[v2,2/3] nvmem: stm32: add OP-TEE support for STM32MP13x

Message ID 20221110164329.v2.2.Ibc43aa73f865090affeb1751af0cc260c7f1dd07@changeid
State New
Headers
Series nvmem: stm32: add OP-TEE support for STM32MP13x |

Commit Message

Patrick Delaunay Nov. 10, 2022, 3:45 p.m. UTC
  For boot with OP-TEE on STM32MP13, the communication with the secure
world no more use STMicroelectronics SMC but communication with the
BSEC TA, for data access (read/write) or lock operation:
- all the request are sent to OP-TEE trusted application,
- for upper OTP with ECC protection and with word programming only
  each OTP are permanently locked when programmed to avoid ECC error
  on the second write operation

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
---

Changes in v2:
- rebase series on linux-next/master
- minor update after V1 revue
- add missing sentinel in stm32_romem_of_match()
- reorder function and remove prototypes for stm32_bsec_pta... functions
- change stm32_bsec_pta_find to static
- add return value in dev_err()
- cleanups some comments, which can be on one line
- remove test on priv->ctx in stm32_bsec_pta_remove
- add missing tee_shm_free(shm) in stm32_bsec_pta_write() when
  tee_shm_get_va failed
- return error in stm32_bsec_pta_find when devm_add_action_or_reset failed
- handle driver_register error in stm32_romem_init

 drivers/nvmem/stm32-romem.c | 445 +++++++++++++++++++++++++++++++++++-
 1 file changed, 441 insertions(+), 4 deletions(-)
  

Comments

Srinivas Kandagatla Nov. 11, 2022, 5:18 p.m. UTC | #1
On 10/11/2022 15:45, Patrick Delaunay wrote:
> For boot with OP-TEE on STM32MP13, the communication with the secure
> world no more use STMicroelectronics SMC but communication with the
> BSEC TA, for data access (read/write) or lock operation:
> - all the request are sent to OP-TEE trusted application,
> - for upper OTP with ECC protection and with word programming only
>    each OTP are permanently locked when programmed to avoid ECC error
>    on the second write operation
> 
> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
> ---
> 
> Changes in v2:
> - rebase series on linux-next/master
> - minor update after V1 revue
> - add missing sentinel in stm32_romem_of_match()
> - reorder function and remove prototypes for stm32_bsec_pta... functions
> - change stm32_bsec_pta_find to static
> - add return value in dev_err()
> - cleanups some comments, which can be on one line
> - remove test on priv->ctx in stm32_bsec_pta_remove
> - add missing tee_shm_free(shm) in stm32_bsec_pta_write() when
>    tee_shm_get_va failed
> - return error in stm32_bsec_pta_find when devm_add_action_or_reset failed
> - handle driver_register error in stm32_romem_init
> 
>   drivers/nvmem/stm32-romem.c | 445 +++++++++++++++++++++++++++++++++++-
>   1 file changed, 441 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
> index d1d03c2ad081..0a0e29d09b67 100644
> --- a/drivers/nvmem/stm32-romem.c
> +++ b/drivers/nvmem/stm32-romem.c
> @@ -11,6 +11,7 @@
>   #include <linux/module.h>
>   #include <linux/nvmem-provider.h>
>   #include <linux/of_device.h>
> +#include <linux/tee_drv.h>
>   
>   /* BSEC secure service access from non-secure */
>   #define STM32_SMC_BSEC			0x82001003
> @@ -25,14 +26,401 @@
>   struct stm32_romem_cfg {
>   	int size;
>   	u8 lower;
> +	bool ta;
>   };
>   
>   struct stm32_romem_priv {
>   	void __iomem *base;
>   	struct nvmem_config cfg;
>   	u8 lower;
> +	struct device *ta;
>   };
>   
> +#if IS_ENABLED(CONFIG_OPTEE)
> +/*

...

