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

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2007 MIPS Technologies, Inc.  All rights reserved.
   7  * Copyright (C) 2013 Imagination Technologies Ltd.
   8  *
   9  * Arbitrary Monitor Interface
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/smp.h>
  13
  14 #include <asm/addrspace.h>
  15 #include <asm/mipsmtregs.h>
  16 #include <asm/mips-boards/launch.h>
  17 #include <asm/vpe.h>
  18
  19 int amon_cpu_avail(int cpu)
  20 {
  21         struct cpulaunch *launch = (struct cpulaunch *)CKSEG0ADDR(CPULAUNCH);
  22
  23         if (cpu < 0 || cpu >= NCPULAUNCH) {
  24                 pr_debug("avail: cpu%d is out of range\n", cpu);
  25                 return 0;
  26         }
  27
  28         launch += cpu;
  29         if (!(launch->flags & LAUNCH_FREADY)) {
  30                 pr_debug("avail: cpu%d is not ready\n", cpu);
  31                 return 0;
  32         }
  33         if (launch->flags & (LAUNCH_FGO|LAUNCH_FGONE)) {
  34                 pr_debug("avail: too late.. cpu%d is already gone\n", cpu);
  35                 return 0;
  36         }
  37
  38         return 1;
  39 }
  40
  41 int amon_cpu_start(int cpu,
  42                     unsigned long pc, unsigned long sp,
  43                     unsigned long gp, unsigned long a0)
  44 {
  45         volatile struct cpulaunch *launch =
  46                 (struct cpulaunch  *)CKSEG0ADDR(CPULAUNCH);
  47
  48         if (!amon_cpu_avail(cpu))
  49                 return -1;
  50         if (cpu == smp_processor_id()) {
  51                 pr_debug("launch: I am cpu%d!\n", cpu);
  52                 return -1;
  53         }
  54         launch += cpu;
  55
  56         pr_debug("launch: starting cpu%d\n", cpu);
  57
  58         launch->pc = pc;
  59         launch->gp = gp;
  60         launch->sp = sp;
  61         launch->a0 = a0;
  62
  63         smp_wmb();              /* Target must see parameters before go */
  64         launch->flags |= LAUNCH_FGO;
  65         smp_wmb();              /* Target must see go before we poll  */
  66
  67         while ((launch->flags & LAUNCH_FGONE) == 0)
  68                 ;
  69         smp_rmb();      /* Target will be updating flags soon */
  70         pr_debug("launch: cpu%d gone!\n", cpu);
  71
  72         return 0;
  73 }
  74
  75 #ifdef CONFIG_MIPS_VPE_LOADER_CMP
  76 int vpe_run(struct vpe *v)
  77 {
  78         struct vpe_notifications *n;
  79
  80         if (amon_cpu_start(aprp_cpu_index(), v->__start, 0, 0, 0) < 0)
  81                 return -1;
  82
  83         list_for_each_entry(n, &v->notify, list)
  84                 n->start(VPE_MODULE_MINOR);
  85
  86         return 0;
  87 }
  88 #endif