Re: [Tee-dev] [PATCHv6] drivers: optee: allow op-tee to access devices on the i2c bus

On Wed, Aug 05, 2020 at 03:35:01PM +0200, Jorge Ramirez-Ortiz, Foundries wrote:

On 22/07/20, 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. Tested on imx8mm LPDDR4

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

v6: compile out if CONFIG_I2C not enabled v5: alphabetic order of includes v4: remove unnecessary extra line in optee_msg.h v3: use from/to msg param to support all types of memory modify OPTEE_MSG_RPC_CMD_I2C_TRANSFER message id drivers/tee/optee/optee_msg.h | 16 +++++++ drivers/tee/optee/rpc.c | 88 +++++++++++++++++++++++++++++++++++ 2 files changed, 104 insertions(+)

diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h index 795bc19ae17a..14b580f55356 100644 --- a/drivers/tee/optee/optee_msg.h +++ b/drivers/tee/optee/optee_msg.h @@ -419,4 +419,20 @@ 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..5fd5c6c93896 100644 --- a/drivers/tee/optee/rpc.c +++ b/drivers/tee/optee/rpc.c @@ -7,6 +7,7 @@ #include <linux/delay.h> #include <linux/device.h> +#include <linux/i2c.h> #include <linux/slab.h> #include <linux/tee_drv.h> #include "optee_private.h" @@ -49,6 +50,90 @@ static void handle_rpc_func_cmd_get_time(struct optee_msg_arg *arg) arg->ret = TEEC_ERROR_BAD_PARAMETERS; } +#if IS_ENABLED(CONFIG_I2C) +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;

+} +#else +static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx,

• 			     struct optee_msg_arg *arg)
  

+{

• arg->ret = TEEC_ERROR_COMMUNICATION;

+} +#endif

static struct wq_entry *wq_entry_get(struct optee_wait_queue *wq, u32 key) { struct wq_entry *w; @@ -382,6 +467,9 @@ 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); }

any comments please?

As you know we're still reviewing the secure world counterpart at https://github.com/OP-TEE/optee_os/pull/3905 Where we're sorting out the ABI. Thanks for your patience.

Cheers, Jens