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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Paul Burton <paul.burton@mips.com>,
	"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Cc: Paul Burton <pburton@wavecomp.com>, Huacai Chen <chenhc@lemote.com>
Subject: Re: [PATCH] MIPS: Drop Loongson _CACHE_* definitions
Date: Mon, 2 Sep 2019 00:53:08 +0200
Message-ID: <b84f3910-6b0d-db6c-1dba-9ddf30d7d86d@amsat.org> (raw)
In-Reply-To: <20190831154145.7328-1-paul.burton@mips.com>

On 8/31/19 5:41 PM, Paul Burton wrote:
> _CACHE_CACHABLE_NONCOHERENT is defined as 3<<_CACHE_SHIFT by default, so
> there's no need to define it as such specifically for Loongson.
> 
> _CACHE_CACHABLE_COHERENT is not used anywhere in the kernel, so there's
> no need to define it at all.
> 
> Finally the comment found alongside these definitions seems incorrect -
> it suggests that we're defining _CACHE_CACHABLE_NONCOHERENT such that it
> actually provides coherence, but the opposite seems to be true & instead
> the unused _CACHE_CACHABLE_COHERENT is defined as the typically
> incoherent value.
> 
> Delete the whole thing, which will have no effect on the compiled code
> anyway.
> 
> Signed-off-by: Paul Burton <paul.burton@mips.com>
> Cc: Huacai Chen <chenhc@lemote.com>
> ---
> 
>  arch/mips/include/asm/pgtable-bits.h | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
> index 5f1ced8cba07..409ae01ed7be 100644
> --- a/arch/mips/include/asm/pgtable-bits.h
> +++ b/arch/mips/include/asm/pgtable-bits.h
> @@ -221,13 +221,6 @@ static inline uint64_t pte_to_entrylo(unsigned long pte_val)
>  
>  #define _CACHE_CACHABLE_NONCOHERENT (5<<_CACHE_SHIFT)
>  
> -#elif defined(CONFIG_CPU_LOONGSON3)
> -
> -/* Using COHERENT flag for NONCOHERENT doesn't hurt. */
> -
> -#define _CACHE_CACHABLE_NONCOHERENT (3<<_CACHE_SHIFT)  /* LOONGSON       */
> -#define _CACHE_CACHABLE_COHERENT    (3<<_CACHE_SHIFT)  /* LOONGSON-3     */
> -
>  #elif defined(CONFIG_MACH_INGENIC)
>  
>  /* Ingenic uses the WA bit to achieve write-combine memory writes */
> 

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

  parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-31 15:41 Paul Burton
2019-09-01  2:41 ` 陈华才
2019-09-02  0:47   ` [PATCH] " Jiaxun Yang
2019-09-01 22:53 ` Philippe Mathieu-Daudé [this message]
2019-09-02  0:51 ` Jiaxun Yang
2019-09-03 20:47 ` Paul Burton

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