From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/w1/w1_family.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 drivers/w1/w1_family.c (limited to 'drivers/w1/w1_family.c') diff --git a/drivers/w1/w1_family.c b/drivers/w1/w1_family.c new file mode 100644 index 000000000..97da4f156 --- /dev/null +++ b/drivers/w1/w1_family.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2004 Evgeniy Polyakov + */ + +#include +#include +#include +#include +#include + +#include "w1_internal.h" + +DEFINE_SPINLOCK(w1_flock); +static LIST_HEAD(w1_families); + +/** + * w1_register_family() - register a device family driver + * @newf: family to register + */ +int w1_register_family(struct w1_family *newf) +{ + struct list_head *ent, *n; + struct w1_family *f; + int ret = 0; + + spin_lock(&w1_flock); + list_for_each_safe(ent, n, &w1_families) { + f = list_entry(ent, struct w1_family, family_entry); + + if (f->fid == newf->fid) { + ret = -EEXIST; + break; + } + } + + if (!ret) { + atomic_set(&newf->refcnt, 0); + list_add_tail(&newf->family_entry, &w1_families); + } + spin_unlock(&w1_flock); + + /* check default devices against the new set of drivers */ + w1_reconnect_slaves(newf, 1); + + return ret; +} +EXPORT_SYMBOL(w1_register_family); + +/** + * w1_unregister_family() - unregister a device family driver + * @fent: family to unregister + */ +void w1_unregister_family(struct w1_family *fent) +{ + struct list_head *ent, *n; + struct w1_family *f; + + spin_lock(&w1_flock); + list_for_each_safe(ent, n, &w1_families) { + f = list_entry(ent, struct w1_family, family_entry); + + if (f->fid == fent->fid) { + list_del(&fent->family_entry); + break; + } + } + spin_unlock(&w1_flock); + + /* deatch devices using this family code */ + w1_reconnect_slaves(fent, 0); + + while (atomic_read(&fent->refcnt)) { + pr_info("Waiting for family %u to become free: refcnt=%d.\n", + fent->fid, atomic_read(&fent->refcnt)); + + if (msleep_interruptible(1000)) + flush_signals(current); + } +} +EXPORT_SYMBOL(w1_unregister_family); + +/* + * Should be called under w1_flock held. + */ +struct w1_family * w1_family_registered(u8 fid) +{ + struct list_head *ent, *n; + struct w1_family *f = NULL; + int ret = 0; + + list_for_each_safe(ent, n, &w1_families) { + f = list_entry(ent, struct w1_family, family_entry); + + if (f->fid == fid) { + ret = 1; + break; + } + } + + return (ret) ? f : NULL; +} + +static void __w1_family_put(struct w1_family *f) +{ + atomic_dec(&f->refcnt); +} + +void w1_family_put(struct w1_family *f) +{ + spin_lock(&w1_flock); + __w1_family_put(f); + spin_unlock(&w1_flock); +} + +#if 0 +void w1_family_get(struct w1_family *f) +{ + spin_lock(&w1_flock); + __w1_family_get(f); + spin_unlock(&w1_flock); +} +#endif /* 0 */ + +void __w1_family_get(struct w1_family *f) +{ + smp_mb__before_atomic(); + atomic_inc(&f->refcnt); + smp_mb__after_atomic(); +} -- cgit v1.2.3