> On January 7, 2019 at 5:23 PM Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > > > 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 > Reviewed-by: Ulrich Hecht <uli+renesas@xxxxxxxx> CU Uli
