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SubjectRe: [PATCH 2/3] soc: amlogic: Add support for Secure power domains controller
Date
Hi Jianxin,

Jianxin Pan <jianxin.pan@amlogic.com> writes:

> Add support for the Amlogic Secure Power controller. In A1/C1 series, power
> control registers are in secure domain, and should be accessed by smc.
>
> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
> Signed-off-by: Zhiqiang Liang <zhiqiang.liang@amlogic.com>

Thanks for the new power domain driver.

> ---
> drivers/soc/amlogic/Kconfig | 13 +++
> drivers/soc/amlogic/Makefile | 1 +
> drivers/soc/amlogic/meson-secure-pwrc.c | 182 ++++++++++++++++++++++++++++++++
> 3 files changed, 196 insertions(+)
> create mode 100644 drivers/soc/amlogic/meson-secure-pwrc.c
>
> diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
> index bc2c912..6cb06e7 100644
> --- a/drivers/soc/amlogic/Kconfig
> +++ b/drivers/soc/amlogic/Kconfig
> @@ -48,6 +48,19 @@ config MESON_EE_PM_DOMAINS
> Say yes to expose Amlogic Meson Everything-Else Power Domains as
> Generic Power Domains.
>
> +config MESON_SECURE_PM_DOMAINS
> + bool "Amlogic Meson Secure Power Domains driver"
> + depends on ARCH_MESON || COMPILE_TEST
> + depends on PM && OF
> + depends on HAVE_ARM_SMCCC
> + default ARCH_MESON
> + select PM_GENERIC_DOMAINS
> + select PM_GENERIC_DOMAINS_OF
> + help
> + Support for the power controller on Amlogic A1/C1 series.
> + Say yes to expose Amlogic Meson Secure Power Domains as Generic
> + Power Domains.
> +
> config MESON_MX_SOCINFO
> bool "Amlogic Meson MX SoC Information driver"
> depends on ARCH_MESON || COMPILE_TEST
> diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
> index de79d044..7b8c5d3 100644
> --- a/drivers/soc/amlogic/Makefile
> +++ b/drivers/soc/amlogic/Makefile
> @@ -5,3 +5,4 @@ obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
> obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
> obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
> obj-$(CONFIG_MESON_EE_PM_DOMAINS) += meson-ee-pwrc.o
> +obj-$(CONFIG_MESON_SECURE_PM_DOMAINS) += meson-secure-pwrc.o
> diff --git a/drivers/soc/amlogic/meson-secure-pwrc.c b/drivers/soc/amlogic/meson-secure-pwrc.c
> new file mode 100644
> index 00000000..00c7232
> --- /dev/null
> +++ b/drivers/soc/amlogic/meson-secure-pwrc.c
> @@ -0,0 +1,182 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Copyright (c) 2019 Amlogic, Inc.
> + * Author: Jianxin Pan <jianxin.pan@amlogic.com>
> + */
> +#include <linux/io.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <dt-bindings/power/meson-a1-power.h>
> +#include <linux/arm-smccc.h>
> +
> +#define PWRC_ON 1
> +#define PWRC_OFF 0
> +#define SMC_PWRC_SET 0x82000093
> +#define SMC_PWRC_GET 0x82000095
> +
> +struct meson_secure_pwrc_domain {
> + struct generic_pm_domain base;
> + unsigned int index;
> +};
> +
> +struct meson_secure_pwrc {
> + struct meson_secure_pwrc_domain *domains;
> + struct genpd_onecell_data xlate;
> +};
> +
> +struct meson_secure_pwrc_domain_desc {
> + unsigned int index;
> + unsigned int flags;
> + char *name;
> + bool (*get_power)(struct meson_secure_pwrc_domain *pwrc_domain);
> +};
> +
> +struct meson_secure_pwrc_domain_data {
> + unsigned int count;
> + struct meson_secure_pwrc_domain_desc *domains;
> +};
> +
> +static bool pwrc_secure_get_power(struct meson_secure_pwrc_domain *pwrc_domain)
> +{
> + struct arm_smccc_res res;
> +
> + arm_smccc_smc(SMC_PWRC_GET, pwrc_domain->index, 0,
> + 0, 0, 0, 0, 0, &res);
> +
> + return res.a0 & 0x1;

Please use a #define with a readable name for this mask.

> +}

What does the return value for this function mean? Does true mean
"powered off" or "powered on"?

See the rename I just did on the ee-pwrc driver:
https://lore.kernel.org/linux-amlogic/20190925213528.21515-2-khilman@kernel.org/