> +
> +static const struct tee_client_device_id stm32_bsec_id_table[] = {
> +	{
> +		UUID_INIT(0x94cf71ad, 0x80e6, 0x40b5,
> +			  0xa7, 0xc6, 0x3d, 0xc5, 0x01, 0xeb, 0x28, 0x03)
> +	},
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(tee, stm32_bsec_id_table);
> +
> +static struct tee_client_driver stm32_bsec_pta_driver = {
> +	.id_table	= stm32_bsec_id_table,
> +	.driver		= {
> +		.name = "stm32-bsec-pta",
> +		.bus = &tee_bus_type,
> +		.probe = stm32_bsec_pta_probe,
> +		.remove = stm32_bsec_pta_remove,
> +	},
> +};
> +
> +static void stm32_bsec_put_device(void *data)
> +{
> +	put_device(data);
> +}
> +
> +static struct device *stm32_bsec_pta_find(struct device *dev)
> +{
> +	struct device *pta_dev;
> +	int ret;
> +
> +	pta_dev = driver_find_next_device(&stm32_bsec_pta_driver.driver, NULL);

This is clearly not representing the dependencies in a proper device model.


If the nvmem provider is a TEE client driver lets model it that way.. 
brining in a additional device and somehow trying to link it with TEE 
driver is  a hack.


> +
> +	if (pta_dev) {
> +		ret = devm_add_action_or_reset(dev, stm32_bsec_put_device, pta_dev);
> +		if (ret)
> +			dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", ret);
> +
> +		return ERR_PTR(ret);
> +	}
> +
> +	return pta_dev;
> +}
> +
> +#else
> +static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
> +			       size_t bytes)
> +{
> +	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
> +
> +	return -ENXIO;
> +}
> +
> +static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
> +				size_t bytes)
> +{
> +	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
> +
> +	return -ENXIO;
> +}
> +
> +static struct device *stm32_bsec_pta_find(struct device *dev)
> +{
> +	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
> +
> +	return NULL;
> +}
> +#endif

ifdefing inside the drvier is really ugly, please move this libary 
functions to a seperate file and add dependecy properly in Kconfig.

> +
>   static int stm32_romem_read(void *context, unsigned int offset, void *buf,
>   			    size_t bytes)
>   {
> @@ -173,15 +561,27 @@ static int stm32_romem_probe(struct platform_device *pdev)
>   	} else {
>   		priv->cfg.size = cfg->size;
>   		priv->lower = cfg->lower;
> -		priv->cfg.reg_read = stm32_bsec_read;
> -		priv->cfg.reg_write = stm32_bsec_write;
> +		if (cfg->ta) {
> +			priv->ta = stm32_bsec_pta_find(dev);
> +			/* wait for OP-TEE client driver to be up and ready */
> +			if (!priv->ta)
> +				return -EPROBE_DEFER;
> +			if (IS_ERR(priv->ta))
> +				return PTR_ERR(priv->ta);
> +
> +			priv->cfg.reg_read = stm32_bsec_pta_read;
> +			priv->cfg.reg_write = stm32_bsec_pta_write;
> +		} else {
> +			priv->cfg.reg_read = stm32_bsec_read;
> +			priv->cfg.reg_write = stm32_bsec_write;
> +		}
>   	}
>   
>   	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
>   }
>   
>   /*
> - * STM32MP15 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
> + * STM32MP15/13 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
>    * => 96 x 32-bits data words
>    * - Lower: 1K bits, 2:1 redundancy, incremental bit programming
>    *   => 32 (x 32-bits) lower shadow registers = words 0 to 31
> @@ -191,6 +591,13 @@ static int stm32_romem_probe(struct platform_device *pdev)
>   static const struct stm32_romem_cfg stm32mp15_bsec_cfg = {
>   	.size = 384,
>   	.lower = 32,
> +	.ta = false,
> +};
> +
> +static const struct stm32_romem_cfg stm32mp13_bsec_cfg = {
> +	.size = 384,
> +	.lower = 32,
> +	.ta = true,
>   };
>   
>   static const struct of_device_id stm32_romem_of_match[] = {
> @@ -198,7 +605,10 @@ static const struct of_device_id stm32_romem_of_match[] = {
>   		.compatible = "st,stm32mp15-bsec",
>   		.data = (void *)&stm32mp15_bsec_cfg,
>   	}, {
> +		.compatible = "st,stm32mp13-bsec",
> +		.data = (void *)&stm32mp13_bsec_cfg,
>   	},
> +	{ /* sentinel */ },
>   };
>   MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
>   
> @@ -209,7 +619,34 @@ static struct platform_driver stm32_romem_driver = {
>   		.of_match_table = of_match_ptr(stm32_romem_of_match),
>   	},
>   };
> -module_platform_driver(stm32_romem_driver);
> +
> +static int __init stm32_romem_init(void)
> +{
> +	int rc;
> +
> +	rc = platform_driver_register(&stm32_romem_driver);
> +	if (rc)
> +		return rc;
> +
> +#if IS_ENABLED(CONFIG_OPTEE)
> +	rc = driver_register(&stm32_bsec_pta_driver.driver);
> +	if (rc)
> +		platform_driver_unregister(&stm32_romem_driver);
> +#endif
> +
> +	return rc;
> +}
> +
> +static void __exit stm32_romem_exit(void)
> +{
> +	platform_driver_unregister(&stm32_romem_driver);
> +#if IS_ENABLED(CONFIG_OPTEE)
> +	driver_unregister(&stm32_bsec_pta_driver.driver);
> +#endif
> +}
> +
> +module_init(stm32_romem_init);
> +module_exit(stm32_romem_exit);
>   
>   MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
>   MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
  
