[PATCH 0/3] MT67XX random number generator support

[PATCH 0/3] MT67XX random number generator support

[neal.liu]

These patch series introduce a generic rng driver for Trustzone
based kernel driver which would like to communicate with ATF
SIP services.

Patch #1 initials SMC fid table for Mediatek SIP interfaces and
adds HWRNG related SMC call.

Patch #2..3 adds mt67xx-rng kernel driver for Trustzone based SoCs.
For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like
entropy sources is not accessible from normal world (linux) and
rather accessible from secure world (ATF/TEE) only. This driver aims
to provide a generic interface to ATF rng service.

Neal Liu (3):
  soc: mediatek: add SMC fid table for SIP interface
  dt-bindings: rng: update bindings for MT67xx SoCs
  hwrng: add mt67xx-rng driver

 Documentation/devicetree/bindings/rng/mtk-rng.txt |   13 ++-
 drivers/char/hw_random/Kconfig                    |   16 ++++
 drivers/char/hw_random/Makefile                   |    1 +
 drivers/char/hw_random/mt67xx-rng.c               |  104 +++++++++++++++++++++
 include/linux/soc/mediatek/mtk_sip_svc.h          |   55 +++++++++++
 5 files changed, 186 insertions(+), 3 deletions(-)
 create mode 100644 drivers/char/hw_random/mt67xx-rng.c
 create mode 100644 include/linux/soc/mediatek/mtk_sip_svc.h

-- 
1.7.9.5

[PATCH 1/3] soc: mediatek: add SMC fid table for SIP interface

[neal.liu]

From: Neal Liu <neal.liu@mediatek.com>

1. Add a header file to provide SIP interface to ARM
Trusted Firmware(ATF)
2. Add hwrng SMC fid

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
---
 include/linux/soc/mediatek/mtk_sip_svc.h |   55 ++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 include/linux/soc/mediatek/mtk_sip_svc.h

diff --git a/include/linux/soc/mediatek/mtk_sip_svc.h b/include/linux/soc/mediatek/mtk_sip_svc.h
new file mode 100644
index 0000000..ac73f68
--- /dev/null
+++ b/include/linux/soc/mediatek/mtk_sip_svc.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2019 MediaTek Inc.
+ */
+
+#ifndef _MTK_SECURE_API_H_
+#define _MTK_SECURE_API_H_
+
+#include <linux/kernel.h>
+
+
+/* Error Code */
+#define SIP_SVC_E_SUCCESS			0
+#define SIP_SVC_E_NOT_SUPPORTED			-1
+#define SIP_SVC_E_INVALID_PARAMS		-2
+#define SIP_SVC_E_INVALID_RANGE			-3
+#define SIP_SVC_E_PERMISSION_DENY		-4
+
+#ifdef CONFIG_ARM64
+#define MTK_SIP_SMC_AARCH_BIT			0x40000000
+#else
+#define MTK_SIP_SMC_AARCH_BIT			0x00000000
+#endif
+
+
+/*******************************************************************************
+ * Defines for Mediatek runtime services func ids
+ ******************************************************************************/
+
+/* Debug feature and ATF related SMC call */
+
+/* CPU operations related SMC call */
+
+/* SPM related SMC call */
+
+/* Low power related SMC call */
+
+/* AMMS related SMC call */
+
+/* Security related SMC call */
+/* HWRNG */
+#define MTK_SIP_KERNEL_GET_RND \
+	(0x82000206 | MTK_SIP_SMC_AARCH_BIT)
+
+/* Storage Encryption related SMC call */
+
+/* Platform related SMC call */
+
+/* Pheripheral related SMC call */
+
+/* MM related SMC call */
+
+
+#endif /* _MTK_SECURE_API_H_ */
+
-- 
1.7.9.5

[PATCH 2/3] dt-bindings: rng: update bindings for MT67xx SoCs

[neal.liu]

From: Neal Liu <neal.liu@mediatek.com>

Document the binding used by the Mediatek MT67xx SoCs random
number generator with TrustZone enabled.

