RE: [PATCH v1 3/6] include: virtio_rpmsg: add virtio rpmsg configuration structure

From: Loic PALLARDY <loic.pallardy@st.com>
To: Wendy Liang <sunnyliangjy@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
	Ohad Ben-Cohen <ohad@wizery.com>,
	"lee.jones@linaro.org" <lee.jones@linaro.org>,
	"Patrice CHOTARD  <patrice.chotard@st.com>,
	linux-remoteproc@vger.kernel.org"
	<linux-remoteproc@vger.kernel.org>,
	"kernel@stlinux.com" <kernel@stlinux.com>
Subject: RE: [PATCH v1 3/6] include: virtio_rpmsg: add virtio rpmsg configuration structure
Date: Wed, 14 Dec 2016 11:24:19 +0000	[thread overview]
Message-ID: <2c642ba7b9be4cb69a17075f0004306d@SFHDAG6NODE1.st.com> (raw)
In-Reply-To: <CAA07jV9+Tq_WO=ER05qY0uM+8v+dChBGZXn+j_vtc1vR7yHt9g@mail.gmail.com>

> -----Original Message-----
> From: Wendy Liang [mailto:sunnyliangjy@gmail.com]
> Sent: Thursday, December 08, 2016 11:00 PM
> To: Loic PALLARDY <loic.pallardy@st.com>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>; Ohad Ben-Cohen
> <ohad@wizery.com>; lee.jones@linaro.org; Patrice CHOTARD
> <patrice.chotard@st.com>; linux-remoteproc@vger.kernel.org;
> kernel@stlinux.com
> Subject: Re: [PATCH v1 3/6] include: virtio_rpmsg: add virtio rpmsg
> configuration structure
> 
> HI Loic,
> 
Hi Wendy,

> As this introduce a new virtio config. How about to add a new header file for
> virtio_rpmsg in the include/uapi/linux directory just like other virtio device
> driver, such as virtio_blk?

I put this new file in include/linux/rpmsg directory for two reasons (from my pov):
- because there is no API/struct shared with user space (only a struct shared between drivers)
- because virtio_rpmsg.c driver is in drivers/rpmsg directory and not in virtio tree. Goal was to be coherent with c file.

Bjorn, what's your view on this point?

Regards,
Loic
> 
> Thanks,
> Wendy
> 
> On Wed, Dec 7, 2016 at 12:35 PM, Loic Pallardy <loic.pallardy@st.com> wrote:
> > Rpmsg channel configuration should be identical on host and
> > coprocessor side.
> > This patch proposes a new structure named struct virtio_rpmsg_cfg to
> > gather all configuration information to characterize the communication
> > link and.
> > This structure will be exchanged with coprocessor via the resource
> > table, expanding struct fw_rsc_vdev. It will guarantee that host and
> > coprocessor will share the same information.
> > virtio_rpmsg will access it thanks to virtio get and set features.
> > Presence of struct virtio_rpmsg_cfg is optional.
> >
> > Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
> > ---
> >  include/linux/rpmsg/virtio_rpmsg.h | 32
> > ++++++++++++++++++++++++++++++++
> >  1 file changed, 32 insertions(+)
> >  create mode 100644 include/linux/rpmsg/virtio_rpmsg.h
> >
> > diff --git a/include/linux/rpmsg/virtio_rpmsg.h
> > b/include/linux/rpmsg/virtio_rpmsg.h
> > new file mode 100644
> > index 0000000..5f3f0d0
> > --- /dev/null
> > +++ b/include/linux/rpmsg/virtio_rpmsg.h
> > @@ -0,0 +1,32 @@
> > +
> > +#ifndef _LINUX_VIRTIO_RPMSG_H
> > +#define _LINUX_VIRTIO_RPMSG_H
> > +
> > +/* Offset in struct fw_rsc_vdev */
> > +#define RPMSG_CONFIG_OFFSET    0
> > +
> > +/**
> > + * struct virtio_rpmsg_cfg - optional configuration field for virtio
> > +rpmsg
> > + * provided at probe time by virtio (get/set)
> > + * @id: virtio cfg id (as in virtio_ids.h)
> > + * @version: virtio_rpmsg_cfg structure version number
> > + * @va: virtual address (used when buffer allocated by low level
> > +driver)
> > + * @da: device address
> > + * @pa: physical address
> > + * @len: length (in bytes)
> > + * @buf_size: size of rpmsg buffer size (defined by firmware else default
> value
> > + *           used)
> > + * @reserved: reserved (must be zero)  */ struct virtio_rpmsg_cfg {
> > +       u32 id;
> > +       u32 version;
> > +       u64 va;
> > +       u32 da;
> > +       u32 pa;
> > +       u32 len;
> > +       u32 buf_size;
> > +       u32 reserved;
> > +} __packed;
> > +
> > +#endif
> > --
> > 1.9.1
> >
> > --
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