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| author |  Wolfram Sang <wsa+renesas@sang-engineering.com>
| 2024-05-06 13:40:19 +0200 |
|---|---|---|
| committer |  Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| 2024-05-10 11:48:33 +0100 |
| commit | 0c9c1ea583f1b9887d248dc26f6921c4ae826b96 (patch) | |
| tree | 67200e17f0736c7f8138416764aebf408c529637 /drivers/tty | |
| parent | serial: sh-sci: describe locking requirements for invalidating RXDMA (diff) | |
| download | linux-0c9c1ea583f1b9887d248dc26f6921c4ae826b96.tar.gz linux-0c9c1ea583f1b9887d248dc26f6921c4ae826b96.tar.bz2 linux-0c9c1ea583f1b9887d248dc26f6921c4ae826b96.zip | |
serial: sh-sci: let timeout timer only run when DMA is scheduled
The hrtimer for RXDMA timeout was unconditionally restarted in the RXDMA
complete handler ignoring the fact that setting up DMA may fail and PIO
is used instead. Explicitly stop the timer when DMA is completed and
only restart it when setting up DMA was successful. This makes the
intention of the timer much clearer, the driver easier to understand and
simplifies assumptions about the timer. The latter avoids race
conditions if these assumptions were not met or confused.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240506114016.30498-9-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 7a7bc18e4705..d31b3aca5987 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1324,14 +1324,14 @@ static void sci_dma_rx_complete(void *arg) dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line, s->active_rx); + hrtimer_cancel(&s->rx_timer); + uart_port_lock_irqsave(port, &flags); active = sci_dma_rx_find_active(s); if (active >= 0) count = sci_dma_rx_push(s, s->rx_buf[active], s->buf_len_rx); - start_hrtimer_us(&s->rx_timer, s->rx_timeout); - if (count) tty_flip_buffer_push(&port->state->port); @@ -1354,6 +1354,9 @@ static void sci_dma_rx_complete(void *arg) uart_port_unlock_irqrestore(port, flags); dev_dbg(port->dev, "%s: cookie %d #%d, new active cookie %d\n", __func__, s->cookie_rx[active], active, s->active_rx); + + start_hrtimer_us(&s->rx_timer, s->rx_timeout); + return; fail: |