Subject: Re: [PATCH v3 02/11] powerpc/mpc5121: Add machine restart support

From: Wolfram Sang <[email-masked]>
Date: Wed, 10 Feb 2010 00:24:06 +0100

Hi,

On Fri, Feb 05, 2010 at 02:42:48PM +0100, Anatolij Gustschin wrote:
> Add reset module registers representation and
> machine restart callback for mpc5121 platform.
> 

Two comments:

> Signed-off-by: Piotr Ziecik <[email-masked]>
> Signed-off-by: Wolfgang Denk <[email-masked]>
> Signed-off-by: Anatolij Gustschin <[email-masked]>
> Cc: Grant Likely <[email-masked]>
> Cc: John Rigby <[email-masked]>
> ---
> Changes since v2:
>  - call mpc512x_restart_init() explicitely from platform
>    init code
> 
> Changes since v1:
>  - use 'struct mpc512x_reset_module *' type for 'reset_module_base'
>  - remove empty line
>  - remove leftover colon and use pr_err() instead of printk.
> 
>  arch/powerpc/include/asm/mpc5xxx.h            |   14 +++++++++-
>  arch/powerpc/platforms/512x/mpc5121_ads.c     |    1 +
>  arch/powerpc/platforms/512x/mpc5121_generic.c |    1 +
>  arch/powerpc/platforms/512x/mpc512x.h         |    1 +
>  arch/powerpc/platforms/512x/mpc512x_shared.c  |   34 +++++++++++++++++++++++++
>  5 files changed, 50 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/mpc5xxx.h b/arch/powerpc/include/asm/mpc5xxx.h
> index 5ce9c5f..0004986 100644
> --- a/arch/powerpc/include/asm/mpc5xxx.h
> +++ b/arch/powerpc/include/asm/mpc5xxx.h
> @@ -18,5 +18,17 @@
>  
>  extern unsigned long mpc5xxx_get_bus_frequency(struct device_node *node);
>  
> -#endif /* __ASM_POWERPC_MPC5xxx_H__ */
> +/* MPC512x Reset module registers */
> +struct mpc512x_reset_module {
> +	u32	rcwlr;	/* Reset Configuration Word Low Register */
> +	u32	rcwhr;	/* Reset Configuration Word High Register */
> +	u32	reserved1;
> +	u32	reserved2;
> +	u32	rsr;	/* Reset Status Register */
> +	u32	rmr;	/* Reset Mode Register */
> +	u32	rpr;	/* Reset Protection Register */
> +	u32	rcr;	/* Reset Control Register */
> +	u32	rcer;	/* Reset Control Enable Register */
> +};
>  
> +#endif /* __ASM_POWERPC_MPC5xxx_H__ */
> diff --git a/arch/powerpc/platforms/512x/mpc5121_ads.c b/arch/powerpc/platforms/512x/mpc5121_ads.c
> index 0f8f2e9..ee6ae12 100644
> --- a/arch/powerpc/platforms/512x/mpc5121_ads.c
> +++ b/arch/powerpc/platforms/512x/mpc5121_ads.c
> @@ -68,4 +68,5 @@ define_machine(mpc5121_ads) {
>  	.init_IRQ		= mpc5121_ads_init_IRQ,
>  	.get_irq		= ipic_get_irq,
>  	.calibrate_decr		= generic_calibrate_decr,
> +	.restart		= mpc512x_restart,
>  };
> diff --git a/arch/powerpc/platforms/512x/mpc5121_generic.c b/arch/powerpc/platforms/512x/mpc5121_generic.c
> index 9b8c9b0..a6c0e3a 100644
> --- a/arch/powerpc/platforms/512x/mpc5121_generic.c
> +++ b/arch/powerpc/platforms/512x/mpc5121_generic.c
> @@ -55,4 +55,5 @@ define_machine(mpc5121_generic) {
>  	.init_IRQ		= mpc512x_init_IRQ,
>  	.get_irq		= ipic_get_irq,
>  	.calibrate_decr		= generic_calibrate_decr,
> +	.restart		= mpc512x_restart,
>  };
> diff --git a/arch/powerpc/platforms/512x/mpc512x.h b/arch/powerpc/platforms/512x/mpc512x.h
> index ac3da1a..b2daca0 100644
> --- a/arch/powerpc/platforms/512x/mpc512x.h
> +++ b/arch/powerpc/platforms/512x/mpc512x.h
> @@ -15,4 +15,5 @@ extern void __init mpc512x_init_IRQ(void);
>  extern void __init mpc512x_init(void);
>  extern int __init mpc5121_clk_init(void);
>  void __init mpc512x_declare_of_platform_devices(void);
> +extern void mpc512x_restart(char *cmd);
>  #endif				/* __MPC512X_H__ */
> diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
> index b683165..ac0400e 100644
> --- a/arch/powerpc/platforms/512x/mpc512x_shared.c
> +++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
> @@ -21,9 +21,42 @@
>  #include <asm/ipic.h>
>  #include <asm/prom.h>
>  #include <asm/time.h>
> +#include <asm/mpc5xxx.h>
>  
>  #include "mpc512x.h"
>  
> +static struct mpc512x_reset_module __iomem *reset_module_base;
> +
> +static int __init mpc512x_restart_init(void)
> +{
> +	struct device_node *np;
> +
> +	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-reset");
> +	if (!np)
> +		return -1;
> +
> +	reset_module_base = of_iomap(np, 0);
> +	of_node_put(np);
> +
> +	return 0;
> +}
> +
> +void mpc512x_restart(char *cmd)
> +{
> +	struct mpc512x_reset_module *rm = reset_module_base;

Why not using reset_module_base directly?

> +
> +	if (rm) {
> +		/* Enable software reset "RSTE" */
> +		out_be32(&rm->rpr, 0x52535445);
> +		/* Set software hard reset */
> +		out_be32(&rm->rcr, 0x2);
> +	} else {
> +		pr_err("Restart module not mapped.\n");
> +	}
> +	for (;;)
> +		;
> +}
> +
>  void __init mpc512x_init_IRQ(void)
>  {
>  	struct device_node *np;
> @@ -62,4 +95,5 @@ void __init mpc512x_init(void)
>  {
>  	mpc512x_declare_of_platform_devices();
>  	mpc5121_clk_init();
> +	mpc512x_restart_init();

If the return value is not checked here, you could as well make the function
void. (Not much one could do in the error-case, too.)

>  }
> -- 

Regards,

   Wolfram

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