@@ -29,6 +29,7 @@ struct imx_sc_chan {
struct mbox_client cl;
struct mbox_chan *ch;
int idx;
+ struct completion tx_done;
};
struct imx_sc_ipc {
@@ -100,6 +101,14 @@ int imx_scu_get_handle(struct imx_sc_ipc
}
EXPORT_SYMBOL(imx_scu_get_handle);
+/* Callback called when the word of a message is ack-ed, eg read by SCU */
+static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
+{
+ struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
+
+ complete(&sc_chan->tx_done);
+}
+
static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
{
struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
@@ -143,6 +152,19 @@ static int imx_scu_ipc_write(struct imx_
for (i = 0; i < hdr->size; i++) {
sc_chan = &sc_ipc->chans[i % 4];
+
+ /*
+ * SCU requires that all messages words are written
+ * sequentially but linux MU driver implements multiple
+ * independent channels for each register so ordering between
+ * different channels must be ensured by SCU API interface.
+ *
+ * Wait for tx_done before every send to ensure that no
+ * queueing happens at the mailbox channel level.
+ */
+ wait_for_completion(&sc_chan->tx_done);
+ reinit_completion(&sc_chan->tx_done);
+
ret = mbox_send_message(sc_chan->ch, &data[i]);
if (ret < 0)
return ret;
@@ -225,6 +247,11 @@ static int imx_scu_probe(struct platform
cl->knows_txdone = true;
cl->rx_callback = imx_scu_rx_callback;
+ /* Initial tx_done completion as "done" */
+ cl->tx_done = imx_scu_tx_done;
+ init_completion(&sc_chan->tx_done);
+ complete(&sc_chan->tx_done);
+
sc_chan->sc_ipc = sc_ipc;
sc_chan->idx = i % 4;
sc_chan->ch = mbox_request_channel_byname(cl, chan_name);