Re: [Tee-dev] [PATCH v2] drivers: optee: allow op-tee to access devices on the i2c bus

On 01/06/20, Jorge Ramirez-Ortiz wrote:

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.

any comments please?

Signed-off-by: Jorge Ramirez-Ortiz jorge@foundries.io

drivers/tee/optee/optee_msg.h | 18 +++++++++++ drivers/tee/optee/rpc.c | 57 +++++++++++++++++++++++++++++++++++ 2 files changed, 75 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..21d452805c6f 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 +49,59 @@ 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:

• i2c_put_adapter(client.adapter);
  

• 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 +436,9 @@ 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); }

-- 2.17.1