diff mbox series

[v7,1/2] rpmsg: core: add API to get MTU

Message ID 20200324170407.16470-2-arnaud.pouliquen@st.com (mailing list archive)
State New, archived
Headers show
Series Add rpmsg tty driver | expand

Commit Message

Arnaud POULIQUEN March 24, 2020, 5:04 p.m. UTC 
Return the rpmsg buffer MTU for sending message, so rpmsg users
can split a long message in several sub rpmsg buffers.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: Suman Anna <s-anna@ti.com>
---
 drivers/rpmsg/rpmsg_core.c       | 21 +++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h   |  2 ++
 drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
 include/linux/rpmsg.h            | 10 ++++++++++
 4 files changed, 43 insertions(+)

Comments

Mathieu Poirier March 31, 2020, 5:36 p.m. UTC | #1 
On Tue, Mar 24, 2020 at 06:04:06PM +0100, Arnaud Pouliquen wrote:
> Return the rpmsg buffer MTU for sending message, so rpmsg users
> can split a long message in several sub rpmsg buffers.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
> Acked-by: Suman Anna <s-anna@ti.com>

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> ---
>  drivers/rpmsg/rpmsg_core.c       | 21 +++++++++++++++++++++
>  drivers/rpmsg/rpmsg_internal.h   |  2 ++
>  drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
>  include/linux/rpmsg.h            | 10 ++++++++++
>  4 files changed, 43 insertions(+)
> 
> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
> index e330ec4dfc33..a6ef54c4779a 100644
> --- a/drivers/rpmsg/rpmsg_core.c
> +++ b/drivers/rpmsg/rpmsg_core.c
> @@ -283,6 +283,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>  }
>  EXPORT_SYMBOL(rpmsg_trysend_offchannel);
>  
> +/**
> + * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
> + * @ept: the rpmsg endpoint
> + *
> + * This function returns maximum buffer size available for a single message.
> + *
> + * Return: the maximum transmission size on success and an appropriate error
> + * value on failure.
> + */
> +
> +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
> +{
> +	if (WARN_ON(!ept))
> +		return -EINVAL;
> +	if (!ept->ops->get_mtu)
> +		return -ENOTSUPP;
> +
> +	return ept->ops->get_mtu(ept);
> +}
> +EXPORT_SYMBOL(rpmsg_get_mtu);
> +
>  /*
>   * match an rpmsg channel with a channel info struct.
>   * this is used to make sure we're not creating rpmsg devices for channels
> diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
> index 3fc83cd50e98..e6f88ee90ff6 100644
> --- a/drivers/rpmsg/rpmsg_internal.h
> +++ b/drivers/rpmsg/rpmsg_internal.h
> @@ -47,6 +47,7 @@ struct rpmsg_device_ops {
>   * @trysendto:		see @rpmsg_trysendto(), optional
>   * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
>   * @poll:		see @rpmsg_poll(), optional
> + * @get_mtu:		see @rpmsg_get_mtu(), optional
>   *
>   * Indirection table for the operations that a rpmsg backend should implement.
>   * In addition to @destroy_ept, the backend must at least implement @send and
> @@ -66,6 +67,7 @@ struct rpmsg_endpoint_ops {
>  			     void *data, int len);
>  	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
>  			     poll_table *wait);
> +	ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
>  };
>  
>  int rpmsg_register_device(struct rpmsg_device *rpdev);
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 376ebbf880d6..6e48fdf24555 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -175,6 +175,7 @@ static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
>  				  int len, u32 dst);
>  static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
>  					   u32 dst, void *data, int len);
> +static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
>  
>  static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
>  	.destroy_ept = virtio_rpmsg_destroy_ept,
> @@ -184,6 +185,7 @@ static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
>  	.trysend = virtio_rpmsg_trysend,
>  	.trysendto = virtio_rpmsg_trysendto,
>  	.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
> +	.get_mtu = virtio_rpmsg_get_mtu,
>  };
>  
>  /**
> @@ -699,6 +701,14 @@ static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
>  	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
>  }
>  
> +static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
> +{
> +	struct rpmsg_device *rpdev = ept->rpdev;
> +	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
> +
> +	return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
> +}
> +
>  static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
>  			     struct rpmsg_hdr *msg, unsigned int len)
>  {
> diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
> index 9fe156d1c018..88d7892ca93d 100644
> --- a/include/linux/rpmsg.h
> +++ b/include/linux/rpmsg.h
> @@ -135,6 +135,8 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>  __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
>  			poll_table *wait);
>  
> +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
> +
>  #else
>  
>  static inline int register_rpmsg_device(struct rpmsg_device *dev)
> @@ -242,6 +244,14 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
>  	return 0;
>  }
>  
> +static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return -ENXIO;
> +}
> +
>  #endif /* IS_ENABLED(CONFIG_RPMSG) */
>  
>  /* use a macro to avoid include chaining to get THIS_MODULE */
> -- 
> 2.17.1
>
Jiri Slaby April 1, 2020, 6:28 a.m. UTC | #2 
On 24. 03. 20, 18:04, Arnaud Pouliquen wrote:
> Return the rpmsg buffer MTU for sending message, so rpmsg users
> can split a long message in several sub rpmsg buffers.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
> Acked-by: Suman Anna <s-anna@ti.com>
> ---
>  drivers/rpmsg/rpmsg_core.c       | 21 +++++++++++++++++++++
>  drivers/rpmsg/rpmsg_internal.h   |  2 ++
>  drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
>  include/linux/rpmsg.h            | 10 ++++++++++
>  4 files changed, 43 insertions(+)
> 
> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
> index e330ec4dfc33..a6ef54c4779a 100644
> --- a/drivers/rpmsg/rpmsg_core.c
> +++ b/drivers/rpmsg/rpmsg_core.c
> @@ -283,6 +283,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>  }
>  EXPORT_SYMBOL(rpmsg_trysend_offchannel);
>  
> +/**
> + * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
> + * @ept: the rpmsg endpoint
> + *
> + * This function returns maximum buffer size available for a single message.
> + *
> + * Return: the maximum transmission size on success and an appropriate error
> + * value on failure.
> + */
> +
> +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
> +{
> +	if (WARN_ON(!ept))
> +		return -EINVAL;
> +	if (!ept->ops->get_mtu)
> +		return -ENOTSUPP;

