source: mainline/kernel/generic/src/ipc/irq.c@ c0f13d2

/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * Copyright (c) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup genericipc
 * @{
 */

/**
 * @file
 * @brief IRQ notification framework.
 *
 * This framework allows applications to register to receive a notification
 * when interrupt is detected. The application may provide a simple 'top-half'
 * handler as part of its registration, which can perform simple operations
 * (read/write port/memory, add information to notification ipc message).
 *
 * The structure of a notification message is as follows:
 * - METHOD: method as registered by the SYS_IPC_REGISTER_IRQ syscall
 * - ARG1: payload modified by a 'top-half' handler
 * - ARG2: payload modified by a 'top-half' handler
 * - ARG3: payload modified by a 'top-half' handler
 * - ARG4: payload modified by a 'top-half' handler
 * - ARG5: payload modified by a 'top-half' handler
 * - in_phone_hash: interrupt counter (may be needed to assure correct order
 *         in multithreaded drivers)
 *
 * Note on synchronization for ipc_irq_register(), ipc_irq_unregister(),
 * ipc_irq_cleanup() and IRQ handlers:
 *
 *   By always taking all of the uspace IRQ hash table lock, IRQ structure lock
 *   and answerbox lock, we can rule out race conditions between the
 *   registration functions and also the cleanup function. Thus the observer can
 *   either see the IRQ structure present in both the hash table and the
 *   answerbox list or absent in both. Views in which the IRQ structure would be
 *   linked in the hash table but not in the answerbox list, or vice versa, are
 *   not possible.
 *
 *   By always taking the hash table lock and the IRQ structure lock, we can
 *   rule out a scenario in which we would free up an IRQ structure, which is
 *   still referenced by, for example, an IRQ handler. The locking scheme forces
 *   us to lock the IRQ structure only after any progressing IRQs on that
 *   structure are finished. Because we hold the hash table lock, we prevent new
 *   IRQs from taking new references to the IRQ structure.
 *
 */

#include <arch.h>
#include <mm/slab.h>
#include <errno.h>
#include <ddi/irq.h>
#include <ipc/ipc.h>
#include <ipc/irq.h>
#include <syscall/copy.h>
#include <console/console.h>
#include <print.h>

/** Free the top-half pseudocode.
 *
 * @param code Pointer to the top-half pseudocode.
 *
 */
static void code_free(irq_code_t *code)
{
        if (code) {
                free(code->cmds);
                free(code);
        }
}

/** Copy the top-half pseudocode from userspace into the kernel.
 *
 * @param ucode Userspace address of the top-half pseudocode.
 *
 * @return Kernel address of the copied pseudocode.
 *
 */
static irq_code_t *code_from_uspace(irq_code_t *ucode)
{
        irq_code_t *code = malloc(sizeof(*code), 0);
        int rc = copy_from_uspace(code, ucode, sizeof(*code));
        if (rc != 0) {
                free(code);
                return NULL;
        }
        
        if (code->cmdcount > IRQ_MAX_PROG_SIZE) {
                free(code);
                return NULL;
        }
        
        irq_cmd_t *ucmds = code->cmds;
        code->cmds = malloc(sizeof(code->cmds[0]) * code->cmdcount, 0);
        rc = copy_from_uspace(code->cmds, ucmds,
            sizeof(code->cmds[0]) * code->cmdcount);
        if (rc != 0) {
                free(code->cmds);
                free(code);
                return NULL;
        }
        
        return code;
}

/** Register an answerbox as a receiving end for IRQ notifications.
 *
 * @param box    Receiving answerbox.
 * @param inr    IRQ number.
 * @param devno  Device number.
 * @param method Method to be associated with the notification.
 * @param ucode  Uspace pointer to top-half pseudocode.
 *
 * @return EBADMEM, ENOENT or EEXISTS on failure or 0 on success.
 *
 */
int ipc_irq_register(answerbox_t *box, inr_t inr, devno_t devno,
    unative_t method, irq_code_t *ucode)
{
        unative_t key[] = {
                (unative_t) inr,
                (unative_t) devno
        };
        
        irq_code_t *code;
        if (ucode) {
                code = code_from_uspace(ucode);
                if (!code)
                        return EBADMEM;
        } else
                code = NULL;
        
