Re: [PATCH v5 6/6] qcom/soc/drivers: Add DTPM description for sdm845

Steev Klimaszewski
2021-12-18T19:48:03Z

Hi Daniel,

On 12/18/21 7:00 AM, Daniel Lezcano wrote:
> The DTPM framework does support now the hierarchy description.
>
> The platform specific code can call the hierarchy creation function
> with an array of struct dtpm_node pointing to their parents.
>
> This patch provides a description of the big and Little CPUs and the
> GPU and tie them together under a virtual package name. Only sdm845 is
> described.
>
> The description could be extended in the future with the memory
> controller with devfreq if it has the energy information.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/soc/qcom/Kconfig | 9 ++++++
> drivers/soc/qcom/Makefile | 1 +
> drivers/soc/qcom/dtpm.c | 65 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 75 insertions(+)
> create mode 100644 drivers/soc/qcom/dtpm.c
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index e718b8735444..f21c1df2f2f9 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -228,4 +228,13 @@ config QCOM_APR
> application processor and QDSP6. APR is
> used by audio driver to configure QDSP6
> ASM, ADM and AFE modules.
> +
> +config QCOM_DTPM
> + tristate "Qualcomm DTPM hierarchy"

Testing this on a Lenovo Yoga C630 here and...

Should this be tristate?  Is it actually possible to unload the module
once it's loaded?

Here I have DTPM=y, DTPM_CPU=y, DTPM_DEVFREQ=y, QCOM_DTPM=m

But if I attempt to modprobe -r dtpm,

modprobe: ERROR: ../libkmod/libkmod-module.c:799
kmod_module_remove_module() could not remove 'dtpm': Device or resource busy

> + depends on DTPM
> + help
> + Describe the hierarchy for the Dynamic Thermal Power
> + Management tree on this platform. That will create all the
> + power capping capable devices.
> +
> endmenu
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index 70d5de69fd7b..cf38496c3f61 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -28,3 +28,4 @@ obj-$(CONFIG_QCOM_LLCC) += llcc-qcom.o
> obj-$(CONFIG_QCOM_RPMHPD) += rpmhpd.o
> obj-$(CONFIG_QCOM_RPMPD) += rpmpd.o
> obj-$(CONFIG_QCOM_KRYO_L2_ACCESSORS) += kryo-l2-accessors.o
> +obj-$(CONFIG_QCOM_DTPM) += dtpm.o
> diff --git a/drivers/soc/qcom/dtpm.c b/drivers/soc/qcom/dtpm.c
> new file mode 100644
> index 000000000000..c15283f59494
> --- /dev/null
> +++ b/drivers/soc/qcom/dtpm.c
> @@ -0,0 +1,65 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2021 Linaro Limited
> + *
> + * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
> + *
> + * DTPM hierarchy description
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/dtpm.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +
> +static struct dtpm_node __initdata sdm845_hierarchy[] = {
> + [0]{ .name = "sdm845" },
> + [1]{ .name = "package",
> + .parent = &sdm845_hierarchy[0] },
> + [2]{ .name = "/cpus/cpu@0",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [3]{ .name = "/cpus/cpu@100",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [4]{ .name = "/cpus/cpu@200",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [5]{ .name = "/cpus/cpu@300",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [6]{ .name = "/cpus/cpu@400",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [7]{ .name = "/cpus/cpu@500",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [8]{ .name = "/cpus/cpu@600",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [9]{ .name = "/cpus/cpu@700",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [10]{ .name = "/soc@0/gpu@5000000",
> + .type = DTPM_NODE_DT,
> + .parent = &sdm845_hierarchy[1] },
> + [11]{ },
> +};
> +
> +static struct of_device_id __initdata sdm845_dtpm_match_table[] = {
> + { .compatible = "qcom,sdm845", .data = sdm845_hierarchy },
> + {},
> +};
> +
> +static int __init sdm845_dtpm_init(void)
> +{
> + return dtpm_create_hierarchy(sdm845_dtpm_match_table);
> +}
> +late_initcall(sdm845_dtpm_init);
> +
> +MODULE_DESCRIPTION("Qualcomm DTPM driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:dtpm");
> +MODULE_AUTHOR("Daniel Lezcano <daniel.lezcano@kernel.org");
> +

It does seem to work aside from not being able to modprobe -r the
module. Although I do see

[   35.849622] dtpm: Registered dtpm node 'sdm845' / 0-0 uW,
[   35.849652] dtpm: Registered dtpm node 'package' / 0-0 uW,
[   35.849676] dtpm: Registered dtpm node 'cpu0-cpufreq' / 40000-436000 uW,
[   35.849702] dtpm: Registered dtpm node 'cpu4-cpufreq' /
520000-5828000 uW,
[   35.849734] dtpm_devfreq: No energy model available for '5000000.gpu'
[   35.849738] dtpm: Failed to setup '/soc@0/gpu@5000000': -22

If the devfreq issue with the gpu isn't expected, are we missing
something for the c630?

-- Steev