Hi,
On 01-09-16 09:57, Antoine Tenart wrote:
Hi all,
This series adds an implementation of the psci suspend function for both sun5i and sun7i. This was tested on Nextthing's CHIP and on a A20, using cpuidle in Linux. My tests showed a power consumption reduced by a factor 2 on the CHIP when the system was idle. It went from ~1W without cpuidle enabled to ~0.45W.
The idea of this suspend function is to put the dram into self-refresh, cut off some plls and to switch cpuclk to a source with a lower frequency. Please note the sun7i implementation lacks some parts as putting the ram into self-refresh and coming back from this state seems a bit tricky. I made some tests but did not managed yet to have a stable solution.
As the sun5i does not have a GIC, I needed to remove some code from the generic psci code. To do this I added an ARM_GIC Kconfig option which needs to be selected by each SoC having a GIC. I already added the relevant lines regarding sunXi SoCs. As this Kconfig option is currently only used in the psci code, it should be safe to add it even of all the SoCs having a GIC do not select it, as long as they don't have psci functions.
Finally the series has a patch to enable the psci support for sun5i SoCs, and another patch to let sun5i SoCs boot the kernel in non-secure mode so that it can call psci functions.
Cool stuff. I've some minor remarks to some of the patches I'll reply to them separately. I also hope someone who knows this stuff better then me can also take a look, but if not then I'm just going to take it for the next u-boot cycle (with the remarks fixed).
Regards,
Hans
Thanks!
Antoine
Antoine Tenart (6): ARM: add the ARM_GIC configuration option sunxi: select ARM_GIC for sun[6789]i ARM: PSCI: protect GIC specific code with ARM_GIC sun5/7i: add an implementation of the psci suspend function sun5i: enable PSCI sun5i: boot in HYP mode by default
arch/arm/Kconfig | 3 + arch/arm/cpu/armv7/nonsec_virt.S | 6 + arch/arm/cpu/armv7/sunxi/Makefile | 9 +- arch/arm/cpu/armv7/sunxi/psci_suspend.c | 175 ++++++++++++++++++++++++++ arch/arm/cpu/armv7/virt-v7.c | 38 +++--- arch/arm/include/asm/arch-sunxi/clock_sun4i.h | 7 ++ arch/arm/include/asm/arch-sunxi/dram_sun4i.h | 11 ++ board/sunxi/Kconfig | 9 ++ include/configs/sun5i.h | 5 + 9 files changed, 248 insertions(+), 15 deletions(-) create mode 100644 arch/arm/cpu/armv7/sunxi/psci_suspend.c