linux/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2015-2018 Netronome Systems, Inc. */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/wait.h>

#include "nfp_cpp.h"
#include "nfp6000/nfp6000.h"

struct nfp_cpp_mutex { … };

static u32 nfp_mutex_locked(u16 interface)
{ … }

static u32 nfp_mutex_unlocked(u16 interface)
{ … }

static u32 nfp_mutex_owner(u32 val)
{ … }

static bool nfp_mutex_is_locked(u32 val)
{ … }

static bool nfp_mutex_is_unlocked(u32 val)
{ … }

/* If you need more than 65536 recursive locks, please rethink your code. */
#define NFP_MUTEX_DEPTH_MAX …

static int
nfp_cpp_mutex_validate(u16 interface, int *target, unsigned long long address)
{ … }

/**
 * nfp_cpp_mutex_init() - Initialize a mutex location
 * @cpp:	NFP CPP handle
 * @target:	NFP CPP target ID (ie NFP_CPP_TARGET_CLS or NFP_CPP_TARGET_MU)
 * @address:	Offset into the address space of the NFP CPP target ID
 * @key:	Unique 32-bit value for this mutex
 *
 * The CPP target:address must point to a 64-bit aligned location, and
 * will initialize 64 bits of data at the location.
 *
 * This creates the initial mutex state, as locked by this
 * nfp_cpp_interface().
 *
 * This function should only be called when setting up
 * the initial lock state upon boot-up of the system.
 *
 * Return: 0 on success, or -errno on failure
 */
int nfp_cpp_mutex_init(struct nfp_cpp *cpp,
		       int target, unsigned long long address, u32 key)
{ … }

/**
 * nfp_cpp_mutex_alloc() - Create a mutex handle
 * @cpp:	NFP CPP handle
 * @target:	NFP CPP target ID (ie NFP_CPP_TARGET_CLS or NFP_CPP_TARGET_MU)
 * @address:	Offset into the address space of the NFP CPP target ID
 * @key:	32-bit unique key (must match the key at this location)
 *
 * The CPP target:address must point to a 64-bit aligned location, and
 * reserve 64 bits of data at the location for use by the handle.
 *
 * Only target/address pairs that point to entities that support the
 * MU Atomic Engine's CmpAndSwap32 command are supported.
 *
 * Return:	A non-NULL struct nfp_cpp_mutex * on success, NULL on failure.
 */
struct nfp_cpp_mutex *nfp_cpp_mutex_alloc(struct nfp_cpp *cpp, int target,
					  unsigned long long address, u32 key)
{ … }

/**
 * nfp_cpp_mutex_free() - Free a mutex handle - does not alter the lock state
 * @mutex:	NFP CPP Mutex handle
 */
void nfp_cpp_mutex_free(struct nfp_cpp_mutex *mutex)
{ … }

/**
 * nfp_cpp_mutex_lock() - Lock a mutex handle, using the NFP MU Atomic Engine
 * @mutex:	NFP CPP Mutex handle
 *
 * Return: 0 on success, or -errno on failure
 */
int nfp_cpp_mutex_lock(struct nfp_cpp_mutex *mutex)
{ … }

/**
 * nfp_cpp_mutex_unlock() - Unlock a mutex handle, using the MU Atomic Engine
 * @mutex:	NFP CPP Mutex handle
 *
 * Return: 0 on success, or -errno on failure
 */
int nfp_cpp_mutex_unlock(struct nfp_cpp_mutex *mutex)
{ … }

/**
 * nfp_cpp_mutex_trylock() - Attempt to lock a mutex handle
 * @mutex:	NFP CPP Mutex handle
 *
 * Return:      0 if the lock succeeded, -errno on failure
 */
int nfp_cpp_mutex_trylock(struct nfp_cpp_mutex *mutex)
{ … }

/**
 * nfp_cpp_mutex_reclaim() - Unlock mutex if held by local endpoint
 * @cpp:	NFP CPP handle
 * @target:	NFP CPP target ID (ie NFP_CPP_TARGET_CLS or NFP_CPP_TARGET_MU)
 * @address:	Offset into the address space of the NFP CPP target ID
 *
 * Release lock if held by local system.  Extreme care is advised, call only
 * when no local lock users can exist.
 *
 * Return:      0 if the lock was OK, 1 if locked by us, -errno on invalid mutex
 */
int nfp_cpp_mutex_reclaim(struct nfp_cpp *cpp, int target,
			  unsigned long long address)
{ … }