Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755476Ab2BWKuZ (ORCPT <rfc822;w@1wt.eu>);
	Thu, 23 Feb 2012 05:50:25 -0500
Received: from mail-pw0-f46.google.com ([209.85.160.46]:46574 "EHLO
	mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755006Ab2BWKuY (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 23 Feb 2012 05:50:24 -0500
Authentication-Results: mr.google.com; spf=pass (google.com: domain of rmallon@gmail.com designates 10.68.194.65 as permitted sender) smtp.mail=rmallon@gmail.com; dkim=pass header.i=rmallon@gmail.com
Message-ID: <4F461A42.2080202@gmail.com>
Date: Thu, 23 Feb 2012 21:51:46 +1100
From: Ryan Mallon <rmallon@gmail.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.27) Gecko/20120216 Thunderbird/3.1.19
MIME-Version: 1.0
To: Nicolas Ferre <nicolas.ferre@atmel.com>
CC: plagnioj@jcrosoft.com, linux@arm.linux.org.uk,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 09/19] ARM: at91: make sdram/ddr register base soc
 independent
References: <1329903585-30738-1-git-send-email-nicolas.ferre@atmel.com> <0acddc0a57ea5a198f662bf37047ebe95e3eb695.1329903206.git.nicolas.ferre@atmel.com> <4F456D1E.8070807@gmail.com> <4F45FF46.3060702@atmel.com> <4F460DD0.1050108@atmel.com>
In-Reply-To: <4F460DD0.1050108@atmel.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2625
Lines: 77

On 23/02/12 20:58, Nicolas Ferre wrote:

> On 02/23/2012 09:56 AM, Nicolas Ferre :
>> On 02/22/2012 11:33 PM, Ryan Mallon :
>>> On 22/02/12 20:39, Nicolas Ferre wrote:
>>>
>>>> From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
>>>>
>>>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
>>>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.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.
> 
> 
> What do you think about that:
> If id is not setup properly, I try to find a way out by using id = 0...
> Then, a panic is added if the iremap() fails.
> 
> 
> --- a/arch/arm/mach-at91/pm.c
> +++ b/arch/arm/mach-at91/pm.c
> @@ -200,13 +200,14 @@ void __iomem *at91_ramc_base[2];
>  
>  void __init at91_ioremap_ramc(int id, u32 addr, u32 size)
>  {
> -       if (id > 1) {
> -               pr_warn("%s: id > 2\n", __func__);
> -               return;
> +       if (id < 0 || id > 1) {
> +               WARN(1, "%s: Wrong RAM controller id (%d), set it to 0\n",
> +                                                               __func__, id);
> +               id = 0;


I don't think you should try to fix the id, just issue the warning and
return. 

~Ryan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/