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
---
 Documentation/devicetree/bindings/rng/mtk-rng.txt |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/rng/mtk-rng.txt b/Documentation/devicetree/bindings/rng/mtk-rng.txt
index 2bc89f1..5f40316 100644
--- a/Documentation/devicetree/bindings/rng/mtk-rng.txt
+++ b/Documentation/devicetree/bindings/rng/mtk-rng.txt
@@ -3,9 +3,12 @@ found in MediaTek SoC family
 
 Required properties:
 - compatible	    : Should be
-			"mediatek,mt7622-rng", 	"mediatek,mt7623-rng" : for MT7622
-			"mediatek,mt7629-rng",  "mediatek,mt7623-rng" : for MT7629
-			"mediatek,mt7623-rng" : for MT7623
+			"mediatek,mt7622-rng", "mediatek,mt7623-rng" for MT7622
+			"mediatek,mt7629-rng", "mediatek,mt7623-rng" for MT7629
+			"mediatek,mt7623-rng" for MT7623
+			"mediatek,mt67xx-rng" for MT67xx ARMv8 SoCs
+
+Optional properties:
 - clocks	    : list of clock specifiers, corresponding to
 		      entries in clock-names property;
 - clock-names	    : Should contain "rng" entries;
@@ -19,3 +22,7 @@ rng: rng@1020f000 {
 	clocks = <&infracfg CLK_INFRA_TRNG>;
 	clock-names = "rng";
 };
+
+hwrng: hwrng {
+	compatible = "mediatek,mt67xx-rng";
+};
-- 
1.7.9.5

[PATCH 3/3] hwrng: add mt67xx-rng driver

[neal.liu]

From: Neal Liu <neal.liu@mediatek.com>

For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like
entropy sources is not accessible from normal world (linux) and
rather accessible from secure world (ATF/TEE) only. This driver aims
to provide a generic interface to ATF rng service.

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
---
 drivers/char/hw_random/Kconfig      |   16 ++++++
 drivers/char/hw_random/Makefile     |    1 +
 drivers/char/hw_random/mt67xx-rng.c |  104 +++++++++++++++++++++++++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 drivers/char/hw_random/mt67xx-rng.c

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 25a7d8f..98751d3 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -398,6 +398,22 @@ config HW_RANDOM_MTK
 
 	  If unsure, say Y.
 