Patrick Delaunay Nov. 14, 2022, 2:20 p.m. UTC | #2
Hi,

On 11/11/22 18:18, Srinivas Kandagatla wrote:
>
>
> On 10/11/2022 15:45, Patrick Delaunay wrote:
>> For boot with OP-TEE on STM32MP13, the communication with the secure
>> world no more use STMicroelectronics SMC but communication with the
>> BSEC TA, for data access (read/write) or lock operation:
>> - all the request are sent to OP-TEE trusted application,
>> - for upper OTP with ECC protection and with word programming only
>>    each OTP are permanently locked when programmed to avoid ECC error
>>    on the second write operation
>>
>> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
>> ---
>>
>> Changes in v2:
>> - rebase series on linux-next/master
>> - minor update after V1 revue
>> - add missing sentinel in stm32_romem_of_match()
>> - reorder function and remove prototypes for stm32_bsec_pta... functions
>> - change stm32_bsec_pta_find to static
>> - add return value in dev_err()
>> - cleanups some comments, which can be on one line
>> - remove test on priv->ctx in stm32_bsec_pta_remove
>> - add missing tee_shm_free(shm) in stm32_bsec_pta_write() when
>>    tee_shm_get_va failed
>> - return error in stm32_bsec_pta_find when devm_add_action_or_reset 
>> failed
>> - handle driver_register error in stm32_romem_init
>>
>>   drivers/nvmem/stm32-romem.c | 445 +++++++++++++++++++++++++++++++++++-
>>   1 file changed, 441 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
>> index d1d03c2ad081..0a0e29d09b67 100644
>> --- a/drivers/nvmem/stm32-romem.c
>> +++ b/drivers/nvmem/stm32-romem.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/module.h>
>>   #include <linux/nvmem-provider.h>
>>   #include <linux/of_device.h>
>> +#include <linux/tee_drv.h>
>>     /* BSEC secure service access from non-secure */
>>   #define STM32_SMC_BSEC            0x82001003
>> @@ -25,14 +26,401 @@
>>   struct stm32_romem_cfg {
>>       int size;
>>       u8 lower;
>> +    bool ta;
>>   };
>>     struct stm32_romem_priv {
>>       void __iomem *base;
>>       struct nvmem_config cfg;
>>       u8 lower;
>> +    struct device *ta;
>>   };
>>   +#if IS_ENABLED(CONFIG_OPTEE)
>> +/*
>
> ...
>
>> +
>> +static const struct tee_client_device_id stm32_bsec_id_table[] = {
>> +    {
>> +        UUID_INIT(0x94cf71ad, 0x80e6, 0x40b5,
>> +              0xa7, 0xc6, 0x3d, 0xc5, 0x01, 0xeb, 0x28, 0x03)
>> +    },
>> +    { }
>> +};
>> +
>> +MODULE_DEVICE_TABLE(tee, stm32_bsec_id_table);
>> +
>> +static struct tee_client_driver stm32_bsec_pta_driver = {
>> +    .id_table    = stm32_bsec_id_table,
>> +    .driver        = {
>> +        .name = "stm32-bsec-pta",
>> +        .bus = &tee_bus_type,
>> +        .probe = stm32_bsec_pta_probe,
>> +        .remove = stm32_bsec_pta_remove,
>> +    },
>> +};
>> +
>> +static void stm32_bsec_put_device(void *data)
>> +{
>> +    put_device(data);
>> +}
>> +
>> +static struct device *stm32_bsec_pta_find(struct device *dev)
>> +{
>> +    struct device *pta_dev;
>> +    int ret;
>> +
>> +    pta_dev = driver_find_next_device(&stm32_bsec_pta_driver.driver, 
>> NULL);
>
> This is clearly not representing the dependencies in a proper device 
> model.
>
>
> If the nvmem provider is a TEE client driver lets model it that way.. 
> brining in a additional device and somehow trying to link it with TEE 
> driver is  a hack.
>

