Messages in this thread | | | Date | Thu, 23 Feb 2012 14:47:06 +0100 | From | Nicolas Ferre <> | Subject | Re: [PATCH v2 09/19] ARM: at91: make sdram/ddr register base soc independent |
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On 02/23/2012 11:51 AM, Ryan Mallon : > 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.
Well, I was trying hard to find a way out: but you may be right: a plain and good-old BUG() should be a safer solution!
Bye, -- Nicolas Ferre
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