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[/] [c0or1k/] [trunk/] [src/] [generic/] [time.c] - Blame information for rev 6

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/*
 * Time.
 *
 * Copyright (C) 2007 Bahadir Balban
 *
 */
#include <l4/types.h>
#include <l4/lib/mutex.h>
#include <l4/lib/printk.h>
#include <l4/generic/irq.h>
#include <l4/generic/scheduler.h>
#include <l4/generic/time.h>
#include <l4/generic/preempt.h>
#include <l4/generic/space.h>
#include INC_ARCH(exception.h)
#include <l4/api/syscall.h>
#include <l4/api/errno.h>
#include INC_GLUE(ipi.h)        /*FIXME: Remove this */
 
/* TODO:
 * 1) Add RTC support.
 * 2) Need to calculate time since EPOCH,
 * 3) Jiffies must be initialised to a reasonable value.
 */
 
volatile u32 jiffies = 0;
 
static inline void increase_jiffies(void)
{
        jiffies++;
}
 
 
/* Internal representation of time since epoch */
struct time_info {
        int reader;
        u32 thz;        /* Ticks in this hertz so far */
        u64 sec;        /* Seconds so far */
};
 
static struct time_info systime = { 0 };
 
/*
 * A very basic (probably erroneous)
 * rule-of-thumb time calculation.
 */
void update_system_time(void)
{
        /* Did we interrupt a reader? Tell it to retry */
        if (systime.reader)
                systime.reader = 0;
 
        /* Increase just like jiffies, but reset every second */
        systime.thz++;
 
        /*
         * On every 1 second of timer ticks, increase seconds
         *
         * TODO: Investigate: how do we make sure timer_irq is
         * called SCHED_TICKS times per second?
         */
        if (systime.thz == CONFIG_SCHED_TICKS) {
                systime.thz = 0;
                systime.sec++;
        }
}
 
/* Read system time */
int sys_time(struct timeval *tv, int set)
{
        int retries = 20;
        int err;
 
        if ((err = check_access((unsigned long)tv, sizeof(*tv),
                                MAP_USR_RW, 1)) < 0)
                return err;
 
        /* Get time */
        if (!set) {
                while(retries > 0) {
                        systime.reader = 1;
                        tv->tv_sec = systime.sec;
                        tv->tv_usec = 1000000 * systime.thz / CONFIG_SCHED_TICKS;
 
                        retries--;
                        if (systime.reader)
                                break;
                }
 
                /*
                 * No need to reset reader since it will be reset
                 * on next timer. If no retries return busy.
                 */
                if (!retries)
                        return -EBUSY;
                else
                        return 0;
 
        /* Set */
        } else {
                /*
                 * Setting the time not supported yet.
                 */
                return -ENOSYS;
        }
}
 
void update_process_times(void)
{
        struct ktcb *cur = current;
 
        if (cur->ticks_left == 0) {
                /*
                 * Nested irqs and irqs during non-preemptive
                 * times could try to deduct ticks below zero.
                 * We ignore such states and return.
                 */
                if (in_nested_irq_context() || !preemptive())
                        return;
                else /* Otherwise its a bug. */
                        BUG();
        }
 
        /*
         * These are TASK_RUNNABLE times, i.e. exludes sleeps
         * In the future we may use timestamps for accuracy
         */
        if (in_kernel())
                cur->kernel_time++;
        else
                cur->user_time++;
 
        cur->ticks_left--;
        cur->sched_granule--;
 
        /* Task has expired its timeslice */
        if (!cur->ticks_left)
                need_resched = 1;
 
        /* Task has expired its schedule granularity */
        if (!cur->sched_granule)
                need_resched = 1;
}
 
int do_timer_irq(void)
{
        increase_jiffies();
        update_process_times();
        update_system_time();
 
#if defined (CONFIG_SMP)
        smp_send_ipi(cpu_mask_others(), IPI_TIMER_EVENT);
#endif
 
        return IRQ_HANDLED;
}
 
/* Secondary cpus call this */
int secondary_timer_irq(void)
{
        update_process_times();
        return IRQ_HANDLED;
}
 

