linux-kernel - Re: [PATCH v4] ARM: cache-l2x0.c: save aux ctrl for resume in case l2x0 is enabled before init

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Message-ID: <CAHkRjk51pATYdhKhmBb9sWywN+0BgeQLpW9bMfTkRgf_09wydg@mail.gmail.com>
Date:	Mon, 30 Apr 2012 14:34:38 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Yilu Mao <ylmao@...vell.com>
Cc:	linux-kernel@...r.kernel.org, linux@....linux.org.uk,
	Baohua.Song@....com, santosh.shilimkar@...com,
	robherring2@...il.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4] ARM: cache-l2x0.c: save aux ctrl for resume in case
 l2x0 is enabled before init

On 30 April 2012 14:16, Yilu Mao <ylmao@...vell.com> wrote:
> If l2x0 controller has been enabled when calling l2x0_init, the aux ctrl
> register will not be saved in l2x0_saved_regs. Therefore we can not use
> l2x0_saved_regs.aux_ctrl for resume later. This patch fixed the problem
> by saving aux ctrl in l2x0_saved_regs just after it's being read from
> the register.
> And in case some bits of aux ctrl register are reserved, re-read and
> save it properly after set it if l2x0 is disabled before init.
>
> Change-Id: I54f3002274ffe9cdc667dba81e36e08f2e121467
> Signed-off-by: Yilu Mao <ylmao@...vell.com>
> ---
>  arch/arm/mm/cache-l2x0.c |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> index a53fd2a..9893e58 100644
> --- a/arch/arm/mm/cache-l2x0.c
> +++ b/arch/arm/mm/cache-l2x0.c
> @@ -320,6 +320,13 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
>        cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
>        aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
>
> +       /*
> +        * In case l2x controller is enabled, the aux ctrl register
> +        * can't be set. So the original value should be stored in
> +        * the l2x0_saved_regs for restoring when resume.
> +        */
> +       l2x0_saved_regs.aux_ctrl = aux;

Why not move this

> +
>        aux &= aux_mask;
>        aux |= aux_val;
>
> @@ -364,6 +371,8 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
>                /* l2x0 controller is disabled */
>                writel_relaxed(aux, l2x0_base + L2X0_AUX_CTRL);
>
> +               /* Re-read it in case some bits are reserved. */
> +               aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);

and this

>                l2x0_saved_regs.aux_ctrl = aux;
>
>                l2x0_inv_all();

somewhere after the if block and we only read the aux once. The
comment may no longer make sense though.

-- 
Catalin
--
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