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References: <20230106170430.1214186-1-patrick.delaunay@foss.st.com> <20230106180414.v5.2.Ibc43aa73f865090affeb1751af0cc260c7f1dd07@changeid>
In-Reply-To: <20230106180414.v5.2.Ibc43aa73f865090affeb1751af0cc260c7f1dd07@changeid>
From:   Etienne Carriere <etienne.carriere@linaro.org>
Date:   Wed, 11 Jan 2023 12:09:24 +0100
Message-ID: <CAN5uoS9kWPVqmFzi2+iZgpYJKpZngjk05J7fb1=+qkLcRp=+1g@mail.gmail.com>
Subject: Re: [PATCH v5 2/3] nvmem: stm32: add OP-TEE support for STM32MP13x
To:     Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc:     Alexandre TORGUE <alexandre.torgue@foss.st.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Fabrice GASNIER <fabrice.gasnier@foss.st.com>,
        Amelie DELAUNAY <amelie.delaunay@foss.st.com>,
        Lionel DEBIEVE <lionel.debieve@foss.st.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hello Patrick,

On Fri, 6 Jan 2023 at 18:04, Patrick Delaunay
<patrick.delaunay@foss.st.com> wrote:
>
> For boot with OP-TEE on STM32MP13, the communication with the secure
> world no more use STMicroelectronics SMC but communication with the
> STM32MP 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>

Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>


> ---
>
> Changes in v5:
> - minor changes after Etienne Carierre review (comments,
>   change %x to %#x, remove goto to out_tee_session)
>
> Changes in v4:
> - fixe warning reported by kernel test robot for 64 bits support in
>   drivers/nvmem/stm32-bsec-optee-ta.c:260:18:
>   warning: format '%d' expects argument of type 'int',
>   but argument 4 has type 'size_t'
>
> Changes in v3:
> - add a separate file stm32-bsec-optee-ta.c with STM32MP BSEC TA
>   communication functions to avoid #if in romem driver.
>
> 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/Kconfig               |  11 +
>  drivers/nvmem/Makefile              |   1 +
>  drivers/nvmem/stm32-bsec-optee-ta.c | 298 ++++++++++++++++++++++++++++
>  drivers/nvmem/stm32-bsec-optee-ta.h |  80 ++++++++
>  drivers/nvmem/stm32-romem.c         |  54 ++++-
>  5 files changed, 441 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/nvmem/stm32-bsec-optee-ta.c
>  create mode 100644 drivers/nvmem/stm32-bsec-optee-ta.h
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 755f551426b5..4d262f69a073 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -290,9 +290,20 @@ config NVMEM_SPRD_EFUSE
>           This driver can also be built as a module. If so, the module
>           will be called nvmem-sprd-efuse.
>
> +config NVMEM_STM32_BSEC_OPTEE_TA
> +       bool "STM32MP BSEC OP-TEE TA support for nvmem-stm32-romem driver"
> +       depends on OPTEE
> +       help
> +         Say y here to enable the accesses to STM32MP SoC OTPs by the OP-TEE
> +         trusted application STM32MP BSEC.
> +
> +         This library is a used by stm32-romem driver or included in the module
> +         called nvmem-stm32-romem.
> +
>  config NVMEM_STM32_ROMEM
>         tristate "STMicroelectronics STM32 factory-programmed memory support"
>         depends on ARCH_STM32 || COMPILE_TEST
> +       imply NVMEM_STM32_BSEC_OPTEE_TA
>         help
>           Say y here to enable read-only access for STMicroelectronics STM32
>           factory-programmed memory area.
