Re: [PATCH v2] omap: serial: fix non-empty uart fifo read abort

From: Nishanth Menon <menon.nishanth@gmail.com>
To: "Pandita, Vikram" <vikram.pandita@ti.com>
Cc: Tony Lindgren <tony@atomide.com>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	"Cousson, Benoit" <b-cousson@ti.com>
Subject: Re: [PATCH v2] omap: serial: fix non-empty uart fifo read abort
Date: Fri, 04 Dec 2009 22:16:08 +0200	[thread overview]
Message-ID: <4B196E08.8010701@gmail.com> (raw)
In-Reply-To: <FCCFB4CDC6E5564B9182F639FC35608702FAA0C9FC@dbde02.ent.ti.com>

Pandita, Vikram said the following on 12/04/2009 09:15 PM:
>   
>> -----Original Message-----
>> From: Tony Lindgren [mailto:tony@atomide.com]
>> Sent: Friday, December 04, 2009 1:04 PM
>> To: Pandita, Vikram
>> Cc: linux-omap@vger.kernel.org; Cousson, Benoit
>> Subject: Re: [PATCH v2] omap: serial: fix non-empty uart fifo read abort
>>
>>     
> <snip>
>   
>>> +
>>> +#ifdef CONFIG_ARCH_OMAP4
>>> +		/* Never read empty UART fifo on omap4 */
>>> +		p->serial_in = serial_in_override;
>>> +#else
>>> +		/* OMAP2/3 */
>>> +		/* Never read empty UART fifo on UARTs with IP rev >=0x52 */
>>> +		if ((serial_read_reg(uart->p, UART_OMAP_MVER) & 0xFF)
>>> +				>= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV)
>>> +			uart->p->serial_in = serial_in_override;
>>> +#endif
>>>  	}
>>>  }
>>>       
>> We need to avoid ifdef else stuff, that just causes problems compiling
>> in support for many omaps. In theory, we should be able to compile in
>> support for all omaps starting with 16xx with v5 options..
>>
>> Using cpu_is_omapxxxx() should do the trick here.
>>     
>
> The intent was to have check entirely based of UART IP revision.
> That worked fine for omap3xxx. But omap4 has totally different IP revision register (as per commit message)
>
> But I can see the point, and v3 of patch I can replace:
> #ifdef CONFIG_ARCH_OMAP4 by cpu_is_omap44xx()
>
> I tried following what was done in current serial.c file of many #ifdef CONFIG_ARCH_OMAP4
>   
a cleanup patch could be welcome as well :)
>
>   
>> Tony
>>     
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>