Re: [PATCH v5 1/3] firmware: Amlogic: Add secure monitor driver

[Ben Dooks <bjdooks@googlemail.com>]

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On 29 May 2016 12:13, "Carlo Caione" <carlo@caione.org> wrote:
>
> From: Carlo Caione <carlo@endlessm.com>
>
> Introduce a driver to provide calls into secure monitor mode.
>
> In the Amlogic SoCs these calls are used for multiple reasons: access to
> NVMEM, set USB boot, enable JTAG, etc...
>
> Signed-off-by: Carlo Caione <carlo@endlessm.com>
> ---
>  drivers/firmware/Kconfig                |   1 +
>  drivers/firmware/Makefile               |   1 +
>  drivers/firmware/meson/Kconfig          |   8 ++
>  drivers/firmware/meson/Makefile         |   1 +
>  drivers/firmware/meson/meson_sm.c       | 223
++++++++++++++++++++++++++++++++
>  include/linux/firmware/meson/meson_sm.h |  32 +++++
>  6 files changed, 266 insertions(+)
>  create mode 100644 drivers/firmware/meson/Kconfig
>  create mode 100644 drivers/firmware/meson/Makefile
>  create mode 100644 drivers/firmware/meson/meson_sm.c
>  create mode 100644 include/linux/firmware/meson/meson_sm.h
>
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index 6664f11..686e395 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -199,5 +199,6 @@ config HAVE_ARM_SMCCC
>  source "drivers/firmware/broadcom/Kconfig"
>  source "drivers/firmware/google/Kconfig"
>  source "drivers/firmware/efi/Kconfig"
> +source "drivers/firmware/meson/Kconfig"
>
>  endmenu
> diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
> index 474bada..fc4bb09 100644
> --- a/drivers/firmware/Makefile
> +++ b/drivers/firmware/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_QCOM_SCM_32)     += qcom_scm-32.o
>  CFLAGS_qcom_scm-32.o :=$(call as-instr,.arch armv7-a\n.arch_extension
sec,-DREQUIRES_SEC=1) -march=armv7-a
>
>  obj-y                          += broadcom/
> +obj-y                          += meson/
>  obj-$(CONFIG_GOOGLE_FIRMWARE)  += google/
>  obj-$(CONFIG_EFI)              += efi/
>  obj-$(CONFIG_UEFI_CPER)                += efi/
> diff --git a/drivers/firmware/meson/Kconfig
b/drivers/firmware/meson/Kconfig
> new file mode 100644
> index 0000000..fff11a3
> --- /dev/null
> +++ b/drivers/firmware/meson/Kconfig
> @@ -0,0 +1,8 @@
> +#
> +# Amlogic Secure Monitor driver
> +#
> +config MESON_SM
> +       bool
> +       default ARCH_MESON
> +       help
> +         Say y here to enable the Amlogic secure monitor driver
> diff --git a/drivers/firmware/meson/Makefile
b/drivers/firmware/meson/Makefile
> new file mode 100644
> index 0000000..9ab3884
> --- /dev/null
> +++ b/drivers/firmware/meson/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_MESON_SM) +=      meson_sm.o
> diff --git a/drivers/firmware/meson/meson_sm.c
b/drivers/firmware/meson/meson_sm.c
> new file mode 100644
> index 0000000..e1ce487
> --- /dev/null
> +++ b/drivers/firmware/meson/meson_sm.c
> @@ -0,0 +1,223 @@
> +/*
> + * Amlogic Secure Monitor driver
> + *
> + * Copyright (C) 2016 Endless Mobile, Inc.