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index fa80fe17e567..6a1efffa88f0 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_NVMEM_SPRD_EFUSE)                += nvmem_sprd_efuse.o
>  nvmem_sprd_efuse-y                     := sprd-efuse.o
>  obj-$(CONFIG_NVMEM_STM32_ROMEM)                += nvmem_stm32_romem.o
>  nvmem_stm32_romem-y                    := stm32-romem.o
> +nvmem_stm32_romem-$(CONFIG_NVMEM_STM32_BSEC_OPTEE_TA) += stm32-bsec-optee-ta.o
>  obj-$(CONFIG_NVMEM_SUNPLUS_OCOTP)      += nvmem_sunplus_ocotp.o
>  nvmem_sunplus_ocotp-y                  := sunplus-ocotp.o
>  obj-$(CONFIG_NVMEM_SUNXI_SID)          += nvmem_sunxi_sid.o
> diff --git a/drivers/nvmem/stm32-bsec-optee-ta.c b/drivers/nvmem/stm32-bsec-optee-ta.c
> new file mode 100644
> index 000000000000..f89ce791dd12
> --- /dev/null
> +++ b/drivers/nvmem/stm32-bsec-optee-ta.c
> @@ -0,0 +1,298 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * OP-TEE STM32MP BSEC PTA interface, used by STM32 ROMEM driver
> + *
> + * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
> + */
> +
> +#include <linux/tee_drv.h>
> +
> +#include "stm32-bsec-optee-ta.h"
> +
> +/*
> + * 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
> + * TEE_ERROR_ACCESS_DENIED - OTP not accessible by caller
> + */
> +#define PTA_BSEC_READ_MEM              0x0
> +
> +/*
> + * 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
> + * TEE_ERROR_ACCESS_DENIED - OTP not accessible by caller
> + */
> +#define PTA_BSEC_WRITE_MEM             0x1
> +
> +/* 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)
> +
> +/* OP-TEE STM32MP BSEC TA UUID */
> +static const uuid_t stm32mp_bsec_ta_uuid =
> +       UUID_INIT(0x94cf71ad, 0x80e6, 0x40b5,
> +                 0xa7, 0xc6, 0x3d, 0xc5, 0x01, 0xeb, 0x28, 0x03);
> +
> +/*
> + * 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_optee_ta_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;
> +}
> +
> +/* Open a session to OP-TEE for STM32MP BSEC TA */
> +static int stm32_bsec_ta_open_session(struct tee_context *ctx, u32 *id)
> +{
> +       struct tee_ioctl_open_session_arg sess_arg;
> +       int rc;
> +
> +       memset(&sess_arg, 0, sizeof(sess_arg));
> +       export_uuid(sess_arg.uuid, &stm32mp_bsec_ta_uuid);
> +       sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
> +       sess_arg.num_params = 0;
> +
> +       rc = tee_client_open_session(ctx, &sess_arg, NULL);
> +       if ((rc < 0) || (sess_arg.ret != 0)) {
> +               pr_err("%s: tee_client_open_session failed err:%#x, ret:%#x\n",
> +                      __func__, sess_arg.ret, rc);
> +               if (!rc)
> +                       rc = -EINVAL;
> +       } else {
> +               *id = sess_arg.session;
> +       }
> +
> +       return rc;
> +}
> +
> +/* close a session to OP-TEE for STM32MP BSEC TA */
> +static void stm32_bsec_ta_close_session(void *ctx, u32 id)
> +{
> +       tee_client_close_session(ctx, id);
> +}
> +
> +/* stm32_bsec_optee_ta_open() - initialize the STM32MP BSEC TA */
> +int stm32_bsec_optee_ta_open(struct tee_context **ctx)
> +{
> +       struct tee_context *tee_ctx;
> +       u32 session_id;
> +       int rc;
> +
> +       /* Open context with TEE driver */
> +       tee_ctx = tee_client_open_context(NULL, stm32_bsec_optee_ta_match, NULL, NULL);
> +       if (IS_ERR(tee_ctx)) {
> +               rc = PTR_ERR(tee_ctx);
> +               if (rc == -ENOENT)
> +                       return -EPROBE_DEFER;
> +               pr_err("%s: tee_client_open_context failed (%d)\n", __func__, rc);
> +
> +               return rc;
> +       }
> +
> +       /* Check STM32MP BSEC TA presence */
> +       rc = stm32_bsec_ta_open_session(tee_ctx, &session_id);
> +       if (rc) {
> +               tee_client_close_context(tee_ctx);
> +               return rc;
> +       }
> +
> +       stm32_bsec_ta_close_session(tee_ctx, session_id);
> +
> +       *ctx = tee_ctx;
> +
> +       return 0;
> +}
> +
> +/* stm32_bsec_optee_ta_open() - release the PTA STM32MP BSEC TA */
> +void stm32_bsec_optee_ta_close(void *ctx)
> +{
> +       tee_client_close_context(ctx);
> +}
> +
> +/* stm32_bsec_optee_ta_read() - nvmem read access using PTA client driver */
> +int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
