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@xxxxxxxxx>
---
v4:
- Let sci_submit_rx() return -EAGAIN instead of -1 on failure,
- Check for negative error in sci_submit_rx() caller,
v3:
- Move label handle_pio inside #ifdef to kill defined but not used
compiler warning when CONFIG_SERIAL_SH_SCI_DMA=n,
- Move the call sci_submit_rx() in sci_rx_interrupt() up, as it may
fail, rendering the modification of scr unused,
- Split in multiple patches.
---
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 e353e03ce2602559..8df0fd8245203f8b 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 @@ static void sci_submit_rx(struct sci_port *s, bool port_lock_held)
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) {
--
2.17.1