Hmm, I don't think all callers of tty_write_room() handle negative values...

But some drivers also return negative values. There is some work to be
done, adding to TODO.

For the time being, I suggest returning 0 instead.

thanks,
Jiri Slaby April 1, 2020, 6:29 a.m. UTC | #3 
On 01. 04. 20, 8:28, Jiri Slaby wrote:
> On 24. 03. 20, 18:04, Arnaud Pouliquen wrote:
>> Return the rpmsg buffer MTU for sending message, so rpmsg users
>> can split a long message in several sub rpmsg buffers.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>> Acked-by: Suman Anna <s-anna@ti.com>
>> ---
>>  drivers/rpmsg/rpmsg_core.c       | 21 +++++++++++++++++++++
>>  drivers/rpmsg/rpmsg_internal.h   |  2 ++
>>  drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
>>  include/linux/rpmsg.h            | 10 ++++++++++
>>  4 files changed, 43 insertions(+)
>>
>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
>> index e330ec4dfc33..a6ef54c4779a 100644
>> --- a/drivers/rpmsg/rpmsg_core.c
>> +++ b/drivers/rpmsg/rpmsg_core.c
>> @@ -283,6 +283,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>>  }
>>  EXPORT_SYMBOL(rpmsg_trysend_offchannel);
>>  
>> +/**
>> + * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
>> + * @ept: the rpmsg endpoint
>> + *
>> + * This function returns maximum buffer size available for a single message.
>> + *
>> + * Return: the maximum transmission size on success and an appropriate error
>> + * value on failure.
>> + */
>> +
>> +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
>> +{
>> +	if (WARN_ON(!ept))
>> +		return -EINVAL;
>> +	if (!ept->ops->get_mtu)
>> +		return -ENOTSUPP;
> 
> Hmm, I don't think all callers of tty_write_room() handle negative values...
> 
> But some drivers also return negative values. There is some work to be
> done, adding to TODO.
> 
> For the time being, I suggest returning 0 instead.

Or better, convert the negative to 0 in rpmsg_tty_write_room for now.

