Subject: Re: [PATCH 3/4] powerpc: pm: add EPU FSM configuration for deep sleep

From: Scott Wood <[email-masked]>
Date: Fri, 31 Jul 2015 19:41:51 -0500

On Fri, 2015-07-31 at 20:53 +0800, Chenhui Zhao wrote:
> In the last stage of deep sleep, software will trigger a Finite
> State Machine (FSM) to control the hardware precedure, such as
> board isolation, killing PLLs, removing power, and so on.
> 
> When the system is waked up by an interrupt, the FSM controls the
> hardware to complete the early resume precedure.
> 
> This patch configure the EPU FSM preparing for deep sleep.
> 
> Signed-off-by: Chenhui Zhao <[email-masked]>
> ---
>  arch/powerpc/platforms/85xx/Makefile    |   2 +-
>  arch/powerpc/platforms/85xx/sleep_fsm.c | 256 
> ++++++++++++++++++++++++++++++++
>  arch/powerpc/platforms/85xx/sleep_fsm.h | 104 +++++++++++++
>  3 files changed, 361 insertions(+), 1 deletion(-)
>  create mode 100644 arch/powerpc/platforms/85xx/sleep_fsm.c
>  create mode 100644 arch/powerpc/platforms/85xx/sleep_fsm.h

When I asked why this was in drivers/platform[1], you said it was to share 
with LS1, and that the values used were the same -- so why did you move it to 
arch/powerpc?

[1] Note that other proposed patches create a drivers/soc/fsl instead of 
drivers/platform/fsl...  We need one of them, not both.

> +void fsl_fsm_setup(void __iomem *base, struct fsm_reg_vals *val)
> +{
> +     struct fsm_reg_vals *data = val;
> +
> +     BUG_ON(!base || !data);

This BUG_ON is useless.  If one of those is NULL you'll get an oops anyway.

> diff --git a/arch/powerpc/platforms/85xx/sleep_fsm.h 
> b/arch/powerpc/platforms/85xx/sleep_fsm.h
> new file mode 100644
> index 0000000..2c60b40
> --- /dev/null
> +++ b/arch/powerpc/platforms/85xx/sleep_fsm.h
> @@ -0,0 +1,104 @@
> +/*
> + * Freescale deep sleep FSM (finite-state machine) configuration
> + *
> + * Copyright 2015 Freescale Semiconductor Inc.
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + */
> +#ifndef _FSL_SLEEP_FSM_H
> +#define _FSL_SLEEP_FSM_H
> +
> +#define FSL_STRIDE_4B        4
> +#define FSL_STRIDE_8B        8

Why not just use 4/8 directly?

> 
> +/* Block offsets */
> +#define RCPM_BLOCK_OFFSET    0x00022000
> +#define EPU_BLOCK_OFFSET     0x00000000
> +#define NPC_BLOCK_OFFSET     0x00001000

I thought you said OK to not putting these offsets in the kernel source...

-Scott