RE: [RFC PATCH v3 0/4] remoteproc: restructure the remoteproc VirtIO device

Peng Fan
2022-02-22T13:07:29Z

> Subject: Re: [RFC PATCH v3 0/4] remoteproc: restructure the remoteproc
> VirtIO device
>
>
>
> On 2/15/22 09:34, Peng Fan wrote:
> >> Subject: [RFC PATCH v3 0/4] remoteproc: restructure the remoteproc
> >> VirtIO device
> >>
> >> Update from V2 [1]:
> >> In order to better handle error cases and to have something more
> >> symmetrical between the functions in charge of rvdev
> >> initialization/deletion, the patchset has been reworked.
> >> - Introduction in the first patch, of rproc_vdev_data structure
> >> which allows to better
> >> decorrelate the rproc from the management of the rvdev structure.
> >> This structure is reused
> >> in the last patch of the series for the creation of the remoteproc
> >> virtio platform device.
> >> - In addition to the previous version, the management of the vring
> >> lifecycle has been fully
> >> migrated to the remoteproc_virtio.c (rproc_parse_vring,
> >> rproc_alloc_vring,
> >> rproc_free_vring)
> >>
> >> [1]
> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkm
> >>
> l.or%2F&amp;data=04%7C01%7Cpeng.fan%40nxp.com%7C31ba612e9d444a
> 845cbf0
> >>
> 8d9f073f744%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63780
> 5203140
> >>
> 739333%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2
> luMzIiLC
> >>
> JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=MDamNuBkyFebgG
> BuP5shcU9
> >> aw%2FdMuM9GBTEEzffQQkA%3D&amp;reserved=0
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> >>
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> >>
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> >>
> WFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLC
> >>
> JXVCI6Mn0%3D%7C3000&amp;sdata=bFfSxpPMpPRGYcMBcwxaQ152mRzf3c
> >> fwoFPjiJ0SIgw%3D&amp;reserved=0
> >>
> >> Patchset description:
> >>
> >> This series is a part of the work initiated a long time ago in the
> >> series
> >> "remoteproc: Decorelate virtio from core"[2]
> >>
> >> Objective of the work:
> >> - Update the remoteproc VirtIO device creation (use platform device)
> >> - Allow to declare remoteproc VirtIO device in DT
> >
> > This means not using resource table anymore with new approach?
> > If yes, would that introduce a problem that different M-core images
> > requires different dtb?
>
> The resource table still exists. The main difference is that the virtio devices
> would be predefined in the DT with their own resources ( memories ,
> mailboxes,...) No need to inherit from the rproc device.
>
>
> On resource table parsing, the remoteproc looks first for pre registered
> rproc_virtio devices. If found then it uses it. Else it instantiates a new one
> (legacy method).
>
>
> >
> >> - declare resources associated to a remote proc VirtIO
> >> - declare a list of VirtIO supported by the platform.
> >> - Prepare the enhancement to more VirtIO devices (e.g I2C, audio,
> video, ...).
> >> For instance be able to declare a I2C device in a virtio-i2C node.
> >
> > As my understanding virtio-i2c is a i2c bus, you could declare a i2c
> > device in the virtual bus without your patchset, would you please share
> more?
>
> Yes virtio-i2c is a bus, There is different methods to declare I2C device on a
> bus[1].
>
> In ST we rely on DT to statically declare an I2C device,as child of the I2C
> adapter node.
> I haven't implemented the virtio-I2C part yet, but it would make sense to
> have such an implementation.

I misunderstood. Virtio-i2c bus with I2C device in DT is preferred.

>
> Which alternative have you in mind?

No. NXP use same method, we have a rpmsg i2c driver, rpmsg i2c bus node
and i2c device in DT.

Regards,
Peng.

