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
  29 int 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
  51 void 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 }