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* Copyright (c) 2006 Ondrej Palkovsky
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* Copyright (c) 2006 Jakub Jermar
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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/** @addtogroup genericipc
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* @brief IRQ notification framework.
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* This framework allows applications to register to receive a notification
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* when interrupt is detected. The application may provide a simple 'top-half'
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* handler as part of its registration, which can perform simple operations
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* (read/write port/memory, add information to notification ipc message).
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* The structure of a notification message is as follows:
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* - METHOD: method as registered by the SYS_IPC_REGISTER_IRQ syscall
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* - ARG1: payload modified by a 'top-half' handler
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* - ARG2: payload modified by a 'top-half' handler
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* - ARG3: payload modified by a 'top-half' handler
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* - ARG4: payload modified by a 'top-half' handler
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* - ARG5: payload modified by a 'top-half' handler
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* - in_phone_hash: interrupt counter (may be needed to assure correct order
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* in multithreaded drivers)
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* Note on synchronization for ipc_irq_register(), ipc_irq_unregister(),
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* ipc_irq_cleanup() and IRQ handlers:
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* By always taking all of the uspace IRQ hash table lock, IRQ structure lock
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* and answerbox lock, we can rule out race conditions between the
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* registration functions and also the cleanup function. Thus the observer can
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* either see the IRQ structure present in both the hash table and the
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* answerbox list or absent in both. Views in which the IRQ structure would be
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* linked in the hash table but not in the answerbox list, or vice versa, are
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* By always taking the hash table lock and the IRQ structure lock, we can
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* rule out a scenario in which we would free up an IRQ structure, which is
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* still referenced by, for example, an IRQ handler. The locking scheme forces
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* us to lock the IRQ structure only after any progressing IRQs on that
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* structure are finished. Because we hold the hash table lock, we prevent new
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* IRQs from taking new references to the IRQ structure.
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#include <syscall/copy.h>
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#include <console/console.h>
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/** Free the top-half pseudocode.
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* @param code Pointer to the top-half pseudocode.
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static void code_free(irq_code_t *code)
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/** Copy the top-half pseudocode from userspace into the kernel.
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* @param ucode Userspace address of the top-half pseudocode.
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* @return Kernel address of the copied pseudocode.
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static irq_code_t *code_from_uspace(irq_code_t *ucode)
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code = malloc(sizeof(*code), 0);
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rc = copy_from_uspace(code, ucode, sizeof(*code));
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if (code->cmdcount > IRQ_MAX_PROG_SIZE) {
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code->cmds = malloc(sizeof(code->cmds[0]) * code->cmdcount, 0);
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rc = copy_from_uspace(code->cmds, ucmds,
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sizeof(code->cmds[0]) * code->cmdcount);
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/** Register an answerbox as a receiving end for IRQ notifications.
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* @param box Receiving answerbox.
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* @param inr IRQ number.
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* @param devno Device number.
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* @param method Method to be associated with the notification.
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* @param ucode Uspace pointer to top-half pseudocode.
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* @return EBADMEM, ENOENT or EEXISTS on failure or 0 on success.
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int ipc_irq_register(answerbox_t *box, inr_t inr, devno_t devno,
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unative_t method, irq_code_t *ucode)
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code = code_from_uspace(ucode);
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* Allocate and populate the IRQ structure.
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irq = malloc(sizeof(irq_t), 0);
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irq->claim = ipc_irq_top_half_claim;
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irq->handler = ipc_irq_top_half_handler;
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irq->notif_cfg.notify = true;
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irq->notif_cfg.answerbox = box;
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irq->notif_cfg.method = method;
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irq->notif_cfg.code = code;
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irq->notif_cfg.counter = 0;
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* Enlist the IRQ structure in the uspace IRQ hash table and the
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ipl = interrupts_disable();
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spinlock_lock(&irq_uspace_hash_table_lock);
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hlp = hash_table_find(&irq_uspace_hash_table, key);
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irq_t *hirq __attribute__((unused))
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= hash_table_get_instance(hlp, irq_t, link);
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spinlock_unlock(&hirq->lock);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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interrupts_restore(ipl);
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spinlock_lock(&irq->lock); /* Not really necessary, but paranoid */
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spinlock_lock(&box->irq_lock);
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hash_table_insert(&irq_uspace_hash_table, key, &irq->link);
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list_append(&irq->notif_cfg.link, &box->irq_head);
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spinlock_unlock(&box->irq_lock);
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spinlock_unlock(&irq->lock);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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interrupts_restore(ipl);
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/** Unregister task from IRQ notification.
