History

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.

James Hogan committed 14 years ago

Commit a2c5d4e1 parent bc3966b10 files · +378 −0Browse files

Unified · Split

10 files
  1. MAINTAINERS +1 −0
  2. arch/metag/include/asm/clock.h +51 −0
  3. arch/metag/include/asm/delay.h +29 −0
  4. arch/metag/include/asm/mach/arch.h +4 −0
  5. arch/metag/kernel/clock.c +53 −0
  6. arch/metag/kernel/time.c +15 −0
  7. drivers/clocksource/Kconfig +5 −0
  8. drivers/clocksource/Makefile +1 −0
  9. drivers/clocksource/metag_generic.c +198 −0
  10. include/clocksource/metag_generic.h +21 −0
MAINTAINERS+1−0
@@ -5039,6 +5039,7 @@ S: Supported · 5038 unmodified lines
50395039 F: arch/metag/
50405040 F: Documentation/metag/
50415041 F: Documentation/devicetree/bindings/metag/
5042+F: drivers/clocksource/metag_generic.c
50425043
50435044 MICROBLAZE ARCHITECTURE
50445045 M: Michal Simek <monstr@monstr.eu>
arch/metag/include/asm/clock.h+51−0
@@ -0,0 +1,51 @@
1+/*
2+ * arch/metag/include/asm/clock.h
3+ *
4+ * Copyright (C) 2012 Imagination Technologies Ltd.
5+ *
6+ * This program is free software; you can redistribute it and/or modify
7+ * it under the terms of the GNU General Public License version 2 as
8+ * published by the Free Software Foundation.
9+ */
10+
11+#ifndef _METAG_CLOCK_H_
12+#define _METAG_CLOCK_H_
13+
14+#include <asm/mach/arch.h>
15+
16+/**
17+ * struct meta_clock_desc - Meta Core clock callbacks.
18+ * @get_core_freq: Get the frequency of the Meta core. If this is NULL, the
19+ * core frequency will be determined like this:
20+ * Meta 1: based on loops_per_jiffy.
21+ * Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
22+ */
23+struct meta_clock_desc {
24+ unsigned long (*get_core_freq)(void);
25+};
26+
27+extern struct meta_clock_desc _meta_clock;
28+
29+/*
30+ * Set up the default clock, ensuring all callbacks are valid - only accessible
31+ * during boot.
32+ */
33+void setup_meta_clocks(struct meta_clock_desc *desc);
34+
35+/**
36+ * get_coreclock() - Get the frequency of the Meta core clock.
37+ *
38+ * Returns: The Meta core clock frequency in Hz.
39+ */
40+static inline unsigned long get_coreclock(void)
41+{
42+ /*
43+ * Use the current clock callback. If set correctly this will provide
44+ * the most accurate frequency as it can be calculated directly from the
45+ * PLL configuration. otherwise a default callback will have been set
46+ * instead.
47+ */
48+ return _meta_clock.get_core_freq();
49+}
50+
51+#endif /* _METAG_CLOCK_H_ */
arch/metag/include/asm/delay.h+29−0
@@ -0,0 +1,29 @@
1+#ifndef _METAG_DELAY_H
2+#define _METAG_DELAY_H
3+
4+/*
5+ * Copyright (C) 1993 Linus Torvalds
6+ *
7+ * Delay routines calling functions in arch/metag/lib/delay.c
8+ */
9+
10+/* Undefined functions to get compile-time errors */
11+extern void __bad_udelay(void);
12+extern void __bad_ndelay(void);
13+
14+extern void __udelay(unsigned long usecs);
15+extern void __ndelay(unsigned long nsecs);
16+extern void __const_udelay(unsigned long xloops);
17+extern void __delay(unsigned long loops);
18+
19+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
20+#define udelay(n) (__builtin_constant_p(n) ? \
21+ ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
22+ __udelay(n))
23+
24+/* 0x5 is 2**32 / 1000000000 (rounded up) */
25+#define ndelay(n) (__builtin_constant_p(n) ? \
26+ ((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
27+ __ndelay(n))
28+
29+#endif /* _METAG_DELAY_H */
