1 | /*-------------------------------------------------------------------------+ |
---|
2 | | timer.c v1.1 - PC386 BSP - 1997/08/07 |
---|
3 | +--------------------------------------------------------------------------+ |
---|
4 | | This file contains the PC386 timer package. |
---|
5 | +--------------------------------------------------------------------------+ |
---|
6 | | NOTE: It is important that the timer start/stop overhead be determined |
---|
7 | | when porting or modifying this code. |
---|
8 | +--------------------------------------------------------------------------+ |
---|
9 | | (C) Copyright 1997 - |
---|
10 | | - NavIST Group - Real-Time Distributed Systems and Industrial Automation |
---|
11 | | |
---|
12 | | http://pandora.ist.utl.pt |
---|
13 | | |
---|
14 | | Instituto Superior Tecnico * Lisboa * PORTUGAL |
---|
15 | +--------------------------------------------------------------------------+ |
---|
16 | | Disclaimer: |
---|
17 | | |
---|
18 | | This file is provided "AS IS" without warranty of any kind, either |
---|
19 | | expressed or implied. |
---|
20 | +--------------------------------------------------------------------------+ |
---|
21 | | This code is base on: |
---|
22 | | timer.c,v 1.7 1995/12/19 20:07:43 joel Exp - go32 BSP |
---|
23 | | With the following copyright notice: |
---|
24 | | ************************************************************************** |
---|
25 | | * COPYRIGHT (c) 1989-1998. |
---|
26 | | * On-Line Applications Research Corporation (OAR). |
---|
27 | | * Copyright assigned to U.S. Government, 1994. |
---|
28 | | * |
---|
29 | | * The license and distribution terms for this file may be |
---|
30 | | * found in found in the file LICENSE in this distribution or at |
---|
31 | | * http://www.OARcorp.com/rtems/license.html. |
---|
32 | | ************************************************************************** |
---|
33 | | |
---|
34 | | $Id$ |
---|
35 | +--------------------------------------------------------------------------*/ |
---|
36 | |
---|
37 | |
---|
38 | #include <stdlib.h> |
---|
39 | |
---|
40 | #include <bsp.h> |
---|
41 | #include <irq.h> |
---|
42 | |
---|
43 | /*-------------------------------------------------------------------------+ |
---|
44 | | Constants |
---|
45 | +--------------------------------------------------------------------------*/ |
---|
46 | #define TIMER_IRQ 0x00 /* Timer IRQ. */ |
---|
47 | #define AVG_OVERHEAD 0 /* 0.1 microseconds to start/stop timer. */ |
---|
48 | #define LEAST_VALID 1 /* Don't trust a value lower than this. */ |
---|
49 | |
---|
50 | /*-------------------------------------------------------------------------+ |
---|
51 | | Global Variables |
---|
52 | +--------------------------------------------------------------------------*/ |
---|
53 | volatile rtems_unsigned32 Ttimer_val; |
---|
54 | rtems_boolean Timer_driver_Find_average_overhead = TRUE; |
---|
55 | |
---|
56 | /*-------------------------------------------------------------------------+ |
---|
57 | | Pentium optimized timer handling. |
---|
58 | +--------------------------------------------------------------------------*/ |
---|
59 | #if defined(pentium) |
---|
60 | |
---|
61 | /*-------------------------------------------------------------------------+ |
---|
62 | | Function: rdtsc |
---|
63 | | Description: Read the value of PENTIUM on-chip cycle counter. |
---|
64 | | Global Variables: None. |
---|
65 | | Arguments: None. |
---|
66 | | Returns: Value of PENTIUM on-chip cycle counter. |
---|
67 | +--------------------------------------------------------------------------*/ |
---|
68 | static inline unsigned long long |
---|
69 | rdtsc(void) |
---|
70 | { |
---|
71 | /* Return the value of the on-chip cycle counter. */ |
---|
72 | unsigned long long result; |
---|
73 | asm volatile(".byte 0x0F, 0x31" : "=A" (result)); |
---|
74 | return result; |
---|
75 | } /* rdtsc */ |
---|
76 | |
---|
77 | |
---|
