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. The arm,scpi-clocks driver registers a clk for this CPU clock, using SCPI to set the rate, right now this is ok. But, arm,scpi-clocks also registers a "scpi-cpufreq" device, which calls scpi_ops->add_opps_to_device() which gets the SCPI OPPs and adds them to the CPU. A way to handle this would be to check if DT has OPPs in drivers/cpufreq/scpi-cpufreq.c _before/instead_ calling scpi_ops->add_opps_to_device() to use the DT OPPs instead of the firmware OPPs, like in drivers/cpufreq/cpufreq-dt.c. calling: ret = dev_pm_opp_of_get_sharing_cpus() if (ret) { scpi_ops->add_opps_to_device() scpi_get_sharing_cpus() } would maybe work. Neil > > Kevin > >