+config HW_RANDOM_MT67XX
+	tristate "Mediatek MT67XX Random Number Generator support"
+	depends on HW_RANDOM
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	default HW_RANDOM
+	help
+	  This driver provides kernel-side support for the Random Number
+	  Generator hardware found on Mediatek MT67xx SoCs. The difference
+	  with mtk-rng is the Random Number Generator hardware is secure
+	  access only.
+
+	  To compile this driver as a module, choose M here. the
+	  module will be called mt67xx-rng.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_S390
 	tristate "S390 True Random Number Generator support"
 	depends on S390
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 7c9ef4a..4be95ab 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
 obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
 obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o
 obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
+obj-$(CONFIG_HW_RANDOM_MT67XX) += mt67xx-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
diff --git a/drivers/char/hw_random/mt67xx-rng.c b/drivers/char/hw_random/mt67xx-rng.c
new file mode 100644
index 0000000..e70cbbe
--- /dev/null
+++ b/drivers/char/hw_random/mt67xx-rng.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 MediaTek Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/of.h>
+#include <linux/arm-smccc.h>
+#include <linux/soc/mediatek/mtk_sip_svc.h>
+
+#define PFX			KBUILD_MODNAME ": "
+#define MT67XX_RNG_MAGIC	0x74726e67
+#define SMC_RET_NUM		4
+
+struct mt67xx_rng_priv {
+	struct hwrng rng;
+};
+
+
+static void __rng_sec_read(uint32_t *val)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(MTK_SIP_KERNEL_GET_RND,
+		      MT67XX_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res);
+
+	val[0] = res.a0;
+	val[1] = res.a1;
+	val[2] = res.a2;
+	val[3] = res.a3;
+}
+
+static int mt67xx_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	int i, retval = 0;
+	uint32_t val[4] = {0};
+	size_t get_rnd_size = sizeof(u32) * SMC_RET_NUM;
+
+	if (!buf) {
+		pr_err("%s, buf is NULL\n", __func__);
+		return -EFAULT;
+	}
+
+	while (max >= get_rnd_size) {
+		__rng_sec_read(val);
+
+		for (i = 0; i < SMC_RET_NUM; i++) {
+			*(u32 *)buf = val[i];
+			buf += sizeof(u32);
+		}
+
+		retval += get_rnd_size;
+		max -= get_rnd_size;
+	}
+
+	return retval;
+}
+
+static int mt67xx_rng_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct mt67xx_rng_priv *priv;
+
+	pr_info(PFX "driver registered\n");
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->rng.name = KBUILD_MODNAME;
+	priv->rng.read = mt67xx_rng_read;
+	priv->rng.priv = (unsigned long)&pdev->dev;
+	priv->rng.quality = 900;
+
+	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register rng device: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mt67xx_rng_match[] = {
+	{ .compatible = "mediatek,mt67xx-rng", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mt67xx_rng_match);
+
+static struct platform_driver mt67xx_rng_driver = {
+	.probe = mt67xx_rng_probe,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.owner = THIS_MODULE,
+		.of_match_table = mt67xx_rng_match,
+	},
+};
+
+module_platform_driver(mt67xx_rng_driver);
+
+MODULE_DESCRIPTION("Mediatek MT67XX Random Number Generator Driver");
+MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Stephan Mueller]

Am Mittwoch, 8. Mai 2019, 05:58:57 CEST schrieb neal.liu@mediatek.com:

Hi liu,

> From: Neal Liu <neal.liu@mediatek.com>
> 
> For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like
> entropy sources is not accessible from normal world (linux) and
> rather accessible from secure world (ATF/TEE) only. This driver aims
> to provide a generic interface to ATF rng service.
> 
> Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> ---
>  drivers/char/hw_random/Kconfig      |   16 ++++++
>  drivers/char/hw_random/Makefile     |    1 +
>  drivers/char/hw_random/mt67xx-rng.c |  104
> +++++++++++++++++++++++++++++++++++ 3 files changed, 121 insertions(+)
>  create mode 100644 drivers/char/hw_random/mt67xx-rng.c
> 
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index 25a7d8f..98751d3 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -398,6 +398,22 @@ config HW_RANDOM_MTK
> 
>  	  If unsure, say Y.
> 
> +config HW_RANDOM_MT67XX
> +	tristate "Mediatek MT67XX Random Number Generator support"
> +	depends on HW_RANDOM
> +	depends on ARCH_MEDIATEK || COMPILE_TEST
> +	default HW_RANDOM
> +	help
> +	  This driver provides kernel-side support for the Random Number
> +	  Generator hardware found on Mediatek MT67xx SoCs. The difference
> +	  with mtk-rng is the Random Number Generator hardware is secure
> +	  access only.
> +
> +	  To compile this driver as a module, choose M here. the
> +	  module will be called mt67xx-rng.
> +
> +	  If unsure, say Y.
> +
>  config HW_RANDOM_S390
>  	tristate "S390 True Random Number Generator support"
>  	depends on S390
> diff --git a/drivers/char/hw_random/Makefile
> b/drivers/char/hw_random/Makefile index 7c9ef4a..4be95ab 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
>  obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
>  obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o
>  obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
> +obj-$(CONFIG_HW_RANDOM_MT67XX) += mt67xx-rng.o
>  obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
>  obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
>  obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
> diff --git a/drivers/char/hw_random/mt67xx-rng.c
> b/drivers/char/hw_random/mt67xx-rng.c new file mode 100644
> index 0000000..e70cbbe
> --- /dev/null
> +++ b/drivers/char/hw_random/mt67xx-rng.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 MediaTek Inc.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/hw_random.h>
> +#include <linux/of.h>
> +#include <linux/arm-smccc.h>
> +#include <linux/soc/mediatek/mtk_sip_svc.h>
> +
> +#define PFX			KBUILD_MODNAME ": "
> +#define MT67XX_RNG_MAGIC	0x74726e67
> +#define SMC_RET_NUM		4
> +
> +struct mt67xx_rng_priv {
> +	struct hwrng rng;
> +};
> +
> +
> +static void __rng_sec_read(uint32_t *val)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(MTK_SIP_KERNEL_GET_RND,
> +		      MT67XX_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res);
> +
> +	val[0] = res.a0;
> +	val[1] = res.a1;
> +	val[2] = res.a2;
> +	val[3] = res.a3;
> +}
> +
> +static int mt67xx_rng_read(struct hwrng *rng, void *buf, size_t max, bool
> wait) +{
> +	int i, retval = 0;
> +	uint32_t val[4] = {0};
> +	size_t get_rnd_size = sizeof(u32) * SMC_RET_NUM;
> +
> +	if (!buf) {
> +		pr_err("%s, buf is NULL\n", __func__);
> +		return -EFAULT;
> +	}
> +
> +	while (max >= get_rnd_size) {
> +		__rng_sec_read(val);
> +
> +		for (i = 0; i < SMC_RET_NUM; i++) {
> +			*(u32 *)buf = val[i];

