Re: [PATCH v2 1/4] soc: Amlogic: Add secure monitor driver

[Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 18/05/16 16:56, Carlo Caione wrote:
> From: Carlo Caione <carlo-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>
>
> 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-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>
> ---
>   drivers/soc/Kconfig                |   1 +
>   drivers/soc/Makefile               |   1 +
>   drivers/soc/meson/Kconfig          |   8 ++
>   drivers/soc/meson/Makefile         |   1 +
>   drivers/soc/meson/meson_sm.c       | 155 +++++++++++++++++++++++++++++++++++++
>   include/linux/soc/meson/meson_sm.h |  22 ++++++
>   6 files changed, 188 insertions(+)
>   create mode 100644 drivers/soc/meson/Kconfig
>   create mode 100644 drivers/soc/meson/Makefile
>   create mode 100644 drivers/soc/meson/meson_sm.c
>   create mode 100644 include/linux/soc/meson/meson_sm.h
>
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index cb58ef0..7e70b52 100644
> --- a/drivers/soc/Kconfig
> +++ b/drivers/soc/Kconfig
> @@ -4,6 +4,7 @@ source "drivers/soc/bcm/Kconfig"
>   source "drivers/soc/brcmstb/Kconfig"
>   source "drivers/soc/fsl/qe/Kconfig"
>   source "drivers/soc/mediatek/Kconfig"
> +source "drivers/soc/meson/Kconfig"
>   source "drivers/soc/qcom/Kconfig"
>   source "drivers/soc/rockchip/Kconfig"
>   source "drivers/soc/samsung/Kconfig"
> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
> index 5ade713..9024d2b 100644
> --- a/drivers/soc/Makefile
> +++ b/drivers/soc/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_ARCH_DOVE)		+= dove/
>   obj-$(CONFIG_MACH_DOVE)		+= dove/
>   obj-y				+= fsl/
>   obj-$(CONFIG_ARCH_MEDIATEK)	+= mediatek/
> +obj-$(CONFIG_ARCH_MESON)	+= meson/
>   obj-$(CONFIG_ARCH_QCOM)		+= qcom/
>   obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
>   obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
> diff --git a/drivers/soc/meson/Kconfig b/drivers/soc/meson/Kconfig
> new file mode 100644
> index 0000000..fff11a3
> --- /dev/null
> +++ b/drivers/soc/meson/Kconfig
> @@ -0,0 +1,8 @@
> +#
> +# Amlogic Secure Monitor driver
> +#
> +config MESON_SM
> +	bool
> +	default ARCH_MESON
> +	help
> +	  Say y here to enable the Amlogic secure monitor driver
> diff --git a/drivers/soc/meson/Makefile b/drivers/soc/meson/Makefile
> new file mode 100644
> index 0000000..9ab3884
> --- /dev/null
> +++ b/drivers/soc/meson/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_MESON_SM) +=	meson_sm.o
> diff --git a/drivers/soc/meson/meson_sm.c b/drivers/soc/meson/meson_sm.c
> new file mode 100644
> index 0000000..16f7e32
> --- /dev/null
> +++ b/drivers/soc/meson/meson_sm.c
> @@ -0,0 +1,155 @@
> +/*
> + * Amlogic Secure Monitor driver
> + *
> + * Copyright (C) 2016 Endless Mobile, Inc.
> + * Author: Carlo Caione <carlo-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>
> + *
> + * 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/smp.h>
> +
> +#include <linux/soc/meson/meson_sm.h>
> +
> +#define SM_MEM_SIZE	0x1000
> +
> +/*
> + * To read from / write to the secure monitor we use two bounce buffers. The
> + * physical addresses of the two buffers are obtained by querying the secure
> + * monitor itself.
> + */
> +
> +static u32 sm_phy_in_base;
> +static u32 sm_phy_out_base;

You can put this two variable in meson_sm_probe, right?

> +
> +static void __iomem *sm_sharemem_in_base;
> +static void __iomem *sm_sharemem_out_base;
> +
> +struct meson_sm_data {
> +	u32 cmd;
> +	u32 arg0;
> +	u32 arg1;
> +	u32 arg2;
> +	u32 arg3;
> +	u32 arg4;
> +	u32 ret;
> +};
> +
> +static void __meson_sm_call(void *info)
> +{
> +	struct meson_sm_data *data = info;
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(data->cmd,
> +		      data->arg0, data->arg1, data->arg2,
> +		      data->arg3, data->arg4, 0, 0, &res);
> +	data->ret = res.a0;
> +}
> +
> +u32 meson_sm_call(u32 cmd, u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4)

Can the function be static or will it be called from another driver?

