[U-Boot] [PATCH] Revert "serial: ns16550: fix debug uart putc called before init"

[U-Boot] [PATCH] Revert "serial: ns16550: fix debug uart putc called before init"

[Simon Goldschmidt]

This reverts commit 6f57c34473d37b8da5e6a3764d0d377d748aeef1 since it
does not seem to work at least on rk3399.

The Rockchip Technical Reference Manual (TRM) for the rk3399 says the baud
rate prescaler register is readable only when USR[0] is zero. Since this
bit is defined as "reserved" in the socfpga cylcone5 TRM, let's rather
drop this than making the ns16550 debug uart more platform specific.

Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
---

 drivers/serial/ns16550.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index f21c240e64..25b9d17243 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -272,26 +272,12 @@ static inline void _debug_uart_init(void)
 	serial_dout(&com_port->lcr, UART_LCRVAL);
 }
 
-static inline int NS16550_read_baud_divisor(struct NS16550 *com_port)
-{
-	int ret;
-
-	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
-	ret = serial_din(&com_port->dll) & 0xff;
-	ret |= (serial_din(&com_port->dlm) & 0xff) << 8;
-	serial_dout(&com_port->lcr, UART_LCRVAL);
-
-	return ret;
-}
-
 static inline void _debug_uart_putc(int ch)
 {
 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
 
-	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
-		if (!NS16550_read_baud_divisor(com_port))
-			return;
-	}
+	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
+		;
 	serial_dout(&com_port->thr, ch);
 }
 
-- 
2.17.1

[U-Boot] [PATCH] Revert "serial: ns16550: fix debug uart putc called before init"

[Philipp Tomsich]

> On 03.12.2018, at 21:55, Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> wrote:
> 
> This reverts commit 6f57c34473d37b8da5e6a3764d0d377d748aeef1 since it
> does not seem to work at least on rk3399.
> 
> The Rockchip Technical Reference Manual (TRM) for the rk3399 says the baud
> rate prescaler register is readable only when USR[0] is zero. Since this
> bit is defined as "reserved" in the socfpga cylcone5 TRM, let's rather
> drop this than making the ns16550 debug uart more platform specific.
> 
> Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

[U-Boot] [PATCH] Revert "serial: ns16550: fix debug uart putc called before init"

[Tom Rini]

On Mon, Dec 03, 2018 at 09:57:06PM +0100, Philipp Tomsich wrote:
> 
> 
> > On 03.12.2018, at 21:55, Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> wrote:
> > 
> > This reverts commit 6f57c34473d37b8da5e6a3764d0d377d748aeef1 since it
> > does not seem to work at least on rk3399.
> > 
> > The Rockchip Technical Reference Manual (TRM) for the rk3399 says the baud
> > rate prescaler register is readable only when USR[0] is zero. Since this
> > bit is defined as "reserved" in the socfpga cylcone5 TRM, let's rather
> > drop this than making the ns16550 debug uart more platform specific.
> > 
> > Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
> > Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
> 
> Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Thanks, I will apply this before release.

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20181203/fc0f88fa/attachment.sig>

[U-Boot] [PATCH] Revert "serial: ns16550: fix debug uart putc called before init"

[Kever Yang]

Hi Simon,


On 12/04/2018 04:55 AM, Simon Goldschmidt wrote:
> This reverts commit 6f57c34473d37b8da5e6a3764d0d377d748aeef1 since it
> does not seem to work at least on rk3399.
>
> The Rockchip Technical Reference Manual (TRM) for the rk3399 says the baud
> rate prescaler register is readable only when USR[0] is zero. Since this
> bit is defined as "reserved" in the socfpga cylcone5 TRM, let's rather
> drop this than making the ns16550 debug uart more platform specific.
>
> Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Reviewed-by:  Kever Yang <kever.yang@rock-chips.com>

Thanks,
- Kever
> ---
>
>  drivers/serial/ns16550.c | 18 ++----------------
>  1 file changed, 2 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index f21c240e64..25b9d17243 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -272,26 +272,12 @@ static inline void _debug_uart_init(void)
>  	serial_dout(&com_port->lcr, UART_LCRVAL);
>  }
>  
> -static inline int NS16550_read_baud_divisor(struct NS16550 *com_port)
> -{
> -	int ret;
> -
> -	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
> -	ret = serial_din(&com_port->dll) & 0xff;
> -	ret |= (serial_din(&com_port->dlm) & 0xff) << 8;
> -	serial_dout(&com_port->lcr, UART_LCRVAL);
> -
> -	return ret;
> -}
> -
>  static inline void _debug_uart_putc(int ch)
>  {
>  	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
>  
> -	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
> -		if (!NS16550_read_baud_divisor(com_port))
> -			return;
> -	}
> +	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
> +		;
>  	serial_dout(&com_port->thr, ch);
>  }
>  

[U-Boot] Revert "serial: ns16550: fix debug uart putc called before init"

[Tom Rini]

On Mon, Dec 03, 2018 at 09:55:33PM +0100, Simon Goldschmidt wrote:

> This reverts commit 6f57c34473d37b8da5e6a3764d0d377d748aeef1 since it
> does not seem to work at least on rk3399.
> 
> The Rockchip Technical Reference Manual (TRM) for the rk3399 says the baud
> rate prescaler register is readable only when USR[0] is zero. Since this
> bit is defined as "reserved" in the socfpga cylcone5 TRM, let's rather
> drop this than making the ns16550 debug uart more platform specific.
> 
> Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
> Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Applied to u-boot/master, thanks!

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20181203/0ed8582d/attachment.sig>