> + * Author: Carlo Caione <carlo@endlessm.com>
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <stdarg.h>
> +#include <asm/cacheflush.h>
> +#include <asm/compiler.h>
> +#include <linux/arm-smccc.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/smp.h>
> +#include <linux/firmware/meson/meson_sm.h>
> +
> +struct meson_sm_cmd {
> +       unsigned int index;
> +       u32 smc_id;
> +};
> +#define CMD(d, s) { .index = (d), .smc_id = (s), }
> +
> +struct meson_sm_chip {
> +       unsigned int shmem_size;
> +       u32 cmd_shmem_in_base;
> +       u32 cmd_shmem_out_base;
> +       struct meson_sm_cmd cmd[];
> +};
> +
> +struct meson_sm_firmware {
> +       struct device *dev;
> +       const struct meson_sm_chip *chip;
> +       void __iomem *sm_shmem_in_base;
> +       void __iomem *sm_shmem_out_base;
> +};
> +
> +struct meson_sm_chip gxbb_chip = {
> +       .shmem_size             = 0x1000,
> +       .cmd_shmem_in_base      = 0x82000020,
> +       .cmd_shmem_out_base     = 0x82000021,
> +       .cmd = {
> +               CMD(SM_EFUSE_READ,      0x82000030),
> +               CMD(SM_EFUSE_WRITE,     0x82000031),
> +               CMD(SM_EFUSE_USER_MAX,  0x82000033),
> +               { /* sentinel */ },
> +       },
> +};
> +
> +static u32 meson_sm_get_cmd(const struct meson_sm_chip *chip, unsigned
int cmd_index)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; chip->cmd[i].smc_id; i++)
> +               if (chip->cmd[i].index == cmd_index)
> +                       return chip->cmd[i].smc_id;
> +
> +       return 0;
> +}
> +
> +static u32 __meson_sm_call(u32 cmd, u32 arg0, u32 arg1, u32 arg2, u32
arg3, u32 arg4)
> +{
> +       struct arm_smccc_res res;
> +
> +       arm_smccc_smc(cmd, arg0, arg1, arg2, arg3, arg4, 0, 0, &res);
> +       return res.a0;
> +}
> +
> +u32 meson_sm_call(struct meson_sm_firmware *fw, unsigned int cmd_index,
> +                 u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)
> +{
> +       u32 cmd;
> +
> +       if (!fw)
> +               return -EINVAL;
> +
> +       cmd = meson_sm_get_cmd(fw->chip, cmd_index);
> +       if (!cmd)
> +               return -EINVAL;
> +
> +       return __meson_sm_call(cmd, arg0, arg1, arg2, arg3, arg4);
> +}
> +EXPORT_SYMBOL(meson_sm_call);
> +
> +u32 meson_sm_call_read(struct meson_sm_firmware *fw, void *buffer,
> +                      unsigned int cmd_index, u32 arg0, u32 arg1,
> +                      u32 arg2, u32 arg3, u32 arg4)
> +{
> +       u32 size;
> +
> +       if (!fw->chip->cmd_shmem_out_base)
> +               return -EINVAL;
> +
> +       size = meson_sm_call(fw, cmd_index, arg0, arg1, arg2, arg3, arg4);
> +       if (size <= 0 || size > fw->chip->shmem_size)
> +               return -EINVAL;
> +
u32 cannot be less than 0

> +       memcpy(buffer, fw->sm_shmem_out_base, size);
> +
> +       return size;
> +}
> +EXPORT_SYMBOL(meson_sm_call_read);
> +
> +u32 meson_sm_call_write(struct meson_sm_firmware *fw, void *buffer,
> +                       unsigned int b_size, unsigned int cmd_index,
> +                       u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)
> +{
> +       u32 size;
> +
> +       if (b_size > fw->chip->shmem_size)
> +               return -EINVAL;
> +
> +       if (!fw->chip->cmd_shmem_in_base)
> +               return -EINVAL;
> +
> +       memcpy(fw->sm_shmem_in_base, buffer, b_size);
> +
> +       size = meson_sm_call(fw, cmd_index, arg0, arg1, arg2, arg3, arg4);
> +       if (size <= 0)
> +               return -EINVAL;
> +
> +       return size;
> +}
> +EXPORT_SYMBOL(meson_sm_call_write);
> +
> +static void __iomem *meson_sm_map_shmem(u32 cmd_shmem, unsigned int size)
> +{
> +       u32 sm_phy_base;
> +
> +       sm_phy_base = __meson_sm_call(cmd_shmem, 0, 0, 0, 0, 0);
> +       if (!sm_phy_base)
> +               return 0;
> +