TEE is a firmware which allow access to secure ressource... including 
BSEC ressources


I think it is also the case on a other driver = mson_sm.c

=> econfig->priv = fw;

       fw is a handle to the firmware (secure monitor) which provide 
access to secure ressource



BSEC is a hardware device on the bus,

it it describe in the device tree, with a compatible,

the same description should be used for any SW, not only Linux kernel.

and the nvmem cell description are sub-node of BSEC node, used as 
phandle by other device.


I need to have a link between the NVMEM driver and the OP-TEE session;

But I use the tee bus discovery here it is a error,

because that create a second uneeded driver "stm32_bsec_pta_driver"...


I will remove this part, and only kept the PTA request with new lib 
functions "stm32_bsec_pta_XXX()".



>
>> +
>> +    if (pta_dev) {
>> +        ret = devm_add_action_or_reset(dev, stm32_bsec_put_device, 
>> pta_dev);
>> +        if (ret)
>> +            dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", 
>> ret);
>> +
>> +        return ERR_PTR(ret);
>> +    }
>> +
>> +    return pta_dev;
>> +}
>> +
>> +#else
>> +static int stm32_bsec_pta_read(void *context, unsigned int offset, 
>> void *buf,
>> +                   size_t bytes)
>> +{
>> +    pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> +    return -ENXIO;
>> +}
>> +
>> +static int stm32_bsec_pta_write(void *context, unsigned int offset, 
>> void *buf,
>> +                size_t bytes)
>> +{
>> +    pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> +    return -ENXIO;
>> +}
>> +
>> +static struct device *stm32_bsec_pta_find(struct device *dev)
>> +{
>> +    pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> +    return NULL;
>> +}
>> +#endif
>
> ifdefing inside the drvier is really ugly, please move this libary 
> functions to a seperate file and add dependecy properly in Kconfig.