> thanks,--
Arnaud POULIQUEN April 1, 2020, 11:34 a.m. UTC | #4 
On 4/1/20 8:29 AM, Jiri Slaby wrote:
> On 01. 04. 20, 8:28, Jiri Slaby wrote:
>> On 24. 03. 20, 18:04, Arnaud Pouliquen wrote:
>>> Return the rpmsg buffer MTU for sending message, so rpmsg users
>>> can split a long message in several sub rpmsg buffers.
>>>
>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>>> Acked-by: Suman Anna <s-anna@ti.com>
>>> ---
>>>  drivers/rpmsg/rpmsg_core.c       | 21 +++++++++++++++++++++
>>>  drivers/rpmsg/rpmsg_internal.h   |  2 ++
>>>  drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++
>>>  include/linux/rpmsg.h            | 10 ++++++++++
>>>  4 files changed, 43 insertions(+)
>>>
>>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
>>> index e330ec4dfc33..a6ef54c4779a 100644
>>> --- a/drivers/rpmsg/rpmsg_core.c
>>> +++ b/drivers/rpmsg/rpmsg_core.c
>>> @@ -283,6 +283,27 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>>>  }
>>>  EXPORT_SYMBOL(rpmsg_trysend_offchannel);
>>>  
>>> +/**
>>> + * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
>>> + * @ept: the rpmsg endpoint
>>> + *
>>> + * This function returns maximum buffer size available for a single message.
>>> + *
>>> + * Return: the maximum transmission size on success and an appropriate error
>>> + * value on failure.
>>> + */
>>> +
>>> +ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
>>> +{
>>> +	if (WARN_ON(!ept))
>>> +		return -EINVAL;
>>> +	if (!ept->ops->get_mtu)
>>> +		return -ENOTSUPP;
>>
>> Hmm, I don't think all callers of tty_write_room() handle negative values...
>>
>> But some drivers also return negative values. There is some work to be
>> done, adding to TODO.
>>
>> For the time being, I suggest returning 0 instead.
> 
> Or better, convert the negative to 0 in rpmsg_tty_write_room for now.
> 
>> thanks,-- 

Right, seems that a negative return of tty_write_room seems not always handled
so i will force to 0 in rpmsg_tty in case of error returned. I will also
add a comment in code that explain the context.
  
Thanks,
Arnaud
diff mbox series

Patch

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index e330ec4dfc33..a6ef54c4779a 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -283,6 +283,27 @@  int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 }
 EXPORT_SYMBOL(rpmsg_trysend_offchannel);
 
+/**
+ * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
+ * @ept: the rpmsg endpoint
+ *
+ * This function returns maximum buffer size available for a single message.
+ *
+ * Return: the maximum transmission size on success and an appropriate error
+ * value on failure.
+ */
+
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->get_mtu)
+		return -ENOTSUPP;
+
+	return ept->ops->get_mtu(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_mtu);
+
 /*
  * match an rpmsg channel with a channel info struct.
  * this is used to make sure we're not creating rpmsg devices for channels
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 3fc83cd50e98..e6f88ee90ff6 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -47,6 +47,7 @@  struct rpmsg_device_ops {
  * @trysendto:		see @rpmsg_trysendto(), optional
  * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
  * @poll:		see @rpmsg_poll(), optional
+ * @get_mtu:		see @rpmsg_get_mtu(), optional
  *
  * Indirection table for the operations that a rpmsg backend should implement.
  * In addition to @destroy_ept, the backend must at least implement @send and
@@ -66,6 +67,7 @@  struct rpmsg_endpoint_ops {
 			     void *data, int len);
 	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
 			     poll_table *wait);
+	ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
 };
 
 int rpmsg_register_device(struct rpmsg_device *rpdev);
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 376ebbf880d6..6e48fdf24555 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -175,6 +175,7 @@  static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
 				  int len, u32 dst);
 static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
 					   u32 dst, void *data, int len);
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
 
 static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
 	.destroy_ept = virtio_rpmsg_destroy_ept,
@@ -184,6 +185,7 @@  static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
 	.trysend = virtio_rpmsg_trysend,
 	.trysendto = virtio_rpmsg_trysendto,
 	.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
+	.get_mtu = virtio_rpmsg_get_mtu,
 };
 
 /**
@@ -699,6 +701,14 @@  static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 }
 
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+	return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
+}
+
 static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
 			     struct rpmsg_hdr *msg, unsigned int len)
 {
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 9fe156d1c018..88d7892ca93d 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -135,6 +135,8 @@  int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 			poll_table *wait);
 
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
+
 #else
 
 static inline int register_rpmsg_device(struct rpmsg_device *dev)
@@ -242,6 +244,14 @@  static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
 	return 0;
 }
 
+static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 
 /* use a macro to avoid include chaining to get THIS_MODULE */