Re: [PATCH 4/4] mfd: Samsung: Add Samsung sysmgr driver
From: Dongjin Yang
Date: Tue Jul 26 2022 - 03:51:22 EST
On 14/07/2022 04:28, Krzysztof Kozlowski wrote:
> On 13/07/2022 06:57, Dongjin Yang wrote:
> > This driver is used for SoCs produced by Samsung Foundry to provide
> > Samsung sysmgr API. The read/write request of sysmgr is delivered to
> > Samsung secure monitor call.
> >
> > Signed-off-by: Dongjin Yang <dj76.yang@xxxxxxxxxxx>
> > ---
> > MAINTAINERS | 2 +
> > drivers/mfd/Kconfig | 11 +++
> > drivers/mfd/Makefile | 1 +
> > drivers/mfd/samsung-sysmgr.c | 167 +++++++++++++++++++++++++++++++++++++
> > include/linux/mfd/samsung-sysmgr.h | 30 +++++++
> > 5 files changed, 211 insertions(+)
> > create mode 100644 drivers/mfd/samsung-sysmgr.c
> > create mode 100644 include/linux/mfd/samsung-sysmgr.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 55cb8901ccdc..44ad4bd406a9 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -1870,9 +1870,11 @@ F: arch/arm/mach-artpec
> > F: drivers/clk/axis
> > F: drivers/crypto/axis
> > F: drivers/firmware/samsung-smc-svc.c
> > +F: drivers/mfd/samsung-sysmgr.c
> > F: drivers/mmc/host/usdhi6rol0.c
> > F: drivers/pinctrl/pinctrl-artpec*
> > F: include/linux/firmware/samsung-smc-svc.h
> > +F: include/linux/mfd/samsung-sysmgr.h
>
> Not related to Axis/Artpec SoC.
>
It is Artpec8 SoC.
> >
> > ARM/ASPEED I2C DRIVER
> > M: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > index 3b59456f5545..ce6ab5842bf0 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -51,6 +51,17 @@ config MFD_ACT8945A
> > linear regulators, along with a complete ActivePath battery
> > charger.
> >
> > +config MFD_SAMSUNG_SYSMGR
> > + bool "System Manager for Samsung Foundry platforms"
> > + depends on ARCH_ARTPEC && OF
>
> Samsung Foundry does not match ARTPEC... Artpec 6 is not Samsung Foundry
> SoC, is it?
>
This is for Artpec8.
> Missing compile test.
>
Sorry, I will run it.
> > + select MFD_SYSCON
> > + select SAMSUNG_SECURE_SERVICE
> > + help
> > + Select this to get System Manager support for SoCs which use
> > + Samsung Foundry platforms.
> > + This System Manager has depedency on Samsung Secure Service
> > + for providing secure service call.
>
> Looking at the driver, it does literally nothing. Looks like workaround
> for incomplete bindings and DTS. It's a no-go.
>
This driver is for providing secure smc read/write to other IP driver in Artpec8 SoC.
> > +
> > config MFD_SUN4I_GPADC
> > tristate "Allwinner sunxi platforms' GPADC MFD driver"
> > select MFD_CORE
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > index 858cacf659d6..490f041d1262 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -248,6 +248,7 @@ obj-$(CONFIG_INTEL_SOC_PMIC_MRFLD) += intel_soc_pmic_mrfld.o
> >
> > obj-$(CONFIG_MFD_ALTERA_A10SR) += altera-a10sr.o
> > obj-$(CONFIG_MFD_ALTERA_SYSMGR) += altera-sysmgr.o
> > +obj-$(CONFIG_MFD_SAMSUNG_SYSMGR) += samsung-sysmgr.o
> > obj-$(CONFIG_MFD_STPMIC1) += stpmic1.o
> > obj-$(CONFIG_MFD_SUN4I_GPADC) += sun4i-gpadc.o
> >
> > diff --git a/drivers/mfd/samsung-sysmgr.c b/drivers/mfd/samsung-sysmgr.c
> > new file mode 100644
> > index 000000000000..a202e8c4c4f2
> > --- /dev/null
> > +++ b/drivers/mfd/samsung-sysmgr.c
> > @@ -0,0 +1,167 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2019 Samsung Electronics, Co. Ltd.
> > + * Copyright (C) 2018-2019, Intel Corporation.
> > + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> > + * Copyright (C) 2012 Linaro Ltd.
> > + *
> > + * Inspired by drivers/mfd/altera-sysmgr.c
> > + */
> > +
> > +#include <linux/arm-smccc.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/mfd/samsung-sysmgr.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +
> > +/**
> > + * struct samsung_sysmgr - Samsung System Manager
> > + * @regmap: the regmap used for System Manager accesses.
> > + * @base : the base address for the System Manager
> > + */
> > +struct samsung_sysmgr {
> > + struct regmap *regmap;
> > + resource_size_t *base;
> > +};
> > +
> > +static struct platform_driver samsung_sysmgr_driver;
>
> No, no static variables.
>
Ok, I will change this.
> > +
> > +static struct regmap_config mmio_regmap_cfg = {
> > + .name = "sysmgr_mmio",
> > + .reg_bits = 32,
> > + .reg_stride = 4,
> > + .val_bits = 32,
> > + .fast_io = true,
> > + .use_single_read = true,
> > + .use_single_write = true,
> > +};
> > +
> > +static struct regmap_config samsung_smccc_regmap_cfg = {
> > + .name = "samsung_sysmgr_smccc",
> > + .reg_bits = 32,
> > + .reg_stride = 4,
> > + .val_bits = 32,
> > + .fast_io = true,
> > + .use_single_read = true,
> > + .use_single_write = true,
> > + .reg_read = samsung_smc_reg_read,
> > + .reg_write = samsung_smc_reg_write,
> > +};
> > +
> > +/**
> > + * samsung_sysmgr_regmap_lookup_by_phandle
> > + * Find the sysmgr previous configured in probe() and return regmap property.
