source: rtems/c/src/lib/libbsp/m68k/gen68340/timer/timer.c @ 08311cc3

4.104.114.84.95
Last change on this file since 08311cc3 was 08311cc3, checked in by Joel Sherrill <joel.sherrill@…>, on Nov 17, 1999 at 5:51:34 PM

Updated copyright notice.

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File size: 8.7 KB
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1/*
2 * Timer_init()
3 *
4 * ATTENTION: AS MC68349 has no built-in Timer, the following code doesn't work
5 *            in a MC68349. You can't use FIFO full mode for the moment, but
6 *            it should be easy to fix this by using an external timer
7 *
8 * Use TIMER 1 for TIMEOUT when using FIFO FULL mode in UART driver
9 * Use TIMER 2 for timing test suites
10 *
11 * Geoffroy Montel
12 * France Telecom - CNET/DSM/TAM/CAT
13 * 4, rue du Clos Courtel
14 * 35512 CESSON-SEVIGNE
15 * FRANCE
16 *
17 * e-mail: g_montel@yahoo.com
18 *
19 *  $Id$
20 */
21
22/*
23 *
24 *  Input parameters:  NONE
25 *
26 *  Output parameters:  NONE
27 *
28 *  NOTE: It is important that the timer start/stop overhead be
29 *        determined when porting or modifying this code.
30 *
31 *  COPYRIGHT (c) 1989-1999.
32 *  On-Line Applications Research Corporation (OAR).
33 *
34 *  The license and distribution terms for this file may be
35 *  found in the file LICENSE in this distribution or at
36 *  http://www.OARcorp.com/rtems/license.html.
37 */
38
39#include <rtems.h>
40#include <bsp.h>
41#include <m340uart.h>
42#include <m340timer.h>
43#include <m68340.h>
44
45#define TIMER1_VECTOR 122
46#define TIMER1_IRQ_LEVEL 5
47#define TIMER1_INTERRUPT_ARBITRATION 5
48
49#define TIMER2_VECTOR 123
50#define TIMER2_IRQ_LEVEL 4
51#define TIMER2_INTERRUPT_ARBITRATION 4
52
53#define CLOCK_SPEED 25          /* in Mhz */
54
55#define max(a,b) (((a)>(b)) ? (a) : (b))
56
57void (*Restart_Fifo_Full_A_Timer)();
58void (*Restart_Check_A_Timer)();
59void (*Restart_Fifo_Full_B_Timer)();
60void (*Restart_Check_B_Timer)();
61
62int preload = 0;
63
64/******************************************************
65  Name: __Restart_Fifo_Full_Timer
66  Input parameters: -
67  Output parameters: -
68  Description: when a character is received, sets
69               the TIMER to raise an interrupt at
70               TIMEOUT.
71               It's necessary to prevent from not
72               getting n-1 characters (with n the
73               Uart Fifo size)
74 *****************************************************/
75void __Restart_Fifo_Full_Timer (void)
76{
77 TSR1 |= m340_TO;
78 TCR1 &= ~m340_CPE;
79 WPREL11 = preload;
80 TCR1 |= m340_CPE;
81}
82
83/******************************************************
84  Name: __Restart_Fifo_Full_Timer
85  Input parameters: -
86  Output parameters: -
87  Description: when no character has been received
88               recently, check now and then if whether
89               a there's a character in the FIFO
90 *****************************************************/
91void __Restart_Check_Timer (void)
92{
93 TSR1 |= m340_TO;
94 TCR1 &= ~m340_CPE;
95 WPREL11 = 0xFFFF;
96 TCR1 |= m340_CPE;
97}
98
99/******************************************************
100  Name: __do_nothing
101  Input parameters: -
102  Output parameters: -
103  Description: we always restart the fifo full timer
104               with a call to Restart_*_Timer
105               if we do not use FIFO full, Restart_*_Timer
106               are set to do __do_nothing
107 *****************************************************/
108void __do_nothing (void)
109{
110}
111
