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 --- drivers/tee/optee/optee_msg.h | 18 +++++++++++ drivers/tee/optee/rpc.c | 56 +++++++++++++++++++++++++++++++++++ 2 files changed, 74 insertions(+)
diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h index 795bc19ae17a..b6cc964fdeea 100644 --- a/drivers/tee/optee/optee_msg.h +++ b/drivers/tee/optee/optee_msg.h @@ -419,4 +419,22 @@ 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 + * + * [io] param[1].u.tmem.buf_ptr physical address + * [io] param[1].u.tmem.size transfer size in bytes + * [io] param[1].u.tmem.shm_ref shared memory reference + * + * [out] param[0].u.value.a bytes transferred + * + */ +#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 8 +#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..6c8457ac2524 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"
@@ -48,6 +49,58 @@ static void handle_rpc_func_cmd_get_time(struct optee_msg_arg *arg) bad: 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_shm *shm; + int i, ret; + char *buf; + uint32_t attr[] = { + OPTEE_MSG_ATTR_TYPE_VALUE_INPUT, + OPTEE_MSG_ATTR_TYPE_TMEM_INOUT, + OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT, + }; + + if (arg->num_params != ARRAY_SIZE(attr)) + goto bad; + + for (i = 0; i < ARRAY_SIZE(attr); i++) + if ((arg->params[i].attr & OPTEE_MSG_ATTR_TYPE_MASK) != attr[i]) + goto bad; + + shm = (struct tee_shm *)(unsigned long)arg->params[1].u.tmem.shm_ref; + buf = (char *)shm->kaddr; + + client.addr = arg->params[0].u.value.c; + client.adapter = i2c_get_adapter(arg->params[0].u.value.b); + if (!client.adapter) + goto bad; + + snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr); + + switch (arg->params[0].u.value.a) { + case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD: + ret = i2c_master_recv(&client, buf, arg->params[1].u.tmem.size); + break; + case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR: + ret = i2c_master_send(&client, buf, arg->params[1].u.tmem.size); + break; + default: + goto bad; + } + + if (ret >= 0) { + arg->params[2].u.value.a = ret; + arg->ret = TEEC_SUCCESS; + } else + arg->ret = TEEC_ERROR_COMMUNICATION; + + i2c_put_adapter(client.adapter); + return; +bad: + arg->ret = TEEC_ERROR_BAD_PARAMETERS; +}
static struct wq_entry *wq_entry_get(struct optee_wait_queue *wq, u32 key) { @@ -382,6 +435,9 @@ 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); }
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Jorge Ramirez-Ortiz