Messages in this thread |  | | Subject | Re: [PATCH 2/2] powernv: Pass PSSCR value and mask to power9_idle_stop | From | Balbir Singh <> | Date | Tue, 4 Oct 2016 22:33:27 +1100 |
| |
On 04/10/16 21:32, Michael Ellerman wrote: > "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> writes: > >> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> >> >> The power9_idle_stop method currently takes only the requested stop >> level as a parameter and picks up the rest of the PSSCR bits from a >> hand-coded macro. This is not a very flexible design, especially when >> the firmware has the capability to communicate the psscr value and the >> mask associated with a particular stop state via device tree. >> >> This patch modifies the power9_idle_stop API to take as parameters the >> PSSCR value and the PSSCR mask corresponding to the stop state that >> needs to be set. These PSSCR value and mask are respectively obtained >> by parsing the "ibm,cpu-idle-state-psscr" and >> "ibm,cpu-idle-state-psscr-mask" fields from the device tree. >> >> In addition to this, the patch adds support for handling stop states >> for which ESL and EC bits in the PSSCR are zero. As per the >> architecture, a wakeup from these stop states resumes execution from >> the subsequent instruction as opposed to waking up at the System >> Vector. > > That looks good. > >> This patch depends on the following skiboot patch that exports the >> PSSCR values and the mask for all the stop states: >> https://lists.ozlabs.org/pipermail/skiboot/2016-September/004869.html > > But we can't depend on a skiboot patch. The kernel has to cope with > running on an old skiboot.
Hi, Michael
I think with an older skiboot the flags don't get exported and the new cpuidle (stop state) does not get discovered. I don't think there is any breakage. Gautham am I missing something?
Balbir Singh.
|  |