path: root/drivers/nvlink/nvlink-core.c

/*
 * nvlink-core.c:
 * This driver manages the entire NVLINK system that the Tegra SOC is connected
 * to. The NVLINK core driver interfaces with the NVLINK endpoint drivers. Each
 * endpoint driver is responsible for the HW programming of 1 particular NVLINK
 * device. The core driver uses the endpoint drivers to manage the NVLINK
 * system.
 *
 * Copyright (c) 2017-2018, 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/platform/tegra/tegra-nvlink.h>

#include <asm/cacheflush.h>

#define NVLINK_MODULE_NAME			"nvlink-core"
#define NVLINK_DEBUGFS_ROOT			"nvlink"
#define NVLINK_DEBUGFS_TESTS			"tests"
#define DEFAULT_LOOP_SLEEP_US			100
#define DEFAULT_LOOP_TIMEOUT_US			1000000
#define NVLINK_TRANSITION_HS_TIMEOUT_MS		2000
#define NVLINK_TRANSITION_SAFE_TIMEOUT_MS	5

struct nvlink_intranode_conn {
	struct nvlink_device *ndev0;
	struct nvlink_device *ndev1;
};

struct topology {
	int slave_dev_id;
	int master_dev_id;
	int slave_link_id;
	int master_link_id;
};

struct nvlink_core {
	struct nvlink_device *ndevs[NVLINK_MAX_DEVICES];
	struct nvlink_link *nlinks[NVLINK_MAX_LINKS];
	struct topology topology;
	struct nvlink_intranode_conn intranode_conn;
	struct mutex mutex;
};

/*
 * We're exporting the NVLINK driver stack's logging APIs to the NVLINK kernel
 * test modules. The logging APIs use nvlink_log_mask. Therefore, we have to
 * export nvlink_log_mask along with the logging APIs.
 */
u32 nvlink_log_mask = NVLINK_DEFAULT_LOG_MASK;
EXPORT_SYMBOL(nvlink_log_mask);

#ifdef CONFIG_DEBUG_FS
/* This is the root debugfs directory for the entire NVLINK driver stack */
struct dentry *nvlink_debugfs_root;

/*
 * This is the parent debugfs directory for NVLINK tests. We need to export this
 * symbol so that the NVLINK kernel test modules can create their debugfs nodes
 * under the correct path.
 */
struct dentry *nvlink_debugfs_tests;
EXPORT_SYMBOL(nvlink_debugfs_tests);
#endif /* CONFIG_DEBUG_FS */

static struct nvlink_core nvlink_core;

static bool nvlink_is_single_lane_mode_supported(
				struct nvlink_intranode_conn *conn)
{
	/*
	 * Single-lane mode is supported on the connection
	 * only when both of the nvlink devices support this feature.
	 */
	return (conn->ndev0->link.is_sl_supported &&
			conn->ndev1->link.is_sl_supported);
}

int nvlink_get_init_state(struct nvlink_device *ndev, enum init_state *state)
{
	int ret = 0;

	if (!ndev) {
		nvlink_err("Inva