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path: root/drivers/mailbox/mailbox.c
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-rw-r--r--drivers/mailbox/mailbox.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 08ce9a1ab53a..6abb35ff49fa 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -284,6 +284,34 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
EXPORT_SYMBOL_GPL(mbox_send_message);
/**
+ * mbox_flush - flush a mailbox channel
+ * @chan: mailbox channel to flush
+ * @timeout: time, in milliseconds, to allow the flush operation to succeed
+ *
+ * Mailbox controllers that need to work in atomic context can implement the
+ * ->flush() callback to busy loop until a transmission has been completed.
+ * The implementation must call mbox_chan_txdone() upon success. Clients can
+ * call the mbox_flush() function at any time after mbox_send_message() to
+ * flush the transmission. After the function returns success, the mailbox
+ * transmission is guaranteed to have completed.
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int mbox_flush(struct mbox_chan *chan, unsigned long timeout)
+{
+ int ret;
+
+ if (!chan->mbox->ops->flush)
+ return -ENOTSUPP;
+
+ ret = chan->mbox->ops->flush(chan, timeout);
+ if (ret < 0)
+ tx_tick(chan, ret);
+
+ return ret;
+}
+
+/**
* mbox_request_channel - Request a mailbox channel.
* @cl: Identity of the client requesting the channel.
* @index: Index of mailbox specifier in 'mboxes' property.