> +static int meson_secure_pwrc_off(struct generic_pm_domain *domain)
> +{
> + struct arm_smccc_res res;
> + struct meson_secure_pwrc_domain *pwrc_domain =
> + container_of(domain, struct meson_secure_pwrc_domain, base);
> +
> + arm_smccc_smc(SMC_PWRC_SET, pwrc_domain->index, PWRC_OFF,
> + 0, 0, 0, 0, 0, &res);
> +
> + return 0;
> +}
> +
> +static int meson_secure_pwrc_on(struct generic_pm_domain *domain)
> +{
> + struct arm_smccc_res res;
> + struct meson_secure_pwrc_domain *pwrc_domain =
> + container_of(domain, struct meson_secure_pwrc_domain, base);
> +
> + arm_smccc_smc(SMC_PWRC_SET, pwrc_domain->index, PWRC_ON,
> + 0, 0, 0, 0, 0, &res);
> +
> + return 0;
> +}
> +
> +#define SEC_PD(__name, __flag) \
> +{ \
> + .name = #__name, \
> + .index = PWRC_##__name##_ID, \
> + .get_power = pwrc_secure_get_power, \
> + .flags = __flag, \
> +}
> +
> +static struct meson_secure_pwrc_domain_desc a1_pwrc_domains[] = {
> + SEC_PD(DSPA, 0),
> + SEC_PD(DSPB, 0),
> + SEC_PD(UART, GENPD_FLAG_ALWAYS_ON),

This flag should only be used for domains where there are no linux
drivers.

Rather than using this flag, you need to add a 'power-domain' property
to the uart driver in DT, and then update the meson_uart driver to use
the runtime PM API so that the domain is enabled whenever the UART is in
use.

> + SEC_PD(DMC, GENPD_FLAG_ALWAYS_ON),

Please explain the need for ALWAYS_ON.

> + SEC_PD(I2C, 0),
> + SEC_PD(PSRAM, 0),
> + SEC_PD(ACODEC, 0),
> + SEC_PD(AUDIO, 0),
> + SEC_PD(OTP, 0),
> + SEC_PD(DMA, 0),
> + SEC_PD(SD_EMMC, 0),
> + SEC_PD(RAMA, 0),
> + SEC_PD(RAMB, GENPD_FLAG_ALWAYS_ON),

Please explain the need for ALWAYS_ON.

> + SEC_PD(IR, 0),
> + SEC_PD(SPICC, 0),
> + SEC_PD(SPIFC, 0),
> + SEC_PD(USB, 0),
> + SEC_PD(NIC, GENPD_FLAG_ALWAYS_ON),

Please explain the need for ALWAYS_ON.

> + SEC_PD(PDMIN, 0),
> + SEC_PD(RSA, 0),
> +};
> +
> +static int meson_secure_pwrc_probe(struct platform_device *pdev)
> +{
> + const struct meson_secure_pwrc_domain_data *match;
> + struct meson_secure_pwrc *pwrc;
> + int i;
> +
> + match = of_device_get_match_data(&pdev->dev);
> + if (!match) {
> + dev_err(&pdev->dev, "failed to get match data\n");
> + return -ENODEV;
> + }
> +
> + pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
> + if (!pwrc)
> + return -ENOMEM;
> +
> + pwrc->xlate.domains = devm_kcalloc(&pdev->dev, match->count,
> + sizeof(*pwrc->xlate.domains),
> + GFP_KERNEL);
> + if (!pwrc->xlate.domains)
> + return -ENOMEM;
> +
> + pwrc->domains = devm_kcalloc(&pdev->dev, match->count,
> + sizeof(*pwrc->domains), GFP_KERNEL);
> + if (!pwrc->domains)
> + return -ENOMEM;
> +
> + pwrc->xlate.num_domains = match->count;
> + platform_set_drvdata(pdev, pwrc);
> +
> + for (i = 0 ; i < match->count ; ++i) {
> + struct meson_secure_pwrc_domain *dom = &pwrc->domains[i];
> +
> + if (!match->domains[i].index)
> + continue;
> +
> + dom->index = match->domains[i].index;
> + dom->base.name = match->domains[i].name;
> + dom->base.flags = match->domains[i].flags;
> + dom->base.power_on = meson_secure_pwrc_on;
> + dom->base.power_off = meson_secure_pwrc_off;
> +
> + pm_genpd_init(&dom->base, NULL,
> + (match->domains[i].get_power ?
> + match->domains[i].get_power(dom) : true));
> +
> + pwrc->xlate.domains[i] = &dom->base;
> + }
> +
> + return of_genpd_add_provider_onecell(pdev->dev.of_node, &pwrc->xlate);
> +}
> +
> +static struct meson_secure_pwrc_domain_data meson_secure_a1_pwrc_data = {
> + .domains = a1_pwrc_domains,
> + .count = ARRAY_SIZE(a1_pwrc_domains),
> +};
> +
> +static const struct of_device_id meson_secure_pwrc_match_table[] = {
> + {
> + .compatible = "amlogic,meson-a1-pwrc",
> + .data = &meson_secure_a1_pwrc_data,
> + },
> + { }

as mentioned by Martin, please add the sentinel string here. Helps for
readability.

> +};
> +
> +static struct platform_driver meson_secure_pwrc_driver = {
> + .probe = meson_secure_pwrc_probe,
> + .driver = {
> + .name = "meson_secure_pwrc",
> + .of_match_table = meson_secure_pwrc_match_table,
> + },
> +};
> +
> +static int meson_secure_pwrc_init(void)
> +{
> + return platform_driver_register(&meson_secure_pwrc_driver);
> +}
> +arch_initcall_sync(meson_secure_pwrc_init);

Please use builtin_platform_driver() or explain in detail why the
initcall is needed.

Thanks,

Kevin

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