When submitting a DMA request fails in sci_dma_rx_complete(), the driver
tries to fall back to PIO, but that does not work: no more data will be
received, or the kernel will even crash.
Fix this similar as in (but not identical to) sci_submit_rx():
- On SCIF, PIO cannot take over if any DMA transactions are pending,
hence they must be terminated first.
- All active cookies must be invalidated, else rx_timer_fn() may
trigger a NULL pointer dereference.
- Restarting the port is not needed, as it is already running, but
serial port interrupts must be directed back from the DMA engine to
the CPU.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v5:
- Call new helpers sci_dma_rx_chan_invalidate() and
sci_dma_rx_reenable_irq() instead of open-coding,
v4:
- No changes,
v3:
- Add missing definition of "u16 scr",
- Move call to dmaengine_terminate_async() inside the spinlock, for
symmetry with sci_submit_rx(),
- Split in multiple patches.
---
drivers/tty/serial/sh-sci.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 4d814c30c4189b56..891833315698b953 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1337,8 +1337,9 @@ static void sci_dma_rx_complete(void *arg)
dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n");
/* Switch to PIO */
spin_lock_irqsave(&port->lock, flags);
- s->chan_rx = NULL;
- sci_start_rx(port);
+ dmaengine_terminate_async(chan);
+ sci_dma_rx_chan_invalidate(s);
+ sci_dma_rx_reenable_irq(s);
spin_unlock_irqrestore(&port->lock, flags);
}
--
2.17.1
