From: Pekka Pessi ppessi@nvidia.com
commit 60de2d2dc284e0dd1c2c897d08625bde24ef3454 upstream.
The txdone can re-fill the mailbox. Keep polling the mailbox during the flush until all the messages have been delivered.
This fixes an issue with the Tegra Combined UART (TCU) where output can get truncated under high traffic load.
Signed-off-by: Pekka Pessi ppessi@nvidia.com Tested-by: Jon Hunter jonathanh@nvidia.com Fixes: 91b1b1c3da8a ("mailbox: tegra-hsp: Add support for shared mailboxes") Cc: stable@vger.kernel.org Signed-off-by: Thierry Reding treding@nvidia.com Reviewed-by: Jon Hunter jonathanh@nvidia.com Signed-off-by: Jassi Brar jaswinder.singh@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mailbox/tegra-hsp.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/mailbox/tegra-hsp.c +++ b/drivers/mailbox/tegra-hsp.c @@ -412,6 +412,11 @@ static int tegra_hsp_mailbox_flush(struc value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX); if ((value & HSP_SM_SHRD_MBOX_FULL) == 0) { mbox_chan_txdone(chan, 0); + + /* Wait until channel is empty */ + if (chan->active_req != NULL) + continue; + return 0; }