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Annotation of prex-old/sys/arch/arm/cats/clock.c, Revision 1.2

1.1       nbrk        1: /*
1.2     ! nbrk        2:  * $Id: clock.c,v 1.1 2008/07/18 20:21:48 nbrk Exp $
1.1       nbrk        3:  */
                      4: /*-
                      5:  * Copyright (c) 2005-2007, Kohsuke Ohtani
                      6:  * All rights reserved.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
                     16:  * 3. Neither the name of the author nor the names of any co-contributors
                     17:  *    may be used to endorse or promote products derived from this software
                     18:  *    without specific prior written permission.
                     19:  *
                     20:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
                     21:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     22:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     23:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
                     24:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     25:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     26:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     27:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     28:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     29:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     30:  * SUCH DAMAGE.
                     31:  */
                     32:
                     33: /*
1.2     ! nbrk       34:  * clock.c - SA-110 Operatin System Timer driver.
1.1       nbrk       35:  */
                     36:
                     37: #include <kernel.h>
                     38: #include <timer.h>
                     39: #include <irq.h>
                     40:
1.2     ! nbrk       41: /*
        !            42:  * This OST is an incrementing counter running at 3.6864 MHz.
        !            43:  * It contains four 32-bit Match Registers which can be programmed
        !            44:  * to cause periodic interrupts in SAIC.
        !            45:  * For our main clock service we use channel 0.
        !            46:  */
        !            47: #define SAOST_INTRNO   26      /* channel 0 match */
        !            48: #define SAOST_FREQ     3686400 /* ticks per second */
        !            49:
        !            50: #define SAOST_BASE     0x90000000
        !            51: #define  SAOST_OSMR(x) (x * 4) /* Match Register x */
        !            52: #define  SAOST_OSCR    0x10
        !            53: #define  SAOST_OSSR    0x14
        !            54: #define  SAOST_OIER    0x1c
1.1       nbrk       55:
                     56: /*
                     57:  * Clock interrupt service routine.
                     58:  * No H/W reprogram is required.
                     59:  */
                     60: static int
                     61: clock_isr(int irq)
                     62: {
                     63:        irq_lock();
1.2     ! nbrk       64:
1.1       nbrk       65:        timer_tick();
1.2     ! nbrk       66:
1.1       nbrk       67:        irq_unlock();
                     68:
                     69:        return INT_DONE;
                     70: }
                     71:
                     72: /*
                     73:  * Initialize clock H/W chip.
                     74:  * Setup clock tick rate and install clock ISR.
                     75:  */
                     76: void
                     77: clock_init(void)
                     78: {
1.2     ! nbrk       79:        int clock_irq;
        !            80:
        !            81:
        !            82:        /* disable interrupts on matching all channels */
        !            83:        *(volatile uint32_t *)(SAOST_BASE + SAOST_OIER) = 0;
        !            84:
        !            85:        /* set channel 0 to 1/100 / sec */
        !            86:        *(volatile uint32_t *)(SAOST_BASE + SAOST_OSMR(0)) = SAOST_FREQ / CONFIG_HZ;
        !            87:
        !            88:        clock_irq = irq_attach(SAOST_INTRNO, IPL_CLOCK, 0, clock_isr, NULL);
        !            89:        ASSERT(clock_irq != -1);
        !            90:
        !            91:        /* enable interrupts on channel 0 compare */
        !            92:        *(volatile uint32_t *)(SAOST_BASE + SAOST_OIER) = 1;
1.1       nbrk       93: }
1.2     ! nbrk       94: