Re: [PATCH 2/4] firmware: Samsung: Add secure monitor driver

From: Dongjin Yang
Date: Mon Jul 25 2022 - 20:04:44 EST



On 14/07/2022 04:28, Krzysztof Kozlowski wrote:
> On 13/07/2022 06:55, Dongjin Yang wrote:
> > Introduce a driver to provide calls into secure monitor mode.
> > This driver is used for SoCs produced by Samsung Foundry to provide
> > SMC call. This patch supports register read/write request to secure
> > monitor. Also, SMC call request which uses shared memory to exchange
> > the data between kernel and secure monitor.
>
> > Signed-off-by: Dongjin Yang <dj76.yang@xxxxxxxxxxx>
> > ---
> >  MAINTAINERS                              |   2 +
> >  drivers/firmware/Kconfig                 |  11 +++
> >  drivers/firmware/Makefile                |   1 +
> >  drivers/firmware/samsung-smc-svc.c       | 154 +++++++++++++++++++++++++++++++
> >  include/linux/firmware/samsung-smc-svc.h |  59 ++++++++++++
> >  5 files changed, 227 insertions(+)
> >  create mode 100644 drivers/firmware/samsung-smc-svc.c
> >  create mode 100644 include/linux/firmware/samsung-smc-svc.h
>
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 6763746c349f..d173043ffb46 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -1868,8 +1868,10 @@ F:        arch/arm/boot/dts/artpec6*
> >  F:        arch/arm/mach-artpec
> >  F:        drivers/clk/axis
> >  F:        drivers/crypto/axis
> > +F:        drivers/firmware/samsung-smc-svc.c
> >  F:        drivers/mmc/host/usdhi6rol0.c
> >  F:        drivers/pinctrl/pinctrl-artpec*
> > +F:        include/linux/firmware/samsung-smc-svc.h
>
> Same as for bindings - not related to Artpec platforms. Either add
> dedicated entry or put it under Samsung SoC.
>

This patch is for Artpec8 SoC.

> >  
> >  ARM/ASPEED I2C DRIVER
> >  M:        Brendan Higgins <brendanhiggins@xxxxxxxxxx>
> > diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> > index e5cfb01353d8..4b0f2d033f58 100644
> > --- a/drivers/firmware/Kconfig
> > +++ b/drivers/firmware/Kconfig
> > @@ -217,6 +217,17 @@ config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
> >  
> >            Say Y here to enable "download mode" by default.
> >  
> > +config SAMSUNG_SECURE_SERVICE
> > +        bool "Samsung Foundry Secure Service Layer"
> > +        depends on HAVE_ARM_SMCCC
> > +        default n
> > +        help
> > +          Support secure service layer for SoCs which is manufactured by
> > +          Samsung Foundry.
> > +
> > +          This option provide support of secure monitor service call using
> > +          Trusted Foundations.
> > +
> >  config SYSFB
> >          bool
> >          default y
> > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
> > index 4e58cb474a68..985e30a9665f 100644
> > --- a/drivers/firmware/Makefile
> > +++ b/drivers/firmware/Makefile
> > @@ -19,6 +19,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
> >  obj-$(CONFIG_FW_CFG_SYSFS)        += qemu_fw_cfg.o
> >  obj-$(CONFIG_QCOM_SCM)                += qcom-scm.o
> >  qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
> > +obj-$(CONFIG_SAMSUNG_SECURE_SERVICE) += samsung-smc-svc.o
> >  obj-$(CONFIG_SYSFB)                += sysfb.o
> >  obj-$(CONFIG_SYSFB_SIMPLEFB)        += sysfb_simplefb.o
> >  obj-$(CONFIG_TI_SCI_PROTOCOL)        += ti_sci.o
> > diff --git a/drivers/firmware/samsung-smc-svc.c b/drivers/firmware/samsung-smc-svc.c
> > new file mode 100644
> > index 000000000000..eb3a5285cf2b
> > --- /dev/null
> > +++ b/drivers/firmware/samsung-smc-svc.c
> > @@ -0,0 +1,154 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2019 Samsung Electronics Co., Ltd.
> > + * Author: Kihyun Yoon<kihyun.yoon@xxxxxxxxxxx>
> > + * Author: Dongjin Yang<dj76.yang@xxxxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
>
> Drop boiler plate with trailing empty '*' comment.
>

