linux-kernel - Re: [PATCH] ARM: SAMSUNG: remove dead #elif CONFIG_S3C24XX

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Message-ID: <CABv5NL_SLyY9-yookdTVdNXzCmUEqJ_QB6ofzw_q0H7Vcwbzfg@mail.gmail.com>
Date:	Thu, 18 Dec 2014 14:43:01 +0100
From:	Stefan Hengelein <stefan.hengelein@....de>
To:	Heiko Stübner <heiko@...ech.de>
Cc:	Arnd Bergmann <arnd@...db.de>,
	linux-arm-kernel@...ts.infradead.org, kgene@...nel.org,
	linux-samsung-soc@...r.kernel.org, linux@....linux.org.uk,
	linux-kernel@...r.kernel.org,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH] ARM: SAMSUNG: remove dead #elif CONFIG_S3C24XX_DMAC

So you actually tested the code I removed in the patch? can you
provide a configuration that compiles that piece of code?

2014-12-17 17:16 GMT+01:00 Heiko Stübner <heiko@...ech.de>:
> Am Mittwoch, 17. Dezember 2014, 16:52:40 schrieb Arnd Bergmann:
>> On Wednesday 17 December 2014 16:40:37 Stefan Hengelein wrote:
>> > The corresponding CPP-block can never be selected since there are
>> > conflicting Kconfig constraints:
>> > - CONFIG_S3C24XX_DMAC has a dependency on ARCH_S3C24XX
>> > - The surrounding CPP-block needs CONFIG_S3C64XX_DEV_SPI0 to be defined.
>> >
>> >   - CONFIG_S3C64XX_DEV_SPI0 is only selected by MACH_WLF_CRAGG_6410
>> >   - MACH_WLF_CRAGG_6410 however has a dependency on ARCH_S3C64XX
>> >
>> >     (through a surrounding if-statement in Kconfig)
>> >
>> > - ARCH_S3C64XX and ARCH_S3C24XX are mutually exclusive since they are
>> >
>> >   declared in the same choice and cannot be enabled at the same time.
>> >
>> > Hence, the innner block
>> >
>> >     "#elif defined(CONFIG_S3C24XX_DMAC)"
>> >
>> > cannot be enabled at the same time with the surrounding block
>> >
>> >     "#ifdef CONFIG_S3C64XX_DEV_SPI0"
>> >
>> > and therefore is dead.
>> >
>> > This (logical) defect has been found with the undertaker tool
>> > (https://undertaker.cs.fau.de)
>>
>> Nice catch!
>>
>> > Signed-off-by: Stefan Hengelein <stefan.hengelein@....de>
>> > ---
>> >
>> >  arch/arm/plat-samsung/devs.c | 2 --
>> >  1 file changed, 2 deletions(-)
>> >
>> > diff --git a/arch/arm/plat-samsung/devs.c b/arch/arm/plat-samsung/devs.c
>> > index 83c7d15..b38b601 100644
>> > --- a/arch/arm/plat-samsung/devs.c
>> > +++ b/arch/arm/plat-samsung/devs.c
>> > @@ -1134,8 +1134,6 @@ void __init s3c64xx_spi0_set_platdata(int
>> > (*cfg_gpio)(void), int src_clk_nr,>
>> >     pd.filter = pl330_filter;
>> >
>> >  #elif defined(CONFIG_S3C64XX_PL080)
>> >
>> >     pd.filter = pl08x_filter_id;
>> >
>> > -#elif defined(CONFIG_S3C24XX_DMAC)
>> > -   pd.filter = s3c24xx_dma_filter;
>> >
>> >  #endif
>> >
>> >     s3c_set_platdata(&pd, sizeof(pd), &s3c64xx_device_spi0);
>>
>> This was introduced in 7f99ef2284b46f ("ARM: SAMSUNG: set
>> s3c24xx_dma_filter for s3c64xx-spi0 device"), but never used on s3c24xx as
>> far as I can tell. Heiko, can you comment on the patch? Did this
>> simply get obsoleted by the DT conversion of s3c2416 and s3c2443?
>
> We just have no in-tree users currently.
>
> The S3C2416 and S3C2450 use the same type of spi controllers as the s3c64xx.
> When writing the s3c24xx dma driver I also used this to test the driver. The
> change was necessary to make the driver talk to my s3c2416 device, so it made
> sense at the time.
>
> As the s3c24xx-dma driver currently is still lacking dt support [burried
> somewhere on my todo list], board files are also currently the only way to do
> fast spi on those at all.
>
> So removing this is dependent on how hard we want to make it for downstream
> users [there seem to be a small number of those]. If this were part of
> removing all non-dt cruft from the driver after s3c64xx migrated to be dt-only
> I wouldn't object, but as it only affects the 2 lines of s3c24xx support,
> personally I'd like to keep it around :-) .
>
>
> Heiko
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