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* @param box Answerbox associated with the notification.
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* @param inr IRQ number.
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* @param devno Device number.
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int ipc_irq_unregister(answerbox_t *box, inr_t inr, devno_t devno)
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ipl = interrupts_disable();
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spinlock_lock(&irq_uspace_hash_table_lock);
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lnk = hash_table_find(&irq_uspace_hash_table, key);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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interrupts_restore(ipl);
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irq = hash_table_get_instance(lnk, irq_t, link);
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spinlock_lock(&box->irq_lock);
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ASSERT(irq->notif_cfg.answerbox == box);
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/* Free up the pseudo code and associated structures. */
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code_free(irq->notif_cfg.code);
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/* Remove the IRQ from the answerbox's list. */
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list_remove(&irq->notif_cfg.link);
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* We need to drop the IRQ lock now because hash_table_remove() will try
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* to reacquire it. That basically violates the natural locking order,
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* but a deadlock in hash_table_remove() is prevented by the fact that
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* we already held the IRQ lock and didn't drop the hash table lock in
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spinlock_unlock(&irq->lock);
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/* Remove the IRQ from the uspace IRQ hash table. */
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hash_table_remove(&irq_uspace_hash_table, key, 2);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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spinlock_unlock(&box->irq_lock);
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/* Free up the IRQ structure. */
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interrupts_restore(ipl);
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/** Disconnect all IRQ notifications from an answerbox.
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* This function is effective because the answerbox contains
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* list of all irq_t structures that are registered to
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* send notifications to it.
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* @param box Answerbox for which we want to carry out the cleanup.
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void ipc_irq_cleanup(answerbox_t *box)
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ipl = interrupts_disable();
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spinlock_lock(&irq_uspace_hash_table_lock);
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spinlock_lock(&box->irq_lock);
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while (box->irq_head.next != &box->irq_head) {
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link_t *cur = box->irq_head.next;
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DEADLOCK_PROBE_INIT(p_irqlock);
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irq = list_get_instance(cur, irq_t, notif_cfg.link);
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if (!spinlock_trylock(&irq->lock)) {
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* Avoid deadlock by trying again.
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spinlock_unlock(&box->irq_lock);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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interrupts_restore(ipl);
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DEADLOCK_PROBE(p_irqlock, DEADLOCK_THRESHOLD);
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ASSERT(irq->notif_cfg.answerbox == box);
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/* Unlist from the answerbox. */
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list_remove(&irq->notif_cfg.link);
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/* Free up the pseudo code and associated structures. */
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code_free(irq->notif_cfg.code);
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* We need to drop the IRQ lock now because hash_table_remove()
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* will try to reacquire it. That basically violates the natural
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* locking order, but a deadlock in hash_table_remove() is
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* prevented by the fact that we already held the IRQ lock and
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* didn't drop the hash table lock in the meantime.
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spinlock_unlock(&irq->lock);
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/* Remove from the hash table. */
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hash_table_remove(&irq_uspace_hash_table, key, 2);
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spinlock_unlock(&box->irq_lock);
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spinlock_unlock(&irq_uspace_hash_table_lock);
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interrupts_restore(ipl);
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/** Add a call to the proper answerbox queue.
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* Assume irq->lock is locked.
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* @param irq IRQ structure referencing the target answerbox.
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* @param call IRQ notification call.
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static void send_call(irq_t *irq, call_t *call)
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spinlock_lock(&irq->notif_cfg.answerbox->irq_lock);
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list_append(&call->link, &irq->notif_cfg.answerbox->irq_notifs);
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spinlock_unlock(&irq->notif_cfg.answerbox->irq_lock);
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waitq_wakeup(&irq->notif_cfg.answerbox->wq, WAKEUP_FIRST);
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/** Apply the top-half pseudo code to find out whether to accept the IRQ or not.