Ok

regards


Patrick
  

Patch

diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index d1d03c2ad081..0a0e29d09b67 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c
@@ -11,6 +11,7 @@ 
 #include <linux/module.h>
 #include <linux/nvmem-provider.h>
 #include <linux/of_device.h>
+#include <linux/tee_drv.h>
 
 /* BSEC secure service access from non-secure */
 #define STM32_SMC_BSEC			0x82001003
@@ -25,14 +26,401 @@ 
 struct stm32_romem_cfg {
 	int size;
 	u8 lower;
+	bool ta;
 };
 
 struct stm32_romem_priv {
 	void __iomem *base;
 	struct nvmem_config cfg;
 	u8 lower;
+	struct device *ta;
 };
 
+#if IS_ENABLED(CONFIG_OPTEE)
+/*
+ * Read OTP memory
+ *
+ * [in]		value[0].a		OTP start offset in byte
+ * [in]		value[0].b		Access type (0:shadow, 1:fuse, 2:lock)
+ * [out]	memref[1].buffer	Output buffer to store read values
+ * [out]	memref[1].size		Size of OTP to be read
+ *
+ * Return codes:
+ * TEE_SUCCESS - Invoke command success
+ * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
+ */
+#define PTA_BSEC_READ_MEM		0x0 /* Read OTP */
+
+/*
+ * Write OTP memory
+ *
+ * [in]		value[0].a		OTP start offset in byte
+ * [in]		value[0].b		Access type (0:shadow, 1:fuse, 2:lock)
+ * [in]		memref[1].buffer	Input buffer to read values
+ * [in]		memref[1].size		Size of OTP to be written
+ *
+ * Return codes:
+ * TEE_SUCCESS - Invoke command success
+ * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
+ */
+#define PTA_BSEC_WRITE_MEM		0x1	/* Write OTP */
+
+/* value of PTA_BSEC access type = value[in] b */
+#define SHADOW_ACCESS	0
+#define FUSE_ACCESS	1
+#define LOCK_ACCESS	2
+
+/* Bitfield definition for LOCK status */
+#define LOCK_PERM			BIT(30)
+
+/**
+ * struct stm32_bsec_pta_priv - OP-TEE BSEC TA private data
+ * @ctx:		OP-TEE context handler.
+ * @session_id:		TA session identifier.
+ */
+struct stm32_bsec_pta_priv {
+	struct tee_context *ctx;
+	u32 session_id;
+};
+
+/*
+ * Check whether this driver supports the BSEC TA in the TEE instance
+ * represented by the params (ver/data) to this function.
+ */
+static int stm32_bsec_pta_match(struct tee_ioctl_version_data *ver, const void *data)
+{
+	/* Currently this driver only supports GP compliant, OP-TEE based TA */
+	if ((ver->impl_id == TEE_IMPL_ID_OPTEE) &&
+		(ver->gen_caps & TEE_GEN_CAP_GP))
+		return 1;
+	else
+		return 0;
+}
+
+/**
+ * stm32_bsec_pta_probe() - initialize the PTA BSEC
+ * @dev: the platform_device description.
+ *
+ * Return:
+ *	On success, 0. On failure, -errno.
+ */
+static int stm32_bsec_pta_probe(struct device *dev)
+{
+	int rc;
+	struct tee_ioctl_open_session_arg sess_arg;
+	struct tee_client_device *tee_device = to_tee_client_device(dev);
+	struct stm32_bsec_pta_priv *priv;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* Open context with TEE driver */
+	priv->ctx = tee_client_open_context(NULL, stm32_bsec_pta_match, NULL, NULL);
+	if (IS_ERR(priv->ctx)) {
+		rc = PTR_ERR(priv->ctx);
+		if (rc == -ENOENT)
+			return -EPROBE_DEFER;
+		dev_err(dev, "%s: tee_client_open_context failed (%d)\n", __func__, rc);
+
+		return rc;
+	}
+
+	/* Open a session with BSEC TA */
+	memset(&sess_arg, 0, sizeof(sess_arg));
+	export_uuid(sess_arg.uuid, &tee_device->id.uuid);
+	sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
+	sess_arg.num_params = 0;
+
+	rc = tee_client_open_session(priv->ctx, &sess_arg, NULL);
+	if ((rc < 0) || (sess_arg.ret != 0)) {
+		dev_err(dev, "%s: tee_client_open_session failed err:%x, ret:%x\n",
+			__func__, sess_arg.ret, rc);
+		rc = -EINVAL;
+		goto out_tee_session;
+	}
+	priv->session_id = sess_arg.session;
+	dev_set_drvdata(dev, priv);
+
+	return 0;
+
+out_tee_session:
