rpmsg: qcom_smd: Implement endpoint "poll"

Add support for polling the status of the write buffer so that user
space can use rpmsg character devices in non-blocking mode.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index 3dd73edaa5258747ce973a03a23ec59947013e68..9e2af6a18aa20edfb9e9b52646d9fc456357c1ae 100644 (file)
--- a/drivers/rpmsg/qcom_smd.c
+++ b/drivers/rpmsg/qcom_smd.c
@@ -919,6 +919,21 @@ static int qcom_smd_trysend(struct rpmsg_endpoint *ept, void *data, int len)
        return __qcom_smd_send(qsept->qsch, data, len, false);
 }
 
+static unsigned int qcom_smd_poll(struct rpmsg_endpoint *ept,
+                                 struct file *filp, poll_table *wait)
+{
+       struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+       struct qcom_smd_channel *channel = qsept->qsch;
+       unsigned int mask = 0;
+
+       poll_wait(filp, &channel->fblockread_event, wait);
+
+       if (qcom_smd_get_tx_avail(channel) > 20)
+               mask |= POLLOUT | POLLWRNORM;
+
+       return mask;
+}
+
 /*
  * Finds the device_node for the smd child interested in this channel.
  */
@@ -951,6 +966,7 @@ static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
        .destroy_ept = qcom_smd_destroy_ept,
        .send = qcom_smd_send,
        .trysend = qcom_smd_trysend,
+       .poll = qcom_smd_poll,
 };
 
 /*