rpmsg: glink: smem: Ensure ordering during tx

Ensure the ordering of the fifo write and the update of the write index,
so that the index is not updated before the data has landed in the fifo.

Acked-By: Chris Lew <clew@codeaurora.org>
Reported-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/rpmsg/qcom_glink_smem.c b/drivers/rpmsg/qcom_glink_smem.c
index 057528e23d3ab36c024a9cd286679ca33a81cb4d..892f2b92a4d854d5122887f21591184e18973b0f 100644 (file)
--- a/drivers/rpmsg/qcom_glink_smem.c
+++ b/drivers/rpmsg/qcom_glink_smem.c
@@ -183,6 +183,9 @@ static void glink_smem_tx_write(struct qcom_glink_pipe *glink_pipe,
        if (head >= pipe->native.length)
                head -= pipe->native.length;
 
+       /* Ensure ordering of fifo and head update */
+       wmb();
+
        *pipe->head = cpu_to_le32(head);
 }