On Tue, May 03, 2022 at 02:11:59PM +0100, Mark Rutland wrote: > Hi Phil, > > This is the only patch from this series that I've received, and judging > by the CC list this hasn't gone to either LKML or LAKML, so I'm missing > the surrounding context for this. > > Looking on lore, this is part of: > > https://lore.kernel.org/linux-devicetree/20220503115557.53370-1-phil.edworthy@xxxxxxxxxxx/T/#t > > ... which is adding support for an arm64 SoC. > > On Tue, May 03, 2022 at 12:55:49PM +0100, Phil Edworthy wrote: > > Some SoCs use a gated clock for the timer and the means to reset the timer. > > Hence add these as optional. > > The clock feeding the architected timer is supposed to be in an > always-on clock domain, and is supopsed to be enabled before running any > Normal World software. > > The arm64 kernel *requires* that this is enabled prior to entry. If the > kernel ever has to touch either the clock or reset, then there are > phases where the counter will not function correctly, which is simply > broken. > > Given that, I do not think this should be in the DT, and instead the > clock should be marked as critical in the provider node (and the reset > should never be touched). That is not yet an accepted DT property, but is currently on the list for review[1]. If that's something people need, chime in. More than 1 person needing something is always better. Rob [1] https://lore.kernel.org/all/20220428110107.149524-1-marex@xxxxxxx/
