[Skiboot] [PATCH] init: Perform pstates-init before dt blob creation
Gautham R Shenoy
ego at linux.vnet.ibm.com
Thu Jul 11 15:24:58 AEST 2019
Hi Vasant,
On Thu, Jul 11, 2019 at 10:40:58AM +0530, Vasant Hegde wrote:
> On 07/10/2019 05:59 PM, Gautham R. Shenoy wrote:
> >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>
>
> Thanks for the fix.
>
> >---
> > 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();
>
> So you will end up calling occ_pstates_init() on simulators as well. Do you
> really want that?
Perhaps not. You are right, I hadn't factored in the simulators. We
should do this only for FSP based systems.
> Today its occ_pstates, tomorrow we may have something else.
> IMO we should continue to have all those things inside platform.exit()
> function and move
> platform.exit function just before creating dtb.
Fine by me. However, in commit 9fc0c1287ada the platform.exit() was
moved from the point right before creation of the dtb to a later
stage to incorporate the op-panel calls into the platform.exit(). Will
it cause any problems if we move the platform.exit() up in the code ?
>
>
> > } else {
> > /* fdt will be rebuilt */
> > free(fdt);
> >diff --git a/platforms/ibm-fsp/common.c b/platforms/ibm-fsp/common.c
> >index 7f7a1f2..6da25d1 100644
> >--- a/platforms/ibm-fsp/common.c
> >+++ b/platforms/ibm-fsp/common.c
> >@@ -186,13 +186,6 @@ void ibm_fsp_exit(void)
> > /* Wait for FW VPD data read to complete */
> > fsp_code_update_wait_vpd(true);
> >
> >- /*
> >- * OCC takes few secs to boot. Call this as late as
> >- * as possible to avoid delay.
> >- */
> >- if (fsp_present())
> >- occ_pstates_init();
>
> Given that its inside fsp exit() function, fsp_present() check is redundant.
> We should cleanup that.
Yeah, will clean that up.
>
> -Vasant
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