+	tee_client_close_context(priv->ctx);
+
+	return rc;
+}
+
+/**
+ * stm32_bsec_pta_remove() - remove the BSEC TEE device
+ * @dev: the platform_device description.
+ *
+ * Return:
+ *	0 always.
+ */
+static int stm32_bsec_pta_remove(struct device *dev)
+{
+	struct stm32_bsec_pta_priv *priv = dev_get_drvdata(dev);
+
+	tee_client_close_session(priv->ctx, priv->session_id);
+	tee_client_close_context(priv->ctx);
+
+	return 0;
+}
+
+/**
+ * stm32_bsec_pta_read() - nvmem read access using PTA client driver
+ * @context: nvmem context => romem privdate data
+ * @offset: nvmem offset
+ * @buf: buffer to fill with nvem values
+ * @bytes: number of bytes to read
+ *
+ * Return:
+ *	On success, 0. On failure, -errno.
+ */
+static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
+			       size_t bytes)
+{
+	struct stm32_romem_priv *romem_priv = context;
+	struct device *dev;
+	struct stm32_bsec_pta_priv *priv;
+	struct tee_shm *shm;
+	struct tee_ioctl_invoke_arg arg;
+	struct tee_param param[2];
+	u8 *shm_buf;
+	u32 start, num_bytes;
+	int ret;
+
+	dev = romem_priv->ta;
+	if (!dev) {
+		pr_err("TA_BSEC invoke without driver\n");
+		return -ENXIO;
+	}
+
+	priv = dev_get_drvdata(dev);
+
+	memset(&arg, 0, sizeof(arg));
+	memset(&param, 0, sizeof(param));
+
+	arg.func = PTA_BSEC_READ_MEM;
+	arg.session = priv->session_id;
+	arg.num_params = 2;
+
+	/* align access on 32bits */
+	start = ALIGN_DOWN(offset, 4);
+	num_bytes = round_up(offset + bytes - start, 4);
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
+	param[0].u.value.a = start;
+	param[0].u.value.b = SHADOW_ACCESS;
+
+	shm = tee_shm_alloc_kernel_buf(priv->ctx, num_bytes);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
+	param[1].u.memref.shm = shm;
+	param[1].u.memref.size = num_bytes;
+
+	ret = tee_client_invoke_func(priv->ctx, &arg, param);
+	if (ret < 0 || arg.ret != 0) {
+		dev_err(dev, "TA_BSEC invoke failed TEE err:%x, ret:%x\n",
+			arg.ret, ret);
+		if (!ret)
+			ret = -EIO;
+	}
+	if (!ret) {
+		shm_buf = tee_shm_get_va(shm, 0);
+		if (IS_ERR(shm_buf)) {
+			ret = PTR_ERR(shm_buf);
+			dev_err(dev, "tee_shm_get_va failed for transmit (%d)\n", ret);
+		} else {
+			/* read data from 32 bits aligned buffer */
+			memcpy(buf, &shm_buf[offset % 4], bytes);
+		}
+	}
+
+	tee_shm_free(shm);
+
+	return ret;
+}
+
+/**
+ * stm32_bsec_pta_write() - nvmem write access using PTA client driver
+ * @context: nvmem context => romem privdate data
+ * @offset: nvmem offset
+ * @buf: buffer with nvem values
+ * @bytes: number of bytes to write
+ *
+ * Return:
+ *	On success, 0. On failure, -errno.
+ */
+static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
+				size_t bytes)
+{
+	struct stm32_romem_priv *romem_priv = context;
+	struct device *dev;
+	struct stm32_bsec_pta_priv *priv;
+	struct tee_shm *shm;
+	struct tee_ioctl_invoke_arg arg;
+	struct tee_param param[2];
+	u8 *shm_buf;
+	int ret;
+
+	dev = romem_priv->ta;
+	if (!dev) {
+		pr_err("TA_BSEC invoke without driver\n");
+		return -ENXIO;
+	}
+
+	/* Allow only writing complete 32-bits aligned words */
+	if ((bytes % 4) || (offset % 4))
+		return -EINVAL;
+
+	priv = dev_get_drvdata(dev);
+
+	memset(&arg, 0, sizeof(arg));
+	memset(&param, 0, sizeof(param));
+
+	arg.func = PTA_BSEC_WRITE_MEM;
+	arg.session = priv->session_id;
+	arg.num_params = 2;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
+	param[0].u.value.a = offset;
+	param[0].u.value.b = FUSE_ACCESS;
+
+	shm = tee_shm_alloc_kernel_buf(priv->ctx, bytes);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
+	param[1].u.memref.shm = shm;
+	param[1].u.memref.size = bytes;
+
+	shm_buf = tee_shm_get_va(shm, 0);
+	if (IS_ERR(shm_buf)) {