        /*
         * Allocate and populate the IRQ structure.
         */
        irq_t *irq = malloc(sizeof(irq_t), 0);
        
        irq_initialize(irq);
        irq->devno = devno;
        irq->inr = inr;
        irq->claim = ipc_irq_top_half_claim;
        irq->handler = ipc_irq_top_half_handler;
        irq->notif_cfg.notify = true;
        irq->notif_cfg.answerbox = box;
        irq->notif_cfg.method = method;
        irq->notif_cfg.code = code;
        irq->notif_cfg.counter = 0;
        
        /*
         * Enlist the IRQ structure in the uspace IRQ hash table and the
         * answerbox's list.
         */
        irq_spinlock_lock(&irq_uspace_hash_table_lock, true);
        
        link_t *hlp = hash_table_find(&irq_uspace_hash_table, key);
        if (hlp) {
                irq_t *hirq = hash_table_get_instance(hlp, irq_t, link);
                
                /* hirq is locked */
                irq_spinlock_unlock(&hirq->lock, false);
                code_free(code);
                irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
                
                free(irq);
                return EEXISTS;
        }
        
        /* Locking is not really necessary, but paranoid */
        irq_spinlock_lock(&irq->lock, false);
        irq_spinlock_lock(&box->irq_lock, false);
        
        hash_table_insert(&irq_uspace_hash_table, key, &irq->link);
        list_append(&irq->notif_cfg.link, &box->irq_head);
        
        irq_spinlock_unlock(&box->irq_lock, false);
        irq_spinlock_unlock(&irq->lock, false);
        irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
        
        return EOK;
}

/** Unregister task from IRQ notification.
 *
 * @param box   Answerbox associated with the notification.
 * @param inr   IRQ number.
 * @param devno Device number.
 *
 */
int ipc_irq_unregister(answerbox_t *box, inr_t inr, devno_t devno)
{
        unative_t key[] = {
                (unative_t) inr,
                (unative_t) devno
        };
        
        irq_spinlock_lock(&irq_uspace_hash_table_lock, true);
        link_t *lnk = hash_table_find(&irq_uspace_hash_table, key);
        if (!lnk) {
                irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
                return ENOENT;
        }
        
        irq_t *irq = hash_table_get_instance(lnk, irq_t, link);
        
        /* irq is locked */
        irq_spinlock_lock(&box->irq_lock, false);
        
        ASSERT(irq->notif_cfg.answerbox == box);
        
        /* Free up the pseudo code and associated structures. */
        code_free(irq->notif_cfg.code);
        
        /* Remove the IRQ from the answerbox's list. */
        list_remove(&irq->notif_cfg.link);
        
        /*
         * We need to drop the IRQ lock now because hash_table_remove() will try
         * to reacquire it. That basically violates the natural locking order,
         * but a deadlock in hash_table_remove() is prevented by the fact that
         * we already held the IRQ lock and didn't drop the hash table lock in
         * the meantime.
         */
        irq_spinlock_unlock(&irq->lock, false);
        
        /* Remove the IRQ from the uspace IRQ hash table. */
        hash_table_remove(&irq_uspace_hash_table, key, 2);
        
        irq_spinlock_unlock(&box->irq_lock, false);
        irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
        