Yes,

> > + */
> > +
> > +#include <linux/types.h>
> > +#include <linux/errno.h>
> > +#include <linux/module.h>
> > +#include <linux/io.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/firmware/samsung-smc-svc.h>
>
> Order the headers by name.
>

Yes I will,

> > +
> > +struct samsung_smc_version {
> > +        u32 major;
> > +        u32 minor;
> > +};
> > +
> > +struct samsung_smc_data {
> > +        struct samsung_smc_version version;
> > +        u32 svc_cmd_list[SAMSUNG_SIP_NR_SIP];
> > +};
> > +
> > +struct samsung_smc_data *svc_data;
>
> No, no globals. Even no static variables.
>

Yes, let me change the driver

> > +
> > +static int samsung_smc_svc_init(void);
> > +
> > +static int __samsung_get_svc_cmd(u32 cmd_idx)
> > +{
> > +        if (cmd_idx >= SAMSUNG_SIP_NR_SIP)
> > +                return SAMSUNG_SIP_NOT_SUPPORTED;
> > +
> > +        /* Initialize this driver if it is not ready */
> > +        if (!svc_data && samsung_smc_svc_init()) {
> > +                pr_err("samsung,smccc_service initialization is failed\n");
> > +                return SAMSUNG_SIP_NOT_SUPPORTED;
> > +        }
> > +
> > +        return svc_data->svc_cmd_list[cmd_idx];
> > +}
> > +
> > +int samsung_smc_call(u32 cmd_idx,
> > +                     unsigned long a0, unsigned long a1,
> > +                     unsigned long a2, unsigned long a3,
> > +                     u32 *val)
> > +
> > +{
> > +        struct arm_smccc_res res;
> > +        u32 cmd = __samsung_get_svc_cmd(cmd_idx);
> > +
> > +        if (cmd == SAMSUNG_SIP_NOT_SUPPORTED)
> > +                return -EOPNOTSUPP;
> > +
> > +        arm_smccc_smc(cmd, a0, a1, a2, a3, 0, 0, 0, &res);
> > +        if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
> > +                return -EINVAL;
> > +
> > +        if (val)
> > +                *val = (u32)res.a1;
> > +
> > +        return 0;
> > +}
> > +EXPORT_SYMBOL(samsung_smc_call);
>
> EXPORT_SYMBOL_GPL
>
> You need kerneldoc for all these.
>

Yes,

> > +
> > +int samsung_smc_reg_read(void *base, u32 reg, u32 *val)
> > +{
> > +        return samsung_smc_call(SAMSUNG_SIP_READ_REG,
> > +                                (unsigned long)base, reg, 0, 0, val);
> > +}
> > +EXPORT_SYMBOL(samsung_smc_reg_read);
> > +
> > +int samsung_smc_reg_write(void *base, u32 reg, u32 val)
> > +{
> > +        return samsung_smc_call(SAMSUNG_SIP_WRITE_REG,
> > +                                  (unsigned long)base, reg, val, 0, NULL);
> > +}
> > +EXPORT_SYMBOL(samsung_smc_reg_write);
> > +
> > +static int samsung_smc_check_version(struct samsung_smc_version *ver)
> > +{
> > +        struct arm_smccc_res res;
> > +
> > +        arm_smccc_smc(SAMSUNG_SIP_SVC_VERSION, 0, 0, 0, 0, 0, 0, 0, &res);
> > +
> > +        if ((u32)res.a0 != ver->major || (u32)res.a1 != ver->minor)
> > +                return -EINVAL;
> > +
> > +        pr_info("Samsung SVC version [%d.%d] is detected\n",
> > +                ver->major, ver->minor);
> > +
> > +        return 0;
> > +}
> > +
> > +static const struct samsung_smc_data svc_0_1 = {
> > +        .version = {
> > +                .major = 0,
> > +                .minor = 1
> > +        },
> > +        .svc_cmd_list = {
> > +                [SAMSUNG_SIP_READ_REG] = 0x82000020,
> > +                [SAMSUNG_SIP_WRITE_REG] = 0x82000021,
> > +                /* TODO: SMC call for clock driver should be added */
> > +        }
> > +};
> > +
> > +static const struct of_device_id samsung_smc_of_match[] = {
> > +        { .compatible = "samsung,smccc-svc", .data = &svc_0_1 },
> > +        { /* sentinel */ }
> > +};
> > +
> > +static int samsung_smc_svc_init(void)
> > +{
> > +        struct device_node *fw_np;
> > +        struct device_node *np;
> > +        const struct of_device_id *match;
> > +        int ret;
> > +
> > +        if (svc_data) {
> > +                pr_info("samsung,smccc_service is already initialized\n");
> > +                return 0;
> > +        }
> > +
> > +        fw_np = of_find_node_by_name(NULL, "firmware");
> > +        if (!fw_np)
> > +                return -ENODEV;
> > +
> > +        np = of_find_matching_node_and_match(fw_np, samsung_smc_of_match,
> > +                                             &match);
> > +        if (!np)
> > +                return -ENODEV;
> > +
> > +        svc_data = (struct samsung_smc_data *)match->data;
> > +        if (!svc_data)
> > +                return -ENODEV;
> > +
> > +        ret = samsung_smc_check_version(&svc_data->version);
> > +        if (ret) {
> > +                pr_err("samsung svc version is not matched\n");
> > +                return ret;
> > +        }
> > +
> > +        pr_info("samsung smc svc is initialized\n");
>
> No useless success printks. We have tracing and sysfs for that.
>

