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 <[email protected]>
---
V1 to V2
V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
- Change patch title,
- as not solution today to support MTU on GLINK make ops optional,
RPMsg client API returns -ENOTSUPP in this case,
- suppress smd and glink patches.
---
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..0e56e046f5c6 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 @get_mpu(), 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
Hi Bjorn, Suman,
Gentleman reminder :)
Thank in advance,
Arnaud
On 11/13/19 6:22 PM, 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 <[email protected]>
> ---
> V1 to V2
>
> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
> - Change patch title,
> - as not solution today to support MTU on GLINK make ops optional,
> RPMsg client API returns -ENOTSUPP in this case,
> - suppress smd and glink patches.
> ---
> 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..0e56e046f5c6 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 @get_mpu(), 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 */
>
On Wed 13 Nov 09:22 PST 2019, Arnaud Pouliquen wrote:
> Return the rpmsg buffer MTU for sending message, so rpmsg users
> can split a long message in several sub rpmsg buffers.
>
I won't merge this new api without a client, and I'm still concerned
about the details.
> Signed-off-by: Arnaud Pouliquen <[email protected]>
> ---
> V1 to V2
>
> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
> - Change patch title,
> - as not solution today to support MTU on GLINK make ops optional,
> RPMsg client API returns -ENOTSUPP in this case,
> - suppress smd and glink patches.
That's ok.
> ---
> 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.
Is the expectation that a call to rpmsg_send() with this size will
eventually succeed?
> + */
[..]
> +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);
I'm still under the impression that the rpmsg protocol doesn't have to
operate on fixed size messages. Would this then return vrp->num_bufs *
vrp->buf_size / 2 - sizeof(rpmsg_hdr)?
> +}
> +
Regards,
Bjorn
Hi Bjorn
On 1/13/20 6:24 PM, Bjorn Andersson wrote:
> On Wed 13 Nov 09:22 PST 2019, Arnaud Pouliquen wrote:
>
>> Return the rpmsg buffer MTU for sending message, so rpmsg users
>> can split a long message in several sub rpmsg buffers.
>>
>
> I won't merge this new api without a client, and I'm still concerned
> about the details.
The client exists: it is the rpmsg tty that i 've been rying to upstream since for a while.
https://patchwork.kernel.org/cover/11130213/
This patch is the result of some comments you did on rpmsg tty thread.
Suman was also interested in and request to merge it independently
(https://lkml.org/lkml/2019/9/3/774).
That's why i'm trying to do it in 2 steps.
>
>> Signed-off-by: Arnaud Pouliquen <[email protected]>
>> ---
>> V1 to V2
>>
>> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
>> - Change patch title,
>> - as not solution today to support MTU on GLINK make ops optional,
>> RPMsg client API returns -ENOTSUPP in this case,
>> - suppress smd and glink patches.
>
> That's ok.
>
>> ---
>> 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.
>
> Is the expectation that a call to rpmsg_send() with this size will
> eventually succeed?
yes, this should be the role of the transport layer
(e.g. RPMsg VirtIO bus) to ensure this.
>
>> + */
> [..]
>> +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);
>
> I'm still under the impression that the rpmsg protocol doesn't have to
> operate on fixed size messages. Would this then return vrp->num_bufs *
> vrp->buf_size / 2 - sizeof(rpmsg_hdr)?
it depends on the transport layer. For RPMsg over virtio, this is the size
of the payload of a buffer so vrp->buf_size - sizeof(rpmsg_hdr)
Regards,
Arnaud
>
>> +}
>> +
>
> Regards,
> Bjorn
>
Hi Arnaud,
On 1/13/20 7:19 AM, Arnaud POULIQUEN wrote:
> Hi Bjorn, Suman,
>
> Gentleman reminder :)
Thanks for the revised version, and very sorry about the delay. Only
one minor nit that you missed from my comments the v6 rpmsg-tty series
[1], otherwise I am good with the changes. See below.
FWIW, I have already been using this patch on our downstream 2020 LTS
based kernel and eliminate the the need to expose the virtio_rpmsg's
rpmsg_hdr to rpmsg client drivers :).
>
> Thank in advance,
>
> Arnaud
>
> On 11/13/19 6:22 PM, 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 <[email protected]>
>> ---
>> V1 to V2
>>
>> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
>> - Change patch title,
>> - as not solution today to support MTU on GLINK make ops optional,
>> RPMsg client API returns -ENOTSUPP in this case,
>> - suppress smd and glink patches.
