Some secure elements like NXP's SE050 sit on I2C buses. For OP-TEE to control this type of cryptographic devices it needs coordinated access to the bus, so collisions and RUNTIME_PM dont get in the way.
This trampoline driver allow OP-TEE to access them.
Signed-off-by: Jorge Ramirez-Ortiz jorge@foundries.io ---
v3: use from/to msg param to support all types of memory modify OPTEE_MSG_RPC_CMD_I2C_TRANSFER id
drivers/tee/optee/optee_msg.h | 17 ++++++++ drivers/tee/optee/rpc.c | 80 +++++++++++++++++++++++++++++++++++ 2 files changed, 97 insertions(+)
diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h index 795bc19ae17a..aa7cb19942b9 100644 --- a/drivers/tee/optee/optee_msg.h +++ b/drivers/tee/optee/optee_msg.h @@ -419,4 +419,21 @@ struct optee_msg_arg { */ #define OPTEE_MSG_RPC_CMD_SHM_FREE 7
+/* + * Access a device on an i2c bus + * + * [in] param[0].u.value.a mode: RD(0), WR(1) + * [in] param[0].u.value.b i2c adapter + * [in] param[0].u.value.c i2c chip + * + * [in/out] memref[1] buffer to exchange the transfer data + * with the secure world + * + * [out] param[0].u.value.a bytes transferred by the driver + */ +#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 21 +#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD 0 +#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR 1 + + #endif /* _OPTEE_MSG_H */ diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c index b4ade54d1f28..2b2939c538f0 100644 --- a/drivers/tee/optee/rpc.c +++ b/drivers/tee/optee/rpc.c @@ -9,6 +9,7 @@ #include <linux/device.h> #include <linux/slab.h> #include <linux/tee_drv.h> +#include <linux/i2c.h> #include "optee_private.h" #include "optee_smc.h"
@@ -49,6 +50,82 @@ static void handle_rpc_func_cmd_get_time(struct optee_msg_arg *arg) arg->ret = TEEC_ERROR_BAD_PARAMETERS; }
+static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, + struct optee_msg_arg *arg) +{ + struct i2c_client client; + struct tee_param *params; + uint32_t type; + int i, ret; + size_t len; + char *buf; + uint32_t attr[] = { + TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT, + TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT, + TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT, + }; + + if (arg->num_params != ARRAY_SIZE(attr)) { + arg->ret = TEEC_ERROR_BAD_PARAMETERS; + return; + } + + params = kmalloc_array(arg->num_params, sizeof(struct tee_param), + GFP_KERNEL); + if (!params) { + arg->ret = TEEC_ERROR_OUT_OF_MEMORY; + return; + } + + if (optee_from_msg_param(params, arg->num_params, arg->params)) + goto bad; + + for (i = 0; i < arg->num_params; i++) { + type = params[i].attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK; + if (type != attr[i]) + goto bad; + } + + client.addr = params[0].u.value.c; + client.adapter = i2c_get_adapter(params[0].u.value.b); + if (!client.adapter) + goto bad; + + snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr); + + buf = params[1].u.memref.shm->kaddr; + len = params[1].u.memref.size; + + switch (params[0].u.value.a) { + case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD: + ret = i2c_master_recv(&client, buf, len); + break; + case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR: + ret = i2c_master_send(&client, buf, len); + break; + default: + i2c_put_adapter(client.adapter); + goto bad; + } + + if (ret >= 0) { + params[2].u.value.a = ret; + arg->ret = TEEC_SUCCESS; + } else { + arg->ret = TEEC_ERROR_COMMUNICATION; + } + + if (optee_to_msg_param(arg->params, arg->num_params, params)) + arg->ret = TEEC_ERROR_BAD_PARAMETERS; + + i2c_put_adapter(client.adapter); + kfree(params); + return; +bad: + kfree(params); + arg->ret = TEEC_ERROR_BAD_PARAMETERS; +} + static struct wq_entry *wq_entry_get(struct optee_wait_queue *wq, u32 key) { struct wq_entry *w; @@ -382,6 +459,9 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee, case OPTEE_MSG_RPC_CMD_SHM_FREE: handle_rpc_func_cmd_shm_free(ctx, arg); break; + case OPTEE_MSG_RPC_CMD_I2C_TRANSFER: + handle_rpc_func_cmd_i2c_transfer(ctx, arg); + break; default: handle_rpc_supp_cmd(ctx, arg); }