78 | /*-------------------------------------------------------------------------+ |
---|
79 | | Function: Timer_exit |
---|
80 | | Description: Timer cleanup routine at RTEMS exit. NOTE: This routine is |
---|
81 | | not really necessary, since there will be a reset at exit. |
---|
82 | | Global Variables: None. |
---|
83 | | Arguments: None. |
---|
84 | | Returns: Nothing. |
---|
85 | +--------------------------------------------------------------------------*/ |
---|
86 | void |
---|
87 | Timer_exit(void) |
---|
88 | { |
---|
89 | PC386_disableIrq(TIMER_IRQ); |
---|
90 | } /* Timer_exit */ |
---|
91 | |
---|
92 | |
---|
93 | /*-------------------------------------------------------------------------+ |
---|
94 | | Function: Timer_initialize |
---|
95 | | Description: Timer initialization routine. |
---|
96 | | Global Variables: Ttimer_val. |
---|
97 | | Arguments: None. |
---|
98 | | Returns: Nothing. |
---|
99 | +--------------------------------------------------------------------------*/ |
---|
100 | void |
---|
101 | Timer_initialize(void) |
---|
102 | { |
---|
103 | static rtems_boolean First = TRUE; |
---|
104 | |
---|
105 | if (First) |
---|
106 | { |
---|
107 | First = FALSE; |
---|
108 | |
---|
109 | atexit(Timer_exit); /* Try not to hose the system at exit. */ |
---|
110 | PC386_enableIrq(TIMER_IRQ); |
---|
111 | /* Disable the programmable timer so ticks don't interfere. */ |
---|
112 | } |
---|
113 | Ttimer_val = rdtsc(); /* read starting time */ |
---|
114 | } /* Timer_initialize */ |
---|
115 | |
---|
116 | |
---|
117 | /*-------------------------------------------------------------------------+ |
---|
118 | | Function: Read_timer |
---|
119 | | Description: Read hardware timer value. |
---|
120 | | Global Variables: Ttimer_val, Timer_driver_Find_average_overhead. |
---|
121 | | Arguments: None. |
---|
122 | | Returns: Nothing. |
---|
123 | +--------------------------------------------------------------------------*/ |
---|
124 | rtems_unsigned32 |
---|
125 | Read_timer(void) |
---|
126 | { |
---|
127 | register rtems_unsigned32 total; |
---|
128 | |
---|
129 | total = (rtems_unsigned32)(rdtsc() - Ttimer_val); |
---|
130 | |
---|
131 | if (Timer_driver_Find_average_overhead) |
---|
132 | return total; |
---|
133 | else if (total < LEAST_VALID) |
---|
134 | return 0; /* below timer resolution */ |
---|
135 | else |
---|
136 | return (total - AVG_OVERHEAD); |
---|
137 | } /* Read_timer */ |
---|
138 | |
---|
139 | #else /* pentium */ |
---|
140 | |
---|
141 | /*-------------------------------------------------------------------------+ |
---|
142 | | Non-Pentium timer handling. |
---|
143 | +--------------------------------------------------------------------------*/ |
---|
144 | #define US_PER_ISR 250 /* Number of micro-seconds per timer interruption */ |
---|
145 | |
---|
146 | /*-------------------------------------------------------------------------+ |
---|
147 | | External Prototypes |
---|
148 | +--------------------------------------------------------------------------*/ |
---|
149 | extern rtems_isr timerisr(rtems_vector_number); |
---|
150 | /* timer (int 08h) Interrupt Service Routine (defined in 'timerisr.s') */ |
---|
151 | |
---|
152 | /*-------------------------------------------------------------------------+ |
---|
153 | | Function: Timer_exit |
---|
154 | | Description: Timer cleanup routine at RTEMS exit. NOTE: This routine is |
---|
155 | | not really necessary, since there will be a reset at exit. |
---|
156 | | Global Variables: None. |
---|
157 | | Arguments: None. |
---|
158 | | Returns: Nothing. |
---|
159 | +--------------------------------------------------------------------------*/ |
---|
160 | void |
---|
161 | Timer_exit(void) |
---|
162 | { |
---|
163 | /* reset timer mode to standard (DOS) value */ |
---|
164 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN); |
---|
165 | outport_byte(TIMER_CNTR0, 0); |
---|
166 | outport_byte(TIMER_CNTR0, 0); |
