[PATCH] ARM i.MX28: change default watchdog reset method

[PATCH] ARM i.MX28: change default watchdog reset method

[Steffen Trumtrar]

The default setting for the imx28 watchdog is to do a power-off reset. If the
SoC is only powered via battery, then the watchdog powers the chip down, though.
According to the datasheet it should still be possible to execute a proper POR
with battery power, but testing showed otherwise.
When the watchdog power-off reset is disabled, a software reset is executed
instead. This works with and without battery power.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
 arch/arm/mach-mxs/soc-imx28.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/mach-mxs/soc-imx28.c b/arch/arm/mach-mxs/soc-imx28.c
index a181b75..a5f3d68 100644
--- a/arch/arm/mach-mxs/soc-imx28.c
+++ b/arch/arm/mach-mxs/soc-imx28.c
@@ -21,6 +21,7 @@
 
 #define HW_CLKCTRL_RESET 0x1e0
 # define HW_CLKCTRL_RESET_CHIP (1 << 1)
+#define HW_CLKCTRL_WDOG_POR_DISABLE (1 << 5)
 
 /* Reset the full i.MX28 SoC via a chipset feature */
 void __noreturn reset_cpu(unsigned long addr)
@@ -35,3 +36,14 @@ void __noreturn reset_cpu(unsigned long addr)
 	/*NOTREACHED*/
 }
 EXPORT_SYMBOL(reset_cpu);
+
+static int imx28_init(void)
+{
+	/*
+	 * The default setting for the WDT is to do a POR. If the SoC is only
+	 * powered via battery, then a WDT reset powers the chip down instead
+	 * of resetting it. Use a software reset only.
+	 */
+	writel(HW_CLKCTRL_WDOG_POR_DISABLE, IMX_CCM_BASE + HW_CLKCTRL_RESET);
+}
+postcore_initcall(imx28_init);
-- 
1.7.10.4


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Re: [PATCH] ARM i.MX28: change default watchdog reset method

[Sascha Hauer]

On Mon, Feb 11, 2013 at 11:42:05AM +0100, Steffen Trumtrar wrote:
> The default setting for the imx28 watchdog is to do a power-off reset. If the
> SoC is only powered via battery, then the watchdog powers the chip down, though.
> According to the datasheet it should still be possible to execute a proper POR
> with battery power, but testing showed otherwise.
> When the watchdog power-off reset is disabled, a software reset is executed
> instead. This works with and without battery power.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>

Applied, thanks

Sascha

> ---
>  arch/arm/mach-mxs/soc-imx28.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/arch/arm/mach-mxs/soc-imx28.c b/arch/arm/mach-mxs/soc-imx28.c
> index a181b75..a5f3d68 100644
> --- a/arch/arm/mach-mxs/soc-imx28.c
> +++ b/arch/arm/mach-mxs/soc-imx28.c
> @@ -21,6 +21,7 @@
>  
>  #define HW_CLKCTRL_RESET 0x1e0
>  # define HW_CLKCTRL_RESET_CHIP (1 << 1)
> +#define HW_CLKCTRL_WDOG_POR_DISABLE (1 << 5)
>  
>  /* Reset the full i.MX28 SoC via a chipset feature */
>  void __noreturn reset_cpu(unsigned long addr)
> @@ -35,3 +36,14 @@ void __noreturn reset_cpu(unsigned long addr)
>  	/*NOTREACHED*/
>  }
>  EXPORT_SYMBOL(reset_cpu);
> +
> +static int imx28_init(void)
> +{
> +	/*
> +	 * The default setting for the WDT is to do a POR. If the SoC is only
> +	 * powered via battery, then a WDT reset powers the chip down instead
> +	 * of resetting it. Use a software reset only.
> +	 */
> +	writel(HW_CLKCTRL_WDOG_POR_DISABLE, IMX_CCM_BASE + HW_CLKCTRL_RESET);
> +}
> +postcore_initcall(imx28_init);
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
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> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

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