> +       return ioremap_cache(sm_phy_base, size);
> +}
> +
> +static int meson_sm_probe(struct platform_device *pdev)
> +{
> +       const struct meson_sm_chip *chip;
> +       struct meson_sm_firmware *fw;
> +
> +       fw = devm_kzalloc(&pdev->dev, sizeof(*fw), GFP_KERNEL);
> +       if (!fw)
> +               return -ENOMEM;
> +
> +       fw->dev = &pdev->dev;
> +
> +       chip = of_device_get_match_data(fw->dev);
> +       if (!chip) {
> +               dev_err(fw->dev, "Unable to setup secure-monitor data\n");
> +               return -ENODEV;
> +       }
-ENODEV not best return here. Return -EINVAL better. -ENODEV won't get
reported by device layer

> +       if (chip->cmd_shmem_in_base) {
> +               fw->sm_shmem_in_base =
meson_sm_map_shmem(chip->cmd_shmem_in_base,
> +
 chip->shmem_size);
> +               if (!fw->sm_shmem_in_base)
> +                       goto out;
> +       }
  Maybe use WarnOn here
> +       if (chip->cmd_shmem_out_base) {
> +               fw->sm_shmem_out_base =
meson_sm_map_shmem(chip->cmd_shmem_out_base,
> +
chip->shmem_size);
> +               if (!fw->sm_shmem_out_base)
> +                       goto out;
> +       }
> +
> +       fw->chip = chip;
> +       platform_set_drvdata(pdev, fw);
> +
> +       dev_info(fw->dev, "secure-monitor enabled\n");
> +
> +       return 0;
> +
> +out:
> +       if (fw->sm_shmem_in_base)
> +               iounmap(fw->sm_shmem_in_base);
> +
> +       return -EINVAL;
> +}
> +
> +struct meson_sm_firmware *meson_sm_get_fw(struct device_node
*firmware_node)
> +{
> +       struct platform_device *pdev =
of_find_device_by_node(firmware_node);
> +
> +       /*
> +        * Returns NULL is the firmware device is not ready.
> +        */
> +       if (!pdev)
> +               return NULL;
> +
> +       return platform_get_drvdata(pdev);
> +}
> +EXPORT_SYMBOL(meson_sm_get_fw);
> +
> +static const struct of_device_id meson_sm_ids[] = {
> +       { .compatible = "amlogic,meson-gxbb-sm", .data = &gxbb_chip },
> +       { /* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, meson_sm_ids);
> +
> +static struct platform_driver meson_sm_platform_driver = {
> +       .probe  = meson_sm_probe,
> +       .driver = {
> +               .name           = "secure-monitor",
> +               .of_match_table = meson_sm_ids,
> +       },
> +};
> +module_platform_driver(meson_sm_platform_driver);
> +
> +MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
> +MODULE_DESCRIPTION("Amlogic secure monitor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/firmware/meson/meson_sm.h
b/include/linux/firmware/meson/meson_sm.h
> new file mode 100644
> index 0000000..f653916
> --- /dev/null
> +++ b/include/linux/firmware/meson/meson_sm.h
> @@ -0,0 +1,32 @@
> +/*
> + * Copyright (C) 2016 Endless Mobile, Inc.
> + * Author: Carlo Caione <carlo@endlessm.com>
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef _MESON_SM_FW_H_
> +#define _MESON_SM_FW_H_
> +
> +#define SM_EFUSE_READ          0
> +#define SM_EFUSE_WRITE         1
> +#define SM_EFUSE_USER_MAX      2
> +
> +struct meson_sm_firmware;
> +
> +u32 meson_sm_call(struct meson_sm_firmware *fw, unsigned int cmd_index,
> +                 u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4);
> +u32 meson_sm_call_write(struct meson_sm_firmware *fw, void *buffer,
> +                       unsigned int b_size, unsigned int cmd_index,
> +                       u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4);
> +u32 meson_sm_call_read(struct meson_sm_firmware *fw, void *buffer,
> +                      unsigned int cmd_index, u32 arg0, u32 arg1,
> +                      u32 arg2, u32 arg3, u32 arg4);
> +struct meson_sm_firmware *meson_sm_get_fw(struct device_node
*firmware_node);
> +
> +#endif /* _MESON_SM_FW_H_ */
> --
> 2.7.4
>
>
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