| Message ID | 1466780356-12623-3-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
On Fri, Jun 24, 2016 at 04:59:14PM +0200, Geert Uytterhoeven wrote: > Make sure the transmitter and receiver are stopped when shutting down > the port, and related interrupts are disabled. > > Without this: > - New input data may be received into the RX FIFO, possibly > triggering a new RX DMA completion, > - Transfers will still be enabled on a subsequent startup of the UART, > before the UART's FIFOs have been reset, causing reading of stale > data. > > Inspired by a patch in the BSP by Koji Matsuoka > <koji.matsuoka.xm@renesas.com>. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > v2: > - Do not clear clock source bits, since the serial console relies on > them, as reported by Shimoda-san. > > v1 was extracted from "[PATCH/RFC v3 0/4] serial: sh-sci: Add DT DMA > support". The issues with the serial console seen before on > r8a7740/armadillo and sh73a0/kzm9g seem to be gone. Changes after > resurrection: > - Write zero to also disable related interrupts, as suggested by > Laurent Pinchart, > - Enhanced patch description. > --- > drivers/tty/serial/sh-sci.c | 5 +++++ > 1 file changed, 5 insertions(+) This patch does not apply to my tree :(
On Sat, Jun 25, 2016 at 09:09:39AM -0700, Greg Kroah-Hartman wrote: > On Fri, Jun 24, 2016 at 04:59:14PM +0200, Geert Uytterhoeven wrote: > > Make sure the transmitter and receiver are stopped when shutting down > > the port, and related interrupts are disabled. > > > > Without this: > > - New input data may be received into the RX FIFO, possibly > > triggering a new RX DMA completion, > > - Transfers will still be enabled on a subsequent startup of the UART, > > before the UART's FIFOs have been reset, causing reading of stale > > data. > > > > Inspired by a patch in the BSP by Koji Matsuoka > > <koji.matsuoka.xm@renesas.com>. > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > --- > > v2: > > - Do not clear clock source bits, since the serial console relies on > > them, as reported by Shimoda-san. > > > > v1 was extracted from "[PATCH/RFC v3 0/4] serial: sh-sci: Add DT DMA > > support". The issues with the serial console seen before on > > r8a7740/armadillo and sh73a0/kzm9g seem to be gone. Changes after > > resurrection: > > - Write zero to also disable related interrupts, as suggested by > > Laurent Pinchart, > > - Enhanced patch description. > > --- > > drivers/tty/serial/sh-sci.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > This patch does not apply to my tree :( But I don't have access to my 2-factor token for about 24 hours, so my tree will not be public until after then, sorry about that, I'll email you when it gets synced up to kernel.org... greg k-h
On Sat, Jun 25, 2016 at 09:10:51AM -0700, Greg Kroah-Hartman wrote: > On Sat, Jun 25, 2016 at 09:09:39AM -0700, Greg Kroah-Hartman wrote: > > On Fri, Jun 24, 2016 at 04:59:14PM +0200, Geert Uytterhoeven wrote: > > > Make sure the transmitter and receiver are stopped when shutting down > > > the port, and related interrupts are disabled. > > > > > > Without this: > > > - New input data may be received into the RX FIFO, possibly > > > triggering a new RX DMA completion, > > > - Transfers will still be enabled on a subsequent startup of the UART, > > > before the UART's FIFOs have been reset, causing reading of stale > > > data. > > > > > > Inspired by a patch in the BSP by Koji Matsuoka > > > <koji.matsuoka.xm@renesas.com>. > > > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > > --- > > > v2: > > > - Do not clear clock source bits, since the serial console relies on > > > them, as reported by Shimoda-san. > > > > > > v1 was extracted from "[PATCH/RFC v3 0/4] serial: sh-sci: Add DT DMA > > > support". The issues with the serial console seen before on > > > r8a7740/armadillo and sh73a0/kzm9g seem to be gone. Changes after > > > resurrection: > > > - Write zero to also disable related interrupts, as suggested by > > > Laurent Pinchart, > > > - Enhanced patch description. > > > --- > > > drivers/tty/serial/sh-sci.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > This patch does not apply to my tree :( > > But I don't have access to my 2-factor token for about 24 hours, so my > tree will not be public until after then, sorry about that, I'll email > you when it gets synced up to kernel.org... It's synced now, sorry for the noise. greg k-h
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index d6ba90c572f7475c..eecace576c3b758f 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1890,12 +1890,17 @@ static void sci_shutdown(struct uart_port *port) { struct sci_port *s = to_sci_port(port); unsigned long flags; + u16 scr; dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); spin_lock_irqsave(&port->lock, flags); sci_stop_rx(port); sci_stop_tx(port); + /* Stop RX and TX, disable related interrupts, keep clock source */ + scr = serial_port_in(port, SCSCR); + serial_port_out(port, SCSCR, scr & (SCSCR_CKE1 | SCSCR_CKE0)); + spin_unlock_irqrestore(&port->lock, flags); #ifdef CONFIG_SERIAL_SH_SCI_DMA
Make sure the transmitter and receiver are stopped when shutting down the port, and related interrupts are disabled. Without this: - New input data may be received into the RX FIFO, possibly triggering a new RX DMA completion, - Transfers will still be enabled on a subsequent startup of the UART, before the UART's FIFOs have been reset, causing reading of stale data. Inspired by a patch in the BSP by Koji Matsuoka <koji.matsuoka.xm@renesas.com>. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- v2: - Do not clear clock source bits, since the serial console relies on them, as reported by Shimoda-san. v1 was extracted from "[PATCH/RFC v3 0/4] serial: sh-sci: Add DT DMA support". The issues with the serial console seen before on r8a7740/armadillo and sh73a0/kzm9g seem to be gone. Changes after resurrection: - Write zero to also disable related interrupts, as suggested by Laurent Pinchart, - Enhanced patch description. --- drivers/tty/serial/sh-sci.c | 5 +++++ 1 file changed, 5 insertions(+)