> > + * Return: regmap if found or error if not found.
> > + */
> > +struct regmap *samsung_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
> > + const char *property)
> > +{
> > + struct device *dev;
> > + struct samsung_sysmgr *sysmgr;
> > + struct device_node *sysmgr_np;
> > +
> > + if (property)
> > + sysmgr_np = of_parse_phandle(np, property, 0);
> > + else
> > + sysmgr_np = np;
> > +
> > + if (!sysmgr_np)
> > + return ERR_PTR(-ENODEV);
> > +
> > + dev = driver_find_device_by_of_node(&samsung_sysmgr_driver.driver,
> > + (void *)sysmgr_np);
> > + of_node_put(sysmgr_np);
> > + if (!dev)
> > + return ERR_PTR(-EPROBE_DEFER);
> > +
> > + sysmgr = dev_get_drvdata(dev);
> > +
> > + return sysmgr->regmap;
> > +}
> > +EXPORT_SYMBOL_GPL(samsung_sysmgr_regmap_lookup_by_phandle);
>
> This breaks layers/encapsulation and looks like a hack for incomplete
> bindings/DTS. No, no exporting regmaps.
>
Similar with syscon (syscon_regmap_lookup_by_phandle), but needed additional secure smc call.
> > +
> > +static int sysmgr_probe(struct platform_device *pdev)
> > +{
> > + struct samsung_sysmgr *sysmgr;
> > + struct regmap *regmap;
> > + struct resource *res;
> > + struct device *dev = &pdev->dev;
> > + struct regmap_config sysmgr_config =
> > + *((struct regmap_config *)of_device_get_match_data(dev));
> > +
> > + sysmgr = devm_kzalloc(dev, sizeof(*sysmgr), GFP_KERNEL);
> > + if (!sysmgr)
> > + return -ENOMEM;
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + if (!res)
> > + return -ENOENT;
> > +
> > + sysmgr_config.max_register = resource_size(res) -
> > + sysmgr_config.reg_stride;
> > + if (sysmgr_config.reg_read) {
> > + /* Need physical address for SMCC call */
> > + sysmgr->base = (resource_size_t *)res->start;
> > + regmap = devm_regmap_init(dev, NULL, sysmgr->base,
> > + &sysmgr_config);
> > + } else {
> > + sysmgr->base = devm_ioremap(dev, res->start,
> > + resource_size(res));
> > + if (!sysmgr->base)
> > + return -ENOMEM;
> > +
> > + regmap = devm_regmap_init_mmio(dev, sysmgr->base,
> > + &sysmgr_config);
> > + }
> > +
> > + if (IS_ERR(regmap)) {
> > + pr_err("regmap init failed\n");
>
> dev_err
Will change it.
>
> > + return PTR_ERR(regmap);
> > + }
> > +
> > + sysmgr->regmap = regmap;
> > +
> > + platform_set_drvdata(pdev, sysmgr);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id samsung_sysmgr_of_match[] = {
> > + { .compatible = "samsung,sys-mgr", .data = &mmio_regmap_cfg },
> > + {
> > + .compatible = "samsung,sys-mgr-smccc",
> > + .data = &samsung_smccc_regmap_cfg
> > + },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, samsung_sysmgr_of_match);
> > +
> > +static struct platform_driver samsung_sysmgr_driver = {
> > + .probe = sysmgr_probe,
> > + .driver = {
> > + .name = "samsung,system_manager",
> > + .of_match_table = samsung_sysmgr_of_match,
> > + },
> > +};
> > +
> > +static int __init samsung_sysmgr_init(void)
> > +{
> > + return platform_driver_register(&samsung_sysmgr_driver);
> > +}
> > +core_initcall(samsung_sysmgr_init);
>
> module_platform_driver() instead.
ok, I will change it.
>
> > +
> > +static void __exit samsung_sysmgr_exit(void)
> > +{
> > + platform_driver_unregister(&samsung_sysmgr_driver);
> > +}
> > +module_exit(samsung_sysmgr_exit);
> > +
> > +MODULE_AUTHOR("Dongjin Yang <dj76.yang@xxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Samsung System Manager driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/mfd/samsung-sysmgr.h b/include/linux/mfd/samsung-sysmgr.h
> > new file mode 100644
> > index 000000000000..d6887cb86ea8
> > --- /dev/null
> > +++ b/include/linux/mfd/samsung-sysmgr.h
> > @@ -0,0 +1,30 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2019 Samsung Electronics, Co. Ltd.
> > + * Copyright (C) 2018-2019 Intel Corporation
> > + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> > + * Copyright (C) 2012 Linaro Ltd.
> > + */
> > +
> > +#ifndef __LINUX_MFD_SAMSUNG_SYSMGR_H__
> > +#define __LINUX_MFD_SAMSUNG_SYSMGR_H__
> > +
> > +#include <linux/err.h>
> > +#include <linux/errno.h>
> > +#include <linux/firmware/samsung-smc-svc.h>
> > +
> > +struct device_node;
> > +
> > +#if defined(CONFIG_MFD_SAMSUNG_SYSMGR)
>
> No ifdefs, no stubs.
>
is it ok to move stub code into samsung-smc-svc.c
>
>
> Best regards,
> Krzysztof