+		ret = PTR_ERR(shm_buf);
+		dev_err(dev, "tee_shm_get_va failed for transmit (%d)\n", ret);
+		tee_shm_free(shm);
+
+		return ret;
+	}
+
+	memcpy(shm_buf, buf, bytes);
+
+	ret = tee_client_invoke_func(priv->ctx, &arg, param);
+	if (ret < 0 || arg.ret != 0) {
+		dev_err(dev, "TA_BSEC invoke failed TEE err:%x, ret:%x\n",
+			arg.ret, ret);
+		if (!ret)
+			ret = -EIO;
+	}
+	dev_dbg(dev, "Write OTPs %d to %d, ret=%d\n",
+		offset / 4, (offset + bytes) / 4, ret);
+
+	/* Lock the upper OTPs with ECC protection, word programming only */
+	if (!ret && ((offset + bytes) >= (romem_priv->lower * 4))) {
+		u32 start, nb_lock;
+		u32 *lock = (u32 *)shm_buf;
+		int i;
+
+		/*
+		 * don't lock the lower OTPs, no ECC protection and incremental
+		 * bit programming, a second write is allowed
+		 */
+		start = max_t(u32, offset, romem_priv->lower * 4);
+		nb_lock = (offset + bytes - start) / 4;
+
+		param[0].u.value.a = start;
+		param[0].u.value.b = LOCK_ACCESS;
+		param[1].u.memref.size = nb_lock * 4;
+
+		for (i = 0; i < nb_lock; i++)
+			lock[i] = LOCK_PERM;
+
+		ret = tee_client_invoke_func(priv->ctx, &arg, param);
+		if (ret < 0 || arg.ret != 0) {
+			dev_err(dev, "TA_BSEC invoke failed TEE err:%x, ret:%x\n",
+				arg.ret, ret);
+			if (!ret)
+				ret = -EIO;
+		}
+		dev_dbg(dev, "Lock upper OTPs %d to %d, ret=%d\n",
+			start / 4, start / 4 + nb_lock, ret);
+	}
+
+	tee_shm_free(shm);
+
+	return ret;
+}
+
+static const struct tee_client_device_id stm32_bsec_id_table[] = {
+	{
+		UUID_INIT(0x94cf71ad, 0x80e6, 0x40b5,
+			  0xa7, 0xc6, 0x3d, 0xc5, 0x01, 0xeb, 0x28, 0x03)
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(tee, stm32_bsec_id_table);
+
+static struct tee_client_driver stm32_bsec_pta_driver = {
+	.id_table	= stm32_bsec_id_table,
+	.driver		= {
+		.name = "stm32-bsec-pta",
+		.bus = &tee_bus_type,
+		.probe = stm32_bsec_pta_probe,
+		.remove = stm32_bsec_pta_remove,
+	},
+};
+
+static void stm32_bsec_put_device(void *data)
+{
+	put_device(data);
+}
+
+static struct device *stm32_bsec_pta_find(struct device *dev)
+{
+	struct device *pta_dev;
+	int ret;
+
+	pta_dev = driver_find_next_device(&stm32_bsec_pta_driver.driver, NULL);
+
+	if (pta_dev) {
+		ret = devm_add_action_or_reset(dev, stm32_bsec_put_device, pta_dev);
+		if (ret)
+			dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", ret);
+
+		return ERR_PTR(ret);
+	}
+
+	return pta_dev;
+}
+
+#else
+static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
+			       size_t bytes)
+{
+	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
+
+	return -ENXIO;
+}
+
+static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
+				size_t bytes)
+{
+	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
+
+	return -ENXIO;
+}
+
+static struct device *stm32_bsec_pta_find(struct device *dev)
+{
+	pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
+
+	return NULL;
+}
+#endif
+
 static int stm32_romem_read(void *context, unsigned int offset, void *buf,
 			    size_t bytes)
 {
@@ -173,15 +561,27 @@  static int stm32_romem_probe(struct platform_device *pdev)
 	} else {
 		priv->cfg.size = cfg->size;
 		priv->lower = cfg->lower;
-		priv->cfg.reg_read = stm32_bsec_read;
-		priv->cfg.reg_write = stm32_bsec_write;
+		if (cfg->ta) {
+			priv->ta = stm32_bsec_pta_find(dev);
+			/* wait for OP-TEE client driver to be up and ready */
+			if (!priv->ta)
+				return -EPROBE_DEFER;
+			if (IS_ERR(priv->ta))
+				return PTR_ERR(priv->ta);
+
+			priv->cfg.reg_read = stm32_bsec_pta_read;
+			priv->cfg.reg_write = stm32_bsec_pta_write;
+		} else {
+			priv->cfg.reg_read = stm32_bsec_read;
+			priv->cfg.reg_write = stm32_bsec_write;
+		}
 	}
 
