arch/powerpc/platforms/cell/spufs/context.c

   1 /*
   2  * SPU file system -- SPU context management
   3  *
   4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
   5  *
   6  * Author: Arnd Bergmann <arndb@de.ibm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26 #include <asm/spu.h>
  27 #include <asm/spu_csa.h>
  28 #include "spufs.h"
  29
  30 struct spu_context *alloc_spu_context(struct address_space *local_store)
  31 {
  32         struct spu_context *ctx;
  33         ctx = kmalloc(sizeof *ctx, GFP_KERNEL);
  34         if (!ctx)
  35                 goto out;
  36         /* Binding to physical processor deferred
  37          * until spu_activate().
  38          */
  39         spu_init_csa(&ctx->csa);
  40         if (!ctx->csa.lscsa) {
  41                 goto out_free;
  42         }
  43         spin_lock_init(&ctx->mmio_lock);
  44         kref_init(&ctx->kref);
  45         init_rwsem(&ctx->state_sema);
  46         init_waitqueue_head(&ctx->ibox_wq);
  47         init_waitqueue_head(&ctx->wbox_wq);
  48         init_waitqueue_head(&ctx->stop_wq);
  49         ctx->ibox_fasync = NULL;
  50         ctx->wbox_fasync = NULL;
  51         ctx->state = SPU_STATE_SAVED;
  52         ctx->local_store = local_store;
  53         ctx->spu = NULL;
  54         ctx->ops = &spu_backing_ops;
  55         ctx->owner = get_task_mm(current);
  56         goto out;
  57 out_free:
  58         kfree(ctx);
  59         ctx = NULL;
  60 out:
  61         return ctx;
  62 }
  63
  64 void destroy_spu_context(struct kref *kref)
  65 {
  66         struct spu_context *ctx;
  67         ctx = container_of(kref, struct spu_context, kref);
  68         down_write(&ctx->state_sema);
  69         spu_deactivate(ctx);
  70         ctx->ibox_fasync = NULL;
  71         ctx->wbox_fasync = NULL;
  72         up_write(&ctx->state_sema);
  73         spu_fini_csa(&ctx->csa);
  74         kfree(ctx);
  75 }
  76
  77 struct spu_context * get_spu_context(struct spu_context *ctx)
  78 {
  79         kref_get(&ctx->kref);
  80         return ctx;
  81 }
  82
  83 int put_spu_context(struct spu_context *ctx)
  84 {
  85         return kref_put(&ctx->kref, &destroy_spu_context);
  86 }
  87
  88 /* give up the mm reference when the context is about to be destroyed */
  89 void spu_forget(struct spu_context *ctx)
  90 {
  91         struct mm_struct *mm;
  92         spu_acquire_saved(ctx);
  93         mm = ctx->owner;
  94         ctx->owner = NULL;
  95         mmput(mm);
  96         spu_release(ctx);
  97 }
  98
  99 void spu_acquire(struct spu_context *ctx)
 100 {
 101         down_read(&ctx->state_sema);
 102 }
 103
 104 void spu_release(struct spu_context *ctx)
 105 {
 106         up_read(&ctx->state_sema);
 107 }
 108
 109 void spu_unmap_mappings(struct spu_context *ctx)
 110 {
 111         unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
 112 }
 113
 114 int spu_acquire_runnable(struct spu_context *ctx)
 115 {
 116         int ret = 0;
 117
 118         down_read(&ctx->state_sema);
 119         if (ctx->state == SPU_STATE_RUNNABLE) {
 120                 ctx->spu->prio = current->prio;
 121                 return 0;
 122         }
 123         up_read(&ctx->state_sema);
 124
 125         down_write(&ctx->state_sema);
 126         /* ctx is about to be freed, can't acquire any more */
 127         if (!ctx->owner) {
 128                 ret = -EINVAL;
 129                 goto out;
 130         }
 131
 132         if (ctx->state == SPU_STATE_SAVED) {
 133                 ret = spu_activate(ctx, 0);
 134                 ctx->state = SPU_STATE_RUNNABLE;
 135         }
 136         if (ret)
 137                 goto out;
 138
 139         downgrade_write(&ctx->state_sema);
 140         /* On success, we return holding the lock */
 141
 142         return ret;
 143 out:
 144         /* Release here, to simplify calling code. */
 145         up_write(&ctx->state_sema);
 146
 147         return ret;
 148 }
 149
 150 void spu_acquire_saved(struct spu_context *ctx)
 151 {
 152         down_read(&ctx->state_sema);
 153
 154         if (ctx->state == SPU_STATE_SAVED)
 155                 return;
 156
 157         up_read(&ctx->state_sema);
 158         down_write(&ctx->state_sema);
 159
 160         if (ctx->state == SPU_STATE_RUNNABLE) {
 161                 spu_deactivate(ctx);
 162                 ctx->state = SPU_STATE_SAVED;
 163         }
 164
 165         downgrade_write(&ctx->state_sema);
 166 }