Subject: [PATCH] drivers: optee: i2c: add bus retry configuration

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

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


2020-09-22 16:40:34

by Jens Wiklander

[permalink] [raw]
Subject: Re: [PATCH] drivers: optee: i2c: add bus retry configuration

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 <[email protected]>
> ---
> 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?

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
>

Subject: Re: [PATCH] drivers: optee: i2c: add bus retry configuration

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 <[email protected]>
> > ---
> > 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)

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

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
> >

Subject: Re: [PATCH] drivers: optee: i2c: add bus retry configuration

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 <[email protected]>
> > > ---
> > > 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
> > >

2020-09-23 12:16:15

by Jens Wiklander

[permalink] [raw]
Subject: Re: [PATCH] drivers: optee: i2c: add bus retry configuration

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 <[email protected]>
> > > > ---
> > > > 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?

Cheers,
Jens

Subject: Re: [PATCH] drivers: optee: i2c: add bus retry configuration

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 <[email protected]>
> > > > > ---
> > > > > 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