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Subject: Re: [PATCH] MIPS: BMIPS: Disable pref 30 for buggy CPUs
To:     Florian Fainelli <f.fainelli@gmail.com>, linux-mips@linux-mips.org
Cc:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        "open list:BROADCOM BMIPS MIPS ARCHITECTURE" 
        <bcm-kernel-feedback-list@broadcom.com>,
        "open list:BROADCOM BMIPS MIPS ARCHITECTURE" 
        <linux-mips@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20200731042401.22871-1-f.fainelli@gmail.com>
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-ID: <21ad5472-1287-acba-5604-09f2e633c043@flygoat.com>
Date:   Fri, 31 Jul 2020 18:34:13 +0800
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?? 2020/7/31 ????12:24, Florian Fainelli д??:
> Disable pref 30 by utilizing the standard quirk method and matching the
> affected SoCs: 7344, 7346, 7425.
>
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>   arch/mips/bmips/setup.c | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
>
> diff --git a/arch/mips/bmips/setup.c b/arch/mips/bmips/setup.c
> index 19308df5f577..df0efea12611 100644
> --- a/arch/mips/bmips/setup.c
> +++ b/arch/mips/bmips/setup.c
> @@ -110,6 +110,20 @@ static void bcm6368_quirks(void)
>   	bcm63xx_fixup_cpu1();
>   }
>   
> +static void bmips5000_pref30_quirk(void)
> +{
> +	__asm__ __volatile__(
> +	"	li	$8, 0x5a455048\n"
> +	"	.word	0x4088b00f\n"	/* mtc0 $8, $22, 15 */
> +	"	nop; nop; nop\n"
> +	"	.word	0x4008b008\n"	/* mfc0 $8, $22, 8 */
> +	/* disable "pref 30" on buggy CPUs */
> +	"	lui	$9, 0x0800\n"
> +	"	or	$8, $9\n"
> +	"	.word	0x4088b008\n"	/* mtc0 $8, $22, 8 */
> +	: : : "$8", "$9");
> +}
Hi,

Is there any toolchain issue blocking read_c0_**** family helpers being
used?

Use .word looks unreasonable.

Thanks

- Jiaxun

> +
>   static const struct bmips_quirk bmips_quirk_list[] = {
>   	{ "brcm,bcm3368",		&bcm6358_quirks			},
>   	{ "brcm,bcm3384-viper",		&bcm3384_viper_quirks		},
> @@ -120,6 +134,9 @@ static const struct bmips_quirk bmips_quirk_list[] = {
>   	{ "brcm,bcm6368",		&bcm6368_quirks			},
>   	{ "brcm,bcm63168",		&bcm6368_quirks			},
>   	{ "brcm,bcm63268",		&bcm6368_quirks			},
> +	{ "brcm,bcm7344",		&bmips5000_pref30_quirk		},
> +	{ "brcm,bcm7346",		&bmips5000_pref30_quirk		},
> +	{ "brcm,bcm7425",		&bmips5000_pref30_quirk		},
>   	{ },
>   };
>