Re: [PATCH] MIPS: Ingenic: Fix bugs when detecting X1000's parameters.

From: Paul Cercueil <paul@crapouillou.net>
To: Zhou Yanjie <zhouyanjie@zoho.com>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	ralf@linux-mips.org, paul.burton@mips.com, jhogan@kernel.org,
	malat@debian.org, chenhc@lemote.com, tglx@linutronix.de,
	allison@lohutok.net, syq@debian.org, jiaxun.yang@flygoat.com
Subject: Re: [PATCH] MIPS: Ingenic: Fix bugs when detecting X1000's parameters.
Date: Tue, 30 Jul 2019 14:02:47 -0400	[thread overview]
Message-ID: <1564509767.15799.0@crapouillou.net> (raw)
In-Reply-To: <1564498510-3751-2-git-send-email-zhouyanjie@zoho.com>

Hi Zhou,

Le mar. 30 juil. 2019 à 10:55, Zhou Yanjie <zhouyanjie@zoho.com> a 
écrit :
> 1.fix bugs when detecting L2 cache sets value.
> 2.fix bugs when detecting L2 cache ways value.
> 3.fix bugs when calculate bogoMips and loops_per_jiffy.
> 
> Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>
> ---
>  arch/mips/kernel/cpu-probe.c |  7 ++++++-
>  arch/mips/mm/sc-mips.c       | 18 +++++++++++++++---
>  2 files changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/mips/kernel/cpu-probe.c 
> b/arch/mips/kernel/cpu-probe.c
> index eb527a1..a914435 100644
> --- a/arch/mips/kernel/cpu-probe.c
> +++ b/arch/mips/kernel/cpu-probe.c
> @@ -1960,11 +1960,16 @@ static inline void cpu_probe_ingenic(struct 
> cpuinfo_mips *c, unsigned int cpu)
>  	c->options &= ~MIPS_CPU_COUNTER;
>  	BUG_ON(!__builtin_constant_p(cpu_has_counter) || cpu_has_counter);
>  	switch (c->processor_id & PRID_IMP_MASK) {
> -	case PRID_IMP_XBURST:
> +	case PRID_IMP_XBURST: {
> +		unsigned int config7;
>  		c->cputype = CPU_XBURST;
>  		c->writecombine = _CACHE_UNCACHED_ACCELERATED;
>  		__cpu_name[cpu] = "Ingenic XBurst";
> +		config7 = read_c0_config7();
> +		config7 |= (1 << 4);
> +		write_c0_config7(config7);

If you add __BUILD_SET_C0(config7) in arch/mips/include/asm/mipsregs.h
(search for this macro) then you can call directly 
set_c0_config7(BIT(4)).

It's preferred to use the BIT(x) macro instead of the (1 << x) 
construct.

Finally, what does that bit do? I can't find it any documentation about
it. Please add a comment describing what it does.

>  		break;
> +	}
>  	default:
>  		panic("Unknown Ingenic Processor ID!");
>  		break;
> diff --git a/arch/mips/mm/sc-mips.c b/arch/mips/mm/sc-mips.c
> index 9385ddb..ed953d4 100644
> --- a/arch/mips/mm/sc-mips.c
> +++ b/arch/mips/mm/sc-mips.c
> @@ -215,6 +215,14 @@ static inline int __init mips_sc_probe(void)
>  	else
>  		return 0;
> 
> +	/*
> +	 * According to config2 it would be 512-sets, but that is 
> contradicted
> +	 * by all documentation.
> +	 */
> +	if (current_cpu_type() == CPU_XBURST &&
> +				mips_machtype == MACH_INGENIC_X1000)
> +		c->scache.sets = 256;
> +
>  	tmp = (config2 >> 0) & 0x0f;
>  	if (tmp <= 7)
>  		c->scache.ways = tmp + 1;
> @@ -225,9 +233,13 @@ static inline int __init mips_sc_probe(void)
>  	 * According to config2 it would be 5-ways, but that is contradicted
>  	 * by all documentation.
>  	 */
> -	if (current_cpu_type() == CPU_XBURST &&
> -				mips_machtype == MACH_INGENIC_JZ4770)
> -		c->scache.ways = 4;
> +	if (current_cpu_type() == CPU_XBURST) {
> +		switch (mips_machtype) {
> +		case MACH_INGENIC_JZ4770:
> +		case MACH_INGENIC_X1000:
> +			c->scache.ways = 4;
> +		}
> +	}
> 
>  	c->scache.waysize = c->scache.sets * c->scache.linesz;
>  	c->scache.waybit = __ffs(c->scache.waysize);
> --
> 2.7.4
> 
> 