4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 71ab1c0336c71ace5725740f200beca9667a339f ]
On (H)SCIF, sci_submit_rx() is called in the receive interrupt handler. Hence if DMA submission fails, the interrupt handler should resume handling reception using PIO, else no more data is received.
Make sci_submit_rx() return an error indicator, so the receive interrupt handler can act appropriately.
Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Reviewed-by: Simon Horman horms+renesas@verge.net.au Acked-by: Wolfram Sang wsa+renesas@sang-engineering.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/sh-sci.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 613007d7165e..21fd3f6ad28e 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1331,7 +1331,7 @@ static void sci_tx_dma_release(struct sci_port *s) dma_release_channel(chan); }
-static void sci_submit_rx(struct sci_port *s, bool port_lock_held) +static int sci_submit_rx(struct sci_port *s, bool port_lock_held) { struct dma_chan *chan = s->chan_rx; struct uart_port *port = &s->port; @@ -1359,7 +1359,7 @@ static void sci_submit_rx(struct sci_port *s, bool port_lock_held) s->active_rx = s->cookie_rx[0];
dma_async_issue_pending(chan); - return; + return 0;
fail: /* Switch to PIO */ @@ -1374,6 +1374,7 @@ fail: sci_start_rx(port); if (!port_lock_held) spin_unlock_irqrestore(&port->lock, flags); + return -EAGAIN; }
static void work_fn_tx(struct work_struct *work) @@ -1668,8 +1669,10 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr) disable_irq_nosync(irq); scr |= SCSCR_RDRQE; } else { + if (sci_submit_rx(s, false) < 0) + goto handle_pio; + scr &= ~SCSCR_RIE; - sci_submit_rx(s, false); } serial_port_out(port, SCSCR, scr); /* Clear current interrupt */ @@ -1681,6 +1684,8 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
return IRQ_HANDLED; } + +handle_pio: #endif
if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0) {