On 23/09/20, Jorge Ramirez-Ortiz, Foundries wrote:

On 22/09/20, Jens Wiklander wrote:

...

On Wed, Sep 16, 2020 at 05:27:32PM +0200, Jorge Ramirez-Ortiz wrote:

...

Allow OP-TEE to specify the number of retries in the adaptor.

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

drivers/tee/optee/rpc.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c index 1e3614e4798f..2d46a9ecb1de 100644 --- a/drivers/tee/optee/rpc.c +++ b/drivers/tee/optee/rpc.c @@ -58,6 +58,7 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, struct tee_param *params; size_t i; int ret = -EOPNOTSUPP;

• int retries = 0; u8 attr[] = { TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT, TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,

@@ -102,12 +103,17 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, client.addr = params[0].u.value.c; snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr);

• /* cache the current value */
• retries = client.adapter->retries;
• switch (params[0].u.value.a) { case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD:

• client.adapter->retries = params[1].u.value.b;
  

Do we need to take any locks befor this?

no I dont think so: there is no need for bus locks when requesting a transfer via i2c_master_recv/send; the lock for the bus segment gets taken later on, when the actual transfer hppens ( __i2c_transfer())

the functionality implemented in this function pretty much mimicks what is done in the normal world via /dev/i2c-X (drivers/i2c/i2c_dev.c)

correction (of course) - i2cdev_read --> i2c_master_recv - i2cdev->write -->i2c_master_send

and now the retry count setup on the adaptor with this commit.

• i2cdev_ioctl I2C_RETRIES

...

Cheers, Jens

...

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:

• client.adapter->retries = params[1].u.value.b;
  

  ret = i2c_master_send(&client, params[2].u.memref.shm->kaddr, params[2].u.memref.size); break;

@@ -126,6 +132,7 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, arg->ret = TEEC_SUCCESS; }

• client.adapter->retries = retries; i2c_put_adapter(client.adapter); kfree(params); return;

-- 2.17.1

On 23/09/20, Jens Wiklander wrote:

On Wed, Sep 23, 2020 at 01:26:31PM +0200, Jorge Ramirez-Ortiz, Foundries wrote:

...

On 23/09/20, Jorge Ramirez-Ortiz, Foundries wrote:

...

On 22/09/20, Jens Wiklander wrote:

...

On Wed, Sep 16, 2020 at 05:27:32PM +0200, Jorge Ramirez-Ortiz wrote:

...

Allow OP-TEE to specify the number of retries in the adaptor.

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

drivers/tee/optee/rpc.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c index 1e3614e4798f..2d46a9ecb1de 100644 --- a/drivers/tee/optee/rpc.c +++ b/drivers/tee/optee/rpc.c @@ -58,6 +58,7 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, struct tee_param *params; size_t i; int ret = -EOPNOTSUPP;

• int retries = 0; u8 attr[] = { TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT, TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,

@@ -102,12 +103,17 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx, client.addr = params[0].u.value.c; snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr);

• /* cache the current value */
• retries = client.adapter->retries;
• switch (params[0].u.value.a) { case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD:

• client.adapter->retries = params[1].u.value.b;
  

Do we need to take any locks befor this?

no I dont think so: there is no need for bus locks when requesting a transfer via i2c_master_recv/send; the lock for the bus segment gets taken later on, when the actual transfer hppens ( __i2c_transfer())

the functionality implemented in this function pretty much mimicks what is done in the normal world via /dev/i2c-X (drivers/i2c/i2c_dev.c)

correction (of course)

• i2cdev_read --> i2c_master_recv
• i2cdev->write -->i2c_master_send

...

and now the retry count setup on the adaptor with this commit.

• i2cdev_ioctl I2C_RETRIES

I don't understand. Do you mean that client.adapter->retries doesn't need to be protected from concurrent updates? Or is it already protected by some other mechanism?

yeah I probably misunderstood your comment. my bad.

um I thought that upon getting the adaptor there would be some protection mechanism in place until it is put back; but that is not the case. looking a bit into it I see no simple way of protecting changes to the adaptor (at any given time any thread could get a pointer to it) so it seems that setting the retry field is not a guarantee that it will be applied.

Cheers, Jens