From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marek.vasut@gmail.com>
Date: Wed, 25 Jan 2012 00:48:59 +0100
Subject: [U-Boot] [RFC] mx28: Fix reboot from the kernel
In-Reply-To: <1327422192-24762-1-git-send-email-fabio.estevam@freescale.com>
References: <1327422192-24762-1-git-send-email-fabio.estevam@freescale.com>
Message-ID: <201201250049.00152.marek.vasut@gmail.com>
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> When running Linux on a mx28evk and issuing a 'reboot'command the following
> behaviour is observed:
> 
> root at freescale /$ reboot
> starting pid 329, tty '': '/etc/rc.d/rcS stop'
> root at freescale /$ Stopping inetd:
> Terminated
> Unmounting filesystems
> umount: tmpfs busy - remounted read-only
> chown: /home/user/.rhosts: Read-only file system
> chown: /home/user: Read-only file system
> chown: /home/user: Read-only file system
> cat: can't open '/proc/devices': No such file or directory
> The system is going down NOW!
> Sent SIGTERM to all processes
> Sent SIGKILL to all processes
> Requesting system reboot
> [   24.240000] Restarting system.
> 
> U-Boot 2011.12-06887-g586ab2f-dirty (Jan 24 2012 - 12:58:50)
> 
> Freescale i.MX28 family
> DRAM:  0
> 
> , and then U-boot hangs.
> 
> Calling mx28_power_init() prior to mxs_iomux_setup_multiple_pads() fixes
> the problem and make U-boot to re-start succesfully.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> This patch fixes the reboot issue, but I am not able to provide a good
> explanation for it, so I am marking it as RFC.
> 
>  arch/arm/cpu/arm926ejs/mx28/spl_boot.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/cpu/arm926ejs/mx28/spl_boot.c
> b/arch/arm/cpu/arm926ejs/mx28/spl_boot.c index dfb8309..0e57252 100644
> --- a/arch/arm/cpu/arm926ejs/mx28/spl_boot.c
> +++ b/arch/arm/cpu/arm926ejs/mx28/spl_boot.c
> @@ -49,8 +49,8 @@ void early_delay(int delay)
>  void mx28_common_spl_init(const iomux_cfg_t *iomux_setup,
>  			const unsigned int iomux_size)
>  {
> -	mxs_iomux_setup_multiple_pads(iomux_setup, iomux_size);
>  	mx28_power_init();
> +	mxs_iomux_setup_multiple_pads(iomux_setup, iomux_size);
>  	mx28_mem_init();
>  	mx28_power_wait_pswitch();
>  }

Can you explain why this patch fixes anything ? It's hard to understand why 
doing this would fix it.