112#define Fifo_Full_on_A (m340_uart_config[UART_CHANNEL_A].rx_mode==UART_FIFO_FULL && m340_uart_config[UART_CHANNEL_A].enable && m340_uart_config[UART_CHANNEL_A].mode==UART_INTERRUPTS)
113#define Fifo_Full_on_B (m340_uart_config[UART_CHANNEL_B].rx_mode==UART_FIFO_FULL && m340_uart_config[UART_CHANNEL_B].enable && m340_uart_config[UART_CHANNEL_B].mode==UART_INTERRUPTS)
114
115/******************************************************
116  Name: Fifo_Full_Timer_initialize
117  Input parameters: -
118  Output parameters: -
119  Description: initialize Timer 1 for FIFO full mode
120 *****************************************************/
121void Fifo_Full_Timer_initialize (void)
122{
123   float max_baud_rate;
124   int prescaler_output_tap = -1;
125   int nb_of_clock_ticks = 0;
126
127   /*
128    *  USE TIMER 1 for UART FIFO FULL mode
129    */
130
131   if ( Fifo_Full_on_A || Fifo_Full_on_B )     
132      {
133        /* Disable the timer */
134        TCR1 &= ~m340_SWR;
135
136        /* Reset the interrupts */
137        TSR1 &= ~(m340_TO | m340_TG | m340_TC);
138
139        /* Init the stop bit for normal operation, ignore FREEZE, user privileges,
140           set interrupt arbitration */
141        TMCR1 = TIMER1_INTERRUPT_ARBITRATION;
142
143        /* interrupt priority level and interrupt vector */
144        TIR1 = TIMER1_VECTOR | (TIMER1_IRQ_LEVEL << 8);
145
146        /* compute prescaler */
147        if ( Fifo_Full_on_A && Fifo_Full_on_B)
148                max_baud_rate = max(m340_uart_config[UART_CHANNEL_A].rx_baudrate, m340_uart_config[UART_CHANNEL_B].rx_baudrate);       
149        else if ( Fifo_Full_on_A )     
150                max_baud_rate = m340_uart_config[UART_CHANNEL_A].rx_baudrate;
151             else max_baud_rate = m340_uart_config[UART_CHANNEL_B].rx_baudrate;
152
153        /* find out config */
154        nb_of_clock_ticks = (10/max_baud_rate)*(CLOCK_SPEED*1000000)*1.2;
155        if (nb_of_clock_ticks < 0xFFFF) {
156           preload = nb_of_clock_ticks;
157           prescaler_output_tap = -1;   
158        } else if (nb_of_clock_ticks/2 < 0xFFFF) {
159           preload = nb_of_clock_ticks/2;
160           prescaler_output_tap = m340_Divide_by_2;
161        } else if (nb_of_clock_ticks/4 < 0xFFFF) {
162           preload = nb_of_clock_ticks/4;
163           prescaler_output_tap = m340_Divide_by_4;
164        } else if (nb_of_clock_ticks/8 < 0xFFFF) {
165           preload = nb_of_clock_ticks/8;
166           prescaler_output_tap = m340_Divide_by_16;
167        } else if (nb_of_clock_ticks/16 < 0xFFFF) {
168           preload = nb_of_clock_ticks/16;
169           prescaler_output_tap = m340_Divide_by_16;
170        } else if (nb_of_clock_ticks/32 < 0xFFFF) {
171           preload = nb_of_clock_ticks/32;
172           prescaler_output_tap = m340_Divide_by_32;
173        } else if (nb_of_clock_ticks/64 < 0xFFFF) {
174           preload = nb_of_clock_ticks/64;
175           prescaler_output_tap = m340_Divide_by_64;
176        } else if (nb_of_clock_ticks/128 < 0xFFFF) {
177           preload = nb_of_clock_ticks/128;
178           prescaler_output_tap = m340_Divide_by_128;
179        } else if (nb_of_clock_ticks/256 < 0xFFFF) {
180           preload = nb_of_clock_ticks/256;
181           prescaler_output_tap = m340_Divide_by_256;
182        } 
183
184        /* Input Capture/Output Compare (ICOC) */
185        TCR1 = m340_SWR | m340_TO_Enabled | m340_ICOC;
186        if (prescaler_output_tap!=-1) TCR1 |= prescaler_output_tap | m340_PSE;
187
188        /* install interrupt vector */
189        {
190         rtems_isr_entry old_handler;
