LXR linux/arch/mips/mti-malta/malta-amon.c

   1/*
   2 * Copyright (C) 2007  MIPS Technologies, Inc.
   3 *      All rights reserved.
   4
   5 *  This program is free software; you can distribute it and/or modify it
   6 *  under the terms of the GNU General Public License (Version 2) as
   7 *  published by the Free Software Foundation.
   8 *
   9 *  This program is distributed in the hope it will be useful, but WITHOUT
  10 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 *  for more details.
  13 *
  14 *  You should have received a copy of the GNU General Public License along
  15 *  with this program; if not, write to the Free Software Foundation, Inc.,
  16 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  17 *
  18 * Arbitrary Monitor interface
  19 */
  20
  21#include <linux/kernel.h>
  22#include <linux/init.h>
  23#include <linux/smp.h>
  24
  25#include <asm/addrspace.h>
  26#include <asm/mips-boards/launch.h>
  27#include <asm/mipsmtregs.h>
  28
  29int amon_cpu_avail(int cpu)
  30{
  31        struct cpulaunch *launch = (struct cpulaunch *)CKSEG0ADDR(CPULAUNCH);
  32
  33        if (cpu < 0 || cpu >= NCPULAUNCH) {
  34                pr_debug("avail: cpu%d is out of range\n", cpu);
  35                return 0;
  36        }
  37
  38        launch += cpu;
  39        if (!(launch->flags & LAUNCH_FREADY)) {
  40                pr_debug("avail: cpu%d is not ready\n", cpu);
  41                return 0;
  42        }
  43        if (launch->flags & (LAUNCH_FGO|LAUNCH_FGONE)) {
  44                pr_debug("avail: too late.. cpu%d is already gone\n", cpu);
  45                return 0;
  46        }
  47
  48        return 1;
  49}
  50
  51void amon_cpu_start(int cpu,
  52                    unsigned long pc, unsigned long sp,
  53                    unsigned long gp, unsigned long a0)
  54{
  55        volatile struct cpulaunch *launch =
  56                (struct cpulaunch  *)CKSEG0ADDR(CPULAUNCH);
  57
  58        if (!amon_cpu_avail(cpu))
  59                return;
  60        if (cpu == smp_processor_id()) {
  61                pr_debug("launch: I am cpu%d!\n", cpu);
  62                return;
  63        }
  64        launch += cpu;
  65
  66        pr_debug("launch: starting cpu%d\n", cpu);
  67
  68        launch->pc = pc;
  69        launch->gp = gp;
  70        launch->sp = sp;
  71        launch->a0 = a0;
  72
  73        smp_wmb();              /* Target must see parameters before go */
  74        launch->flags |= LAUNCH_FGO;
  75        smp_wmb();              /* Target must see go before we poll  */
  76
  77        while ((launch->flags & LAUNCH_FGONE) == 0)
  78                ;
  79        smp_rmb();      /* Target will be updating flags soon */
  80        pr_debug("launch: cpu%d gone!\n", cpu);
  81}
  82