linux-kernel - Re: [PATCH v2 09/19] ARM: at91: make sdram/ddr register base soc independent

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Date:	Thu, 23 Feb 2012 09:56:38 +0100
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Ryan Mallon <rmallon@...il.com>
CC:	plagnioj@...osoft.com, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux@....linux.org.uk
Subject: Re: [PATCH v2 09/19] ARM: at91: make sdram/ddr register base soc
 independent

On 02/22/2012 11:33 PM, Ryan Mallon :
> On 22/02/12 20:39, Nicolas Ferre wrote:
> 
>> From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
>>
>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
>> Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
>> ---
> 
> <snip>
> 
>> +void __init at91_ioremap_ramc(int id, u32 addr, u32 size)
>> +{
>> +	if (id > 1) {
>> +		pr_warn("%s: id > 2\n", __func__);
>> +		return;
>> +	}
>> +	at91_ramc_base[id] = ioremap(addr, size);
>> +	if (!at91_ramc_base[id])
>> +		pr_warn("Impossible to ioremap ramc.%d 0x%x\n", id, addr);
>> +}
> 
> 
> If this fails then you will oops if you call either at91_ramc_read or
> at91_ramc_write since they don't check if at91_ramc_base[id] is a valid
> pointer. Either this function should panic, like the other at91_ioremap
> functions, or the at91_ramc_read/write functions should check for a
> valid pointer.

Yes, as you pointed out, it is done in a not-related following patch.
I will bring the code here.


> Nitpick: The id check should probably also be BUG() or WARN() since it
> indicates a bug in the core AT91 code. pr_warn is likely to missed and
> not reported by users. Since the value is int, the check should be:
> 
>   if (id < 0 || id > 1)
> 
> Obviously the chance of this error happening are slim, but if you are
> going to check and warn for it, it should be done properly :-).

Yes, I agree and modify it at the very moment.

thanks, best regards,
-- 
Nicolas Ferre
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