Messages in this thread Patch in this message | | | Date | Wed, 12 Aug 2020 10:44:03 +0200 | From | Jens Wiklander <> | Subject | Re: [PATCHv7] drivers: optee: allow op-tee to access devices on the i2c bus |
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On Tue, Aug 11, 2020 at 07:55:31PM +0200, 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. > > Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io> > --- > v7: add support for ten bit i2c slave addressing > 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 | 21 ++++++++ > drivers/tee/optee/rpc.c | 95 +++++++++++++++++++++++++++++++++++ > 2 files changed, 116 insertions(+) > > diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h > index 795bc19ae17a..7b2d919da2ac 100644 > --- a/drivers/tee/optee/optee_msg.h > +++ b/drivers/tee/optee/optee_msg.h > @@ -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 */ > diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c > index b4ade54d1f28..b6178761d79f 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 +50,97 @@ 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 = { 0 }; > + struct tee_param *params; > + int i, ret = -EOPNOTSUPP; > + uint32_t attr[] = { uint32_t seems a randomly chosen type here. The TEE_IOCTL_PARAM_ATTR_TYPE_* defines fit in a u8. Consider u8 attr[] = { instead.
> + 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++) { arg->num_params has an unsigned type. Consider giving i an unsigned type too.
> + if ((params[i].attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) > + != attr[i]) It looks a bit funny with the comparison at the beginning of the line, normally we try to leave those at the end of the line. But optee_from_msg_param() doesn't set any higher bits in params[i].attr so you could also simplify the expression as: 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; > + arg->ret = TEEC_SUCCESS; > + > + if (optee_to_msg_param(arg->params, arg->num_params, params)) > + arg->ret = TEEC_ERROR_BAD_PARAMETERS; Need arg->ret = TEEC_SUCCESS; when everything is OK.
> + } > + > + 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; I'd prefer TEEC_ERROR_NOT_SUPPORTED here. TEEC_ERROR_NOT_SUPPORTED would need to be defined as: #define TEEC_ERROR_NOT_SUPPORTED 0xFFFF000A in optee_private.h
Cheers, Jens
> +} > +#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); > } > -- > 2.17.1 >
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