target/linux/brcm47xx-2.6/files/arch/mips/bcm947xx/time.c

   1 /*
   2  *  Copyright (C) 2004 Florian Schirmer (jolt@tuxbox.org)
   3  *
   4  *  This program is free software; you can redistribute  it and/or modify it
   5  *  under  the terms of  the GNU General  Public License as published by the
   6  *  Free Software Foundation;  either version 2 of the  License, or (at your
   7  *  option) any later version.
   8  *
   9  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  10  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  11  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  12  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  13  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  14  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  15  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  16  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  17  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  18  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  19  *
  20  *  You should have received a copy of the  GNU General Public License along
  21  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  22  *  675 Mass Ave, Cambridge, MA 02139, USA.
  23  */
  24
  25 #include <linux/init.h>
  26 #include <linux/kernel.h>
  27 #include <linux/sched.h>
  28 #include <linux/serial_reg.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/ssb/ssb.h>
  31 #include <asm/addrspace.h>
  32 #include <asm/io.h>
  33 #include <asm/time.h>
  34
  35 extern struct ssb_bus ssb;
  36
  37 void __init
  38 bcm47xx_time_init(void)
  39 {
  40         unsigned long hz;
  41
  42         /*
  43          * Use deterministic values for initial counter interrupt
  44          * so that calibrate delay avoids encountering a counter wrap.
  45          */
  46         write_c0_count(0);
  47         write_c0_compare(0xffff);
  48
  49         hz = ssb_cpu_clock(&ssb.mipscore) / 2;
  50         if (!hz)
  51                 hz = 100000000;
  52
  53         /* Set MIPS counter frequency for fixed_rate_gettimeoffset() */
  54         mips_hpt_frequency = hz;
  55 }
  56
  57 void __init
  58 plat_timer_setup(struct irqaction *irq)
  59 {
  60         /* Enable the timer interrupt */
  61         setup_irq(7, irq);
  62 }