> +{
> +	struct meson_sm_data data;
> +
> +	data.cmd = cmd;
> +	data.arg0 = arg0;
> +	data.arg1 = arg1;
> +	data.arg2 = arg2;
> +	data.arg3 = arg3;
> +	data.arg4 = arg4;
> +	data.ret = 0;
> +
> +	__meson_sm_call(&data);
> +
> +	return data.ret;
> +}
> +
> +u32 meson_sm_call_read(void *buffer, u32 cmd, u32 arg0, u32 arg1,
> +		       u32 arg2, u32 arg3, u32 arg4)
> +{
> +	u32 size;
> +
> +	size = meson_sm_call(cmd, arg0, arg1, arg2, arg3, arg4);
> +
> +	if (!size || size > SM_MEM_SIZE)
> +		return -EINVAL;
> +
> +	memcpy(buffer, sm_sharemem_out_base, size);
> +	return size;
> +}

This function will be needed to be exported to be callable from modules.

> +
> +u32 meson_sm_call_write(void *buffer, unsigned int b_size, u32 cmd, u32 arg0,
> +			u32 arg1, u32 arg2, u32 arg3, u32 arg4)
> +{
> +	u32 size;
> +
> +	if (b_size > SM_MEM_SIZE)
> +		return -EINVAL;
> +
> +	memcpy(sm_sharemem_in_base, buffer, b_size);
> +
> +	size = meson_sm_call(cmd, arg0, arg1, arg2, arg3, arg4);
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	return size;
> +}
> +

Same here.

Regards,
Matthias

> +static int meson_sm_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	int cmd_in, cmd_out;
> +
> +	if (of_property_read_u32(np, "amlogic,sm_cmd_input_base", &cmd_in))
> +		return -EINVAL;
> +
> +	if (of_property_read_u32(np, "amlogic,sm_cmd_output_base", &cmd_out))
> +		return -EINVAL;
> +
> +	sm_phy_in_base = meson_sm_call(cmd_in, 0, 0, 0, 0, 0);
> +	sm_sharemem_in_base = ioremap_cache(sm_phy_in_base, SM_MEM_SIZE);
> +	if (!sm_sharemem_in_base)
> +		return -EINVAL;
> +
> +	sm_phy_out_base = meson_sm_call(cmd_out, 0, 0, 0, 0, 0);
> +	sm_sharemem_out_base = ioremap_cache(sm_phy_out_base, SM_MEM_SIZE);
> +	if (!sm_sharemem_out_base) {
> +		iounmap(sm_sharemem_in_base);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id meson_sm_ids[] = {
> +	{ .compatible = "amlogic,meson-sm" },
> +	{ /* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, meson_sm_ids);
> +
> +static struct platform_driver meson_sm_platform_driver = {
> +	.probe	= meson_sm_probe,
> +	.driver	= {
> +		.name		= "secmon",
> +		.of_match_table	= meson_sm_ids,
> +	},
> +};
> +module_platform_driver(meson_sm_platform_driver);
> +
> +MODULE_AUTHOR("Carlo Caione <carlo-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>");
> +MODULE_DESCRIPTION("Amlogic secure monitor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/soc/meson/meson_sm.h b/include/linux/soc/meson/meson_sm.h
> new file mode 100644
> index 0000000..6ff8317
> --- /dev/null
> +++ b/include/linux/soc/meson/meson_sm.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright (C) 2016 Endless Mobile, Inc.
> + * Author: Carlo Caione <carlo-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>
> + *
> + * 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_H_
> +#define _MESON_SM_H_
> +
> +u32 meson_sm_call(u32 cmd, u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4);
> +u32 meson_sm_call_read(void *buffer, u32 cmd, u32 arg0, u32 arg1, u32 arg2,
> +		       u32 arg3, u32 arg4);
> +u32 meson_sm_call_write(void *buffer, unsigned int b_size, u32 cmd, u32 arg0,
> +			u32 arg1, u32 arg2, u32 arg3, u32 arg4);
> +
> +#endif /* _MESON_SM_H_ */
>
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