arch/metag/include/asm/mach/arch.h+4−0
@@ -16,10 +16,13 @@ · 15 unmodified lines
1616
1717 #include <linux/stddef.h>
1818
19+#include <asm/clock.h>
20+
1921 /**
2022 * struct machine_desc - Describes a board controlled by a Meta.
2123 * @name: Board/SoC name.
2224 * @dt_compat: Array of device tree 'compatible' strings.
25+ * @clocks: Clock callbacks.
2326 *
2427 * @nr_irqs: Maximum number of IRQs.
2528 * If 0, defaults to NR_IRQS in asm-generic/irq.h.
@@ -37,6 +40,7 @@ · 11 unmodified lines
3740 struct machine_desc {
3841 const char *name;
3942 const char **dt_compat;
43+ struct meta_clock_desc *clocks;
4044
4145 unsigned int nr_irqs;
4246
arch/metag/kernel/clock.c+53−0
@@ -0,0 +1,53 @@
1+/*
2+ * arch/metag/kernel/clock.c
3+ *
4+ * Copyright (C) 2012 Imagination Technologies Ltd.
5+ *
6+ * This program is free software; you can redistribute it and/or modify
7+ * it under the terms of the GNU General Public License version 2 as
8+ * published by the Free Software Foundation.
9+ */
10+
11+#include <linux/delay.h>
12+#include <linux/io.h>
13+
14+#include <asm/param.h>
15+#include <asm/clock.h>
16+
17+struct meta_clock_desc _meta_clock;
18+
19+/* Default machine get_core_freq callback. */
20+static unsigned long get_core_freq_default(void)
21+{
22+#ifdef CONFIG_METAG_META21
23+ /*
24+ * Meta 2 cores divide down the core clock for the Meta timers, so we
25+ * can estimate the core clock from the divider.
26+ */
27+ return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
28+#else
29+ /*
30+ * On Meta 1 we don't know the core clock, but assuming the Meta timer
31+ * is correct it can be estimated based on loops_per_jiffy.
32+ */
33+ return (loops_per_jiffy * HZ * 5) >> 1;
34+#endif
35+}
36+
37+/**
38+ * setup_meta_clocks() - Set up the Meta clock.
39+ * @desc: Clock descriptor usually provided by machine description
40+ *
41+ * Ensures all callbacks are valid.
42+ */
43+void __init setup_meta_clocks(struct meta_clock_desc *desc)
44+{
45+ /* copy callbacks */
46+ if (desc)
47+ _meta_clock = *desc;
48+
49+ /* set fallback functions */
50+ if (!_meta_clock.get_core_freq)
51+ _meta_clock.get_core_freq = get_core_freq_default;
52+}
53+
arch/metag/kernel/time.c+15−0
@@ -0,0 +1,15 @@
1+/*
2+ * Copyright (C) 2005-2013 Imagination Technologies Ltd.
3+ *
4+ * This file contains the Meta-specific time handling details.
5+ *
6+ */
7+
8+#include <linux/init.h>
9+
10+#include <clocksource/metag_generic.h>
11+
12+void __init time_init(void)
13+{
14+ metag_generic_timer_init();
15+}
drivers/clocksource/Kconfig+5−0
@@ -58,3 +58,8 @@ config CLKSRC_ARM_GENERIC · 57 unmodified lines
5858 def_bool y if ARM64
5959 help
6060 This option enables support for the ARM generic timer.
61+
62+config CLKSRC_METAG_GENERIC
63+ def_bool y if METAG
64+ help
65+ This option enables support for the Meta per-thread timers.
drivers/clocksource/Makefile+1−0
@@ -18,3 +18,4 @@ obj-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o · 17 unmodified lines
1818 obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o
1919
2020 obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o
21+obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
drivers/clocksource/metag_generic.c+198−0
@@ -0,0 +1,198 @@
1+/*
2+ * Copyright (C) 2005-2013 Imagination Technologies Ltd.
3+ *
4+ * This program is free software; you can redistribute it and/or modify
5+ * it under the terms of the GNU General Public License version 2 as