I am not sure this cast is right - or how is it guaranteed that buf is word-
aligned?

> +			buf += sizeof(u32);
> +		}
> +
> +		retval += get_rnd_size;
> +		max -= get_rnd_size;
> +	}
> +
> +	return retval;
> +}
> +
> +static int mt67xx_rng_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct mt67xx_rng_priv *priv;
> +
> +	pr_info(PFX "driver registered\n");
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->rng.name = KBUILD_MODNAME;
> +	priv->rng.read = mt67xx_rng_read;
> +	priv->rng.priv = (unsigned long)&pdev->dev;
> +	priv->rng.quality = 900;
> +
> +	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register rng device: %d\n", 
ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mt67xx_rng_match[] = {
> +	{ .compatible = "mediatek,mt67xx-rng", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, mt67xx_rng_match);
> +
> +static struct platform_driver mt67xx_rng_driver = {
> +	.probe = mt67xx_rng_probe,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +		.owner = THIS_MODULE,
> +		.of_match_table = mt67xx_rng_match,
> +	},
> +};
> +
> +module_platform_driver(mt67xx_rng_driver);
> +
> +MODULE_DESCRIPTION("Mediatek MT67XX Random Number Generator Driver");
> +MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
> +MODULE_LICENSE("GPL");



Ciao
Stephan

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Neal Liu]

Hi Stephan,
	We think the cast is fine, and it cannot guarantee the buf is
word-align.
	I reference multiple rng driver's implementation and found it's common
usage for this. So it might be general usage for community. Is there any
suggestion that is more appropriate?