 	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
 }
 
 /*
- * STM32MP15 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
+ * STM32MP15/13 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
  * => 96 x 32-bits data words
  * - Lower: 1K bits, 2:1 redundancy, incremental bit programming
  *   => 32 (x 32-bits) lower shadow registers = words 0 to 31
@@ -191,6 +591,13 @@  static int stm32_romem_probe(struct platform_device *pdev)
 static const struct stm32_romem_cfg stm32mp15_bsec_cfg = {
 	.size = 384,
 	.lower = 32,
+	.ta = false,
+};
+
+static const struct stm32_romem_cfg stm32mp13_bsec_cfg = {
+	.size = 384,
+	.lower = 32,
+	.ta = true,
 };
 
 static const struct of_device_id stm32_romem_of_match[] = {
@@ -198,7 +605,10 @@  static const struct of_device_id stm32_romem_of_match[] = {
 		.compatible = "st,stm32mp15-bsec",
 		.data = (void *)&stm32mp15_bsec_cfg,
 	}, {
+		.compatible = "st,stm32mp13-bsec",
+		.data = (void *)&stm32mp13_bsec_cfg,
 	},
+	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
 
@@ -209,7 +619,34 @@  static struct platform_driver stm32_romem_driver = {
 		.of_match_table = of_match_ptr(stm32_romem_of_match),
 	},
 };
-module_platform_driver(stm32_romem_driver);
+
+static int __init stm32_romem_init(void)
+{
+	int rc;
+
+	rc = platform_driver_register(&stm32_romem_driver);
+	if (rc)
+		return rc;
+
+#if IS_ENABLED(CONFIG_OPTEE)
+	rc = driver_register(&stm32_bsec_pta_driver.driver);
+	if (rc)
+		platform_driver_unregister(&stm32_romem_driver);
+#endif
+
+	return rc;
+}
+
+static void __exit stm32_romem_exit(void)
+{
+	platform_driver_unregister(&stm32_romem_driver);
+#if IS_ENABLED(CONFIG_OPTEE)
+	driver_unregister(&stm32_bsec_pta_driver.driver);
+#endif
+}
+
+module_init(stm32_romem_init);
+module_exit(stm32_romem_exit);
 
 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");