6+ * published by the Free Software Foundation.
7+ *
8+ * This program is distributed in the hope that it will be useful,
9+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
10+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11+ * GNU General Public License for more details.
12+ *
13+ * You should have received a copy of the GNU General Public License
14+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
15+ *
16+ *
17+ * Support for Meta per-thread timers.
18+ *
19+ * Meta hardware threads have 2 timers. The background timer (TXTIMER) is used
20+ * as a free-running time base (hz clocksource), and the interrupt timer
21+ * (TXTIMERI) is used for the timer interrupt (clock event). Both counters
22+ * traditionally count at approximately 1MHz.
23+ */
24+
25+#include <clocksource/metag_generic.h>
26+#include <linux/cpu.h>
27+#include <linux/errno.h>
28+#include <linux/sched.h>
29+#include <linux/kernel.h>
30+#include <linux/param.h>
31+#include <linux/time.h>
32+#include <linux/init.h>
33+#include <linux/proc_fs.h>
34+#include <linux/clocksource.h>
35+#include <linux/clockchips.h>
36+#include <linux/interrupt.h>
37+
38+#include <asm/clock.h>
39+#include <asm/hwthread.h>
40+#include <asm/core_reg.h>
41+#include <asm/metag_mem.h>
42+#include <asm/tbx.h>
43+
44+#define HARDWARE_FREQ 1000000 /* 1MHz */
45+#define HARDWARE_DIV 1 /* divide by 1 = 1MHz clock */
46+#define HARDWARE_TO_NS_SHIFT 10 /* convert ticks to ns */
47+
48+static unsigned int hwtimer_freq = HARDWARE_FREQ;
49+static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
50+static DEFINE_PER_CPU(char [11], local_clockevent_name);
51+
52+static int metag_timer_set_next_event(unsigned long delta,
53+ struct clock_event_device *dev)
54+{
55+ __core_reg_set(TXTIMERI, -delta);
56+ return 0;
57+}
58+
59+static void metag_timer_set_mode(enum clock_event_mode mode,
60+ struct clock_event_device *evt)
61+{
62+ switch (mode) {
63+ case CLOCK_EVT_MODE_ONESHOT:
64+ case CLOCK_EVT_MODE_RESUME:
65+ break;
66+
67+ case CLOCK_EVT_MODE_SHUTDOWN:
68+ /* We should disable the IRQ here */
69+ break;
70+
71+ case CLOCK_EVT_MODE_PERIODIC:
72+ case CLOCK_EVT_MODE_UNUSED:
73+ WARN_ON(1);
74+ break;
75+ };
76+}
77+
78+static cycle_t metag_clocksource_read(struct clocksource *cs)
79+{
80+ return __core_reg_get(TXTIMER);
81+}
82+
83+static struct clocksource clocksource_metag = {
84+ .name = "META",
85+ .rating = 200,
86+ .mask = CLOCKSOURCE_MASK(32),
87+ .read = metag_clocksource_read,
88+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
89+};
90+
91+static irqreturn_t metag_timer_interrupt(int irq, void *dummy)
92+{
93+ struct clock_event_device *evt = &__get_cpu_var(local_clockevent);
94+
95+ evt->event_handler(evt);
96+
97+ return IRQ_HANDLED;
98+}
99+
100+static struct irqaction metag_timer_irq = {
101+ .name = "META core timer",
102+ .handler = metag_timer_interrupt,
103+ .flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
104+};
105+
106+unsigned long long sched_clock(void)
107+{
108+ unsigned long long ticks = __core_reg_get(TXTIMER);
109+ return ticks << HARDWARE_TO_NS_SHIFT;
110+}
111+
112+static void __cpuinit arch_timer_setup(unsigned int cpu)
113+{
114+ unsigned int txdivtime;
115+ struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
116+ char *name = per_cpu(local_clockevent_name, cpu);
117+
118+ txdivtime = __core_reg_get(TXDIVTIME);
119+
120+ txdivtime &= ~TXDIVTIME_DIV_BITS;
121+ txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS);
