[Skiboot] [PATCH] init: Perform pstates-init before dt blob creation

[Vaidyanathan Srinivasan]

* Gautham R Shenoy <ego at linux.vnet.ibm.com> [2019-07-10 17:59:19]:

> From: "Gautham R. Shenoy" <ego at linux.vnet.ibm.com>
> 
> On FSP based systems (particularly POWER8), we perform
> occ_pstates_init() late in the boot to allow OCC to be loaded. Hence
> this was being performed in platform.exit(). occ_pstates_init() would
> add pstate information into the device-tree.
> 
> A recent commit 9fc0c1287ada ("Move FSP specific op-panel calls to
> platform.exit()") moved the invocation of platform.exit() after the
> creation of device-tree blob. As a result, on FSP based systems, we
> don't have the pstate information in the device-tree, and thus the
> Kernel is unable to perform frequency scaling.
> 
> Fix this by moving occ_pstates_init() out of ibm_fsp_exit() and call
> it before the creation of the device-tree blob.
> 
> Fixes: commit 9fc0c1287ada ("Move FSP specific op-panel calls to
> platform.exit()")
> 
> Signed-off-by: Gautham R. Shenoy <ego at linux.vnet.ibm.com>

Reviewed-by: Vaidyanathan Srinivasan <svaidy at linux.ibm.com>

> ---
>  core/init.c                | 6 ++++++
>  platforms/ibm-fsp/common.c | 7 -------
>  2 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/core/init.c b/core/init.c
> index d0f28f2..8eb0729 100644
> --- a/core/init.c
> +++ b/core/init.c
> @@ -557,6 +557,12 @@ void __noreturn load_and_boot_kernel(bool is_reboot)
>  		if (!occ_sensors_init())
>  			dts_sensor_create_nodes(sensor_node);
> 
> +		/*
> +		 * OCC takes few secs to boot on FSP systems. Call
> +		 * this as late as as possible to avoid delay.
> +		 */
> +		if (!platform.bmc)
> +			occ_pstates_init();
>  	} else {
>  		/* fdt will be rebuilt */
>  		free(fdt);

Thanks Gautham for the fix.

We need to add the DT binding before it is wrapped up and passed to
host OS kernel.

--Vaidy