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* @param irq IRQ structure.
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* @return IRQ_ACCEPT if the interrupt is accepted by the
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* pseudocode. IRQ_DECLINE otherwise.
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irq_ownership_t ipc_irq_top_half_claim(irq_t *irq)
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irq_code_t *code = irq->notif_cfg.code;
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unative_t *scratch = irq->notif_cfg.scratch;
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if (!irq->notif_cfg.notify)
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for (i = 0; i < code->cmdcount; i++) {
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unsigned int srcarg = code->cmds[i].srcarg;
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unsigned int dstarg = code->cmds[i].dstarg;
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if (srcarg >= IPC_CALL_LEN)
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if (dstarg >= IPC_CALL_LEN)
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switch (code->cmds[i].cmd) {
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dstval = pio_read_8((ioport8_t *) code->cmds[i].addr);
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scratch[dstarg] = dstval;
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case CMD_PIO_READ_16:
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dstval = pio_read_16((ioport16_t *) code->cmds[i].addr);
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scratch[dstarg] = dstval;
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case CMD_PIO_READ_32:
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dstval = pio_read_32((ioport32_t *) code->cmds[i].addr);
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scratch[dstarg] = dstval;
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case CMD_PIO_WRITE_8:
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pio_write_8((ioport8_t *) code->cmds[i].addr,
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(uint8_t) code->cmds[i].value);
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case CMD_PIO_WRITE_16:
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pio_write_16((ioport16_t *) code->cmds[i].addr,
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(uint16_t) code->cmds[i].value);
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case CMD_PIO_WRITE_32:
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pio_write_32((ioport32_t *) code->cmds[i].addr,
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(uint32_t) code->cmds[i].value);
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if (srcarg && dstarg) {
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dstval = scratch[srcarg] & code->cmds[i].value;
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scratch[dstarg] = dstval;
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if (srcarg && !scratch[srcarg]) {
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i += code->cmds[i].value;
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/* IRQ top-half handler.
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* We expect interrupts to be disabled and the irq->lock already held.
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* @param irq IRQ structure.
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void ipc_irq_top_half_handler(irq_t *irq)
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if (irq->notif_cfg.answerbox) {
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call = ipc_call_alloc(FRAME_ATOMIC);
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call->flags |= IPC_CALL_NOTIF;
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/* Put a counter to the message */
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call->priv = ++irq->notif_cfg.counter;
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IPC_SET_METHOD(call->data, irq->notif_cfg.method);
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IPC_SET_ARG1(call->data, irq->notif_cfg.scratch[1]);
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IPC_SET_ARG2(call->data, irq->notif_cfg.scratch[2]);
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IPC_SET_ARG3(call->data, irq->notif_cfg.scratch[3]);
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IPC_SET_ARG4(call->data, irq->notif_cfg.scratch[4]);
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IPC_SET_ARG5(call->data, irq->notif_cfg.scratch[5]);
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send_call(irq, call);
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/** Send notification message.
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* @param irq IRQ structure.
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* @param a1 Driver-specific payload argument.
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* @param a2 Driver-specific payload argument.
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* @param a3 Driver-specific payload argument.
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* @param a4 Driver-specific payload argument.
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* @param a5 Driver-specific payload argument.
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void ipc_irq_send_msg(irq_t *irq, unative_t a1, unative_t a2, unative_t a3,
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unative_t a4, unative_t a5)
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spinlock_lock(&irq->lock);
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if (irq->notif_cfg.answerbox) {
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call = ipc_call_alloc(FRAME_ATOMIC);
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spinlock_unlock(&irq->lock);
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call->flags |= IPC_CALL_NOTIF;
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/* Put a counter to the message */
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call->priv = ++irq->notif_cfg.counter;
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IPC_SET_METHOD(call->data, irq->notif_cfg.method);
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IPC_SET_ARG1(call->data, a1);
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IPC_SET_ARG2(call->data, a2);
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IPC_SET_ARG3(call->data, a3);
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IPC_SET_ARG4(call->data, a4);
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IPC_SET_ARG5(call->data, a5);
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send_call(irq, call);
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spinlock_unlock(&irq->lock);