---|
167 | } /* Timer_exit */ |
---|
168 | |
---|
169 | |
---|
170 | /*-------------------------------------------------------------------------+ |
---|
171 | | Function: Timer_initialize |
---|
172 | | Description: Timer initialization routine. |
---|
173 | | Global Variables: Ttimer_val. |
---|
174 | | Arguments: None. |
---|
175 | | Returns: Nothing. |
---|
176 | +--------------------------------------------------------------------------*/ |
---|
177 | void |
---|
178 | Timer_initialize(void) |
---|
179 | { |
---|
180 | static rtems_boolean First = TRUE; |
---|
181 | |
---|
182 | if (First) |
---|
183 | { |
---|
184 | First = FALSE; |
---|
185 | |
---|
186 | atexit(Timer_exit); /* Try not to hose the system at exit. */ |
---|
187 | |
---|
188 | /* install a raw interrupt handler for timer */ |
---|
189 | PC386_installRawIrqHandler(TIMER_IRQ, timerisr); |
---|
190 | |
---|
191 | /* load timer for US_PER_ISR microsecond period */ |
---|
192 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN); |
---|
193 | outport_byte(TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 0 & 0xff); |
---|
194 | outport_byte(TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 8 & 0xff); |
---|
195 | } |
---|
196 | /* wait for ISR to be called at least once */ |
---|
197 | Ttimer_val = 0; |
---|
198 | while (Ttimer_val == 0) |
---|
199 | continue; |
---|
200 | Ttimer_val = 0; |
---|
201 | } /* Timer_initialize */ |
---|
202 | |
---|
203 | |
---|
204 | /*-------------------------------------------------------------------------+ |
---|
205 | | Function: Read_timer |
---|
206 | | Description: Read hardware timer value. |
---|
207 | | Global Variables: Ttimer_val, Timer_driver_Find_average_overhead. |
---|
208 | | Arguments: None. |
---|
209 | | Returns: Nothing. |
---|
210 | +--------------------------------------------------------------------------*/ |
---|
211 | rtems_unsigned32 |
---|
212 | Read_timer(void) |
---|
213 | { |
---|
214 | register rtems_unsigned32 total, clicks; |
---|
215 | register rtems_unsigned8 lsb, msb; |
---|
216 | |
---|
217 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_LATCH); |
---|
218 | inport_byte(TIMER_CNTR0, lsb); |
---|
219 | inport_byte(TIMER_CNTR0, msb); |
---|
220 | clicks = (msb << 8) | lsb; |
---|
221 | total = (Ttimer_val * US_PER_ISR) + (US_PER_ISR - TICK_TO_US(clicks)); |
---|
222 | |
---|
223 | if (Timer_driver_Find_average_overhead) |
---|
224 | return total; |
---|
225 | else if (total < LEAST_VALID) |
---|
226 | return 0; /* below timer resolution */ |
---|
227 | else |
---|
228 | return (total - AVG_OVERHEAD); |
---|
229 | } |
---|
230 | |
---|
231 | #endif /* pentium */ |
---|
232 | |
---|
233 | |
---|
234 | /*-------------------------------------------------------------------------+ |
---|
235 | | Function: Empty_function |
---|
236 | | Description: Empty function used in time tests. |
---|
237 | | Global Variables: None. |
---|
238 | | Arguments: None. |
---|
239 | | Returns: Nothing. |
---|
240 | +--------------------------------------------------------------------------*/ |
---|
241 | rtems_status_code Empty_function(void) |
---|
242 | { |
---|
243 | return RTEMS_SUCCESSFUL; |
---|
244 | } /* Empty function */ |
---|
245 | |
---|
246 | |
---|
247 | /*-------------------------------------------------------------------------+ |
---|
248 | | Function: Set_find_average_overhead |
---|
249 | | Description: Set internal Timer_driver_Find_average_overhead flag value. |
---|
250 | | Global Variables: Timer_driver_Find_average_overhead. |
---|
251 | | Arguments: find_flag - new value of the flag. |
---|
252 | | Returns: Nothing. |
---|
253 | +--------------------------------------------------------------------------*/ |
---|
254 | void |
---|
255 | Set_find_average_overhead(rtems_boolean find_flag) |
---|
256 | { |
---|
257 | Timer_driver_Find_average_overhead = find_flag; |
---|
258 | } /* Set_find_average_overhead */ |
---|