Hi Neil, On Wed, Dec 11, 2019 at 9:49 AM Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote: > > On 10/12/2019 22:47, Kevin Hilman wrote: > > Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> writes: > > > >> On Tue, Dec 10, 2019 at 7:13 PM Kevin Hilman <khilman@xxxxxxxxxxxx> wrote: > >>> > >>> Anand Moon <linux.amoon@xxxxxxxxx> writes: > >>> > >>>> Hi Neil / Kevin, > >>>> > >>>> On Tue, 10 Dec 2019 at 14:13, Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote: > >>>>> > >>>>> On 09/12/2019 23:12, Kevin Hilman wrote: > >>>>>> Anand Moon <linux.amoon@xxxxxxxxx> writes: > >>>>>> > >>>>>>> Some how this patch got lost, so resend this again. > >>>>>>> > >>>>>>> [0] https://patchwork.kernel.org/patch/11136545/ > >>>>>>> > >>>>>>> This patch enable DVFS on GXBB Odroid C2. > >>>>>>> > >>>>>>> DVFS has been tested by running the arm64 cpuburn > >>>>>>> [1] https://github.com/ssvb/cpuburn-arm/blob/master/cpuburn-a53.S > >>>>>>> PM-QA testing > >>>>>>> [2] https://git.linaro.org/power/pm-qa.git [cpufreq testcase] > >>>>>>> > >>>>>>> Tested on latest U-Boot 2019.07-1 (Aug 01 2019 - 23:58:01 +0000) Arch Linux ARM > >>>>>> > >>>>>> Have you tested with the Harkernel u-boot? > >>>>>> > >>>>>> Last I remember, enabling CPUfreq will cause system hangs with the > >>>>>> Hardkernel u-boot because of improperly enabled frequencies, so I'm not > >>>>>> terribly inclined to merge this patch. > >>>> > >>>> HK u-boot have many issue with loading the kernel, with load address > >>>> *it's really hard to build the kernel for HK u-boot*, > >>>> to get the configuration correctly. > >>>> > >>>> Well I have tested with mainline u-boot with latest ATF . > >>>> I would prefer mainline u-boot for all the Amlogic SBC, since > >>>> they sync with latest driver changes. > >>> > >>> Yes, we would all prefer mainline u-boot, but the mainline kernel needs > >>> to support the vendor u-boot that is shipping with the boards. So > >>> until Hardkernel (and other vendors) switch to mainline u-boot we do not > >>> want to have upstream kernel defaults that will not boot with the vendor > >>> u-boot. > >>> > >>> We can always support these features, but they just cannot be enabled > >>> by default. > >> (I don't have an Odroid-C2 but I'm curious) > >> should Anand submit a patch to mainline u-boot instead? > > > > It would be in addition to $SUBJECT patch, not instead, I think. > > > >> the &scpi_clocks node could be enabled at runtime by mainline u-boot > > > > That would work, but I don't know about u-boot maintainers opinions on > > this kind of thing, so let's see what Neil thinks. > > U-Boot doesn't anything to do with SCPI, SCPI discusses directly with the SCP > processor, and the CPU clock is set to 1,56GHz by the BL2 boot stage before > U-boot starts. > > The only viable solution I see now is to find if we could add a DT OPP table > only for Odroid-C2 dts to bypass the SCPI OPP table. my understanding is that mainline u-boot (with whatever SCP firmware it uses) provides the *correct* OPP table in this case it would be "safe" to have SCPI enabled with mainline u-boot @Anand: please correct me if I misunderstood you my idea to "enable SCPI with mainline u-boot" is to have u-boot update the "status" property of the scpi_clocks node. u-boot does something similar with the mac-address property of the Ethernet controller for example. as result of this users of mainline u-boot would have working CPU DVFS, while users of the old vendor u-boot would run at fixed 1.54GHz. Martin
