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-rw-r--r--drivers/nvmem/stm32-bsec-optee-ta.c298
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/nvmem/stm32-bsec-optee-ta.c b/drivers/nvmem/stm32-bsec-optee-ta.c
new file mode 100644
index 0000000000..f89ce791dd
--- /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;
+}