diff options
Diffstat (limited to 'drivers/mailbox/omap-mailbox.c')
| -rw-r--r-- | drivers/mailbox/omap-mailbox.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c new file mode 100644 index 000000000000..d79a646b9042 --- /dev/null +++ b/drivers/mailbox/omap-mailbox.c @@ -0,0 +1,469 @@ +/* + * OMAP mailbox driver + * + * Copyright (C) 2006-2009 Nokia Corporation. All rights reserved. + * + * Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA + * 02110-1301 USA + * + */ + +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/kfifo.h> +#include <linux/err.h> +#include <linux/notifier.h> +#include <linux/module.h> + +#include "omap-mbox.h" + +static struct omap_mbox **mboxes; + +static int mbox_configured; +static DEFINE_MUTEX(mbox_configured_lock); + +static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE; +module_param(mbox_kfifo_size, uint, S_IRUGO); +MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)"); + +/* Mailbox FIFO handle functions */ +static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox) +{ + return mbox->ops->fifo_read(mbox); +} +static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg) +{ + mbox->ops->fifo_write(mbox, msg); +} +static inline int mbox_fifo_empty(struct omap_mbox *mbox) +{ + return mbox->ops->fifo_empty(mbox); +} +static inline int mbox_fifo_full(struct omap_mbox *mbox) +{ + return mbox->ops->fifo_full(mbox); +} + +/* Mailbox IRQ handle functions */ +static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq) +{ + if (mbox->ops->ack_irq) + mbox->ops->ack_irq(mbox, irq); +} +static inline int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq) +{ + return mbox->ops->is_irq(mbox, irq); +} + +/* + * message sender + */ +static int __mbox_poll_for_space(struct omap_mbox *mbox) +{ + int ret = 0, i = 1000; + + while (mbox_fifo_full(mbox)) { + if (mbox->ops->type == OMAP_MBOX_TYPE2) + return -1; + if (--i == 0) + return -1; + udelay(1); + } + return ret; +} + +int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg) +{ + struct omap_mbox_queue *mq = mbox->txq; + int ret = 0, len; + + spin_lock_bh(&mq->lock); + + if (kfifo_avail(&mq->fifo) < sizeof(msg)) { + ret = -ENOMEM; + goto out; + } + + if (kfifo_is_empty(&mq->fifo) && !__mbox_poll_for_space(mbox)) { + mbox_fifo_write(mbox, msg); + goto out; + } + + len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg)); + WARN_ON(len != sizeof(msg)); + + tasklet_schedule(&mbox->txq->tasklet); + +out: + spin_unlock_bh(&mq->lock); + return ret; +} +EXPORT_SYMBOL(omap_mbox_msg_send); + +void omap_mbox_save_ctx(struct omap_mbox *mbox) +{ + if (!mbox->ops->save_ctx) { + dev_err(mbox->dev, "%s:\tno save\n", __func__); + return; + } + + mbox->ops->save_ctx(mbox); +} +EXPORT_SYMBOL(omap_mbox_save_ctx); + +void omap_mbox_restore_ctx(struct omap_mbox *mbox) +{ + if (!mbox->ops->restore_ctx) { + dev_err(mbox->dev, "%s:\tno restore\n", __func__); + return; + } + + mbox->ops->restore_ctx(mbox); +} +EXPORT_SYMBOL(omap_mbox_restore_ctx); + +void omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq) +{ + mbox->ops->enable_irq(mbox, irq); +} +EXPORT_SYMBOL(omap_mbox_enable_irq); + +void omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq) +{ + mbox->ops->disable_irq(mbox, irq); +} +EXPORT_SYMBOL(omap_mbox_disable_irq); + +static void mbox_tx_tasklet(unsigned