/*
* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*/
#ifndef SEMAPHORE_GK20A_H
#define SEMAPHORE_GK20A_H
#include <linux/kref.h>
#include "gk20a_allocator.h"
#include "mm_gk20a.h"
/* A memory pool for holding semaphores. */
struct gk20a_semaphore_pool {
struct mem_desc mem;
struct gk20a *g;
struct list_head maps;
struct mutex maps_mutex;
struct kref ref;
struct gk20a_allocator alloc;
};
enum gk20a_mem_rw_flag {
gk20a_mem_flag_none = 0,
gk20a_mem_flag_read_only = 1,
gk20a_mem_flag_write_only = 2,
};
/* A semaphore pool can be mapped to multiple GPU address spaces. */
struct gk20a_semaphore_pool_map {
u64 gpu_va;
enum gk20a_mem_rw_flag rw_flag;
struct vm_gk20a *vm;
struct list_head list;
};
/* A semaphore that lives inside a semaphore pool. */
struct gk20a_semaphore {
struct gk20a_semaphore_pool *pool;
/*
* value exists within the pool's memory at the specified offset.
* 0=acquired, 1=released.
*/
u32 offset; /* byte offset within pool */
struct kref ref;
};
/* Create a semaphore pool that can hold at most 'capacity' semaphores. */
struct gk20a_semaphore_pool *
gk20a_semaphore_pool_alloc(struct gk20a *, const char *unique_name,
size_t capacity);
void gk20a_semaphore_pool_put(struct gk20a_semaphore_pool *);
int gk20a_semaphore_pool_map(struct gk20a_semaphore_pool *,
struct vm_gk20a *,
enum gk20a_mem_rw_flag);
void gk20a_semaphore_pool_unmap(struct gk20a_semaphore_pool *,
struct vm_gk20a *);
u64 gk20a_semaphore_pool_gpu_va(struct gk20a_semaphore_pool *,
struct vm_gk20a *);
/* Allocate a semaphore from the semaphore pool. The newly allocated
* semaphore will be in acquired state (value=0). */
struct gk20a_semaphore *
gk20a_semaphore_alloc(struct gk20a_semaphore_pool *);
void gk20a_semaphore_put(struct gk20a_semaphore *);
void gk20a_semaphore_get(struct gk20a_semaphore *);
static inline u64 gk20a_semaphore_gpu_va(struct gk20a_semaphore *s,
struct vm_gk20a *vm)
{
return gk20a_semaphore_pool_gpu_va(s->pool, vm) + s->offset;
}
static inline bool gk20a_semaphore_is_acquired(struct gk20a_semaphore *s)
{
u32 v = gk20a_mem_rd(s->pool->g, &s->pool->mem, s->offset);
/* When often block on value reaching a certain threshold. We must make
* sure that if we get unblocked, we haven't read anything too early. */
smp_rmb();
return v == 0;
}
static inline void gk20a_semaphore_release(struct gk20a_semaphore *s)
{
smp_wmb();
gk20a_mem_wr(s->pool->g, &s->pool->mem, s->offset, 1);
}
#endif
