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/*
* SPU file system -- SPU context management
*
* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
*
* Author: Arnd Bergmann <arndb@de.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/spu.h>
#include <asm/spu_csa.h>
#include "spufs.h"
struct spu_context *alloc_spu_context(struct spu_gang *gang)
{
struct spu_context *ctx;
ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
if (!ctx)
goto out;
/* Binding to physical processor deferred
* until spu_activate().
*/
spu_init_csa(&ctx->csa);
if (!ctx->csa.lscsa) {
goto out_free;
}
spin_lock_init(&ctx->mmio_lock);
kref_init(&ctx->kref);
init_rwsem(&ctx->state_sema);
init_MUTEX(&ctx->run_sema);
init_waitqueue_head(&ctx->ibox_wq);
init_waitqueue_head(&ctx->wbox_wq);
init_waitqueue_head(&ctx->stop_wq);
init_waitqueue_head(&ctx->mfc_wq);
ctx->state = SPU_STATE_SAVED;
ctx->ops = &spu_backing_ops;
ctx->owner = get_task_mm(current);
if (gang)
spu_gang_add_ctx(gang, ctx);
goto out;
out_free:
kfree(ctx);
ctx = NULL;
out:
return ctx;
}
void destroy_spu_context(struct kref *kref)
{
struct spu_context *ctx;
ctx = container_of(kref, struct spu_context, kref);
down_write(&ctx->state_sema);
spu_deactivate(ctx);
up_write(&ctx->state_sema);
spu_fini_csa(&ctx->csa);
if (ctx->gang)
spu_gang_remove_ctx(ctx->gang, ctx);
kfree(ctx);
}
struct spu_context * get_spu_context(struct spu_context *ctx)
{
kref_get(&ctx->kref);
return ctx;
}
int put_spu_context(struct spu_context *ctx)
{
return kref_put(&ctx->kref, &destroy_spu_context);
}
/* give up the mm reference when the context is about to be destroyed */
void spu_forget(struct spu_context *ctx)
{
struct mm_struct *mm;
spu_acquire_saved(ctx);
mm = ctx->owner;
ctx->owner = NULL;
mmput(mm);
spu_release(ctx);
}
void spu_acquire(struct spu_context *ctx)
{
down_read(&ctx->state_sema);
}
void spu_release(struct spu_context *ctx)
{
up_read(&ctx->state_sema);
}
void spu_unmap_mappings(struct spu_context *ctx)
{
if (ctx->local_store)
unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
if (ctx->mfc)
unmap_mapping_range(ctx->mfc, 0, 0x4000, 1);
if (ctx->cntl)
unmap_mapping_range(ctx->cntl, 0, 0x4000, 1);
if (ctx->signal1)
unmap_mapping_range(ctx->signal1, 0, 0x4000, 1);
if (ctx->signal2)
unmap_mapping_range(ctx->signal2, 0, 0x4000, 1);
}
int spu_acquire_exclusive(struct spu_context *ctx)
{
int ret = 0;
down_write(&ctx->state_sema);
/* ctx is about to be freed, can't acquire any more */
if (!ctx->owner) {
ret = -EINVAL;
goto out;
}
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
goto out;
ctx->state = SPU_STATE_RUNNABLE;
} else {
/* We need to exclude userspace access to the context. */
spu_unmap_mappings(ctx);
}
out:
if (ret)
up_write(&ctx->state_sema);
return ret;
}
int spu_acquire_runnable(struct spu_context *ctx)
{
int ret = 0;
down_read(&ctx->state_sema);
if (ctx->state == SPU_STATE_RUNNABLE) {
ctx->spu->prio = current->prio;
return 0;
}
up_read(&ctx->state_sema);
down_write(&ctx->state_sema);
/* ctx is about to be freed, can't acquire any more */
if (!ctx->owner) {
ret = -EINVAL;
goto out;
}
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
goto out;
ctx->state = SPU_STATE_RUNNABLE;
}
downgrade_write(&ctx->state_sema);
/* On success, we return holding the lock */
return ret;
out:
/* Release here, to simplify calling code. */
up_write(&ctx->state_sema);
return ret;
}
void spu_acquire_saved(struct spu_context *ctx)
{
down_read(&ctx->state_sema);
if (ctx->state == SPU_STATE_SAVED)
return;
up_read(&ctx->state_sema);
down_write(&ctx->state_sema);
if (ctx->state == SPU_STATE_RUNNABLE) {
spu_deactivate(ctx);
ctx->state = SPU_STATE_SAVED;
}
downgrade_write(&ctx->state_sema);
}
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