long tx_data) +{ + struct omap_mbox *mbox = (struct omap_mbox *)tx_data; + struct omap_mbox_queue *mq = mbox->txq; + mbox_msg_t msg; + int ret; + + while (kfifo_len(&mq->fifo)) { + if (__mbox_poll_for_space(mbox)) { + omap_mbox_enable_irq(mbox, IRQ_TX); + break; + } + + ret = kfifo_out(&mq->fifo, (unsigned char *)&msg, + sizeof(msg)); + WARN_ON(ret != sizeof(msg)); + + mbox_fifo_write(mbox, msg); + } +} + +/* + * Message receiver(workqueue) + */ +static void mbox_rx_work(struct work_struct *work) +{ + struct omap_mbox_queue *mq = + container_of(work, struct omap_mbox_queue, work); + mbox_msg_t msg; + int len; + + while (kfifo_len(&mq->fifo) >= sizeof(msg)) { + len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg)); + WARN_ON(len != sizeof(msg)); + + blocking_notifier_call_chain(&mq->mbox->notifier, len, + (void *)msg); + spin_lock_irq(&mq->lock); + if (mq->full) { + mq->full = false; + omap_mbox_enable_irq(mq->mbox, IRQ_RX); + } + spin_unlock_irq(&mq->lock); + } +} + +/* + * Mailbox interrupt handler + */ +static void __mbox_tx_interrupt(struct omap_mbox *mbox) +{ + omap_mbox_disable_irq(mbox, IRQ_TX); + ack_mbox_irq(mbox, IRQ_TX); + tasklet_schedule(&mbox->txq->tasklet); +} + +static void __mbox_rx_interrupt(struct omap_mbox *mbox) +{ + struct omap_mbox_queue *mq = mbox->rxq; + mbox_msg_t msg; + int len; + + while (!mbox_fifo_empty(mbox)) { + if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) { + omap_mbox_disable_irq(mbox, IRQ_RX); + mq->full = true; + goto nomem; + } + + msg = mbox_fifo_read(mbox); + + len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg)); + WARN_ON(len != sizeof(msg)); + + if (mbox->ops->type == OMAP_MBOX_TYPE1) + break; + } + + /* no more messages in the fifo. clear IRQ source. */ + ack_mbox_irq(mbox, IRQ_RX); +nomem: + schedule_work(&mbox->rxq->work); +} + +static irqreturn_t mbox_interrupt(int irq, void *p) +{ + struct omap_mbox *mbox = p; + + if (is_mbox_irq(mbox, IRQ_TX)) + __mbox_tx_interrupt(mbox); + + if (is_mbox_irq(mbox, IRQ_RX)) + __mbox_rx_interrupt(mbox); + + return IRQ_HANDLED; +} + +static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox, + void (*work) (struct work_struct *), + void (*tasklet)(unsigned long)) +{ + struct omap_mbox_queue *mq; + + mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL); + if (!mq) + return NULL; + + spin_lock_init(&mq->lock); + + if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL)) + goto error; + + if (work) + INIT_WORK(&mq->work, work); + + if (tasklet) + tasklet_init(&mq->tasklet, tasklet, (unsigned long)mbox); + return mq; +error: + kfree(mq); + return NULL; +} + +static void mbox_queue_free(struct omap_mbox_queue *q) +{ + kfifo_free(&q->fifo); + kfree(q); +} + +static int omap_mbox_startup(struct omap_mbox *mbox) +{ + int ret = 0; + struct omap_mbox_queue *mq; + + mutex_lock(&mbox_configured_lock); + if (!mbox_configured++) { + if (likely(mbox->ops->startup)) { + ret = mbox->ops->startup(mbox); + if (unlikely(ret)) + goto fail_startup; + } else + goto fail_startup; + } + + if (!mbox->use_count++) { + mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet); + if (!mq) { + ret = -ENOMEM; + goto fail_alloc_txq; + } + mbox->txq = mq; + + mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL); + if (!mq) { + ret = -ENOMEM; + goto