// SPDX-License-Identifier: GPL-2.0 /* * Functions for registration of I/O interruption subclasses on s390. * * Copyright IBM Corp. 2008 * Authors: Sebastian Ott <sebott@linux.vnet.ibm.com> */ #include <linux/spinlock.h> #include <linux/module.h> #include <asm/isc.h> static unsigned int isc_refs[MAX_ISC + 1]; static DEFINE_SPINLOCK(isc_ref_lock); /** * isc_register - register an I/O interruption subclass. * @isc: I/O interruption subclass to register * * The number of users for @isc is increased. If this is the first user to * register @isc, the corresponding I/O interruption subclass mask is enabled. * * Context: * This function must not be called in interrupt context. */ void isc_register(unsigned int isc) { if (isc > MAX_ISC) { WARN_ON(1); return; } spin_lock(&isc_ref_lock); if (isc_refs[isc] == 0) system_ctl_set_bit(6, 31 - isc); isc_refs[isc]++; spin_unlock(&isc_ref_lock); } EXPORT_SYMBOL_GPL(isc_register); /** * isc_unregister - unregister an I/O interruption subclass. * @isc: I/O interruption subclass to unregister * * The number of users for @isc is decreased. If this is the last user to * unregister @isc, the corresponding I/O interruption subclass mask is * disabled. * Note: This function must not be called if isc_register() hasn't been called * before by the driver for @isc. * * Context: * This function must not be called in interrupt context. */ void isc_unregister(unsigned int isc) { spin_lock(&isc_ref_lock); /* check for misuse */ if (isc > MAX_ISC || isc_refs[isc] == 0) { WARN_ON(1); goto out_unlock; } if (isc_refs[isc] == 1) system_ctl_clear_bit(6, 31 - isc); isc_refs[isc]--; out_unlock: spin_unlock(&isc_ref_lock); } EXPORT_SYMBOL_GPL(isc_unregister);