122+
123+ __core_reg_set(TXDIVTIME, txdivtime);
124+
125+ sprintf(name, "META %d", cpu);
126+ clk->name = name;
127+ clk->features = CLOCK_EVT_FEAT_ONESHOT,
128+
129+ clk->rating = 200,
130+ clk->shift = 12,
131+ clk->irq = tbisig_map(TBID_SIGNUM_TRT),
132+ clk->set_mode = metag_timer_set_mode,
133+ clk->set_next_event = metag_timer_set_next_event,
134+
135+ clk->mult = div_sc(hwtimer_freq, NSEC_PER_SEC, clk->shift);
136+ clk->max_delta_ns = clockevent_delta2ns(0x7fffffff, clk);
137+ clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
138+ clk->cpumask = cpumask_of(cpu);
139+
140+ clockevents_register_device(clk);
141+
142+ /*
143+ * For all non-boot CPUs we need to synchronize our free
144+ * running clock (TXTIMER) with the boot CPU's clock.
145+ *
146+ * While this won't be accurate, it should be close enough.
147+ */
148+ if (cpu) {
149+ unsigned int thread0 = cpu_2_hwthread_id[0];
150+ unsigned long val;
151+
152+ val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0);
153+ __core_reg_set(TXTIMER, val);
154+ }
155+}
156+
157+static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
158+ unsigned long action, void *hcpu)
159+{
160+ int cpu = (long)hcpu;
161+
162+ switch (action) {
163+ case CPU_STARTING:
164+ case CPU_STARTING_FROZEN:
165+ arch_timer_setup(cpu);
166+ break;
167+ }
168+
169+ return NOTIFY_OK;
170+}
171+
172+static struct notifier_block __cpuinitdata arch_timer_cpu_nb = {
173+ .notifier_call = arch_timer_cpu_notify,
174+};
175+
176+int __init metag_generic_timer_init(void)
177+{
178+ /*
179+ * On Meta 2 SoCs, the actual frequency of the timer is based on the
180+ * Meta core clock speed divided by an integer, so it is only
181+ * approximately 1MHz. Calculating the real frequency here drastically
182+ * reduces clock skew on these SoCs.
183+ */
184+#ifdef CONFIG_METAG_META21
185+ hwtimer_freq = get_coreclock() / (metag_in32(EXPAND_TIMER_DIV) + 1);
186+#endif
187+ clocksource_register_hz(&clocksource_metag, hwtimer_freq);
188+
189+ setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq);
190+
191+ /* Configure timer on boot CPU */
192+ arch_timer_setup(smp_processor_id());
193+
194+ /* Hook cpu boot to configure other CPU's timers */
195+ register_cpu_notifier(&arch_timer_cpu_nb);
196+
197+ return 0;
198+}
include/clocksource/metag_generic.h+21−0
@@ -0,0 +1,21 @@
1+/*
2+ * Copyright (C) 2013 Imaginaton Technologies Ltd.
3+ *
4+ * This program is free software; you can redistribute it and/or modify
5+ * it under the terms of the GNU General Public License version 2 as
6+ * published by the Free Software Foundation.
7+ *
8+ * This program is distributed in the hope that it will be useful,
9+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
10+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11+ * GNU General Public License for more details.
12+ *
13+ * You should have received a copy of the GNU General Public License
14+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
15+ */
16+#ifndef __CLKSOURCE_METAG_GENERIC_H
17+#define __CLKSOURCE_METAG_GENERIC_H
18+
19+extern int metag_generic_timer_init(void);
20+
21+#endif /* __CLKSOURCE_METAG_GENERIC_H */

Keyboard shortcuts

General

Show keyboard shortcuts
?
Focus the current search
/

Issues and pull requests

Open filters
f

Issues, pull requests and Inbox

Select next item
j↓
Select previous item
k↑
Open selected item
Enter
Dismiss filters or clear selection
Esc

Repository code

Go to file
t