191         rtems_status_code sc;
192
193         extern void _Debug_ISR_Handler_Console(void);
194
195         sc = rtems_interrupt_catch (InterruptHandler,
196                                     TIMER1_VECTOR,
197                                     &old_handler);
198
199         /* uncomment this if you want to pass control to your own ISR handler
200            it may be usefull to do so to check for performances with an oscilloscope */
201         /*
202         {
203          proc_ptr ignored;
204          _CPU_ISR_install_raw_handler( TIMER1_VECTOR, _Debug_ISR_Handler_Console, &ignored );
205         }
206         */
207        }
208       } /* fifo full mode on a uart */
209
210       /* install routines */
211       Restart_Check_A_Timer = Fifo_Full_on_A ? __Restart_Check_Timer : __do_nothing;
212       Restart_Fifo_Full_A_Timer = Fifo_Full_on_A ? __Restart_Fifo_Full_Timer : __do_nothing;
213       Restart_Check_B_Timer = Fifo_Full_on_B ? __Restart_Check_Timer : __do_nothing;
214       Restart_Fifo_Full_B_Timer = Fifo_Full_on_B ? __Restart_Fifo_Full_Timer : __do_nothing;
215       /* start checking timer */
216       Restart_Check_A_Timer();
217       Restart_Check_B_Timer();
218}
219
220/******************************************************
221  Name: Timer_initialize
222  Input parameters: -
223  Output parameters: -
224  Description: init Timer for timing test suites
225 *****************************************************/
226void Timer_initialize (void)
227{
228        /* Disable the timer */
229        TCR2 &= ~m340_SWR;
230
231        /* Reset the interrupts */
232        TSR2 &= ~(m340_TO | m340_TG | m340_TC);
233
234        /* Init the stop bit for normal operation, ignore FREEZE, user privileges,
235           set interrupt arbitration */
236        TMCR1 = TIMER2_INTERRUPT_ARBITRATION;
237
238        /* interrupt priority level and interrupt vector */
239        TIR1 = TIMER2_VECTOR | (TIMER2_IRQ_LEVEL << 8);
240
241        /* Init the stop bit for normal operation, ignore FREEZE, user privileges,
242           set interrupt arbitration */
243        TMCR2 = TIMER2_INTERRUPT_ARBITRATION;
244
245        /* Preload register 1 */
246        WPREL21 = 0xFFFF;
247
248        /* Input Capture/Output Compare (ICOC) */
249        TCR2 = m340_SWR | m340_ICOC | m340_PSE | m340_Divide_by_16 | m340_CPE;
250}
251
252/******************************************************
253  Name: Read_timer
254  Input parameters: -
255  Output parameters: -
256  Description: Return timer value in microsecond units
257 *****************************************************/
258int
259Read_timer (void)
260{
261 /* there's CLOCK_SPEED / 16 micro seconds between two timer register decrement */
262 return (((0xFFFF - TCNTR2) * CLOCK_SPEED) / 16);
263}
264
265/******************************************************
266  Name: Empty_function
267  Input parameters: -
268  Output parameters: -
269  Description: Empty function call used in loops to
270               measure basic cost of looping
271               in Timing Test Suite.
272 *****************************************************/
273rtems_status_code
274Empty_function (void)
275{
276        return RTEMS_SUCCESSFUL;
277}
278
279/******************************************************
280  Name: Set_find_average_overhead
281  Input parameters: -
282  Output parameters: -
283  Description: -
284 *****************************************************/
285void
286Set_find_average_overhead(rtems_boolean find_flag)
287{
288}
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