); + + /* Read counters again exactly on rising edge of update flag. */ + while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); + count = read_c0_count(); + if (mips_gic_present()) + giccount = read_gic_counter(); + + /* Wait for falling edge before reading RTC again. */ + while (CMOS_READ(RTC_REG_A) & RTC_UIP); + secs2 = CMOS_READ(RTC_SECONDS); + + ctrl = CMOS_READ(RTC_CONTROL); + + local_irq_restore(flags); + + if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { + secs1 = bcd2bin(secs1); + secs2 = bcd2bin(secs2); + } + secs = secs2 - secs1; + if (secs < 1) + secs += 60; + + count -= start; + count /= secs; + mips_hpt_frequency = count; + + if (mips_gic_present()) { + giccount = div_u64(giccount - gicstart, secs); + gic_frequency = giccount; + } +} + +void read_persistent_clock64(struct timespec64 *ts) +{ + ts->tv_sec = mc146818_get_cmos_time(); + ts->tv_nsec = 0; +} + +int get_c0_fdc_int(void) +{ + /* + * Some cores claim the FDC is routable through the GIC, but it doesn't + * actually seem to be connected for those Malta bitstreams. + */ + switch (current_cpu_type()) { + case CPU_INTERAPTIV: + case CPU_PROAPTIV: + return -1; + } + + if (cpu_has_veic) + return -1; + else if (mips_gic_present()) + return gic_get_c0_fdc_int(); + else if (cp0_fdc_irq >= 0) + return MIPS_CPU_IRQ_BASE + cp0_fdc_irq; + else + return -1; +} + +int get_c0_perfcount_int(void) +{ + if (cpu_has_veic) { + set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch); + mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR; + } else if (mips_gic_present()) { + mips_cpu_perf_irq = gic_get_c0_perfcount_int(); + } else if (cp0_perfcount_irq >= 0) { + mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq; + } else { + mips_cpu_perf_irq = -1; + } + + return mips_cpu_perf_irq; +} +EXPORT_SYMBOL_GPL(get_c0_perfcount_int); + +unsigned int get_c0_compare_int(void) +{ + if (cpu_has_veic) { + set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch); + mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR; + } else if (mips_gic_present()) { + mips_cpu_timer_irq = gic_get_c0_compare_int(); + } else { + mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq; + } + + return mips_cpu_timer_irq; +} + +static void __init init_rtc(void) +{ + unsigned char freq, ctrl; + + /* Set 32KHz time base if not already set */ + freq = CMOS_READ(RTC_FREQ_SELECT); + if ((freq & RTC_DIV_CTL) != RTC_REF_CLCK_32KHZ) + CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT); + + /* Ensure SET bit is clear so RTC can run */ + ctrl = CMOS_READ(RTC_CONTROL); + if (ctrl & RTC_SET) + CMOS_WRITE(ctrl & ~RTC_SET, RTC_CONTROL); +} + +#ifdef CONFIG_CLKSRC_MIPS_GIC +static u32 gic_frequency_dt; + +static struct property gic_frequency_prop = { + .name = "clock-frequency", + .length = sizeof(u32), + .value = &gic_frequency_dt, +}; + +static void update_gic_frequency_dt(void) +{ + struct device_node *node; + + gic_frequency_dt = cpu_to_be32(gic_frequency); + + node = of_find_compatible_node(NULL, NULL, "mti,gic-timer"); + if (!node) { + pr_err("mti,gic-timer device node not found\n"); + return; + } + + if (of_update_property(node, &gic_frequency_prop) < 0) + pr_err("error updating gic frequency property\n"); + + of_node_put(node); +} + +#endif + +void __init plat_time_init(void) +{ + unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK); + unsigned int freq; + + init_rtc(); + estimate_frequencies(); + + freq = mips_hpt_frequency; + if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) && + (prid != (PRID_COMP_MIPS | PRID_IMP_25KF))) + freq *= 2; + freq = freqround(freq, 5000); + printk("CPU frequency %d.%02d MHz\n", freq/1000000, + (freq%1000000)*100/1000000); + +#ifdef CONFIG_I8253 + /* Only Malta has a PIT. */ + setup_pit_timer(); +#endif + + if (mips_gic_present()) { + freq = freqround(gic_frequency, 5000); + printk("GIC frequency %d.%02d MHz\n", freq/1000000, + (freq%1000000)*100/1000000); +#ifdef CONFIG_CLKSRC_MIPS_GIC + update_gic_frequency_dt(); + timer_probe(); +#endif + } +} |