	Thanks
Best Regards,
-Neal Liu


On Wed, 2019-05-08 at 08:34 +0200, Stephan Mueller wrote:
> Am Mittwoch, 8. Mai 2019, 05:58:57 CEST schrieb neal.liu@mediatek.com:
> 
> Hi liu,
> 
> > From: Neal Liu <neal.liu@mediatek.com>
> > 
> > For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like
> > entropy sources is not accessible from normal world (linux) and
> > rather accessible from secure world (ATF/TEE) only. This driver aims
> > to provide a generic interface to ATF rng service.
> > 
> > Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> > ---
> >  drivers/char/hw_random/Kconfig      |   16 ++++++
> >  drivers/char/hw_random/Makefile     |    1 +
> >  drivers/char/hw_random/mt67xx-rng.c |  104
> > +++++++++++++++++++++++++++++++++++ 3 files changed, 121 insertions(+)
> >  create mode 100644 drivers/char/hw_random/mt67xx-rng.c
> > 
> > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> > index 25a7d8f..98751d3 100644
> > --- a/drivers/char/hw_random/Kconfig
> > +++ b/drivers/char/hw_random/Kconfig
> > @@ -398,6 +398,22 @@ config HW_RANDOM_MTK
> > 
> >  	  If unsure, say Y.
> > 
> > +config HW_RANDOM_MT67XX
> > +	tristate "Mediatek MT67XX Random Number Generator support"
> > +	depends on HW_RANDOM
> > +	depends on ARCH_MEDIATEK || COMPILE_TEST
> > +	default HW_RANDOM
> > +	help
> > +	  This driver provides kernel-side support for the Random Number
> > +	  Generator hardware found on Mediatek MT67xx SoCs. The difference
> > +	  with mtk-rng is the Random Number Generator hardware is secure
> > +	  access only.
> > +
> > +	  To compile this driver as a module, choose M here. the
> > +	  module will be called mt67xx-rng.
> > +
> > +	  If unsure, say Y.
> > +
> >  config HW_RANDOM_S390
> >  	tristate "S390 True Random Number Generator support"
> >  	depends on S390
> > diff --git a/drivers/char/hw_random/Makefile
> > b/drivers/char/hw_random/Makefile index 7c9ef4a..4be95ab 100644
> > --- a/drivers/char/hw_random/Makefile
> > +++ b/drivers/char/hw_random/Makefile
> > @@ -36,6 +36,7 @@ obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
> >  obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
> >  obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o
> >  obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
> > +obj-$(CONFIG_HW_RANDOM_MT67XX) += mt67xx-rng.o
> >  obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
> >  obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
> >  obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
> > diff --git a/drivers/char/hw_random/mt67xx-rng.c
> > b/drivers/char/hw_random/mt67xx-rng.c new file mode 100644
> > index 0000000..e70cbbe
> > --- /dev/null
> > +++ b/drivers/char/hw_random/mt67xx-rng.c
> > @@ -0,0 +1,104 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2019 MediaTek Inc.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/hw_random.h>
> > +#include <linux/of.h>
> > +#include <linux/arm-smccc.h>
> > +#include <linux/soc/mediatek/mtk_sip_svc.h>
> > +
> > +#define PFX			KBUILD_MODNAME ": "
> > +#define MT67XX_RNG_MAGIC	0x74726e67
> > +#define SMC_RET_NUM		4
> > +
> > +struct mt67xx_rng_priv {
> > +	struct hwrng rng;
> > +};
> > +
> > +
> > +static void __rng_sec_read(uint32_t *val)
> > +{
> > +	struct arm_smccc_res res;
> > +
> > +	arm_smccc_smc(MTK_SIP_KERNEL_GET_RND,
> > +		      MT67XX_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res);
> > +
> > +	val[0] = res.a0;
> > +	val[1] = res.a1;
> > +	val[2] = res.a2;
> > +	val[3] = res.a3;
> > +}
> > +
> > +static int mt67xx_rng_read(struct hwrng *rng, void *buf, size_t max, bool
> > wait) +{
> > +	int i, retval = 0;
> > +	uint32_t val[4] = {0};
> > +	size_t get_rnd_size = sizeof(u32) * SMC_RET_NUM;
> > +
> > +	if (!buf) {
> > +		pr_err("%s, buf is NULL\n", __func__);
> > +		return -EFAULT;
> > +	}
> > +
> > +	while (max >= get_rnd_size) {
> > +		__rng_sec_read(val);
> > +
> > +		for (i = 0; i < SMC_RET_NUM; i++) {
> > +			*(u32 *)buf = val[i];
> 
> I am not sure this cast is right - or how is it guaranteed that buf is word-
> aligned?
> 
> > +			buf += sizeof(u32);
> > +		}
> > +
> > +		retval += get_rnd_size;
> > +		max -= get_rnd_size;
> > +	}
> > +
> > +	return retval;
> > +}
> > +
> > +static int mt67xx_rng_probe(struct platform_device *pdev)
> > +{
> > +	int ret;
> > +	struct mt67xx_rng_priv *priv;
> > +
> > +	pr_info(PFX "driver registered\n");
> > +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> > +	if (!priv)
> > +		return -ENOMEM;
> > +
> > +	priv->rng.name = KBUILD_MODNAME;
> > +	priv->rng.read = mt67xx_rng_read;
> > +	priv->rng.priv = (unsigned long)&pdev->dev;
> > +	priv->rng.quality = 900;
> > +
> > +	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "failed to register rng device: %d\n", 
> ret);
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id mt67xx_rng_match[] = {
> > +	{ .compatible = "mediatek,mt67xx-rng", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, mt67xx_rng_match);
> > +
> > +static struct platform_driver mt67xx_rng_driver = {
> > +	.probe = mt67xx_rng_probe,
> > +	.driver = {
> > +		.name = KBUILD_MODNAME,
> > +		.owner = THIS_MODULE,
> > +		.of_match_table = mt67xx_rng_match,
> > +	},
> > +};
> > +
> > +module_platform_driver(mt67xx_rng_driver);
> > +
> > +MODULE_DESCRIPTION("Mediatek MT67XX Random Number Generator Driver");
> > +MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
> > +MODULE_LICENSE("GPL");
> 
> 
> 
> Ciao
> Stephan
> 
> 

