LXR linux/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
  31void __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}
  82