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authorJames Hogan <james.hogan@imgtec.com>2012-10-09 10:54:39 +0100
committerJames Hogan <james.hogan@imgtec.com>2013-03-02 20:09:22 +0000
commita2c5d4ed92bbc02ff4a37efc2adffe7d145abe4f (patch)
tree21fc65e4f0b04928025565f208a410a7a64ab523 /arch
parentbc3966bf1583a6c22b76397535174445c43952de (diff)
metag: Time keeping
Add time keeping code for metag. Meta hardware threads have 2 timers. The background timer (TXTIMER) is used as a free-running time base, and the interrupt timer (TXTIMERI) is used for the timer interrupt. Both counters traditionally count at approximately 1MHz. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/metag/include/asm/clock.h51
-rw-r--r--arch/metag/include/asm/delay.h29
-rw-r--r--arch/metag/include/asm/mach/arch.h4
-rw-r--r--arch/metag/kernel/clock.c53
-rw-r--r--arch/metag/kernel/time.c15
5 files changed, 152 insertions, 0 deletions
diff --git a/arch/metag/include/asm/clock.h b/arch/metag/include/asm/clock.h
new file mode 100644
index 000000000000..3e2915a280c7
--- /dev/null
+++ b/arch/metag/include/asm/clock.h
@@ -0,0 +1,51 @@
+/*
+ * arch/metag/include/asm/clock.h
+ *
+ * Copyright (C) 2012 Imagination Technologies Ltd.
+ *
+ * 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.
+ */
+
+#ifndef _METAG_CLOCK_H_
+#define _METAG_CLOCK_H_
+
+#include <asm/mach/arch.h>
+
+/**
+ * struct meta_clock_desc - Meta Core clock callbacks.
+ * @get_core_freq: Get the frequency of the Meta core. If this is NULL, the
+ * core frequency will be determined like this:
+ * Meta 1: based on loops_per_jiffy.
+ * Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
+ */
+struct meta_clock_desc {
+ unsigned long (*get_core_freq)(void);
+};
+
+extern struct meta_clock_desc _meta_clock;
+
+/*
+ * Set up the default clock, ensuring all callbacks are valid - only accessible
+ * during boot.
+ */
+void setup_meta_clocks(struct meta_clock_desc *desc);
+
+/**
+ * get_coreclock() - Get the frequency of the Meta core clock.
+ *
+ * Returns: The Meta core clock frequency in Hz.
+ */
+static inline unsigned long get_coreclock(void)
+{
+ /*
+ * Use the current clock callback. If set correctly this will provide
+ * the most accurate frequency as it can be calculated directly from the
+ * PLL configuration. otherwise a default callback will have been set
+ * instead.
+ */
+ return _meta_clock.get_core_freq();
+}
+
+#endif /* _METAG_CLOCK_H_ */
diff --git a/arch/metag/include/asm/delay.h b/arch/metag/include/asm/delay.h
new file mode 100644
index 000000000000..9c92f996957a
--- /dev/null
+++ b/arch/metag/include/asm/delay.h
@@ -0,0 +1,29 @@
+#ifndef _METAG_DELAY_H
+#define _METAG_DELAY_H
+
+/*
+ * Copyright (C) 1993 Linus Torvalds
+ *
+ * Delay routines calling functions in arch/metag/lib/delay.c
+ */
+
+/* Undefined functions to get compile-time errors */
+extern void __bad_udelay(void);
+extern void __bad_ndelay(void);
+
+extern void __udelay(unsigned long usecs);
+extern void __ndelay(unsigned long nsecs);
+extern void __const_udelay(unsigned long xloops);
+extern void __delay(unsigned long loops);
+
+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
+#define udelay(n) (__builtin_constant_p(n) ? \
+ ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
+ __udelay(n))
+
+/* 0x5 is 2**32 / 1000000000 (rounded up) */
+#define ndelay(n) (__builtin_constant_p(n) ? \
+ ((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
+ __ndelay(n))
+
+#endif /* _METAG_DELAY_H */
diff --git a/arch/metag/include/asm/mach/arch.h b/arch/metag/include/asm/mach/arch.h
index 6845d80857e4..12c5664fea6e 100644
--- a/arch/metag/include/asm/mach/arch.h
+++ b/arch/metag/include/asm/mach/arch.h
@@ -16,10 +16,13 @@
#include <linux/stddef.h>
+#include <asm/clock.h>
+
/**
* struct machine_desc - Describes a board controlled by a Meta.
* @name: Board/SoC name.
* @dt_compat: Array of device tree 'compatible' strings.
+ * @clocks: Clock callbacks.
*
* @nr_irqs: Maximum number of IRQs.
* If 0, defaults to NR_IRQS in asm-generic/irq.h.
@@ -37,6 +40,7 @@
struct machine_desc {
const char *name;
const char **dt_compat;
+ struct meta_clock_desc *clocks;
unsigned int nr_irqs;
diff --git a/arch/metag/kernel/clock.c b/arch/metag/kernel/clock.c
new file mode 100644
index 000000000000..defc84056f18
--- /dev/null
+++ b/arch/metag/kernel/clock.c
@@ -0,0 +1,53 @@
+/*
+ * arch/metag/kernel/clock.c
+ *
+ * Copyright (C) 2012 Imagination Technologies Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+
+#include <asm/param.h>
+#include <asm/clock.h>
+
+struct meta_clock_desc _meta_clock;
+
+/* Default machine get_core_freq callback. */
+static unsigned long get_core_freq_default(void)
+{
+#ifdef CONFIG_METAG_META21
+ /*
+ * Meta 2 cores divide down the core clock for the Meta timers, so we
+ * can estimate the core clock from the divider.
+ */
+ return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
+#else
+ /*
+ * On Meta 1 we don't know the core clock, but assuming the Meta timer
+ * is correct it can be estimated based on loops_per_jiffy.
+ */
+ return (loops_per_jiffy * HZ * 5) >> 1;
+#endif
+}
+
+/**
+ * setup_meta_clocks() - Set up the Meta clock.
+ * @desc: Clock descriptor usually provided by machine description
+ *
+ * Ensures all callbacks are valid.
+ */
+void __init setup_meta_clocks(struct meta_clock_desc *desc)
+{
+ /* copy callbacks */
+ if (desc)
+ _meta_clock = *desc;
+
+ /* set fallback functions */
+ if (!_meta_clock.get_core_freq)
+ _meta_clock.get_core_freq = get_core_freq_default;
+}
+
diff --git a/arch/metag/kernel/time.c b/arch/metag/kernel/time.c
new file mode 100644
index 000000000000..17dc10733b2f
--- /dev/null
+++ b/arch/metag/kernel/time.c
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2005-2013 Imagination Technologies Ltd.
+ *
+ * This file contains the Meta-specific time handling details.
+ *
+ */
+
+#include <linux/init.h>
+
+#include <clocksource/metag_generic.h>
+
+void __init time_init(void)
+{
+ metag_generic_timer_init();
+}