source: mainline/kernel/generic/src/ipc/irq.c@ b76a2217

/*
 * 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
 * - in_phone_hash: interrupt counter (may be needed to assure correct order
 *         in multithreaded drivers)
 */

#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>

/** Execute code associated with IRQ notification.
 *
 * @param call          Notification call.
 * @param code          Top-half pseudocode.
 */
static void code_execute(call_t *call, irq_code_t *code)
{
        int i;
        unative_t dstval = 0;
        
        if (!code)
                return;
        
        for (i = 0; i < code->cmdcount; i++) {
                switch (code->cmds[i].cmd) {
                case CMD_MEM_READ_1:
                        dstval = *((uint8_t *) code->cmds[i].addr);
                        break;
                case CMD_MEM_READ_2:
                        dstval = *((uint16_t *) code->cmds[i].addr);
                        break;
                case CMD_MEM_READ_4:
                        dstval = *((uint32_t *) code->cmds[i].addr);
                        break;
                case CMD_MEM_READ_8:
                        dstval = *((uint64_t *) code->cmds[i].addr);
                        break;
                case CMD_MEM_WRITE_1:
                        *((uint8_t *) code->cmds[i].addr) = code->cmds[i].value;
                        break;
                case CMD_MEM_WRITE_2:
                        *((uint16_t *) code->cmds[i].addr) = code->cmds[i].value;
                        break;
                case CMD_MEM_WRITE_4:
                        *((uint32_t *) code->cmds[i].addr) = code->cmds[i].value;
                        break;
                case CMD_MEM_WRITE_8:
                        *((uint64_t *) code->cmds[i].addr) = code->cmds[i].value;
                        break;
#if defined(ia32) || defined(amd64)
                case CMD_PORT_READ_1:
                        dstval = inb((long) code->cmds[i].addr);
                        break;
                case CMD_PORT_WRITE_1:
                        outb((long) code->cmds[i].addr, code->cmds[i].value);
                        break;
#endif
#if defined(ia64) && defined(SKI)
                case CMD_IA64_GETCHAR:
                        dstval = _getc(&ski_uconsole);
                        break;
#endif
#if defined(ppc32)
                case CMD_PPC32_GETCHAR:
                        dstval = cuda_get_scancode();
                        break;
#endif
                default:
                        break;
                }
                if (code->cmds[i].dstarg && code->cmds[i].dstarg < 4) {
                        call->data.args[code->cmds[i].dstarg] = dstval;
                }
        }
}

/** Free 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 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;
        irq_cmd_t *ucmds;
        int rc;

        code = malloc(sizeof(*code), 0);
        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;
        }
        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;
}

/** Unregister task from IRQ notification.
 *
 * @param box           Answerbox associated with the notification.
 * @param inr           IRQ number.
 * @param devno         Device number.
 */
void ipc_irq_unregister(answerbox_t *box, inr_t inr, devno_t devno)
{
        ipl_t ipl;
        irq_t *irq;

        ipl = interrupts_disable();
        irq = irq_find_and_lock(inr, devno);
        if (irq) {
                if (irq->notif_cfg.answerbox == box) {
                        code_free(irq->notif_cfg.code);
                        irq->notif_cfg.notify = false;
                        irq->notif_cfg.answerbox = NULL;
                        irq->notif_cfg.code = NULL;
                        irq->notif_cfg.method = 0;
                        irq->notif_cfg.counter = 0;

                        spinlock_lock(&box->irq_lock);
                        list_remove(&irq->notif_cfg.link);
                        spinlock_unlock(&box->irq_lock);
                        
                        spinlock_unlock(&irq->lock);
                }
        }
        interrupts_restore(ipl);
}

/** 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)
{
        ipl_t ipl;
        irq_code_t *code;
        irq_t *irq;

        if (ucode) {
                code = code_from_uspace(ucode);
                if (!code)
                        return EBADMEM;
        } else {
                code = NULL;
        }

        ipl = interrupts_disable();
        irq = irq_find_and_lock(inr, devno);
        if (!irq) {
                interrupts_restore(ipl);
                code_free(code);
                return ENOENT;
        }
        
        if (irq->notif_cfg.answerbox) {
                spinlock_unlock(&irq->lock);
                interrupts_restore(ipl);
                code_free(code);
                return EEXISTS;
        }
        
        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;

        spinlock_lock(&box->irq_lock);
        list_append(&irq->notif_cfg.link, &box->irq_head);
        spinlock_unlock(&box->irq_lock);

        spinlock_unlock(&irq->lock);
        interrupts_restore(ipl);

        return 0;
}

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

/** 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.
 */
void ipc_irq_send_msg(irq_t *irq, unative_t a1, unative_t a2, unative_t a3)
{
        call_t *call;

        spinlock_lock(&irq->lock);

        if (irq->notif_cfg.answerbox) {
                call = ipc_call_alloc(FRAME_ATOMIC);
                if (!call) {
                        spinlock_unlock(&irq->lock);
                        return;
                }
                call->flags |= IPC_CALL_NOTIF;
                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);
                /* Put a counter to the message */
                call->priv = ++irq->notif_cfg.counter;
                
                send_call(irq, call);
        }
        spinlock_unlock(&irq->lock);
}

/** Notify a task that an IRQ had occurred.
 *
 * We expect interrupts to be disabled and the irq->lock already held.
 *
 * @param irq           IRQ structure.
 */
void ipc_irq_send_notif(irq_t *irq)
{
        call_t *call;

        ASSERT(irq);

        if (irq->notif_cfg.answerbox) {
                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);

                /* Execute code to handle irq */
                code_execute(call, irq->notif_cfg.code);
                
                send_call(irq, call);
        }
}

/** 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)
{
        ipl_t ipl;
        
loop:
        ipl = interrupts_disable();
        spinlock_lock(&box->irq_lock);
        
        while (box->irq_head.next != &box->irq_head) {
                link_t *cur = box->irq_head.next;
                irq_t *irq;
                DEADLOCK_PROBE_INIT(p_irqlock);
                
                irq = list_get_instance(cur, irq_t, notif_cfg.link);
                if (!spinlock_trylock(&irq->lock)) {
                        /*
                         * Avoid deadlock by trying again.
                         */
                        spinlock_unlock(&box->irq_lock);
                        interrupts_restore(ipl);
                        DEADLOCK_PROBE(p_irqlock, DEADLOCK_THRESHOLD);
                        goto loop;
                }
                
                ASSERT(irq->notif_cfg.answerbox == box);
                
                list_remove(&irq->notif_cfg.link);
                
                /*
                 * Don't forget to free any top-half pseudocode.
                 */
                code_free(irq->notif_cfg.code);
                
                irq->notif_cfg.notify = false;
                irq->notif_cfg.answerbox = NULL;
                irq->notif_cfg.code = NULL;
                irq->notif_cfg.method = 0;
                irq->notif_cfg.counter = 0;

                spinlock_unlock(&irq->lock);
        }
        
        spinlock_unlock(&box->irq_lock);
        interrupts_restore(ipl);
}

/** @}
 */