[PATCH 8/9] mailbox: add no_irq send message

[Loic Pallardy]

For debug purpose, mailbox must be available when
interrupts are disabled to collect dump information.

Signed-off-by: Loic Pallardy <loic.pallardy at st.com>
---
 drivers/mailbox/mailbox.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mailbox.h   |  3 +++
 2 files changed, 69 insertions(+)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 57cb566..2f50226 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -110,6 +110,72 @@ out:
 }
 EXPORT_SYMBOL(mailbox_msg_send);
 
+#define TRANSFER_TIMEOUT 30000 /* Becomes ~3s timeout */
+
+static struct mailbox_msg no_irq_msg_res;
+
+struct mailbox_msg *mailbox_msg_send_receive_no_irq(struct mailbox *mbox,
+		struct mailbox_msg *msg)
+{
+	int ret = 0;
+	int count = 0;
+
+	BUG_ON(!irqs_disabled());
+
+	if (likely(mbox->ops->write && mbox->ops->read)) {
+		if (__mbox_poll_for_space(mbox)) {
+			ret = -EBUSY;
+			goto out;
+		}
+		mbox->ops->write(mbox, msg);
+		while (!is_mbox_irq(mbox, IRQ_RX)) {
+			udelay(100);
+			cpu_relax();
+			count++;
+			if (count > TRANSFER_TIMEOUT) {
+				pr_err("%s: Error: transfer timed out\n",
+						__func__);
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+		mbox->ops->read(mbox, &no_irq_msg_res);
+		ack_mbox_irq(mbox, IRQ_RX);
+	} else {
+		ret = -EINVAL;
+	}
+
+out:
+	BUG_ON(ret < 0);
+
+	return &no_irq_msg_res;
+}
+EXPORT_SYMBOL(mailbox_msg_send_receive_no_irq);
+
+int mailbox_msg_send_no_irq(struct mailbox *mbox,
+		struct mailbox_msg *msg)
+{
+	int ret = 0;
+
+	BUG_ON(!irqs_disabled());
+
+	if (likely(mbox->ops->write)) {
+		if (__mbox_poll_for_space(mbox)) {
+			ret = -EBUSY;
+			goto out;
+		}
+		mbox->ops->write(mbox, msg);
+	} else {
+		ret = -EINVAL;
+	}
+
+out:
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(mailbox_msg_send_no_irq);
+
 void mailbox_save_ctx(struct mailbox *mbox)
 {
 	if (!mbox->ops->save_ctx) {
diff --git a/include/linux/mailbox.h b/include/linux/mailbox.h
index d256e1a..3f9ec1e 100644
--- a/include/linux/mailbox.h
+++ b/include/linux/mailbox.h
@@ -23,6 +23,9 @@ struct mailbox_msg {
 	MAILBOX_FILL_MSG(_msg, _header, NULL, 0);
 
 int mailbox_msg_send(struct mailbox *, struct mailbox_msg *msg);
+struct mailbox_msg *mailbox_msg_send_receive_no_irq(struct mailbox *,
+		struct mailbox_msg *msg);
+int mailbox_msg_send_no_irq(struct mailbox *, struct mailbox_msg *msg);
 
 struct mailbox *mailbox_get(const char *, struct notifier_block *nb);
 void mailbox_put(struct mailbox *mbox, struct notifier_block *nb);
-- 
1.7.11.1