        /* Free up the IRQ structure. */
        free(irq);
        
        return EOK;
}

/** Disconnect all IRQ notifications from an answerbox.
 *
 * This function is effective because the answerbox contains
 * list of all irq_t structures that are registered to
 * send notifications to it.
 *
 * @param box Answerbox for which we want to carry out the cleanup.
 *
 */
void ipc_irq_cleanup(answerbox_t *box)
{
loop:
        irq_spinlock_lock(&irq_uspace_hash_table_lock, true);
        irq_spinlock_lock(&box->irq_lock, false);
        
        while (box->irq_head.next != &box->irq_head) {
                DEADLOCK_PROBE_INIT(p_irqlock);
                
                irq_t *irq = list_get_instance(box->irq_head.next, irq_t,
                    notif_cfg.link);
                
                if (!irq_spinlock_trylock(&irq->lock)) {
                        /*
                         * Avoid deadlock by trying again.
                         */
                        irq_spinlock_unlock(&box->irq_lock, false);
                        irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
                        DEADLOCK_PROBE(p_irqlock, DEADLOCK_THRESHOLD);
                        goto loop;
                }
                
                unative_t key[2];
                key[0] = irq->inr;
                key[1] = irq->devno;
                
                ASSERT(irq->notif_cfg.answerbox == box);
                
                /* Unlist from the answerbox. */
                list_remove(&irq->notif_cfg.link);
                
                /* Free up the pseudo code and associated structures. */
                code_free(irq->notif_cfg.code);
                
                /*
                 * We need to drop the IRQ lock now because hash_table_remove()
                 * will try to reacquire it. That basically violates the natural
                 * locking order, but a deadlock in hash_table_remove() is
                 * prevented by the fact that we already held the IRQ lock and
                 * didn't drop the hash table lock in the meantime.
                 */
                irq_spinlock_unlock(&irq->lock, false);
                
                /* Remove from the hash table. */
                hash_table_remove(&irq_uspace_hash_table, key, 2);
                
                free(irq);
        }
        
        irq_spinlock_unlock(&box->irq_lock, false);
        irq_spinlock_unlock(&irq_uspace_hash_table_lock, true);
}

/** Add a call to the proper answerbox queue.
 *
 * Assume irq->lock is locked and interrupts disabled.
 *
 * @param irq  IRQ structure referencing the target answerbox.
 * @param call IRQ notification call.
 *
 */
static void send_call(irq_t *irq, call_t *call)
{
        irq_spinlock_lock(&irq->notif_cfg.answerbox->irq_lock, false);
        list_append(&call->link, &irq->notif_cfg.answerbox->irq_notifs);
        irq_spinlock_unlock(&irq->notif_cfg.answerbox->irq_lock, false);
        
        waitq_wakeup(&irq->notif_cfg.answerbox->wq, WAKEUP_FIRST);
}

/** Apply the top-half pseudo code to find out whether to accept the IRQ or not.
 *
 * @param irq IRQ structure.
 *
 * @return IRQ_ACCEPT if the interrupt is accepted by the
 *         pseudocode, IRQ_DECLINE otherwise.
 *
 */
irq_ownership_t ipc_irq_top_half_claim(irq_t *irq)
{
        irq_code_t *code = irq->notif_cfg.code;
        uint32_t *scratch = irq->notif_cfg.scratch;
        
        if (!irq->notif_cfg.notify)
                return IRQ_DECLINE;
        
        if (!code)
                return IRQ_DECLINE;
        
        size_t i;
        for (i = 0; i < code->cmdcount; i++) {
                uint32_t dstval;
                uintptr_t srcarg = code->cmds[i].srcarg;
                uintptr_t dstarg = code->cmds[i].dstarg;
                
                if (srcarg >= IPC_CALL_LEN)
                        break;
                
                if (dstarg >= IPC_CALL_LEN)
                        break;
        
