[U-Boot] [PATCH] serial, ns16550: bugfix: ns16550 fifo not enabled

[Ladislav Michl]

Hi Heiko,

On Tue, Jan 10, 2017 at 08:08:51AM +0100, Heiko Schocher wrote:
> commit: 65f83802b7a5b "serial: 16550: Add getfcr accessor"
> breaks u-boot commandline working with long commands
> sending to the board.
> 
> Since the above patch, you have to setup the fcr register.
> 
> For board/archs which enable OF_PLATDATA, the new field
> fcr in struct ns16550_platdata is not filled with a
> default value ...
> 
> This leads in not setting up the uarts fifo, which ends
> in problems, when you send long commands to u-boots
> commandline.
> 
> Detected this issue with automated tbot tests on am335x
> based shc board.
> 
> The error does not popup, if you type commands. You need
> to copy&paste a long command to u-boots commandshell
> (or send a long command with tbot)
> 
> Possible boards/plattforms with problems:
> ./arch/arm/cpu/arm926ejs/lpc32xx/devices.c
> ./arch/arm/mach-tegra/board.c
> ./board/isee/igep00x0/igep00x0.c
> ./board/overo/overo.c
> ./board/quipos/cairo/cairo.c
> ./board/logicpd/omap3som/omap3logic.c
> ./board/logicpd/zoom1/zoom1.c
> ./board/timll/devkit8000/devkit8000.c
> ./board/lg/sniper/sniper.c
> ./board/ti/beagle/beagle.c
> ./drivers/serial/serial_rockchip.c

Quick test shows igep00x0 also suffers from this issue.
Are you going to collect fixes and apply them as one patch or
shall I sent a separate patch?

Anyway, here's fix for igep00x0:

Signed-off-by: Ladislav Michl <ladis at linux-mips.org>

diff --git a/board/isee/igep00x0/igep00x0.c b/board/isee/igep00x0/igep00x0.c
index ae7959b1eb..8bea199a44 100644
--- a/board/isee/igep00x0/igep00x0.c
+++ b/board/isee/igep00x0/igep00x0.c
@@ -32,7 +32,8 @@ DECLARE_GLOBAL_DATA_PTR;
 static const struct ns16550_platdata igep_serial = {
 	.base = OMAP34XX_UART3,
 	.reg_shift = 2,
-	.clock = V_NS16550_CLK
+	.clock = V_NS16550_CLK,
+	.fcr = UART_FCR_FIFO_EN | UART_FCR_RXSR | UART_FCR_TXSR,
 };
 
 U_BOOT_DEVICE(igep_uart) = {

> This patch fixes only:
> ./arch/arm/mach-omap2/am33xx/board.c
> 
> Signed-off-by: Heiko Schocher <hs at denx.de>
> ---
> 
>  arch/arm/mach-omap2/am33xx/board.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/am33xx/board.c b/arch/arm/mach-omap2/am33xx/board.c
> index 581c0ab..a0ce62c 100644
> --- a/arch/arm/mach-omap2/am33xx/board.c
> +++ b/arch/arm/mach-omap2/am33xx/board.c
> @@ -39,15 +39,26 @@
>  DECLARE_GLOBAL_DATA_PTR;
>  
>  #if !CONFIG_IS_ENABLED(OF_CONTROL)
> +/* Clear & enable FIFOs */
> +#define UART_FCRVAL (UART_FCR_FIFO_EN |	\
> +		     UART_FCR_RXSR |	\
> +		     UART_FCR_TXSR)
> +
>  static const struct ns16550_platdata am33xx_serial[] = {
> -	{ .base = CONFIG_SYS_NS16550_COM1, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> +	{ .base = CONFIG_SYS_NS16550_COM1, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
>  # ifdef CONFIG_SYS_NS16550_COM2
> -	{ .base = CONFIG_SYS_NS16550_COM2, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> +	{ .base = CONFIG_SYS_NS16550_COM2, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
>  #  ifdef CONFIG_SYS_NS16550_COM3
> -	{ .base = CONFIG_SYS_NS16550_COM3, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> -	{ .base = CONFIG_SYS_NS16550_COM4, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> -	{ .base = CONFIG_SYS_NS16550_COM5, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> -	{ .base = CONFIG_SYS_NS16550_COM6, .reg_shift = 2, .clock = CONFIG_SYS_NS16550_CLK },
> +	{ .base = CONFIG_SYS_NS16550_COM3, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
> +	{ .base = CONFIG_SYS_NS16550_COM4, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
> +	{ .base = CONFIG_SYS_NS16550_COM5, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
> +	{ .base = CONFIG_SYS_NS16550_COM6, .reg_shift = 2,
> +	  .clock = CONFIG_SYS_NS16550_CLK, .fcr = UART_FCRVAL },
>  #  endif
>  # endif
>  };
> -- 
> 2.7.4