[PATCH 5.19 162/207] serial: tegra: Use uart_xmit_advance(), fixes icount.tx accounting

Greg Kroah-Hartman
2022-09-26T11:56:41Z

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

commit 754f68044c7dd6c52534ba3e0f664830285c4b15 upstream.

DMA complete & stop paths did not correctly account Tx'ed characters
into icount.tx. Using uart_xmit_advance() fixes the problem.

Fixes: e9ea096dd225 ("serial: tegra: add serial driver")
Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance()
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/serial-tegra.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -525,7 +525,7 @@ static void tegra_uart_tx_dma_complete(v
count = tup->tx_bytes_requested - state.residue;
async_tx_ack(tup->tx_dma_desc);
spin_lock_irqsave(&tup->uport.lock, flags);
- xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+ uart_xmit_advance(&tup->uport, count);
tup->tx_in_progress = 0;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&tup->uport);
@@ -613,7 +613,6 @@ static unsigned int tegra_uart_tx_empty(
static void tegra_uart_stop_tx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
- struct circ_buf *xmit = &tup->uport.state->xmit;
struct dma_tx_state state;
unsigned int count;

@@ -624,7 +623,7 @@ static void tegra_uart_stop_tx(struct ua
dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
count = tup->tx_bytes_requested - state.residue;
async_tx_ack(tup->tx_dma_desc);
- xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+ uart_xmit_advance(&tup->uport, count);
tup->tx_in_progress = 0;
}