Re: [PATCH] MIPS: cevt-r4k: Enable intimer for Loongson64 CPUs with extimer

From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: linux-mips@vger.kernel.org, "Huacai Chen" <chenhc@lemote.com>,
	"Serge Semin" <Sergey.Semin@baikalelectronics.ru>,
	"Alexey Malahov" <Alexey.Malahov@baikalelectronics.ru>,
	"WANG Xuerui" <git@xen0n.name>,
	"Paul Burton" <paulburton@kernel.org>,
	"周琰杰 (Zhou Yanjie)" <zhouyanjie@wanyeetech.com>,
	"afzal mohammed" <afzal.mohd.ma@gmail.com>,
	"Paul Cercueil" <paul@crapouillou.net>,
	"Liangliang Huang" <huanglllzu@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] MIPS: cevt-r4k: Enable intimer for Loongson64 CPUs with extimer
Date: Sun, 4 Oct 2020 22:12:49 +0200	[thread overview]
Message-ID: <20201004201249.GA8186@alpha.franken.de> (raw)
In-Reply-To: <CA420A99-C226-4A22-B3A6-4464DD8CFA1D@flygoat.com>

On Sat, Oct 03, 2020 at 02:25:42PM +0800, Jiaxun Yang wrote:
> 
> 
> 于 2020年10月2日 GMT+08:00 下午9:27:21, Thomas Bogendoerfer <tsbogend@alpha.franken.de> 写到:
> >On Wed, Sep 23, 2020 at 07:02:54PM +0800, Jiaxun Yang wrote:
> >>  
> >> +#ifdef CONFIG_CPU_LOONGSON64
> >> +static int c0_compare_int_enable(struct clock_event_device *cd)
> >> +{
> >> +	if (cpu_has_extimer)
> >> +		set_c0_config6(LOONGSON_CONF6_INTIMER);
> >
> >why are you not simply do this in loognson64 board setup code and avoid
> >the whole cluttering of #ifdef CONFIG_CPU_LOONGSON64 over common code ?
> 
> Because I'm going to add extimer support later that require dynamic
> switch of cevt-r4k.

another case of misdesigned hardware or why does this need to be
dynamic ?

> This callback is required.

please find a solution without #ifdef CONFIG_CPU_LOONGSON64. I dislike
the pollution of common code with all kinds of #ifdefs and in this case
there are better options.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]