On Thu, 17 Dec 2020 at 19:07, Dmitry Osipenko <dig...@gmail.com> wrote:
>
> NVIDIA Tegra SoCs have multiple power domains, each domain corresponds
> to an external SoC power rail. Core power domain covers vast majority of
> hardware blocks within a Tegra SoC. The voltage of a power domain should
> be set to a value which satisfies all devices within a power domain. Add
> driver for the core power domain in order to manage the voltage state of
> the domain. This allows us to support a system-wide DVFS on Tegra.
>
> Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
FYI: from a genpd provider driver point of view, this looks good to
me. However, withholding my ack for the next version, just to make
sure I take a second look.
Kind regards
Uffe
> ---
> drivers/soc/tegra/Kconfig | 6 ++
> drivers/soc/tegra/Makefile | 1 +
> drivers/soc/tegra/core-power-domain.c | 125 ++++++++++++++++++++++++++
> include/soc/tegra/common.h | 6 ++
> 4 files changed, 138 insertions(+)
> create mode 100644 drivers/soc/tegra/core-power-domain.c
>
> diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig
> index bcd61ae59ba3..fccbc168dd87 100644
> --- a/drivers/soc/tegra/Kconfig
> +++ b/drivers/soc/tegra/Kconfig
> @@ -16,6 +16,7 @@ config ARCH_TEGRA_2x_SOC
> select SOC_TEGRA_COMMON
> select SOC_TEGRA_FLOWCTRL
> select SOC_TEGRA_PMC
> + select SOC_TEGRA_CORE_POWER_DOMAIN
> select SOC_TEGRA20_VOLTAGE_COUPLER
> select TEGRA_TIMER
> help
> @@ -31,6 +32,7 @@ config ARCH_TEGRA_3x_SOC
> select SOC_TEGRA_COMMON
> select SOC_TEGRA_FLOWCTRL
> select SOC_TEGRA_PMC
> + select SOC_TEGRA_CORE_POWER_DOMAIN
> select SOC_TEGRA30_VOLTAGE_COUPLER
> select TEGRA_TIMER
> help
> @@ -170,3 +172,7 @@ config SOC_TEGRA20_VOLTAGE_COUPLER
> config SOC_TEGRA30_VOLTAGE_COUPLER
> bool "Voltage scaling support for Tegra30 SoCs"
> depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
> +
> +config SOC_TEGRA_CORE_POWER_DOMAIN
> + bool
> + select PM_GENERIC_DOMAINS
> diff --git a/drivers/soc/tegra/Makefile b/drivers/soc/tegra/Makefile
> index 9c809c1814bd..8f1294f954b4 100644
> --- a/drivers/soc/tegra/Makefile
> +++ b/drivers/soc/tegra/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_SOC_TEGRA_PMC) += pmc.o
> obj-$(CONFIG_SOC_TEGRA_POWERGATE_BPMP) += powergate-bpmp.o
> obj-$(CONFIG_SOC_TEGRA20_VOLTAGE_COUPLER) += regulators-tegra20.o
> obj-$(CONFIG_SOC_TEGRA30_VOLTAGE_COUPLER) += regulators-tegra30.o
> +obj-$(CONFIG_SOC_TEGRA_CORE_POWER_DOMAIN) += core-power-domain.o
> diff --git a/drivers/soc/tegra/core-power-domain.c
> b/drivers/soc/tegra/core-power-domain.c
> new file mode 100644
> index 000000000000..7c0cec8c79fd
> --- /dev/null
> +++ b/drivers/soc/tegra/core-power-domain.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * NVIDIA Tegra SoC Core Power Domain Driver
> + */
> +
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_opp.h>
> +#include <linux/slab.h>
> +
> +#include <soc/tegra/common.h>
> +
> +static struct lock_class_key tegra_core_domain_lock_class;
> +static bool tegra_core_domain_state_synced;
> +
> +static int tegra_genpd_set_performance_state(struct generic_pm_domain *genpd,
> + unsigned int level)
> +{
> + struct dev_pm_opp *opp;
> + int err;
> +
> + opp = dev_pm_opp_find_level_ceil(&genpd->dev, &level);
> + if (IS_ERR(opp)) {
> + dev_err(&genpd->dev, "failed to find OPP for level %u: %pe\n",
> + level, opp);
> + return PTR_ERR(opp);
> + }
> +
> + err = dev_pm_opp_set_voltage(&genpd->dev, opp);
> + dev_pm_opp_put(opp);
