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Subject[PATCH v3 2/3] nvmem: stm32: add OP-TEE support for STM32MP13x
Date
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>
---

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 | 55 ++++-
5 files changed, 442 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 ec8a49c04003..607e7c4c087b 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..cddcf9cb51d4
--- /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
+ */
+#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)
+
+/* 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 BASEC TA presence */
+ rc = stm32_bsec_ta_open_session(tee_ctx, &session_id);
+ if (rc)
+ goto out_tee_session;
+ stm32_bsec_ta_close_session(tee_ctx, session_id);
+
+ *ctx = tee_ctx;
+
+ return 0;
+
+out_tee_session:
+ tee_client_close_context(tee_ctx);
+
+ return rc;
+}
+
+/* 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 %d, 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..e2fb3eb747dd 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;
+ 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;
+ }
+ }
+ if (priv->ctx) {
+ 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);

@@ -209,6 +257,7 @@ static struct platform_driver stm32_romem_driver = {
.of_match_table = of_match_ptr(stm32_romem_of_match),
},
};
+
module_platform_driver(stm32_romem_driver);

MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
--
2.25.1
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