arch/mips/bcm47xx/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/ssb/ssb.h>
  27 #include <asm/time.h>
  28 #include <bcm47xx.h>
  29 #include <bcm47xx_board.h>
  30
  31 void __init plat_time_init(void)
  32 {
  33         unsigned long hz = 0;
  34         u16 chip_id = 0;
  35         char buf[10];
  36         int len;
  37         enum bcm47xx_board board = bcm47xx_board_get();
  38
  39         /*
  40          * Use deterministic values for initial counter interrupt
  41          * so that calibrate delay avoids encountering a counter wrap.
  42          */
  43         write_c0_count(0);
  44         write_c0_compare(0xffff);
  45
  46         switch (bcm47xx_bus_type) {
  47 #ifdef CONFIG_BCM47XX_SSB
  48         case BCM47XX_BUS_TYPE_SSB:
  49                 hz = ssb_cpu_clock(&bcm47xx_bus.ssb.mipscore) / 2;
  50                 chip_id = bcm47xx_bus.ssb.chip_id;
  51                 break;
  52 #endif
  53 #ifdef CONFIG_BCM47XX_BCMA
  54         case BCM47XX_BUS_TYPE_BCMA:
  55                 hz = bcma_cpu_clock(&bcm47xx_bus.bcma.bus.drv_mips) / 2;
  56                 chip_id = bcm47xx_bus.bcma.bus.chipinfo.id;
  57                 break;
  58 #endif
  59         }
  60
  61         if (chip_id == 0x5354) {
  62                 len = bcm47xx_nvram_getenv("clkfreq", buf, sizeof(buf));
  63                 if (len >= 0 && !strncmp(buf, "200", 4))
  64                         hz = 100000000;
  65         }
  66
  67         switch (board) {
  68         case BCM47XX_BOARD_ASUS_WL520GC:
  69         case BCM47XX_BOARD_ASUS_WL520GU:
  70                 hz = 100000000;
  71                 break;
  72         default:
  73                 break;
  74         }
  75
  76         if (!hz)
  77                 hz = 100000000;
  78
  79         /* Set MIPS counter frequency for fixed_rate_gettimeoffset() */
  80         mips_hpt_frequency = hz;
  81 }