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Herbert Xu]

On Wed, May 08, 2019 at 06:35:37PM +0800, Neal Liu wrote:
> Hi Stephan,
> 	We think the cast is fine, and it cannot guarantee the buf is
> word-align.
> 	I reference multiple rng driver's implementation and found it's common
> usage for this. So it might be general usage for community. Is there any
> suggestion that is more appropriate?

If you don't know whether it's unaligned or not then you should
do an unaligned operation.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Neal Liu]

On Thu, 2019-05-09 at 13:26 +0800, Herbert Xu wrote:
> On Wed, May 08, 2019 at 06:35:37PM +0800, Neal Liu wrote:
> > Hi Stephan,
> > 	We think the cast is fine, and it cannot guarantee the buf is
> > word-align.
> > 	I reference multiple rng driver's implementation and found it's common
> > usage for this. So it might be general usage for community. Is there any
> > suggestion that is more appropriate?
> 
> If you don't know whether it's unaligned or not then you should
> do an unaligned operation.

Hi Stephan/Herbert,
	My mistake. This buffer is allocated by kmalloc with larger than 32
bytes. So yes, it's word-align for sure.
	reference:
https://elixir.bootlin.com/linux/latest/source/drivers/char/hw_random/core.c#L590

	Thanks
Best Regards,
-Neal Liu

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Herbert Xu]

On Thu, May 09, 2019 at 10:54:46PM +0800, Neal Liu wrote:
>
> Hi Stephan/Herbert,
> 	My mistake. This buffer is allocated by kmalloc with larger than 32
> bytes. So yes, it's word-align for sure.
> 	reference:
> https://elixir.bootlin.com/linux/latest/source/drivers/char/hw_random/core.c#L590

Yes you're right.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Neal Liu]

Hi Herbert,
	Could you kindly help to review our patches?
	Thanks

From	Neal Liu <>
Subject	[PATCH 0/3] MT67XX random number generator support
Date	Wed, 8 May 2019 11:58:54 +0800
share
These patch series introduce a generic rng driver for Trustzone
based kernel driver which would like to communicate with ATF
SIP services.

