1 files changed, 256 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..7efcfe0c9
--- /dev/null
+++ b/arch/mips/mti-malta/malta-time.c
@@ -0,0 +1,256 @@
+// 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;
+
+#if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
+	mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
+	return;
+#endif
+
+	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");
+}
+
+#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
+	}
+}