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From: Peter Hurley <peter@hurleysoftware.com>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"robh@kernel.org" <robh@kernel.org>,
	"jslaby@suse.cz" <jslaby@suse.cz>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v2 2/3] serial: 8250_early: prepare for dynamic BASE_BAUD
Date: Mon, 05 Jan 2015 08:33:59 -0500	[thread overview]
Message-ID: <54AA92C7.8070209@hurleysoftware.com> (raw)
In-Reply-To: <C2D7FE5348E1B147BCA15975FBA2307565BC9CCD@IN01WEMBXA.internal.synopsys.com>

On 01/05/2015 08:21 AM, Vineet Gupta wrote:
> Hi Peter,
> 
> On Monday 05 January 2015 06:31 PM, Peter Hurley wrote:
>> Hi Vineet,
>>
>> On 01/05/2015 06:30 AM, Vineet Gupta wrote:
>>> -	port->uartclk = BASE_BAUD * 16;
>>> +	port->uartclk = earlycon_base_baud(options) * 16;
>> I don't understand why BASE_BAUD can't be defined by arc as arc_earlycon_base_baud().
>> Why is the weak binding necessary?
> 
> Indeed weak semantics are not really needed - even now we have what u r suggesting
> - the missing part was existing conditional definition which will simply go away
> if I implement the fdt parsing in that singly defined function. Thx for the tip :-)
> 
> In that case this requires no change to driver and I can fixup the platform -
> perhaps ur Ack on next version will be nice.

Will do.

> Also what do u think of the early IER optimization ?

Seems ok except the commit changelog is wrong: IER is disabled twice per _line_.
How did you profile it? It's ok if the answer is "seemed faster"; I'm just
curious.

Regards,
Peter Hurley

>> I'm pushing back on this because port initialization (and especially 8250)
>> is already a ridiculous spiderweb.
> 
> I totally agree.
> 
> Thx,
> -Vineet
> 
>>
>> Regards,
>> Peter Hurley
>>
>>>  	options = strchr(options, ',');
>>>  	if (options) {
>>> @@ -156,7 +165,7 @@ int __init of_setup_earlycon(unsigned long addr,
>>>  
>>>  	port->iotype = UPIO_MEM;
>>>  	port->mapbase = addr;
>>> -	port->uartclk = BASE_BAUD * 16;
>>> +	port->uartclk = earlycon_base_baud(NULL) * 16;
>>>  	port->membase = earlycon_map(addr, SZ_4K);
>>>  
>>>  	early_console_dev.con->data = &early_console_dev;
>>>
>>
> 

  reply	other threads:[~2015-01-05 13:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-05 11:30 [PATCH v2 0/3] Early 8250 fixlets Vineet Gupta
2015-01-05 11:30 ` [PATCH v2 1/3] serial: 8250_early: optimize early 8250 uart Vineet Gupta
2015-01-05 11:30 ` [PATCH v2 2/3] serial: 8250_early: prepare for dynamic BASE_BAUD Vineet Gupta
2015-01-05 13:00   ` Peter Hurley
2015-01-05 13:21     ` Vineet Gupta
2015-01-05 13:33       ` Peter Hurley [this message]
2015-01-05 13:52         ` Vineet Gupta
2015-01-05 14:05           ` Peter Hurley
2015-01-05 11:30 ` [PATCH v2 3/3] ARC: runtime determine BASE_BAUD per machine Vineet Gupta

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