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