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authorGeert Uytterhoeven <geert+renesas@glider.be>2019-01-07 19:23:19 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-08 18:56:52 +0300
commit26f073993665683f1debf4d66d8bc274ac6df771 (patch)
tree8cbd15adf833abe95d482de95a0ace3bf28265b7 /drivers/tty/serial/sh-sci.c
parent38766e4b612ba10844afadf2fce12f8f90465c64 (diff)
downloadlinux-26f073993665683f1debf4d66d8bc274ac6df771.tar.xz
serial: sh-sci: Fix fallback to PIO in sci_dma_rx_complete()
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@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
-rw-r--r--drivers/tty/serial/sh-sci.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 4d814c30c418..891833315698 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1337,8 +1337,9 @@ fail:
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);
}