Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Precise Delay Loops for S390 |
3 | * | |
d3d238c7 HC |
4 | * Copyright IBM Corp. 1999,2008 |
5 | * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, | |
6 | * Heiko Carstens <heiko.carstens@de.ibm.com>, | |
1da177e4 LT |
7 | */ |
8 | ||
1da177e4 LT |
9 | #include <linux/sched.h> |
10 | #include <linux/delay.h> | |
d54853ef | 11 | #include <linux/timex.h> |
1485c5c8 | 12 | #include <linux/module.h> |
d54853ef | 13 | #include <linux/irqflags.h> |
bf6f6aa4 | 14 | #include <linux/interrupt.h> |
b3966378 | 15 | #include <asm/div64.h> |
4c1051e3 | 16 | #include <asm/timer.h> |
1da177e4 LT |
17 | |
18 | void __delay(unsigned long loops) | |
19 | { | |
20 | /* | |
21 | * To end the bloody studid and useless discussion about the | |
22 | * BogoMips number I took the liberty to define the __delay | |
23 | * function in a way that that resulting BogoMips number will | |
24 | * yield the megahertz number of the cpu. The important function | |
25 | * is udelay and that is done using the tod clock. -- martin. | |
26 | */ | |
94c12cc7 | 27 | asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); |
1da177e4 LT |
28 | } |
29 | ||
0cd6a403 | 30 | static void __udelay_disabled(unsigned long long usecs) |
1da177e4 | 31 | { |
4c1051e3 MS |
32 | unsigned long cr0, cr6, new; |
33 | u64 clock_saved, end; | |
d54853ef | 34 | |
e8129c64 | 35 | end = get_clock() + (usecs << 12); |
d3d238c7 | 36 | clock_saved = local_tick_disable(); |
4c1051e3 MS |
37 | __ctl_store(cr0, 0, 0); |
38 | __ctl_store(cr6, 6, 6); | |
39 | new = (cr0 & 0xffff00e0) | 0x00000800; | |
40 | __ctl_load(new , 0, 0); | |
41 | new = 0; | |
42 | __ctl_load(new, 6, 6); | |
bb8c29ca | 43 | lockdep_off(); |
e8129c64 HC |
44 | do { |
45 | set_clock_comparator(end); | |
4c1051e3 | 46 | vtime_stop_cpu(); |
e8129c64 HC |
47 | local_irq_disable(); |
48 | } while (get_clock() < end); | |
bb8c29ca | 49 | lockdep_on(); |
4c1051e3 MS |
50 | __ctl_load(cr0, 0, 0); |
51 | __ctl_load(cr6, 6, 6); | |
d3d238c7 | 52 | local_tick_enable(clock_saved); |
d3d238c7 | 53 | } |
d54853ef | 54 | |
0cd6a403 | 55 | static void __udelay_enabled(unsigned long long usecs) |
d3d238c7 | 56 | { |
4c1051e3 | 57 | u64 clock_saved, end; |
d3d238c7 | 58 | |
0cd6a403 | 59 | end = get_clock() + (usecs << 12); |
d54853ef | 60 | do { |
78d81f2f CB |
61 | clock_saved = 0; |
62 | if (end < S390_lowcore.clock_comparator) { | |
63 | clock_saved = local_tick_disable(); | |
64 | set_clock_comparator(end); | |
65 | } | |
4c1051e3 | 66 | vtime_stop_cpu(); |
d54853ef | 67 | local_irq_disable(); |
78d81f2f CB |
68 | if (clock_saved) |
69 | local_tick_enable(clock_saved); | |
d54853ef | 70 | } while (get_clock() < end); |
d3d238c7 | 71 | } |
1da177e4 | 72 | |
d3d238c7 HC |
73 | /* |
74 | * Waits for 'usecs' microseconds using the TOD clock comparator. | |
75 | */ | |
0cd6a403 | 76 | void __udelay(unsigned long long usecs) |
d3d238c7 HC |
77 | { |
78 | unsigned long flags; | |
79 | ||
80 | preempt_disable(); | |
81 | local_irq_save(flags); | |
82 | if (in_irq()) { | |
83 | __udelay_disabled(usecs); | |
84 | goto out; | |
85 | } | |
86 | if (in_softirq()) { | |
87 | if (raw_irqs_disabled_flags(flags)) | |
88 | __udelay_disabled(usecs); | |
89 | else | |
90 | __udelay_enabled(usecs); | |
91 | goto out; | |
d54853ef | 92 | } |
d3d238c7 HC |
93 | if (raw_irqs_disabled_flags(flags)) { |
94 | local_bh_disable(); | |
95 | __udelay_disabled(usecs); | |
bf6f6aa4 | 96 | _local_bh_enable(); |
d3d238c7 HC |
97 | goto out; |
98 | } | |
99 | __udelay_enabled(usecs); | |
100 | out: | |
d54853ef | 101 | local_irq_restore(flags); |
d3d238c7 | 102 | preempt_enable(); |
1da177e4 | 103 | } |
1485c5c8 | 104 | EXPORT_SYMBOL(__udelay); |
5a0d0e65 HC |
105 | |
106 | /* | |
107 | * Simple udelay variant. To be used on startup and reboot | |
108 | * when the interrupt handler isn't working. | |
109 | */ | |
0cd6a403 | 110 | void udelay_simple(unsigned long long usecs) |
5a0d0e65 HC |
111 | { |
112 | u64 end; | |
113 | ||
0cd6a403 | 114 | end = get_clock() + (usecs << 12); |
5a0d0e65 HC |
115 | while (get_clock() < end) |
116 | cpu_relax(); | |
117 | } | |
b3966378 HC |
118 | |
119 | void __ndelay(unsigned long long nsecs) | |
120 | { | |
121 | u64 end; | |
122 | ||
123 | nsecs <<= 9; | |
124 | do_div(nsecs, 125); | |
125 | end = get_clock() + nsecs; | |
126 | if (nsecs & ~0xfffUL) | |
127 | __udelay(nsecs >> 12); | |
128 | while (get_clock() < end) | |
129 | barrier(); | |
130 | } | |
131 | EXPORT_SYMBOL(__ndelay); |