Re: [PATCH v2 3/9] rpmsg: virtio: Move from virtio to rpmsg byte conversion

[Arnaud POULIQUEN]

On 10/14/20 1:25 AM, Mathieu Poirier wrote:
> Use rpmsg byte conversion functions in order for the RPMSG
> headers and generic functions to be used by external entities.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> ---
>  drivers/rpmsg/virtio_rpmsg_bus.c | 60 +++++++++++++++++++-------------
>  1 file changed, 35 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 9006fc7f73d0..793fe924671f 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -19,11 +19,11 @@
>  #include <linux/mutex.h>
>  #include <linux/of_device.h>
>  #include <linux/rpmsg.h>
> +#include <linux/rpmsg_byteorder.h>
>  #include <linux/scatterlist.h>
>  #include <linux/slab.h>
>  #include <linux/sched.h>
>  #include <linux/virtio.h>
> -#include <linux/virtio_byteorder.h>
>  #include <linux/virtio_ids.h>
>  #include <linux/virtio_config.h>
>  #include <linux/wait.h>
> @@ -85,11 +85,11 @@ struct virtproc_info {
>   * Every message sent(/received) on the rpmsg bus begins with this header.
>   */
>  struct rpmsg_hdr {
> -	__virtio32 src;
> -	__virtio32 dst;
> -	__virtio32 reserved;
> -	__virtio16 len;
> -	__virtio16 flags;
> +	__rpmsg32 src;
> +	__rpmsg32 dst;
> +	__rpmsg32 reserved;
> +	__rpmsg16 len;
> +	__rpmsg16 flags;
>  	u8 data[];
>  } __packed;
>  
> @@ -107,8 +107,8 @@ struct rpmsg_hdr {
>   */
>  struct rpmsg_ns_msg {
>  	char name[RPMSG_NAME_SIZE];
> -	__virtio32 addr;
> -	__virtio32 flags;
> +	__rpmsg32 addr;
> +	__rpmsg32 flags;
>  } __packed;
>  
>  /**
> @@ -280,6 +280,14 @@ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
>  	return NULL;
>  }
>  
> +static bool virtio_rpmsg_is_little_endian(struct rpmsg_device *rpdev)
> +{
> +	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
> +	struct virtproc_info *vrp = vch->vrp;
> +
> +	return virtio_is_little_endian(vrp->vdev);
> +}

Regarding this i wonder if the endianess could not be a rpmsg_device field that would be set on 
__rpmsg_create_channel?
I don't think that the endianess could change, so perhaps no need to call ops for each conversion
using interface implemented in rpmsg.h...
But perhaps I missed something?
 
