arch/mips/kernel/csrc-bcm1480.c

   1 /*
   2  * Copyright (C) 2000,2001,2004 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18 #include <linux/clocksource.h>
  19
  20 #include <asm/addrspace.h>
  21 #include <asm/io.h>
  22 #include <asm/time.h>
  23
  24 #include <asm/sibyte/bcm1480_regs.h>
  25 #include <asm/sibyte/sb1250_regs.h>
  26 #include <asm/sibyte/bcm1480_int.h>
  27 #include <asm/sibyte/bcm1480_scd.h>
  28
  29 #include <asm/sibyte/sb1250.h>
  30
  31 static cycle_t bcm1480_hpt_read(struct clocksource *cs)
  32 {
  33         return (cycle_t) __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
  34 }
  35
  36 struct clocksource bcm1480_clocksource = {
  37         .name   = "zbbus-cycles",
  38         .rating = 200,
  39         .read   = bcm1480_hpt_read,
  40         .mask   = CLOCKSOURCE_MASK(64),
  41         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  42 };
  43
  44 void __init sb1480_clocksource_init(void)
  45 {
  46         struct clocksource *cs = &bcm1480_clocksource;
  47         unsigned int plldiv;
  48         unsigned long zbbus;
  49
  50         plldiv = G_BCM1480_SYS_PLL_DIV(__raw_readq(IOADDR(A_SCD_SYSTEM_CFG)));
  51         zbbus = ((plldiv >> 1) * 50000000) + ((plldiv & 1) * 25000000);
  52         clocksource_set_clock(cs, zbbus);
  53         clocksource_register(cs);
  54 }