[U-Boot] [PATCH] serial: 16550: Add JZ47xx support

[Daniel Schwierzeck <daniel.schwierzeck@gmail.com>]

Am 26.05.2016 um 00:21 schrieb Marek Vasut:
> On 05/26/2016 12:17 AM, Daniel Schwierzeck wrote:
>>
>>
>> Am 25.05.2016 um 02:19 schrieb Marek Vasut:
>>> The Ingenic JZ47xx requires special bit (UART_EN) set in FCR register
>>> in order to work at all. Add this special case handling into the driver.
>>>
>>> Signed-off-by: Marek Vasut <marex@denx.de>
>>> Cc: Tom Rini <trini@konsulko.com>
>>> Cc: Simon Glass <sjg@chromium.org>
>>> Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
>>> Cc: Paul Burton <paul.burton@imgtec.com>
>>> ---
>>>  drivers/serial/ns16550.c | 8 ++++++++
>>>  1 file changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
>>> index 30ba0aa..1323881 100644
>>> --- a/drivers/serial/ns16550.c
>>> +++ b/drivers/serial/ns16550.c
>>> @@ -50,6 +50,14 @@ DECLARE_GLOBAL_DATA_PTR;
>>>  #endif
>>>  #endif
>>>  
>>> +#ifdef CONFIG_ARCH_JZ47XX
>>> +#undef UART_FCRVAL
>>> +/* Ingenic JZ47xx SoCs require that a 'UART Module Enable' bit be set */
>>> +#define UART_FCR_UME		0x10
>>> +#define UART_FCRVAL (UART_FCR_FIFO_EN | UART_FCR_RXSR |	\
>>> +		     UART_FCR_TXSR | UART_FCR_UME)
>>> +#endif
>>
>> I think this could be added as DT property
> 
> Not for SPL, which has 14 kiB size limit and it is itching to overflow.
> I am literally counting bytes in the SPL and removing slop from
> structures to make it fit, just barely. With the USB loader, I can
> brutalize the SPL into having extremely rudimentary UART support now
> (like printch() being the most advanced output mechanism, but you can
> only use it three times, otherwise the code won't fit and the board is
> eaten by demons) and this is where this patch comes into play.
> 
> So yes, for full u-boot, this _should_ be part of DT. For SPL, please apply.
> 

ok, but wouldn't it be better to introduce an option like
CONFIG_SYS_NS16550_UME instead of using the SoC-specific
CONFIG_ARCH_JZ47XX. This driver is messed up enough ;)

>>> +
>>>  #ifndef CONFIG_SYS_NS16550_IER
>>>  #define CONFIG_SYS_NS16550_IER  0x00
>>>  #endif /* CONFIG_SYS_NS16550_IER */
>>>
>>
> 
> 

-- 
- Daniel

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