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

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 <[email protected]>
---
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


2020-06-01 06:32:32

by Sumit Garg

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

Hi Jorge,

On Mon, 1 Jun 2020 at 04:41, Jorge Ramirez-Ortiz <[email protected]> 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.
>

This sounds like an interesting use-case but I would like to
understand how secure is this communication interface with the secure
element? Like in the case of RPMB, secure world data is encrypted
which flows via tee-supplicant to RPMB device.

-Sumit

> Signed-off-by: Jorge Ramirez-Ortiz <[email protected]>
> ---
> 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
>
> _______________________________________________
> Tee-dev mailing list
> [email protected]
> https://lists.linaro.org/mailman/listinfo/tee-dev

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

On 01/06/20, Sumit Garg wrote:
> Hi Jorge,

hey

>
> On Mon, 1 Jun 2020 at 04:41, Jorge Ramirez-Ortiz <[email protected]> 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.
> >
>
> This sounds like an interesting use-case but I would like to
> understand how secure is this communication interface with the secure
> element? Like in the case of RPMB, secure world data is encrypted
> which flows via tee-supplicant to RPMB device.

right, the data in the buffer should be encrypted in both directions
(in the case of the SE050 [1] we have the option to operate with or
without encryption which is what I am doing during development
[2]).

But ultimately -before any product can be shipped- all comms must be
encrypted: this means that when OP-TEE uses the SE050 for crypto, it
must encrypt the data on write and decrypt what is comming from the
SE050 on read. I am now looking into how to enable this.

[1] https://www.nxp.com/docs/en/data-sheet/SE050-DATASHEET.pdf
[2] https://github.com/ldts/optee_os/commits/se050

>
> -Sumit
>
> > Signed-off-by: Jorge Ramirez-Ortiz <[email protected]>
> > ---
> > 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
> >
> > _______________________________________________
> > Tee-dev mailing list
> > [email protected]
> > https://lists.linaro.org/mailman/listinfo/tee-dev

Subject: Re: [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 <[email protected]>
> ---
> 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
>

2020-06-08 06:51:20

by Jens Wiklander

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

On Mon, Jun 01, 2020 at 09:24:46AM +0200, Jorge Ramirez-Ortiz, Foundries wrote:
> On 01/06/20, Sumit Garg wrote:
> > Hi Jorge,
>
> hey
>
> >
> > On Mon, 1 Jun 2020 at 04:41, Jorge Ramirez-Ortiz <[email protected]> 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.
> > >
> >
> > This sounds like an interesting use-case but I would like to
> > understand how secure is this communication interface with the secure
> > element? Like in the case of RPMB, secure world data is encrypted
> > which flows via tee-supplicant to RPMB device.
>
> right, the data in the buffer should be encrypted in both directions
> (in the case of the SE050 [1] we have the option to operate with or
> without encryption which is what I am doing during development
> [2]).
>
> But ultimately -before any product can be shipped- all comms must be
> encrypted: this means that when OP-TEE uses the SE050 for crypto, it
> must encrypt the data on write and decrypt what is comming from the
> SE050 on read. I am now looking into how to enable this.
>
> [1] https://www.nxp.com/docs/en/data-sheet/SE050-DATASHEET.pdf
> [2] https://github.com/ldts/optee_os/commits/se050
This link doesn't work.

>
> >
> > -Sumit
> >
> > > Signed-off-by: Jorge Ramirez-Ortiz <[email protected]>
> > > ---
> > > 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

This should be "[in/out] memref[1]" instead to be able to use
all kinds of memory references.

> > > + *
> > > + * [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;

Use optee_from_msg_param() to translate this into a struct tee_param,
that way you cover all kinds of memory references. Before returning it
nees to be translated back with optee_to_msg_param().

Cheers,
Jens

> > > +
> > > + 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
> > >
> > > _______________________________________________
> > > Tee-dev mailing list
> > > [email protected]
> > > https://lists.linaro.org/mailman/listinfo/tee-dev

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

On 08/06/20, Jens Wiklander wrote:
> On Mon, Jun 01, 2020 at 09:24:46AM +0200, Jorge Ramirez-Ortiz, Foundries wrote:
> > On 01/06/20, Sumit Garg wrote:
> > > Hi Jorge,
> >
> > hey
> >
> > >
> > > On Mon, 1 Jun 2020 at 04:41, Jorge Ramirez-Ortiz <[email protected]> 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.
> > > >
> > >
> > > This sounds like an interesting use-case but I would like to
> > > understand how secure is this communication interface with the secure
> > > element? Like in the case of RPMB, secure world data is encrypted
> > > which flows via tee-supplicant to RPMB device.
> >
> > right, the data in the buffer should be encrypted in both directions
> > (in the case of the SE050 [1] we have the option to operate with or
> > without encryption which is what I am doing during development
> > [2]).
> >
> > But ultimately -before any product can be shipped- all comms must be
> > encrypted: this means that when OP-TEE uses the SE050 for crypto, it
> > must encrypt the data on write and decrypt what is comming from the
> > SE050 on read. I am now looking into how to enable this.
> >
> > [1] https://www.nxp.com/docs/en/data-sheet/SE050-DATASHEET.pdf
> > [2] https://github.com/ldts/optee_os/commits/se050
> This link doesn't work.

apologies, I updated the SDK release to 2.14 (latest)

please use the following:
https://github.com/ldts/optee_os/commits/se050.2.14



>
> >
> > >
> > > -Sumit
> > >
> > > > Signed-off-by: Jorge Ramirez-Ortiz <[email protected]>
> > > > ---
> > > > 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
>
> This should be "[in/out] memref[1]" instead to be able to use
> all kinds of memory references.
>
> > > > + *
> > > > + * [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;
>
> Use optee_from_msg_param() to translate this into a struct tee_param,
> that way you cover all kinds of memory references. Before returning it
> nees to be translated back with optee_to_msg_param().
>
> Cheers,
> Jens
>
> > > > +
> > > > + 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
> > > >
> > > > _______________________________________________
> > > > Tee-dev mailing list
> > > > [email protected]
> > > > https://lists.linaro.org/mailman/listinfo/tee-dev