Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite

From	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite
Date	2017-05-19 12:40 +0200
Message-ID	<tINu9-QO-5@gated-at.bofh.it> (permalink)
References	<tHnV7-cB-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, 2017-05-15 at 16:07 +0300, Ivan Mikhaylov wrote:
> +#ifdef CONFIG_FSP2
> +       /*
> +        * Prevent a kernel panic caused by unintentionally clearing TCR
> +        * watchdog bits.  At this point in the kernel boot, the watchdog has
> +        * already been enabled by u-boot.  The original code's attempt to
> +        * write to the TCR register results in an inadvertent clearing of the
> +        * watchdog configuration bits, causing the 440 to reset.
> +        */
> +       tcr = mfspr(SPRN_TCR);
> +       tcr &= TCR_WP_MASK; /* clear all bits except for TCR[WP] */
> +       tcr |= TCR_DIE; /* enable decrementer */
> +       mtspr(SPRN_TCR, tcr);
> +#else

This should be a runtime test, not a compile time option.

Cheers,
Ben.

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[PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite Ivan Mikhaylov <ivan@de.ibm.com> - 2017-05-15 15:10 +0200
  Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite Michael Ellerman <mpe@ellerman.id.au> - 2017-05-19 12:30 +0200
    Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite Ivan Mikhaylov <ivan@de.ibm.com> - 2017-05-19 17:50 +0200
      Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of whole rewrite Michael Ellerman <mpe@ellerman.id.au> - 2017-05-23 06:20 +0200
  Re: [PATCH 4/4] arch/powerpc/44x/fsp2: wdt tcr update instead of  whole rewrite Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-05-19 12:40 +0200

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