430 lines
9.1 KiB
C
430 lines
9.1 KiB
C
/*
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* OMAP mailbox driver
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*
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* Copyright (C) 2006-2009 Nokia Corporation. All rights reserved.
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*
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* Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*
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*/
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/kfifo.h>
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#include <linux/err.h>
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#include <linux/notifier.h>
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#include <plat/mailbox.h>
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static struct omap_mbox **mboxes;
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static int mbox_configured;
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static DEFINE_MUTEX(mbox_configured_lock);
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static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
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module_param(mbox_kfifo_size, uint, S_IRUGO);
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MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
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/* Mailbox FIFO handle functions */
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static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
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{
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return mbox->ops->fifo_read(mbox);
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}
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static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
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{
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mbox->ops->fifo_write(mbox, msg);
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}
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static inline int mbox_fifo_empty(struct omap_mbox *mbox)
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{
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return mbox->ops->fifo_empty(mbox);
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}
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static inline int mbox_fifo_full(struct omap_mbox *mbox)
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{
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return mbox->ops->fifo_full(mbox);
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}
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/* Mailbox IRQ handle functions */
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static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
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{
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if (mbox->ops->ack_irq)
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mbox->ops->ack_irq(mbox, irq);
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}
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static inline int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
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{
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return mbox->ops->is_irq(mbox, irq);
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}
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/*
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* message sender
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*/
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static int __mbox_poll_for_space(struct omap_mbox *mbox)
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{
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int ret = 0, i = 1000;
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while (mbox_fifo_full(mbox)) {
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if (mbox->ops->type == OMAP_MBOX_TYPE2)
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return -1;
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if (--i == 0)
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return -1;
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udelay(1);
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}
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return ret;
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}
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int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg)
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{
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struct omap_mbox_queue *mq = mbox->txq;
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int ret = 0, len;
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spin_lock_bh(&mq->lock);
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if (kfifo_avail(&mq->fifo) < sizeof(msg)) {
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ret = -ENOMEM;
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goto out;
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}
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if (kfifo_is_empty(&mq->fifo) && !__mbox_poll_for_space(mbox)) {
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mbox_fifo_write(mbox, msg);
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goto out;
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}
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len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
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WARN_ON(len != sizeof(msg));
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tasklet_schedule(&mbox->txq->tasklet);
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out:
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spin_unlock_bh(&mq->lock);
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return ret;
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}
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EXPORT_SYMBOL(omap_mbox_msg_send);
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static void mbox_tx_tasklet(unsigned long tx_data)
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{
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struct omap_mbox *mbox = (struct omap_mbox *)tx_data;
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struct omap_mbox_queue *mq = mbox->txq;
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mbox_msg_t msg;
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int ret;
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while (kfifo_len(&mq->fifo)) {
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if (__mbox_poll_for_space(mbox)) {
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omap_mbox_enable_irq(mbox, IRQ_TX);
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break;
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}
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ret = kfifo_out(&mq->fifo, (unsigned char *)&msg,
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sizeof(msg));
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WARN_ON(ret != sizeof(msg));
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mbox_fifo_write(mbox, msg);
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}
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}
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/*
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* Message receiver(workqueue)
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*/
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static void mbox_rx_work(struct work_struct *work)
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{
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struct omap_mbox_queue *mq =
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container_of(work, struct omap_mbox_queue, work);
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mbox_msg_t msg;
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int len;
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while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
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len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
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WARN_ON(len != sizeof(msg));
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blocking_notifier_call_chain(&mq->mbox->notifier, len,
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(void *)msg);
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spin_lock_irq(&mq->lock);
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if (mq->full) {
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mq->full = false;
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omap_mbox_enable_irq(mq->mbox, IRQ_RX);
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}
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spin_unlock_irq(&mq->lock);
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}
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}
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/*
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* Mailbox interrupt handler
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*/
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static void __mbox_tx_interrupt(struct omap_mbox *mbox)
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{
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omap_mbox_disable_irq(mbox, IRQ_TX);
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ack_mbox_irq(mbox, IRQ_TX);
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tasklet_schedule(&mbox->txq->tasklet);
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}
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static void __mbox_rx_interrupt(struct omap_mbox *mbox)
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{
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struct omap_mbox_queue *mq = mbox->rxq;
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mbox_msg_t msg;
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int len;
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while (!mbox_fifo_empty(mbox)) {
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if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
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omap_mbox_disable_irq(mbox, IRQ_RX);
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mq->full = true;
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goto nomem;
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}
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msg = mbox_fifo_read(mbox);
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len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
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WARN_ON(len != sizeof(msg));
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if (mbox->ops->type == OMAP_MBOX_TYPE1)
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break;
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}
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/* no more messages in the fifo. clear IRQ source. */
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ack_mbox_irq(mbox, IRQ_RX);
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nomem:
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schedule_work(&mbox->rxq->work);
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}
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static irqreturn_t mbox_interrupt(int irq, void *p)
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{
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struct omap_mbox *mbox = p;
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if (is_mbox_irq(mbox, IRQ_TX))
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__mbox_tx_interrupt(mbox);
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if (is_mbox_irq(mbox, IRQ_RX))
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__mbox_rx_interrupt(mbox);
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return IRQ_HANDLED;
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}
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static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
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void (*work) (struct work_struct *),
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void (*tasklet)(unsigned long))
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{
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struct omap_mbox_queue *mq;
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mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
