Re: [PATCH] OMAP3: PM: Fix for Silicon bug on Context Restore on OMAP3430

[Kevin Hilman <khilman@deeprootsystems.com>]

y@india.ti.com writes:

> From: Shweta Gulati <shweta.gulati@ti.com>

Please add descriptive changelog, including Erratta number and
summary of the bug.

> Signed-off-by: Shweta Gulati <shweta.gulati@ti.com>
> ---
>  arch/arm/mach-omap2/pm34xx.c |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index a9eda25..38f4781 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -140,6 +140,12 @@ static void omap3_core_save_context(void)
>  	omap_ctrl_readl(OMAP343X_CONTROL_PADCONF_OFF);
>  	control_padconf_off |= START_PADCONF_SAVE;
>  	omap_ctrl_writel(control_padconf_off, OMAP343X_CONTROL_PADCONF_OFF);
> +	/* Due to Silicon Bug on context restore it is found
> +	 * that the CONTROL_PAD_CONF_ETK14 register is not saved into
> +	 * scratch pad memory sometimes. To rectify it delay acess by Mpu
> +	 * for 300us for scm to finish saving task
> +	 */
> +	udelay(300);

Why 300 usecs?
Is ETK14 the only register not saved?

>  	/* wait for the save to complete */
>  	while (!omap_ctrl_readl(OMAP343X_CONTROL_GENERAL_PURPOSE_STATUS)
>  			& PADCONF_SAVE_DONE)

And please describe why this loop doesn't work.

Kevin