Patch #1 initials SMC fid table for Mediatek SIP interfaces and
adds HWRNG related SMC call.

Patch #2..3 adds mt67xx-rng kernel driver for Trustzone based SoCs.
For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like
entropy sources is not accessible from normal world (linux) and
rather accessible from secure world (ATF/TEE) only. This driver aims
to provide a generic interface to ATF rng service.

Neal Liu (3):
  soc: mediatek: add SMC fid table for SIP interface
  dt-bindings: rng: update bindings for MT67xx SoCs
  hwrng: add mt67xx-rng driver

 Documentation/devicetree/bindings/rng/mtk-rng.txt |   13 ++-
 drivers/char/hw_random/Kconfig                    |   16 ++++
 drivers/char/hw_random/Makefile                   |    1 +
 drivers/char/hw_random/mt67xx-rng.c               |  104
+++++++++++++++++++++
 include/linux/soc/mediatek/mtk_sip_svc.h          |   55 +++++++++++
 5 files changed, 186 insertions(+), 3 deletions(-)
 create mode 100644 drivers/char/hw_random/mt67xx-rng.c
 create mode 100644 include/linux/soc/mediatek/mtk_sip_svc.h

-- 
1.7.9.5

Best Regards,
-Neal Liu

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Herbert Xu]

On Fri, May 24, 2019 at 03:42:34PM +0800, Neal Liu wrote:
> Hi Herbert,
> 	Could you kindly help to review our patches?

You need acks for patches 1 and 2.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 3/3] hwrng: add mt67xx-rng driver

[Sean Wang]

Hi Neal,

On Tue, May 7, 2019 at 9:00 PM <neal.liu@mediatek.com> wrote:
>
> From: Neal Liu <neal.liu@mediatek.com>
>
> For Mediatek SoCs on ARMv8 with TrustZone enabled, peripherals like

MediaTek

> entropy sources is not accessible from normal world (linux) and
> rather accessible from secure world (ATF/TEE) only. This driver aims
> to provide a generic interface to ATF rng service.

Could we rename the mt67xx-rng.c to mtk-sec-rng.c? It seems all
MediaTek SoCs with ATF/TEE can reuse this driver, not be limited in
MT67xx.

>
> Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> ---
>  drivers/char/hw_random/Kconfig      |   16 ++++++
>  drivers/char/hw_random/Makefile     |    1 +
>  drivers/char/hw_random/mt67xx-rng.c |  104 +++++++++++++++++++++++++++++++++++
>  3 files changed, 121 insertions(+)
>  create mode 100644 drivers/char/hw_random/mt67xx-rng.c
>
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index 25a7d8f..98751d3 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -398,6 +398,22 @@ config HW_RANDOM_MTK
>
>           If unsure, say Y.
>
> +config HW_RANDOM_MT67XX
> +       tristate "Mediatek MT67XX Random Number Generator support"

MediaTek Security

> +       depends on HW_RANDOM
> +       depends on ARCH_MEDIATEK || COMPILE_TEST
> +       default HW_RANDOM
> +       help
> +         This driver provides kernel-side support for the Random Number
> +         Generator hardware found on Mediatek MT67xx SoCs. The difference

MediaTek

> +         with mtk-rng is the Random Number Generator hardware is secure
> +         access only.
> +
> +         To compile this driver as a module, choose M here. the
> +         module will be called mt67xx-rng.
> +
> +         If unsure, say Y.
> +
>  config HW_RANDOM_S390
>         tristate "S390 True Random Number Generator support"
>         depends on S390
> diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
> index 7c9ef4a..4be95ab 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
>  obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
>  obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o
>  obj-$(CONFIG_HW_RANDOM_MTK)    += mtk-rng.o
> +obj-$(CONFIG_HW_RANDOM_MT67XX) += mt67xx-rng.o
>  obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
>  obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
>  obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
> diff --git a/drivers/char/hw_random/mt67xx-rng.c b/drivers/char/hw_random/mt67xx-rng.c
> new file mode 100644
> index 0000000..e70cbbe
> --- /dev/null
> +++ b/drivers/char/hw_random/mt67xx-rng.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 MediaTek Inc.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/hw_random.h>
> +#include <linux/of.h>
> +#include <linux/arm-smccc.h>
> +#include <linux/soc/mediatek/mtk_sip_svc.h>
> +

