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Message-ID: <1389743456.24905.143.camel@snotra.buserror.net>
Subject: Re: [PATCH 2/3] powerpc/85xx: Provide two functions to save/restore
 the core registers
From: Scott Wood <scottwood@freescale.com>
To: Dongsheng Wang <dongsheng.wang@freescale.com>
Date: Tue, 14 Jan 2014 17:50:56 -0600
In-Reply-To: <1389686397-46555-2-git-send-email-dongsheng.wang@freescale.com>
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 <1389686397-46555-2-git-send-email-dongsheng.wang@freescale.com>
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On Tue, 2014-01-14 at 15:59 +0800, Dongsheng Wang wrote:
> From: Wang Dongsheng <dongsheng.wang@freescale.com>
> 
> Add fsl_cpu_state_save/fsl_cpu_state_restore functions, used for deep
> sleep and hibernation to save/restore core registers. We abstract out
> save/restore code for use in various modules, to make them don't need
> to maintain.
> 
> Currently supported processors type are E6500, E5500, E500MC, E500v2 and
> E500v1.
> 
> Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>

What is there that is specfic to a particular core type that can't be
handled from C code?

> +	/*
> +	 * Need to save float-point registers if MSR[FP] = 1.
> +	 */
> +	mfmsr	r12
> +	andi.	r12, r12, MSR_FP
> +	beq	1f
> +	do_sr_fpr_regs(save)

C code should have already ensured that MSR[FP] is not 1 (and thus the
FP context has been saved).

> +/*
> + * r3 = the virtual address of buffer
> + * r4 = suspend type, 0-BASE_SAVE, 1-ALL_SAVE

#define these magic numbers, and define what is meant by "base save"
versus "all save".

-Scott