1 | /* clock.c |
---|
2 | * |
---|
3 | * This routine initializes the PIT on the MPC8xx. |
---|
4 | * The tick frequency is specified by the bsp. |
---|
5 | * |
---|
6 | * Author: Jay Monkman (jmonkman@frasca.com) |
---|
7 | * Copyright (C) 1998 by Frasca International, Inc. |
---|
8 | * |
---|
9 | * Derived from c/src/lib/libcpu/ppc/ppc403/clock/clock.c: |
---|
10 | * |
---|
11 | * Author: Andrew Bray <andy@i-cubed.co.uk> |
---|
12 | * |
---|
13 | * COPYRIGHT (c) 1995 by i-cubed ltd. |
---|
14 | * |
---|
15 | * To anyone who acknowledges that this file is provided "AS IS" |
---|
16 | * without any express or implied warranty: |
---|
17 | * permission to use, copy, modify, and distribute this file |
---|
18 | * for any purpose is hereby granted without fee, provided that |
---|
19 | * the above copyright notice and this notice appears in all |
---|
20 | * copies, and that the name of i-cubed limited not be used in |
---|
21 | * advertising or publicity pertaining to distribution of the |
---|
22 | * software without specific, written prior permission. |
---|
23 | * i-cubed limited makes no representations about the suitability |
---|
24 | * of this software for any purpose. |
---|
25 | * |
---|
26 | * Derived from c/src/lib/libcpu/hppa1_1/clock/clock.c: |
---|
27 | * |
---|
28 | * COPYRIGHT (c) 1989-1998. |
---|
29 | * On-Line Applications Research Corporation (OAR). |
---|
30 | * Copyright assigned to U.S. Government, 1994. |
---|
31 | * |
---|
32 | * The license and distribution terms for this file may be |
---|
33 | * found in the file LICENSE in this distribution or at |
---|
34 | * http://www.OARcorp.com/rtems/license.html. |
---|
35 | * |
---|
36 | * $Id$ |
---|
37 | */ |
---|
38 | |
---|
39 | #include <bsp.h> |
---|
40 | #include <clockdrv.h> |
---|
41 | #include <rtems/libio.h> |
---|
42 | |
---|
43 | #include <stdlib.h> /* for atexit() */ |
---|
44 | #include <mpc8xx.h> |
---|
45 | |
---|
46 | extern rtems_cpu_table Cpu_table; /* owned by BSP */ |
---|
47 | |
---|
48 | volatile rtems_unsigned32 Clock_driver_ticks; |
---|
49 | extern volatile m8xx_t m8xx; |
---|
50 | |
---|
51 | void Clock_exit( void ); |
---|
52 | |
---|
53 | /* |
---|
54 | * These are set by clock driver during its init |
---|
55 | */ |
---|
56 | |
---|
57 | rtems_device_major_number rtems_clock_major = ~0; |
---|
58 | rtems_device_minor_number rtems_clock_minor; |
---|
59 | |
---|
60 | /* |
---|
61 | * ISR Handler |
---|
62 | */ |
---|
63 | rtems_isr Clock_isr(rtems_vector_number vector) |
---|
64 | { |
---|
65 | m8xx.piscr |= M8xx_PISCR_PS; |
---|
66 | Clock_driver_ticks++; |
---|
67 | rtems_clock_tick(); |
---|
68 | } |
---|
69 | |
---|
70 | void Install_clock(rtems_isr_entry clock_isr) |
---|
71 | { |
---|
72 | #ifdef EPPCBUG_SMC1 |
---|
73 | extern unsigned32 simask_copy; |
---|
74 | #endif /* EPPCBUG_SMC1 */ |
---|
75 | |
---|
76 | rtems_isr_entry previous_isr; |
---|
77 | rtems_unsigned32 pit_value; |
---|
78 | |
---|
79 | Clock_driver_ticks = 0; |
---|
80 | |
---|
81 | pit_value = (BSP_Configuration.microseconds_per_tick * |
---|
82 | Cpu_table.clicks_per_usec) - 1 ; |
---|
83 | |
---|
84 | if (pit_value > 0xffff) { /* pit is only 16 bits long */ |
---|
85 | rtems_fatal_error_occurred(-1); |
---|
86 | } |
---|
87 | if (BSP_Configuration.ticks_per_timeslice) { |