Line No.	Rev	Author	Line
1	2	drasko	`/*`
2			`* Time.`
3			`*`
4			`* Copyright (C) 2007 Bahadir Balban`
5			`*`
6			`*/`
7			`#include <l4/types.h>`
8			`#include <l4/lib/mutex.h>`
9			`#include <l4/lib/printk.h>`
10			`#include <l4/generic/irq.h>`
11			`#include <l4/generic/scheduler.h>`
12			`#include <l4/generic/time.h>`
13			`#include <l4/generic/preempt.h>`
14			`#include <l4/generic/space.h>`
15			`#include INC_ARCH(exception.h)`
16			`#include <l4/api/syscall.h>`
17			`#include <l4/api/errno.h>`
18			`#include INC_GLUE(ipi.h) /FIXME: Remove this /`
19
20			`/* TODO:`
21			`* 1) Add RTC support.`
22			`* 2) Need to calculate time since EPOCH,`
23			`* 3) Jiffies must be initialised to a reasonable value.`
24			`*/`
25
26			`volatile u32 jiffies = 0;`
27
28			`static inline void increase_jiffies(void)`
29			`{`
30			`jiffies++;`
31			`}`
32
33
34			`/* Internal representation of time since epoch */`
35			`struct time_info {`
36			`int reader;`
37			`u32 thz; /* Ticks in this hertz so far */`
38			`u64 sec; /* Seconds so far */`
39			`};`
40
41			`static struct time_info systime = { 0 };`
42
43			`/*`
44			`* A very basic (probably erroneous)`
45			`* rule-of-thumb time calculation.`
46			`*/`
47			`void update_system_time(void)`
48			`{`
49			`/* Did we interrupt a reader? Tell it to retry */`
50			`if (systime.reader)`
51			`systime.reader = 0;`
52
53			`/* Increase just like jiffies, but reset every second */`
54			`systime.thz++;`
55
56			`/*`
57			`* On every 1 second of timer ticks, increase seconds`
58			`*`
59			`* TODO: Investigate: how do we make sure timer_irq is`
60			`* called SCHED_TICKS times per second?`
61			`*/`
62			`if (systime.thz == CONFIG_SCHED_TICKS) {`
63			`systime.thz = 0;`
64			`systime.sec++;`
65			`}`
66			`}`
67
68			`/* Read system time */`
69			`int sys_time(struct timeval *tv, int set)`
70			`{`
71			`int retries = 20;`
72			`int err;`
73
74			`if ((err = check_access((unsigned long)tv, sizeof(*tv),`
75			`MAP_USR_RW, 1)) < 0)`
76			`return err;`
77
78			`/* Get time */`
79			`if (!set) {`
80			`while(retries > 0) {`
81			`systime.reader = 1;`
82			`tv->tv_sec = systime.sec;`
83			`tv->tv_usec = 1000000 * systime.thz / CONFIG_SCHED_TICKS;`
84
85			`retries--;`
86			`if (systime.reader)`
87			`break;`
88			`}`
89
90			`/*`
91			`* No need to reset reader since it will be reset`
92			`* on next timer. If no retries return busy.`
93			`*/`
94			`if (!retries)`
95			`return -EBUSY;`
96			`else`
97			`return 0;`
98
99			`/* Set */`
100			`} else {`
101			`/*`
102			`* Setting the time not supported yet.`
103			`*/`
104			`return -ENOSYS;`
105			`}`
106			`}`
107
108			`void update_process_times(void)`
109			`{`
110			`struct ktcb *cur = current;`
111
112			`if (cur->ticks_left == 0) {`
113			`/*`
114			`* Nested irqs and irqs during non-preemptive`
115			`* times could try to deduct ticks below zero.`
116			`* We ignore such states and return.`
117			`*/`
118			`if (in_nested_irq_context() \|\| !preemptive())`
119			`return;`
120			`else /* Otherwise its a bug. */`
121			`BUG();`
122			`}`
123
124			`/*`
125			`* These are TASK_RUNNABLE times, i.e. exludes sleeps`
126			`* In the future we may use timestamps for accuracy`
127			`*/`
128			`if (in_kernel())`
129			`cur->kernel_time++;`
130			`else`
131			`cur->user_time++;`
132
133			`cur->ticks_left--;`
134			`cur->sched_granule--;`
135
136			`/* Task has expired its timeslice */`
137			`if (!cur->ticks_left)`
138			`need_resched = 1;`
139
140			`/* Task has expired its schedule granularity */`
141			`if (!cur->sched_granule)`
142			`need_resched = 1;`
143			`}`
144
145			`int do_timer_irq(void)`
146			`{`
147			`increase_jiffies();`
148			`update_process_times();`
149			`update_system_time();`
150
151			`#if defined (CONFIG_SMP)`
152			`smp_send_ipi(cpu_mask_others(), IPI_TIMER_EVENT);`
153			`#endif`
154
155			`return IRQ_HANDLED;`
156			`}`
157
158			`/* Secondary cpus call this */`
159			`int secondary_timer_irq(void)`
160			`{`
161			`update_process_times();`
162			`return IRQ_HANDLED;`
163			`}`
164

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[/] [c0or1k/] [trunk/] [src/] [generic/] [time.c] - Blame information for rev 6