> +                            void *buf, size_t bytes)
> +{
> +       struct tee_shm *shm;
> +       struct tee_ioctl_invoke_arg arg;
> +       struct tee_param param[2];
> +       u8 *shm_buf;
> +       u32 start, num_bytes;
> +       int ret;
> +       u32 session_id;
> +
> +       ret = stm32_bsec_ta_open_session(ctx, &session_id);
> +       if (ret)
> +               return ret;
> +
> +       memset(&arg, 0, sizeof(arg));
> +       memset(&param, 0, sizeof(param));
> +
> +       arg.func = PTA_BSEC_READ_MEM;
> +       arg.session = 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(ctx, num_bytes);
> +       if (IS_ERR(shm)) {
> +               ret = PTR_ERR(shm);
> +               goto out_tee_session;
> +       }
> +
> +       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(ctx, &arg, param);
> +       if (ret < 0 || arg.ret != 0) {
> +               pr_err("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);
> +                       pr_err("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);
> +
> +out_tee_session:
> +       stm32_bsec_ta_close_session(ctx, session_id);
> +
> +       return ret;
> +}
> +
> +/* stm32_bsec_optee_ta_write() - nvmem write access using PTA client driver */
> +int stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
> +                             unsigned int offset, void *buf, size_t bytes)
> +{      struct tee_shm *shm;
> +       struct tee_ioctl_invoke_arg arg;
> +       struct tee_param param[2];
> +       u8 *shm_buf;
> +       int ret;
> +       u32 session_id;
> +
> +       ret = stm32_bsec_ta_open_session(ctx, &session_id);
> +       if (ret)
> +               return ret;
> +
> +       /* Allow only writing complete 32-bits aligned words */
> +       if ((bytes % 4) || (offset % 4))
> +               return -EINVAL;
> +
> +       memset(&arg, 0, sizeof(arg));
> +       memset(&param, 0, sizeof(param));
> +
> +       arg.func = PTA_BSEC_WRITE_MEM;
> +       arg.session = 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(ctx, bytes);
> +       if (IS_ERR(shm)) {
> +               ret = PTR_ERR(shm);
> +               goto out_tee_session;
> +       }
> +
> +       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);
> +               pr_err("tee_shm_get_va failed for transmit (%d)\n", ret);
> +               tee_shm_free(shm);
> +
> +               goto out_tee_session;
> +       }
> +
> +       memcpy(shm_buf, buf, bytes);
> +
> +       ret = tee_client_invoke_func(ctx, &arg, param);
> +       if (ret < 0 || arg.ret != 0) {
> +               pr_err("TA_BSEC invoke failed TEE err:%#x, ret:%#x\n", arg.ret, ret);
> +               if (!ret)
> +                       ret = -EIO;
> +       }
> +       pr_debug("Write OTPs %d to %zu, ret=%d\n", offset / 4, (offset + bytes) / 4, ret);
> +
> +       /* Lock the upper OTPs with ECC protection, word programming only */
> +       if (!ret && ((offset + bytes) >= (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, 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(ctx, &arg, param);
> +               if (ret < 0 || arg.ret != 0) {
> +                       pr_err("TA_BSEC invoke failed TEE err:%#x, ret:%#x\n", arg.ret, ret);
> +                       if (!ret)
> +                               ret = -EIO;
> +               }
> +               pr_debug("Lock upper OTPs %d to %d, ret=%d\n",
> +                        start / 4, start / 4 + nb_lock, ret);
> +       }
> +
> +       tee_shm_free(shm);
> +
> +out_tee_session:
> +       stm32_bsec_ta_close_session(ctx, session_id);
> +
> +       return ret;
> +}
> diff --git a/drivers/nvmem/stm32-bsec-optee-ta.h b/drivers/nvmem/stm32-bsec-optee-ta.h
> new file mode 100644
> index 000000000000..3966a0535179
> --- /dev/null
> +++ b/drivers/nvmem/stm32-bsec-optee-ta.h
> @@ -0,0 +1,80 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * OP-TEE STM32MP BSEC PTA interface, used by STM32 ROMEM driver
> + *
> + * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
> + */
> +
> +#if IS_ENABLED(CONFIG_NVMEM_STM32_BSEC_OPTEE_TA)
> +/**
> + * stm32_bsec_optee_ta_open() - initialize the STM32 BSEC TA
> + * @ctx: the OP-TEE context on success
> + *
> + * Return:
> + *     On success, 0. On failure, -errno.