sort these headers in alphabetical order

> +#define PFX                    KBUILD_MODNAME ": "

PFX can be dropped that is less useful

> +#define MT67XX_RNG_MAGIC       0x74726e67
> +#define SMC_RET_NUM            4
> +
> +struct mt67xx_rng_priv {
> +       struct hwrng rng;
> +};
> +
> +
> +static void __rng_sec_read(uint32_t *val)
> +{

add a prefix like mt67xx, the function call is specific to mtk

> +       struct arm_smccc_res res;
> +
> +       arm_smccc_smc(MTK_SIP_KERNEL_GET_RND,
> +                     MT67XX_RNG_MAGIC, 0, 0, 0, 0, 0, 0, &res);
> +
> +       val[0] = res.a0;
> +       val[1] = res.a1;
> +       val[2] = res.a2;
> +       val[3] = res.a3;
> +}
> +
> +static int mt67xx_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
> +{
> +       int i, retval = 0;
> +       uint32_t val[4] = {0};
> +       size_t get_rnd_size = sizeof(u32) * SMC_RET_NUM;

sort declarations in the reverse-Xmas tree. and get_rnd_size always be
unchanged so it can be a macro

> +
> +       if (!buf) {

the sanity check is unnecessary, the parameter max would ensure the
size of the whole buffer

> +               pr_err("%s, buf is NULL\n", __func__);
> +               return -EFAULT;
> +       }
> +
> +       while (max >= get_rnd_size) {
> +               __rng_sec_read(val);
> +
> +               for (i = 0; i < SMC_RET_NUM; i++) {
> +                       *(u32 *)buf = val[i];
> +                       buf += sizeof(u32);
> +               }
> +
> +               retval += get_rnd_size;
> +               max -= get_rnd_size;
> +       }
> +
> +       return retval;
> +}
> +
> +static int mt67xx_rng_probe(struct platform_device *pdev)
> +{
> +       int ret;
> +       struct mt67xx_rng_priv *priv;

sort declarations in the reverse-Xmas tree.

> +
> +       pr_info(PFX "driver registered\n");

drop the message

> +       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;
> +
> +       priv->rng.name = KBUILD_MODNAME;

suggest using the device name

priv->rng.name = pdev->name;

> +       priv->rng.read = mt67xx_rng_read;
> +       priv->rng.priv = (unsigned long)&pdev->dev;
> +       priv->rng.quality = 900;
> +
> +       ret = devm_hwrng_register(&pdev->dev, &priv->rng);
> +       if (ret) {
> +               dev_err(&pdev->dev, "failed to register rng device: %d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id mt67xx_rng_match[] = {
> +       { .compatible = "mediatek,mt67xx-rng", },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, mt67xx_rng_match);
> +
> +static struct platform_driver mt67xx_rng_driver = {
> +       .probe = mt67xx_rng_probe,
> +       .driver = {
> +               .name = KBUILD_MODNAME,
> +               .owner = THIS_MODULE,
> +               .of_match_table = mt67xx_rng_match,
> +       },
> +};
> +
> +module_platform_driver(mt67xx_rng_driver);
> +
> +MODULE_DESCRIPTION("Mediatek MT67XX Random Number Generator Driver");

MediaTek

> +MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
> +MODULE_LICENSE("GPL");
> --
> 1.7.9.5
>
>
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