| Message ID | 20190606142255.29454-1-nsaenzjulienne@suse.de (mailing list archive) |
|---|---|
| Headers | show |
| Series | cpufreq support for Raspberry Pi | expand |
Am 06.06.19 um 16:22 schrieb Nicolas Saenz Julienne: > Hi all, > this aims at adding cpufreq support to the Raspberry Pi family of > boards. > > The series first factors out 'pllb' from clk-bcm2385 and creates a new > clk driver that operates it over RPi's firmware interface[1]. We are > forced to do so as the firmware 'owns' the pll and we're not allowed to > change through the register interface directly as we might race with the > over-temperature and under-voltage protections provided by the firmware. > > Next it creates a minimal cpufreq driver that populates the CPU's opp > table, and registers cpufreq-dt. Which is needed as the firmware > controls the max and min frequencies available. Here some figures from the Raspberry Pi 3 B+ as before/after comparison: Dhrystone Benchmark 2.1 A7 32 Bit 600 MHz, w/o Turbo (1): 1216.11 VAX MIPS 1400 MHz, w/o Turbo (2): 2839.67 VAX MIPS 1400 MHz, w Turbo (3): 2839.45 VAX MIPS Whetstone Single Precision C Benchmark vfpv4 32 Bit 600 MHz, w/o Turbo: 454.565 MWIPS 1400 MHz, w/o Turbo: 1062.494 MWIPS 1400 MHz, w Turbo: 1061.723 MWIPS Power consumption (32 bit, without Ethernet) with load ( cat /dev/zero ) 600 MHz, w/o Turbo: 2.48 W 1400 MHz, w/o Turbo: 3.2 W 1400 MHz, w Turbo: 3.15 W Note 1: This is the maximum performance before enabling any cpufreq driver. Note 2: This is the maximum performance after enabling V2 of the cpufreq driver http://lists.infradead.org/pipermail/linux-arm-kernel/2019-June/657768.html Note 3: This is the maximum performance after enabling the initial cpufreq driver http://lists.infradead.org/pipermail/linux-rpi-kernel/2019-April/008634.html
Hi all, this aims at adding cpufreq support to the Raspberry Pi family of boards. The series first factors out 'pllb' from clk-bcm2385 and creates a new clk driver that operates it over RPi's firmware interface[1]. We are forced to do so as the firmware 'owns' the pll and we're not allowed to change through the register interface directly as we might race with the over-temperature and under-voltage protections provided by the firmware. Next it creates a minimal cpufreq driver that populates the CPU's opp table, and registers cpufreq-dt. Which is needed as the firmware controls the max and min frequencies available. This was tested on a RPi3b+ and RPI2b, both using multi_v7_defconfig and arm64's defconfig. @Eric: Even though some things change, namely to properly support being built as a module, I still added your Acked-by as it didn't change the overall design. I hope it's OK. That's all, kind regards, Nicolas [1] https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface --- Changes since v1: - Enabled by default on the whole family of devices - Added/Fixed module support - clk device now registered by firmware driver - raspberrypi-cpufreq device now registered by clk driver - Reimplemented clk rounding unsing determine_rate() - Enabled in configs for arm and arm64 Changes since RFC: - Move firmware clk device into own driver Nicolas Saenz Julienne (7): clk: bcm2835: remove pllb clk: bcm283x: add driver interfacing with Raspberry Pi's firmware firmware: raspberrypi: register clk device cpufreq: add driver for Raspbery Pi clk: raspberrypi: register platform device for raspberrypi-cpufreq ARM: defconfig: enable cpufreq driver for RPi arm64: defconfig: enable cpufreq support for RPi3 arch/arm/configs/bcm2835_defconfig | 9 + arch/arm/configs/multi_v7_defconfig | 2 + arch/arm64/configs/defconfig | 2 + drivers/clk/bcm/Kconfig | 7 + drivers/clk/bcm/Makefile | 1 + drivers/clk/bcm/clk-bcm2835.c | 28 +-- drivers/clk/bcm/clk-raspberrypi.c | 316 ++++++++++++++++++++++++++ drivers/cpufreq/Kconfig.arm | 8 + drivers/cpufreq/Makefile | 1 + drivers/cpufreq/raspberrypi-cpufreq.c | 100 ++++++++ drivers/firmware/raspberrypi.c | 10 + 11 files changed, 460 insertions(+), 24 deletions(-) create mode 100644 drivers/clk/bcm/clk-raspberrypi.c create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c