mailbox/omap: move the OMAP mailbox framework to drivers

The mailbox hardware (in OMAP) uses a queued mailbox interrupt
mechanism that provides a communication channel between processors
through a set of registers and their associated interrupt signals
by sending and receiving messages.

The OMAP mailbox framework/driver code is moved to be under
drivers/mailbox, in preparation for adapting to a common mailbox
driver framework. This allows the build for OMAP mailbox to be
enabled (it was disabled during the multi-platform support).

As part of the migration from plat and mach code:
- Kconfig symbols have been renamed to build OMAP1 or OMAP2+ drivers.
- mailbox.h under plat-omap/plat/include has been split into a public
  and private header files. The public header has only the API related
  functions and types.
- The module name mailbox.ko from plat-omap is changed to
  omap-mailbox.ko
- The module name mailbox_mach.ko from mach-omapX is changed as
    mailbox_omap1.ko for OMAP1
    mailbox_omap2.ko for OMAP2+

Cc: Tony Lindgren <tony@atomide.com>
[gregkh@linuxfoundation.org: ack for staging part]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Omar Ramirez Luna <omar.ramirez@copitl.com>
Signed-off-by: Suman Anna <s-anna@ti.com>

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");