>> ---
>> 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..0e56e046f5c6 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 @get_mpu(), optional
In the description for the ops, 'mpu' is a typo. My earlier comment was
essentially,
%s/see @get_mpu()/see @rpmsg_get_mtu()/
regards
Suman
[1] https://patchwork.kernel.org/patch/11130209/
>> *
>> * 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 */
>>
On 1/14/20 3:06 AM, Arnaud POULIQUEN wrote:
> Hi Bjorn
>
> On 1/13/20 6:24 PM, Bjorn Andersson wrote:
>> On Wed 13 Nov 09:22 PST 2019, Arnaud Pouliquen wrote:
>>
>>> Return the rpmsg buffer MTU for sending message, so rpmsg users
>>> can split a long message in several sub rpmsg buffers.
>>>
>>
>> I won't merge this new api without a client, and I'm still concerned
>> about the details.
> The client exists: it is the rpmsg tty that i 've been rying to upstream since for a while.
> https://patchwork.kernel.org/cover/11130213/
> This patch is the result of some comments you did on rpmsg tty thread.
> Suman was also interested in and request to merge it independently
> (https://lkml.org/lkml/2019/9/3/774).
> That's why i'm trying to do it in 2 steps.
>
>>
>>> Signed-off-by: Arnaud Pouliquen <[email protected]>
>>> ---
>>> V1 to V2
>>>
>>> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
>>> - Change patch title,
>>> - as not solution today to support MTU on GLINK make ops optional,
>>> RPMsg client API returns -ENOTSUPP in this case,
>>> - suppress smd and glink patches.
>>
>> That's ok.
>>
>>> ---
>>> 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.
>>
>> Is the expectation that a call to rpmsg_send() with this size will
>> eventually succeed?
> yes, this should be the role of the transport layer
> (e.g. RPMsg VirtIO bus) to ensure this.
>
>>
>>> + */
>> [..]
>>> +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);
>>
>> I'm still under the impression that the rpmsg protocol doesn't have to
>> operate on fixed size messages. Would this then return vrp->num_bufs *
>> vrp->buf_size / 2 - sizeof(rpmsg_hdr)?
There was some discussion in the past to remove the 512 bytes
hard-coding and replace it with a configurable value, but that is not
yet done. There was some code restructuring towards the same, but it it
still fixed atm in virtio_rpmsg transport.
> it depends on the transport layer. For RPMsg over virtio, this is the size
> of the payload of a buffer so vrp->buf_size - sizeof(rpmsg_hdr)
The vrp->num_bufs is the number of buffers available in the vring
transport, vrp->buf_size is the size for each transport buffer, and
every message includes the rpmsg_hdr structure, so the amount available
for rpmsg clients is less by that much.
regards
Suman
Hi Suman,
On 1/15/20 12:40 AM, Suman Anna wrote:
> Hi Arnaud,
>
> On 1/13/20 7:19 AM, Arnaud POULIQUEN wrote:
>> Hi Bjorn, Suman,
>>
>> Gentleman reminder :)
>
> Thanks for the revised version, and very sorry about the delay. Only
> one minor nit that you missed from my comments the v6 rpmsg-tty series
> [1], otherwise I am good with the changes. See below.
>
> FWIW, I have already been using this patch on our downstream 2020 LTS
> based kernel and eliminate the the need to expose the virtio_rpmsg's
> rpmsg_hdr to rpmsg client drivers :).
Right without this API the client needs also to know the RPMSG buffer size to
compute the MTU.
>
>>
>> Thank in advance,
>>
>> Arnaud
>>
>> On 11/13/19 6:22 PM, 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 <[email protected]>
>>> ---
>>> V1 to V2
>>>
>>> V1 patch:https://lore.kernel.org/patchwork/patch/1124684/
>>> - Change patch title,
>>> - as not solution today to support MTU on GLINK make ops optional,
>>> RPMsg client API returns -ENOTSUPP in this case,
>>> - suppress smd and glink patches.
>>> ---
>>> 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..0e56e046f5c6 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 @get_mpu(), optional
>
> In the description for the ops, 'mpu' is a typo. My earlier comment was
> essentially,
> %s/see @get_mpu()/see @rpmsg_get_mtu()/
Sorry, completly missed it i sent a v3
Thanks,
Arnaud
>
> regards
> Suman
>
> [1] https://patchwork.kernel.org/patch/11130209/
>
>>> *
>>> * 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 */
>>>
>