fail_alloc_rxq; + } + mbox->rxq = mq; + mq->mbox = mbox; + ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED, + mbox->name, mbox); + if (unlikely(ret)) { + pr_err("failed to register mailbox interrupt:%d\n", + ret); + goto fail_request_irq; + } + + omap_mbox_enable_irq(mbox, IRQ_RX); + } + mutex_unlock(&mbox_configured_lock); + return 0; + +fail_request_irq: + mbox_queue_free(mbox->rxq); +fail_alloc_rxq: + mbox_queue_free(mbox->txq); +fail_alloc_txq: + if (mbox->ops->shutdown) + mbox->ops->shutdown(mbox); + mbox->use_count--; +fail_startup: + mbox_configured--; + mutex_unlock(&mbox_configured_lock); + return ret; +} + +static void omap_mbox_fini(struct omap_mbox *mbox) +{ + mutex_lock(&mbox_configured_lock); + + if (!--mbox->use_count) { + omap_mbox_disable_irq(mbox, IRQ_RX); + free_irq(mbox->irq, mbox); + tasklet_kill(&mbox->txq->tasklet); + flush_work(&mbox->rxq->work); + mbox_queue_free(mbox->txq); + mbox_queue_free(mbox->rxq); + } + + if (likely(mbox->ops->shutdown)) { + if (!--mbox_configured) + mbox->ops->shutdown(mbox); + } + + mutex_unlock(&mbox_configured_lock); +} + +struct omap_mbox *omap_mbox_get(const char *name, struct notifier_block *nb) +{ + struct omap_mbox *_mbox, *mbox = NULL; + int i, ret; + + if (!mboxes) + return ERR_PTR(-EINVAL); + + for (i = 0; (_mbox = mboxes[i]); i++) { + if (!strcmp(_mbox->name, name)) { + mbox = _mbox; + break; + } + } + + if (!mbox) + return ERR_PTR(-ENOENT); + + if (nb) + blocking_notifier_chain_register(&mbox->notifier, nb); + + ret = omap_mbox_startup(mbox); + if (ret) { + blocking_notifier_chain_unregister(&mbox->notifier, nb); + return ERR_PTR(-ENODEV); + } + + return mbox; +} +EXPORT_SYMBOL(omap_mbox_get); + +void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&mbox->notifier, nb); + omap_mbox_fini(mbox); +} +EXPORT_SYMBOL(omap_mbox_put); + +static struct class omap_mbox_class = { .name = "mbox", }; + +int omap_mbox_register(struct device *parent, struct omap_mbox **list) +{ + int ret; + int i; + + mboxes = list; + if (!mboxes) + return -EINVAL; + + for (i = 0; mboxes[i]; i++) { + struct omap_mbox *mbox = mboxes[i]; + mbox->dev = device_create(&omap_mbox_class, + parent, 0, mbox, "%s", mbox->name); + if (IS_ERR(mbox->dev)) { + ret = PTR_ERR(mbox->dev); + goto err_out; + } + + BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier); + } + return 0; + +err_out: + while (i--) + device_unregister(mboxes[i]->dev); + return ret; +} +EXPORT_SYMBOL(omap_mbox_register); + +int omap_mbox_unregister(void) +{ + int i; + + if (!mboxes) + return -EINVAL; + + for (i = 0; mboxes[i]; i++) + device_unregister(mboxes[i]->dev); + mboxes = NULL; + return 0; +} +EXPORT_SYMBOL(omap_mbox_unregister); + +static int __init omap_mbox_init(void) +{ + int err; + + err = class_register(&omap_mbox_class); + if (err) + return err; + + /* kfifo size sanity check: alignment and minimal size */ + mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t)); + mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, + sizeof(mbox_msg_t)); + + return 0; +} +subsys_initcall(omap_mbox_init); + +static void __exit omap_mbox_exit(void) +{ + class_unregister(&omap_mbox_class); +} +module_exit(omap_mbox_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging"); +MODULE_AUTHOR("Toshihiro Kobayashi"); +MODULE_AUTHOR("Hiroshi DOYU"); |