> +
>  static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
>  						      rpmsg_rx_cb_t cb,
>  						      void *priv,
> @@ -336,8 +344,8 @@ static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
>  		struct rpmsg_ns_msg nsm;
>  
>  		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
> -		nsm.addr = cpu_to_virtio32(vrp->vdev, rpdev->ept->addr);
> -		nsm.flags = cpu_to_virtio32(vrp->vdev, RPMSG_NS_CREATE);
> +		nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
> +		nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_CREATE);
>  
>  		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
>  		if (err)
> @@ -360,8 +368,8 @@ static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
>  		struct rpmsg_ns_msg nsm;
>  
>  		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
> -		nsm.addr = cpu_to_virtio32(vrp->vdev, rpdev->ept->addr);
> -		nsm.flags = cpu_to_virtio32(vrp->vdev, RPMSG_NS_DESTROY);
> +		nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
> +		nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_DESTROY);
>  
>  		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
>  		if (err)
> @@ -372,6 +380,7 @@ static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
>  }
>  
>  static const struct rpmsg_device_ops virtio_rpmsg_ops = {
> +	.is_little_endian = virtio_rpmsg_is_little_endian,
>  	.create_ept = virtio_rpmsg_create_ept,
>  	.announce_create = virtio_rpmsg_announce_create,
>  	.announce_destroy = virtio_rpmsg_announce_destroy,
> @@ -613,10 +622,10 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
>  		}
>  	}
>  
> -	msg->len = cpu_to_virtio16(vrp->vdev, len);
> +	msg->len = cpu_to_rpmsg16(rpdev, len);
>  	msg->flags = 0;
> -	msg->src = cpu_to_virtio32(vrp->vdev, src);
> -	msg->dst = cpu_to_virtio32(vrp->vdev, dst);
> +	msg->src = cpu_to_rpmsg32(rpdev, src);
> +	msg->dst = cpu_to_rpmsg32(rpdev, dst);
>  	msg->reserved = 0;
>  	memcpy(msg->data, data, len);
>  
> @@ -705,14 +714,15 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
>  {
>  	struct rpmsg_endpoint *ept;
>  	struct scatterlist sg;
> -	unsigned int msg_len = virtio16_to_cpu(vrp->vdev, msg->len);
> +	bool little_endian = rpmsg_is_little_endian();
> +	unsigned int msg_len = __rpmsg16_to_cpu(little_endian, msg->len);
>  	int err;
>  
>  	dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
> -		virtio32_to_cpu(vrp->vdev, msg->src),
> -		virtio32_to_cpu(vrp->vdev, msg->dst), msg_len,
> -		virtio16_to_cpu(vrp->vdev, msg->flags),
> -		virtio32_to_cpu(vrp->vdev, msg->reserved));
> +		__rpmsg32_to_cpu(little_endian, msg->src),
> +		__rpmsg32_to_cpu(little_endian, msg->dst), msg_len,
> +		__rpmsg16_to_cpu(little_endian, msg->flags),
> +		__rpmsg32_to_cpu(little_endian, msg->reserved));

Nitpicking: sometime rpmsgXX_to_cpu is used, sometime __rpmsgXX_to_cpu, 
Perhaps only one API should be used... But i don't see any blocking point to use both...:)

Thanks,
Arnaud

>  #if defined(CONFIG_DYNAMIC_DEBUG)
>  	dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
>  			 msg, sizeof(*msg) + msg_len, true);
> @@ -731,7 +741,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
>  	/* use the dst addr to fetch the callback of the appropriate user */
>  	mutex_lock(&vrp->endpoints_lock);
>  
> -	ept = idr_find(&vrp->endpoints, virtio32_to_cpu(vrp->vdev, msg->dst));
> +	ept = idr_find(&vrp->endpoints, __rpmsg32_to_cpu(little_endian, msg->dst));
>  
>  	/* let's make sure no one deallocates ept while we use it */
>  	if (ept)
> @@ -745,7 +755,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
>  
>  		if (ept->cb)
>  			ept->cb(ept->rpdev, msg->data, msg_len, ept->priv,
> -				virtio32_to_cpu(vrp->vdev, msg->src));
> +				__rpmsg32_to_cpu(little_endian, msg->src));
>  
>  		mutex_unlock(&ept->cb_lock);
>  
> @@ -853,13 +863,13 @@ static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
>  
>  	strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
>  	chinfo.src = RPMSG_ADDR_ANY;
> -	chinfo.dst = virtio32_to_cpu(vrp->vdev, msg->addr);
> +	chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);
>  
>  	dev_info(dev, "%sing channel %s addr 0x%x\n",
> -		 virtio32_to_cpu(vrp->vdev, msg->flags) & RPMSG_NS_DESTROY ?
> +		 rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY ?
>  		 "destroy" : "creat", msg->name, chinfo.dst);
>  
> -	if (virtio32_to_cpu(vrp->vdev, msg->flags) & RPMSG_NS_DESTROY) {
> +	if (rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY) {
>  		ret = rpmsg_unregister_device(&vrp->vdev->dev, &chinfo);
>  		if (ret)
>  			dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
>