> +
> + if (err) {
> + dev_err(&genpd->dev, "failed to set voltage to %duV: %d\n",
> + level, err);
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static unsigned int
> +tegra_genpd_opp_to_performance_state(struct generic_pm_domain *genpd,
> + struct dev_pm_opp *opp)
> +{
> + return dev_pm_opp_get_level(opp);
> +}
> +
> +static int tegra_core_domain_probe(struct platform_device *pdev)
> +{
> + struct generic_pm_domain *genpd;
> + struct opp_table *opp_table;
> + const char *rname = "power";
> + int err;
> +
> + genpd = devm_kzalloc(&pdev->dev, sizeof(*genpd), GFP_KERNEL);
> + if (!genpd)
> + return -ENOMEM;
> +
> + genpd->name = pdev->dev.of_node->name;
> + genpd->set_performance_state = tegra_genpd_set_performance_state;
> + genpd->opp_to_performance_state =
> tegra_genpd_opp_to_performance_state;
> +
> + opp_table = devm_pm_opp_set_regulators(&pdev->dev, &rname, 1);
> + if (IS_ERR(opp_table))
> + return dev_err_probe(&pdev->dev, PTR_ERR(opp_table),
> + "failed to set OPP regulator\n");
> +
> + err = pm_genpd_init(genpd, NULL, false);
> + if (err) {
> + dev_err(&pdev->dev, "failed to init genpd: %d\n", err);
> + return err;
> + }
> +
> + /*
> + * We have a "PMC -> Core" hierarchy of the power domains where
> + * PMC needs to resume and change performance (voltage) of the
> + * Core domain from the PMC GENPD on/off callbacks, hence we need
> + * to annotate the lock in order to remove confusion from the
> + * lockdep checker when a nested access happens.
> + */
> + lockdep_set_class(&genpd->mlock, &tegra_core_domain_lock_class);
> +
> + err = of_genpd_add_provider_simple(pdev->dev.of_node, genpd);
> + if (err) {
> + dev_err(&pdev->dev, "failed to add genpd: %d\n", err);
> + goto remove_genpd;
> + }
> +
> + return 0;
> +
> +remove_genpd:
> + pm_genpd_remove(genpd);
> +
> + return err;
> +}
> +
> +bool tegra_soc_core_domain_state_synced(void)
> +{
> + return tegra_core_domain_state_synced;
> +}
> +
> +static void tegra_core_domain_sync_state(struct device *dev)
> +{
> + tegra_core_domain_state_synced = true;
> +
> + dev_pm_opp_sync_regulators(dev);
> +}
> +
> +static const struct of_device_id tegra_core_domain_match[] = {
> + { .compatible = "nvidia,tegra20-core-domain", },
> + { .compatible = "nvidia,tegra30-core-domain", },
> + { }
> +};
> +
> +static struct platform_driver tegra_core_domain_driver = {
> + .driver = {
> + .name = "tegra-core-power",
> + .of_match_table = tegra_core_domain_match,
> + .suppress_bind_attrs = true,
> + .sync_state = tegra_core_domain_sync_state,
> + },
> + .probe = tegra_core_domain_probe,
> +};
> +builtin_platform_driver(tegra_core_domain_driver);
> diff --git a/include/soc/tegra/common.h b/include/soc/tegra/common.h
> index 57b56793a9e5..6c2ccbbbf073 100644
> --- a/include/soc/tegra/common.h
> +++ b/include/soc/tegra/common.h
> @@ -27,6 +27,7 @@ struct tegra_core_opp_params {
>
> #ifdef CONFIG_ARCH_TEGRA
> bool soc_is_tegra(void);
> +bool tegra_soc_core_domain_state_synced(void);
> int devm_tegra_core_dev_init_opp_table(struct device *dev,
> struct tegra_core_opp_params *cfg);
> #else
> @@ -35,6 +36,11 @@ static inline bool soc_is_tegra(void)
> return false;
> }
>
> +static inline bool tegra_soc_core_domain_state_synced(void)
> +{
> + return false;
> +}
> +
> static inline int
> devm_tegra_core_dev_init_opp_table(struct device *dev,
> struct tegra_core_opp_params *cfg)
> --
> 2.29.2
>
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