Ok,

> > +        return 0;
> > +}
> > +
> > +early_initcall(samsung_smc_svc_init);
>
> No. Make it a platform driver.
>

Ok, I will change,

> > diff --git a/include/linux/firmware/samsung-smc-svc.h b/include/linux/firmware/samsung-smc-svc.h
> > new file mode 100644
> > index 000000000000..9c94fd3e10a2
> > --- /dev/null
> > +++ b/include/linux/firmware/samsung-smc-svc.h
> > @@ -0,0 +1,59 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +
> > +#ifndef __SAMSUNG_SMC_H
> > +#define __SAMSUNG_SMC_H
>
> Extend the header gaurd to match path.
>

Yes,

> > +
> > +#include <linux/arm-smccc.h>
> > +
> > +#ifdef CONFIG_SAMSUNG_SECURE_SERVICE
>
> No ifdefs in headers. This is not a subsystem.
>

Yes, I will remove,

> > +
> > +#define SAMSUNG_SIP_CALL_VAL(x) \
> > +                ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
> > +                ARM_SMCCC_SMC_32, ARM_SMCCC_OWNER_SIP, x)
>
> Need kerneldoc.
>

Yes, I will add kerneldoc.

> > +
> > +/* Common SIP SVC number */
> > +#define SAMSUING_SIP_SVC_CALL_COUNT        SAMSUNG_SIP_CALL_VAL(0xff00)
> > +#define SAMSUING_SIP_SVC_UID                SAMSUNG_SIP_CALL_VAL(0xff01)
> > +#define SAMSUNG_SIP_SVC_VERSION                SAMSUNG_SIP_CALL_VAL(0xff03)
> > +#define SAMSUNG_SIP_NOT_SUPPORTED        0x0
>
> Need kerneldoc.
>
>
> > +
> > +enum {
> > +        /* SIP enumeration for V0.1 */
> > +        SAMSUNG_SIP_READ_REG,
> > +        SAMSUNG_SIP_WRITE_REG,
> > +        /* Add here for later version */
> > +        SAMSUNG_SIP_NR_SIP
> > +};
>
> Need kerneldoc.
>
>
> > +
> > +int samsung_smc_call(u32 cmd_idx,
> > +                     unsigned long a0, unsigned long a1,
> > +                     unsigned long a2, unsigned long a3,
> > +                     u32 *val);
> > +int samsung_smc_reg_read(void *addr, unsigned int reg, u32 *val);
> > +int samsung_smc_reg_write(void *addr, unsigned int reg, u32 val);
> > +
>
> Need kerneldoc in the driver.
>
>
> > +#else
> > +
>
> No stubs, no ifdefs. It's not a subsystem.
>
>
>
> Best regards,
> Krzysztof