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drivers: optee: allow op-tee to access devices on the i2c bus

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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>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
This commit is contained in:
Jorge Ramirez-Ortiz 2020-08-14 13:12:21 +02:00 committed by Jens Wiklander
parent 9123e3a74e
commit c05210ab97
3 changed files with 117 additions and 0 deletions
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21
drivers/tee/optee/optee_msg.h
View File

@ -419,4 +419,25 @@ 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] param[1].u.value.a i2c control flags
*
* [in/out] memref[2] buffer to exchange the transfer data
* with the secure world
*
* [out] param[3].u.value.a bytes transferred by the driver
*/
#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 21
/* I2C master transfer modes */
#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD 0
#define OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR 1
/* I2C master control flags */
#define OPTEE_MSG_RPC_CMD_I2C_FLAGS_TEN_BIT BIT(0)
#endif /* _OPTEE_MSG_H */

1
drivers/tee/optee/optee_private.h
View File

@ -17,6 +17,7 @@
/* Some Global Platform error codes used in this driver */
#define TEEC_SUCCESS 0x00000000
#define TEEC_ERROR_BAD_PARAMETERS 0xFFFF0006
#define TEEC_ERROR_NOT_SUPPORTED 0xFFFF000A
#define TEEC_ERROR_COMMUNICATION 0xFFFF000E
#define TEEC_ERROR_OUT_OF_MEMORY 0xFFFF000C
#define TEEC_ERROR_SHORT_BUFFER 0xFFFF0010

95
drivers/tee/optee/rpc.c
View File

@ -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 +50,97 @@ bad:
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 = { 0 };
struct tee_param *params;
size_t i;
int ret = -EOPNOTSUPP;
u8 attr[] = {
TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
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++) {
if (params[i].attr != attr[i])
goto bad;
}
client.adapter = i2c_get_adapter(params[0].u.value.b);
if (!client.adapter)
goto bad;
if (params[1].u.value.a & OPTEE_MSG_RPC_CMD_I2C_FLAGS_TEN_BIT) {
if (!i2c_check_functionality(client.adapter,
I2C_FUNC_10BIT_ADDR)) {
i2c_put_adapter(client.adapter);
goto bad;
}
client.flags = I2C_CLIENT_TEN;
}
client.addr = params[0].u.value.c;
snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr);
switch (params[0].u.value.a) {
case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD:
ret = i2c_master_recv(&client, params[2].u.memref.shm->kaddr,
params[2].u.memref.size);
break;
case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR:
ret = i2c_master_send(&client, params[2].u.memref.shm->kaddr,
params[2].u.memref.size);
break;
default:
i2c_put_adapter(client.adapter);
goto bad;
}
if (ret < 0) {
arg->ret = TEEC_ERROR_COMMUNICATION;
} else {
params[3].u.value.a = ret;
if (optee_to_msg_param(arg->params, arg->num_params, params))
arg->ret = TEEC_ERROR_BAD_PARAMETERS;
else
arg->ret = TEEC_SUCCESS;
}
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_NOT_SUPPORTED;
}
#endif
static struct wq_entry *wq_entry_get(struct optee_wait_queue *wq, u32 key)
{
struct wq_entry *w;
@ -382,6 +474,9 @@ 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);
}