                switch (code->cmds[i].cmd) {
                case CMD_PIO_READ_8:
                        dstval = pio_read_8((ioport8_t *) code->cmds[i].addr);
                        if (dstarg)
                                scratch[dstarg] = dstval;
                        break;
                case CMD_PIO_READ_16:
                        dstval = pio_read_16((ioport16_t *) code->cmds[i].addr);
                        if (dstarg)
                                scratch[dstarg] = dstval;
                        break;
                case CMD_PIO_READ_32:
                        dstval = pio_read_32((ioport32_t *) code->cmds[i].addr);
                        if (dstarg)
                                scratch[dstarg] = dstval;
                        break;
                case CMD_PIO_WRITE_8:
                        pio_write_8((ioport8_t *) code->cmds[i].addr,
                            (uint8_t) code->cmds[i].value);
                        break;
                case CMD_PIO_WRITE_16:
                        pio_write_16((ioport16_t *) code->cmds[i].addr,
                            (uint16_t) code->cmds[i].value);
                        break;
                case CMD_PIO_WRITE_32:
                        pio_write_32((ioport32_t *) code->cmds[i].addr,
                            (uint32_t) code->cmds[i].value);
                        break;
                case CMD_BTEST:
                        if ((srcarg) && (dstarg)) {
                                dstval = scratch[srcarg] & code->cmds[i].value;
                                scratch[dstarg] = dstval;
                        }
                        break;
                case CMD_PREDICATE:
                        if ((srcarg) && (!scratch[srcarg])) {
                                i += code->cmds[i].value;
                                continue;
                        }
                        break;
                case CMD_ACCEPT:
                        return IRQ_ACCEPT;
                case CMD_DECLINE:
                default:
                        return IRQ_DECLINE;
                }
        }
        
        return IRQ_DECLINE;
}

/* IRQ top-half handler.
 *
 * We expect interrupts to be disabled and the irq->lock already held.
 *
 * @param irq IRQ structure.
 *
 */
void ipc_irq_top_half_handler(irq_t *irq)
{
        ASSERT(irq);

        ASSERT(interrupts_disabled());
        ASSERT(irq_spinlock_locked(&irq->lock));
        
        if (irq->notif_cfg.answerbox) {
                call_t *call = ipc_call_alloc(FRAME_ATOMIC);
                if (!call)
                        return;
                
                call->flags |= IPC_CALL_NOTIF;
                /* Put a counter to the message */
                call->priv = ++irq->notif_cfg.counter;
                
                /* Set up args */
                IPC_SET_METHOD(call->data, irq->notif_cfg.method);
                IPC_SET_ARG1(call->data, irq->notif_cfg.scratch[1]);
                IPC_SET_ARG2(call->data, irq->notif_cfg.scratch[2]);
                IPC_SET_ARG3(call->data, irq->notif_cfg.scratch[3]);
                IPC_SET_ARG4(call->data, irq->notif_cfg.scratch[4]);
                IPC_SET_ARG5(call->data, irq->notif_cfg.scratch[5]);
                
                send_call(irq, call);
        }
}

/** Send notification message.
 *
 * @param irq IRQ structure.
 * @param a1  Driver-specific payload argument.
 * @param a2  Driver-specific payload argument.
 * @param a3  Driver-specific payload argument.
 * @param a4  Driver-specific payload argument.
 * @param a5  Driver-specific payload argument.
 *
 */
void ipc_irq_send_msg(irq_t *irq, unative_t a1, unative_t a2, unative_t a3,
    unative_t a4, unative_t a5)
{
        irq_spinlock_lock(&irq->lock, true);
        
        if (irq->notif_cfg.answerbox) {
                call_t *call = ipc_call_alloc(FRAME_ATOMIC);
                if (!call) {
                        irq_spinlock_unlock(&irq->lock, true);
                        return;
                }
                
                call->flags |= IPC_CALL_NOTIF;
                /* Put a counter to the message */
                call->priv = ++irq->notif_cfg.counter;
                
                IPC_SET_METHOD(call->data, irq->notif_cfg.method);
                IPC_SET_ARG1(call->data, a1);
                IPC_SET_ARG2(call->data, a2);
                IPC_SET_ARG3(call->data, a3);
                IPC_SET_ARG4(call->data, a4);
                IPC_SET_ARG5(call->data, a5);
                
                send_call(irq, call);
        }
        
        irq_spinlock_unlock(&irq->lock, true);
}

/** @}
 */