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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
5039F: arch/metag/5039F: arch/metag/
5040F: Documentation/metag/5040F: Documentation/metag/
5041F: Documentation/devicetree/bindings/metag/5041F: Documentation/devicetree/bindings/metag/
5042F: drivers/clocksource/metag_generic.c
5042 5043
5043MICROBLAZE ARCHITECTURE5044MICROBLAZE ARCHITECTURE
5044M: Michal Simek <monstr@monstr.eu>5045M: 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 */
23struct meta_clock_desc {
24 unsigned long (*get_core_freq)(void);
25};
26
27extern 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 */
33void 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 */
40static 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 */
11extern void __bad_udelay(void);
12extern void __bad_ndelay(void);
13
14extern void __udelay(unsigned long usecs);
15extern void __ndelay(unsigned long nsecs);
16extern void __const_udelay(unsigned long xloops);
17extern 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
16 16
17#include <linux/stddef.h>17#include <linux/stddef.h>
18 18
19#include <asm/clock.h>
20
19/**21/**
20 * struct machine_desc - Describes a board controlled by a Meta.22 * struct machine_desc - Describes a board controlled by a Meta.
21 * @name: Board/SoC name.23 * @name: Board/SoC name.
22 * @dt_compat: Array of device tree 'compatible' strings.24 * @dt_compat: Array of device tree 'compatible' strings.
25 * @clocks: Clock callbacks.
23 *26 *
24 * @nr_irqs: Maximum number of IRQs.27 * @nr_irqs: Maximum number of IRQs.
25 * If 0, defaults to NR_IRQS in asm-generic/irq.h.28 * If 0, defaults to NR_IRQS in asm-generic/irq.h.
@@ -37,6 +40,7 @@ · 11 unmodified lines
37struct machine_desc {40struct machine_desc {
38 const char *name;41 const char *name;
39 const char **dt_compat;42 const char **dt_compat;
43 struct meta_clock_desc *clocks;
40 44
41 unsigned int nr_irqs;45 unsigned int nr_irqs;
42 46
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
17struct meta_clock_desc _meta_clock;
18
19/* Default machine get_core_freq callback. */
20static 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 */
43void __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
12void __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
58 def_bool y if ARM6458 def_bool y if ARM64
59 help59 help
60 This option enables support for the ARM generic timer.60 This option enables support for the ARM generic timer.
61
62config 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-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o · 17 unmodified lines
18obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o18obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o
19 19
20obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o20obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o
21obj-$(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
48static unsigned int hwtimer_freq = HARDWARE_FREQ;
49static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
50static DEFINE_PER_CPU(char [11], local_clockevent_name);
51
52static 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
59static 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
78static cycle_t metag_clocksource_read(struct clocksource *cs)
79{
80 return __core_reg_get(TXTIMER);
81}
82
83static 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
91static 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
100static 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
106unsigned long long sched_clock(void)
107{
108 unsigned long long ticks = __core_reg_get(TXTIMER);
109 return ticks << HARDWARE_TO_NS_SHIFT;
110}
111
112static 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
157static 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
172static struct notifier_block __cpuinitdata arch_timer_cpu_nb = {
173 .notifier_call = arch_timer_cpu_notify,
174};
175
176int __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
19extern int metag_generic_timer_init(void);
20
21#endif /* __CLKSOURCE_METAG_GENERIC_H */

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