---|
88 | |
---|
89 | /* |
---|
90 | * initialize the interval here |
---|
91 | * First tick is set to right amount of time in the future |
---|
92 | * Future ticks will be incremented over last value set |
---|
93 | * in order to provide consistent clicks in the face of |
---|
94 | * interrupt overhead |
---|
95 | */ |
---|
96 | |
---|
97 | rtems_interrupt_catch(clock_isr, PPC_IRQ_LVL0, &previous_isr); |
---|
98 | |
---|
99 | m8xx.sccr &= ~(1<<24); |
---|
100 | m8xx.pitc = pit_value; |
---|
101 | |
---|
102 | /* set PIT irq level, enable PIT, PIT interrupts */ |
---|
103 | /* and clear int. status */ |
---|
104 | m8xx.piscr = M8xx_PISCR_PIRQ(0) | |
---|
105 | M8xx_PISCR_PTE | M8xx_PISCR_PS | M8xx_PISCR_PIE; |
---|
106 | |
---|
107 | #ifdef EPPCBUG_SMC1 |
---|
108 | simask_copy = m8xx.simask | M8xx_SIMASK_LVM0; |
---|
109 | #endif /* EPPCBUG_SMC1 */ |
---|
110 | m8xx.simask |= M8xx_SIMASK_LVM0; |
---|
111 | } |
---|
112 | atexit(Clock_exit); |
---|
113 | } |
---|
114 | |
---|
115 | void |
---|
116 | ReInstall_clock(rtems_isr_entry new_clock_isr) |
---|
117 | { |
---|
118 | rtems_isr_entry previous_isr; |
---|
119 | rtems_unsigned32 isrlevel = 0; |
---|
120 | |
---|
121 | rtems_interrupt_disable(isrlevel); |
---|
122 | |
---|
123 | rtems_interrupt_catch(new_clock_isr, PPC_IRQ_LVL0, &previous_isr); |
---|
124 | |
---|
125 | rtems_interrupt_enable(isrlevel); |
---|
126 | } |
---|
127 | |
---|
128 | |
---|
129 | /* |
---|
130 | * Called via atexit() |
---|
131 | * Remove the clock interrupt handler by setting handler to NULL |
---|
132 | */ |
---|
133 | void |
---|
134 | Clock_exit(void) |
---|
135 | { |
---|
136 | if ( BSP_Configuration.ticks_per_timeslice ) { |
---|
137 | /* disable PIT and PIT interrupts */ |
---|
138 | m8xx.piscr &= ~(M8xx_PISCR_PTE | M8xx_PISCR_PIE); |
---|
139 | |
---|
140 | (void) set_vector(0, PPC_IRQ_LVL0, 1); |
---|
141 | } |
---|
142 | } |
---|
143 | |
---|
144 | rtems_device_driver Clock_initialize( |
---|
145 | rtems_device_major_number major, |
---|
146 | rtems_device_minor_number minor, |
---|
147 | void *pargp |
---|
148 | ) |
---|
149 | { |
---|
150 | Install_clock( Clock_isr ); |
---|
151 | |
---|
152 | /* |
---|
153 | * make major/minor avail to others such as shared memory driver |
---|
154 | */ |
---|
155 | |
---|
156 | rtems_clock_major = major; |
---|
157 | rtems_clock_minor = minor; |
---|
158 | |
---|
159 | return RTEMS_SUCCESSFUL; |
---|
160 | } |
---|
161 | |
---|
162 | rtems_device_driver Clock_control( |
---|
163 | rtems_device_major_number major, |
---|
164 | rtems_device_minor_number minor, |
---|
165 | void *pargp |
---|
166 | ) |
---|
167 | { |
---|
168 | rtems_libio_ioctl_args_t *args = pargp; |
---|
169 | |
---|
170 | if (args == 0) |
---|
171 | goto done; |
---|
172 | |
---|
173 | /* |
---|
174 | * This is hokey, but until we get a defined interface |
---|
175 | * to do this, it will just be this simple... |
---|
176 | */ |
---|
177 | |
---|
178 | if (args->command == rtems_build_name('I', 'S', 'R', ' ')) { |
---|
179 | Clock_isr(PPC_IRQ_LVL0); |
---|
180 | } |
---|
181 | else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) { |
---|
182 | ReInstall_clock(args->buffer); |
---|
183 | } |
---|
184 | |
---|
185 | done: |
---|
186 | return RTEMS_SUCCESSFUL; |
---|
187 | } |
---|
188 | |
---|