> + */
> +int stm32_bsec_optee_ta_open(struct tee_context **ctx);
> +
> +/**
> + * stm32_bsec_optee_ta_close() - release the STM32 BSEC TA
> + * @ctx: the OP-TEE context
> + *
> + * This function used to clean the OP-TEE resources initialized in
> + * stm32_bsec_optee_ta_open(); it can be used as callback to
> + * devm_add_action_or_reset()
> + */
> +void stm32_bsec_optee_ta_close(void *ctx);
> +
> +/**
> + * stm32_bsec_optee_ta_read() - nvmem read access using TA client driver
> + * @ctx: the OP-TEE context provided by stm32_bsec_optee_ta_open
> + * @offset: nvmem offset
> + * @buf: buffer to fill with nvem values
> + * @bytes: number of bytes to read
> + *
> + * Return:
> + *     On success, 0. On failure, -errno.
> + */
> +int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
> +                            void *buf, size_t bytes);
> +
> +/**
> + * stm32_bsec_optee_ta_write() - nvmem write access using TA client driver
> + * @ctx: the OP-TEE context provided by stm32_bsec_optee_ta_open
> + * @lower: number of lower OTP, not protected by ECC
> + * @offset: nvmem offset
> + * @buf: buffer with nvem values
> + * @bytes: number of bytes to write
> + *
> + * Return:
> + *     On success, 0. On failure, -errno.
> + */
> +int stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
> +                             unsigned int offset, void *buf, size_t bytes);
> +
> +#else
> +
> +static inline int stm32_bsec_optee_ta_open(struct tee_context **ctx)
> +{
> +       return -EOPNOTSUPP;
> +}
> +
> +static inline void stm32_bsec_optee_ta_close(void *ctx)
> +{
> +}
> +
> +static inline int stm32_bsec_optee_ta_read(struct tee_context *ctx,
> +                                          unsigned int offset, void *buf,
> +                                          size_t bytes)
> +{
> +       return -EOPNOTSUPP;
> +}
> +
> +static inline int stm32_bsec_optee_ta_write(struct tee_context *ctx,
> +                                           unsigned int lower,
> +                                           unsigned int offset, void *buf,
> +                                           size_t bytes)
> +{
> +       return -EOPNOTSUPP;
> +}
> +#endif /* CONFIG_NVMEM_STM32_BSEC_OPTEE_TA */
> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
> index d1d03c2ad081..978a63edf297 100644
> --- a/drivers/nvmem/stm32-romem.c
> +++ b/drivers/nvmem/stm32-romem.c
> @@ -11,6 +11,9 @@
>  #include <linux/module.h>
>  #include <linux/nvmem-provider.h>
>  #include <linux/of_device.h>
> +#include <linux/tee_drv.h>
> +
> +#include "stm32-bsec-optee-ta.h"
>
>  /* BSEC secure service access from non-secure */
>  #define STM32_SMC_BSEC                 0x82001003
> @@ -25,12 +28,14 @@
>  struct stm32_romem_cfg {
>         int size;
>         u8 lower;
> +       bool ta;
>  };
>
>  struct stm32_romem_priv {
>         void __iomem *base;
>         struct nvmem_config cfg;
>         u8 lower;
> +       struct tee_context *ctx;
>  };
>
>  static int stm32_romem_read(void *context, unsigned int offset, void *buf,
> @@ -138,12 +143,29 @@ static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
>         return 0;
>  }
>
> +static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
> +                              size_t bytes)
> +{
> +       struct stm32_romem_priv *priv = context;
> +
> +       return stm32_bsec_optee_ta_read(priv->ctx, offset, buf, bytes);
> +}
> +
> +static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
> +                               size_t bytes)
> +{
> +       struct stm32_romem_priv *priv = context;
> +
> +       return stm32_bsec_optee_ta_write(priv->ctx, priv->lower, offset, buf, bytes);
> +}
> +
>  static int stm32_romem_probe(struct platform_device *pdev)
>  {
>         const struct stm32_romem_cfg *cfg;
>         struct device *dev = &pdev->dev;
>         struct stm32_romem_priv *priv;
>         struct resource *res;
> +       int rc;
>
>         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>         if (!priv)
> @@ -173,15 +195,31 @@ 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) {
> +                       rc = stm32_bsec_optee_ta_open(&priv->ctx);
> +                       /* wait for OP-TEE client driver to be up and ready */
> +                       if (rc)
> +                               return rc;
> +               }
> +               if (priv->ctx) {
> +                       rc = devm_add_action_or_reset(dev, stm32_bsec_optee_ta_close, priv->ctx);
> +                       if (rc) {
> +                               dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", rc);
> +                               return rc;
> +                       }
> +                       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 +229,13 @@ 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 +243,10 @@ 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);
>
> --
> 2.25.1
>