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if (!mq)
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return NULL;
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spin_lock_init(&mq->lock);
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if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL))
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goto error;
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if (work)
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INIT_WORK(&mq->work, work);
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if (tasklet)
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tasklet_init(&mq->tasklet, tasklet, (unsigned long)mbox);
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return mq;
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error:
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kfree(mq);
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return NULL;
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}
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static void mbox_queue_free(struct omap_mbox_queue *q)
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{
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kfifo_free(&q->fifo);
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kfree(q);
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}
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static int omap_mbox_startup(struct omap_mbox *mbox)
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{
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int ret = 0;
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struct omap_mbox_queue *mq;
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mutex_lock(&mbox_configured_lock);
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if (!mbox_configured++) {
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if (likely(mbox->ops->startup)) {
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ret = mbox->ops->startup(mbox);
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if (unlikely(ret))
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goto fail_startup;
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} else
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goto fail_startup;
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}
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if (!mbox->use_count++) {
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ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
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mbox->name, mbox);
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if (unlikely(ret)) {
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pr_err("failed to register mailbox interrupt:%d\n",
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ret);
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goto fail_request_irq;
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}
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mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
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if (!mq) {
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ret = -ENOMEM;
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goto fail_alloc_txq;
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}
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mbox->txq = mq;
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mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
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if (!mq) {
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ret = -ENOMEM;
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goto fail_alloc_rxq;
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}
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mbox->rxq = mq;
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mq->mbox = mbox;
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}
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mutex_unlock(&mbox_configured_lock);
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return 0;
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fail_alloc_rxq:
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mbox_queue_free(mbox->txq);
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fail_alloc_txq:
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free_irq(mbox->irq, mbox);
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fail_request_irq:
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if (mbox->ops->shutdown)
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mbox->ops->shutdown(mbox);
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mbox->use_count--;
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fail_startup:
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mbox_configured--;
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mutex_unlock(&mbox_configured_lock);
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return ret;
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}
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static void omap_mbox_fini(struct omap_mbox *mbox)
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{
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mutex_lock(&mbox_configured_lock);
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if (!--mbox->use_count) {
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free_irq(mbox->irq, mbox);
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tasklet_kill(&mbox->txq->tasklet);
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flush_work_sync(&mbox->rxq->work);
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mbox_queue_free(mbox->txq);
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mbox_queue_free(mbox->rxq);
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}
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if (likely(mbox->ops->shutdown)) {
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if (!--mbox_configured)
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mbox->ops->shutdown(mbox);
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}
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mutex_unlock(&mbox_configured_lock);
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}
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struct omap_mbox *omap_mbox_get(const char *name, struct notifier_block *nb)
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{
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struct omap_mbox *_mbox, *mbox = NULL;
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int i, ret;
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if (!mboxes)
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return ERR_PTR(-EINVAL);
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for (i = 0; (_mbox = mboxes[i]); i++) {
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if (!strcmp(_mbox->name, name)) {
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mbox = _mbox;
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break;
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}
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}
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if (!mbox)
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return ERR_PTR(-ENOENT);
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ret = omap_mbox_startup(mbox);
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if (ret)
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return ERR_PTR(-ENODEV);
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if (nb)
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blocking_notifier_chain_register(&mbox->notifier, nb);
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return mbox;
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}
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EXPORT_SYMBOL(omap_mbox_get);
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void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb)
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{
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blocking_notifier_chain_unregister(&mbox->notifier, nb);
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omap_mbox_fini(mbox);
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}
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EXPORT_SYMBOL(omap_mbox_put);
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static struct class omap_mbox_class = { .name = "mbox", };
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int omap_mbox_register(struct device *parent, struct omap_mbox **list)
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{
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int ret;
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int i;
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mboxes = list;
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if (!mboxes)
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return -EINVAL;
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for (i = 0; mboxes[i]; i++) {
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struct omap_mbox *mbox = mboxes[i];
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mbox->dev = device_create(&omap_mbox_class,
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parent, 0, mbox, "%s", mbox->name);
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if (IS_ERR(mbox->dev)) {
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ret = PTR_ERR(mbox->dev);
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goto err_out;
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}
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BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
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}
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return 0;
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err_out:
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while (i--)
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device_unregister(mboxes[i]->dev);
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return ret;
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}
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EXPORT_SYMBOL(omap_mbox_register);
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int omap_mbox_unregister(void)
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{
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int i;
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if (!mboxes)
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return -EINVAL;
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for (i = 0; mboxes[i]; i++)
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device_unregister(mboxes[i]->dev);
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mboxes = NULL;
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return 0;
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}
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EXPORT_SYMBOL(omap_mbox_unregister);
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static int __init omap_mbox_init(void)
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{
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int err;
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err = class_register(&omap_mbox_class);
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if (err)
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return err;
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/* kfifo size sanity check: alignment and minimal size */
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mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
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mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
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sizeof(mbox_msg_t));
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return 0;
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}
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subsys_initcall(omap_mbox_init);
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static void __exit omap_mbox_exit(void)
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{
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class_unregister(&omap_mbox_class);
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}
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module_exit(omap_mbox_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
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MODULE_AUTHOR("Toshihiro Kobayashi");
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MODULE_AUTHOR("Hiroshi DOYU");
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