On Thu, 2022-05-19 at 11:24 +0800, Chen-Yu Tsai wrote: > On Wed, May 18, 2022 at 8:19 PM Johnson Wang < > johnson.wang@xxxxxxxxxxxx> wrote: > > > > Hi Chen-Yu, > > > > On Fri, 2022-05-13 at 11:54 +0800, Chen-Yu Tsai wrote: > > > On Fri, May 13, 2022 at 11:31 AM Johnson Wang < > > > johnson.wang@xxxxxxxxxxxx> wrote: > > > > > > > > We introduce a devfreq driver for the MediaTek Cache Coherent > > > > Interconnect > > > > (CCI) used by some MediaTek SoCs. > > > > > > > > In this driver, we use the passive devfreq driver to get target > > > > frequencies > > > > and adjust voltages accordingly. In MT8183 and MT8186, the > > > > MediaTek > > > > CCI > > > > is supplied by the same regulators with the little core CPUs. > > > > > > > > Signed-off-by: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx> > > > > Signed-off-by: Johnson Wang <johnson.wang@xxxxxxxxxxxx> > > > > Acked-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> > > > > --- > > > > This patch depends on "devfreq-testing"[1]. > > > > [1] > > > > https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing__;!!CTRNKA9wMg0ARbw!zzOSoso9udvDV3h6kYlmizFtbn3ACA5aS2jCAjKyvtu4z0fobv1mD5uF9YbPSme8l_NnR05unTxkZfDdzohu8asWZQ$ > > > > > > > > --- > > > > drivers/devfreq/Kconfig | 10 + > > > > drivers/devfreq/Makefile | 1 + > > > > drivers/devfreq/mtk-cci-devfreq.c | 474 > > > > ++++++++++++++++++++++++++++++ > > > > 3 files changed, 485 insertions(+) > > > > create mode 100644 drivers/devfreq/mtk-cci-devfreq.c > > > > > > > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > > > > index 87eb2b837e68..9754d8b31621 100644 > > > > --- a/drivers/devfreq/Kconfig > > > > +++ b/drivers/devfreq/Kconfig > > > > @@ -120,6 +120,16 @@ config ARM_TEGRA_DEVFREQ > > > > It reads ACTMON counters of memory controllers and > > > > adjusts the > > > > operating frequencies and voltages with OPP support. > > > > > > > > +config ARM_MEDIATEK_CCI_DEVFREQ > > > > + tristate "MEDIATEK CCI DEVFREQ Driver" > > > > + depends on ARM_MEDIATEK_CPUFREQ || COMPILE_TEST > > > > + select DEVFREQ_GOV_PASSIVE > > > > + help > > > > + This adds a devfreq driver for MediaTek Cache > > > > Coherent > > > > Interconnect > > > > + which is shared the same regulators with the cpu > > > > cluster. > > > > It can track > > > > + buck voltages and update a proper CCI frequency. Use > > > > the > > > > notification > > > > + to get the regulator status. > > > > + > > > > config ARM_RK3399_DMC_DEVFREQ > > > > tristate "ARM RK3399 DMC DEVFREQ Driver" > > > > depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) || \ > > > > diff --git a/drivers/devfreq/Makefile > > > > b/drivers/devfreq/Makefile > > > > index 0b6be92a25d9..bf40d04928d0 100644 > > > > --- a/drivers/devfreq/Makefile > > > > +++ b/drivers/devfreq/Makefile > > > > @@ -11,6 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += > > > > governor_passive.o > > > > obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o > > > > obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o > > > > obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o > > > > +obj-$(CONFIG_ARM_MEDIATEK_CCI_DEVFREQ) += mtk-cci-devfreq.o > > > > obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o > > > > obj-$(CONFIG_ARM_SUN8I_A33_MBUS_DEVFREQ) += sun8i-a33- > > > > mbus.o > > > > obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30- > > > > devfreq.o > > > > diff --git a/drivers/devfreq/mtk-cci-devfreq.c > > > > b/drivers/devfreq/mtk-cci-devfreq.c > > > > new file mode 100644 > > > > index 000000000000..aa8c37eb4a06 > > > > --- /dev/null > > > > +++ b/drivers/devfreq/mtk-cci-devfreq.c > > > > @@ -0,0 +1,474 @@ > > [...] > > > > > + if (IS_ERR(drv->sram_reg)) > > > > + drv->sram_reg = NULL; > > > > + else { > > > > + ret = regulator_enable(drv->sram_reg); > > > > + if (ret) { > > > > + dev_err(dev, "failed to enable sram > > > > regulator\n"); > > > > + goto out_free_resources; > > > > + } > > > > + } > > > > + > > > > + /* > > > > + * We assume min voltage is 0 and tracking target > > > > voltage > > > > using > > > > + * min_volt_shift for each iteration. > > > > + * The retry_max is 3 times of expeted iteration count. > > > > > > expected? > > > > > > > Maybe "the maximum" will be more appropriate? > > > I was merely pointing out a typo in "expeted". > > Looking at it again, I'm not sure why retry attempts are tied to the > voltage. > > > ChenYu Hi Chen-Yu, Thanks for you reminder. Whenever the voltages are scaled up/down one step, meaning that there is another iteration in the while loop. Thus, our thought is to use times of the voltages step up/down to set iteration limit. BRs, Johnson Wang
