Re: [Xen-devel] [PATCH] xen/arm: add OMAP5432 UART support for early_printk

[Chen Baozi <baozich@xxxxxxxxx>]

On Jun 27, 2013, at 4:54 PM, Chen Baozi <baozich@xxxxxxxxx> wrote:

> 
> On Jun 27, 2013, at 4:22 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> 
>> On Thu, 2013-06-27 at 15:20 +0800, Chen Baozi wrote:
>>> To enable it, add "CONFIG_EARLY_PRINTK := omap5432" to Config.mk
>> 
>> From the register offsets this looks like it might be a somewhat 8250
>> compatible UART logic block?
> From TI's data manual, it is said this is a 16C750 compatible UART. So could 
> it be called an 9250 compatible UART?
Sorry, 8250.

> 
>> 
>> Bamvor also implemented a driver for an 8250 like device on the
>> sun6i[0]. Rather than having multiple drivers for similar platforms I
>> asked him to produce a single configurable 8250 driver. Perhaps you
>> could work together to make sure this works for you both?
> Sure, it is OK for me.
> 
>> 
>> Thanks,
>> Ian.
>> 
>> [0] see "xen/arm: introduce Allwinner sun6i SOC basic support"
>> <1370004814-30686-3-git-send-email-bjzhang@xxxxxxxx>.
>> 
>>> +ifeq ($(CONFIG_EARLY_PRINTK), omap5432)
>>> +EARLY_PRINTK_INC := omap
>>> +EARLY_PRINTK_INIT_UART := y
>> 
>> Does your bootloader not setup the UART? Preferably we would simply
>> inherit that setup (avoids more code and mismatched baud rate etc).
> Yes, it does. I thought re-initilization is necessary and found that is also 
> ok to inherit the u-boot setup just after finishing the patch. Well, in this 
> case, things are much easier :-)
> 
> Thanks,
> 
> Baozi
> 
>> 
>> Ian.
>> 
> 


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