>
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
> kernel.org%2Fdoc%2Fhtml%2Flatest%2Fi2c%2Finstantiating-devices.html&a
> mp;data=04%7C01%7Cpeng.fan%40nxp.com%7C31ba612e9d444a845cbf08d
> 9f073f744%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6378052
> 03140739333%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ
> QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=C1S
> BPEtDhp7Y9XLB8wHgTLaQ%2BBE6T%2BD8eUr34SFRJYQ%3D&amp;reserved
> =0
>
> Thanks,
> Arnaud
>
> >
> > Thanks,
> > Peng.
> >
> >> - Keep the legacy working!
> >> - Try to improve the picture about concerns reported by Christoph
> >> Hellwing [3][4]
> >>
> >> [2]
> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkm
> >>
> l.or%2F&amp;data=04%7C01%7Cpeng.fan%40nxp.com%7C31ba612e9d444a
> 845cbf0
> >>
> 8d9f073f744%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63780
> 5203140
> >>
> 739333%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2
> luMzIiLC
> >>
> JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=MDamNuBkyFebgG
> BuP5shcU9
> >> aw%2FdMuM9GBTEEzffQQkA%3D&amp;reserved=0
> >>
> g%2Flkml%2F2020%2F4%2F16%2F1817&amp;data=04%7C01%7Cpeng.fan%4
> >>
> 0nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e855e2%7C686ea1d3bc2b4c6fa
> >>
> 92cd99c5c301635%7C0%7C0%7C637788110748757786%7CUnknown%7CT
> >>
> WFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLC
> >>
> JXVCI6Mn0%3D%7C3000&amp;sdata=O2BZw5PCY19eD5xMGxrGUKC%2Fty1
> >> Sdc3LE6rhK4cSXvs%3D&amp;reserved=0
> >> [3]
> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkm
> >>
> l.or%2F&amp;data=04%7C01%7Cpeng.fan%40nxp.com%7C31ba612e9d444a
> 845cbf0
> >>
> 8d9f073f744%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63780
> 5203140
> >>
> 739333%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2
> luMzIiLC
> >>
> JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=MDamNuBkyFebgG
> BuP5shcU9
> >> aw%2FdMuM9GBTEEzffQQkA%3D&amp;reserved=0
> >>
> g%2Flkml%2F2021%2F6%2F23%2F607&amp;data=04%7C01%7Cpeng.fan%40
> >>
> nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e855e2%7C686ea1d3bc2b4c6fa9
> >>
> 2cd99c5c301635%7C0%7C0%7C637788110748757786%7CUnknown%7CTW
> >>
> FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX
> >>
> VCI6Mn0%3D%7C3000&amp;sdata=xqX50iDeL%2BtFBOgyADnEUE5HH4gogK
> >> C0MwyqZSxVqNo%3D&amp;reserved=0
> >> [4]
> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpat
> >> ch
> work.kernel.org%2Fproject%2Flinux-remoteproc%2Fpatch%2FAOKowLclCbO
> >>
> CKxyiJ71WeNyuAAj2q8EUtxrXbyky5E%40cp7-web-042.plabs.ch%2F&amp;da
> >>
> ta=04%7C01%7Cpeng.fan%40nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e85
> >>
> 5e2%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637788110748
> >>
> 757786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2
> >>
> luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=mvSm3wM
> >> LgQ%2BDFhqjXIkG8de58zFjwPSURzw55JhGNaA%3D&amp;reserved=0
> >>
> >> In term of device tree this would result in such hiearchy (stm32mp1
> >> example with 2 virtio RPMSG):
> >>
> >> m4_rproc: m4@10000000 {
> >> compatible = "st,stm32mp1-m4";
> >> reg = <0x10000000 0x40000>,
> >> <0x30000000 0x40000>,
> >> <0x38000000 0x10000>;
> >> memory-region = <&retram>, <&mcuram>,<&mcuram2>;
> >> mboxes = <&ipcc 2>, <&ipcc 3>;
> >> mbox-names = "shutdown", "detach";
> >> status = "okay";
> >>
> >> #address-cells = <1>;
> >> #size-cells = <0>;
> >>
> >> vdev@0 {
> >> compatible = "rproc-virtio";
> >> reg = <0>;
> >> virtio,id = <7>; /* RPMSG */
> >> memory-region = <&vdev0vring0>, <&vdev0vring1>,
> <&vdev0buffer>;
> >> mboxes = <&ipcc 0>, <&ipcc 1>;
> >> mbox-names = "vq0", "vq1";
> >> status = "okay";
> >> };
> >>
> >> vdev@1 {
> >> compatible = "rproc-virtio";
> >> reg = <1>;
> >> virtio,id = <7>; /*RPMSG */
> >> memory-region = <&vdev1vring0>, <&vdev1vring1>,
> <&vdev1buffer>;
> >> mboxes = <&ipcc 4>, <&ipcc 5>;
> >> mbox-names = "vq0", "vq1";
> >> status = "okay";
> >> };
> >> };
> >>
> >> I have divided the work in 4 steps to simplify the review, This
> >> series implements only the step 1:
> >> step 1: redefine the remoteproc VirtIO device as a platform device
> >> - migrate rvdev management in remoteproc virtio.c,
> >> - create a remotproc virtio config ( can be disabled for platform
> >> that not use VirtIO IPC.
> >> step 2: add possibility to declare and prob a VirtIO sub node
> >> - VirtIO bindings declaration,
> >> - multi DT VirtIO devices support,
> >> - introduction of a remote proc virtio bind device mechanism , =>
> >>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.
> >>
> com%2Farnopo%2Flinux%2Fcommits%2Fstep2-virtio-in-DT&amp;data=04%7
> >>
> C01%7Cpeng.fan%40nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e855e2%7C
> >>
> 686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637788110748757786
> >> %7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> zIiL
> >>
> CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=X%2B462681gcxe6
> >> 2GP%2BV7ji2nef%2FuTbQVvIlddcMQwtmg%3D&amp;reserved=0
> >> step 3: Add memory declaration in VirtIO subnode =>
> >>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.
> >>
> com%2Farnopo%2Flinux%2Fcommits%2Fstep3-virtio-memories&amp;data=0
> >>
> 4%7C01%7Cpeng.fan%40nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e855e2
> >> %7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637788110748
> 757
> >>
> 786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> >>
> zIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=eMlXgCgrV6l46
> >> h3Ywv1%2BCoX3gLBabdTZs9ybsm4t4ys%3D&amp;reserved=0
> >> step 4: Add mailbox declaration in VirtIO subnode =>
> >>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.
> >>
> com%2Farnopo%2Flinux%2Fcommits%2Fstep4-virtio-mailboxes&amp;data=0
> >>
> 4%7C01%7Cpeng.fan%40nxp.com%7C9e663eefc30a4fbb1fdb08d9e0e855e2
> >> %7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637788110748
> 757
> >>
> 786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> >>
> zIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=75hApOwihqMZ
> >> UUKz1VcitY2VPDc6KAIwAvH8enEZOPY%3D&amp;reserved=0
> >>
> >> Arnaud Pouliquen (4):
> >> remoteproc: core: Introduce virtio device add/remove functions
> >> remoteproc: core: Introduce rproc_register_rvdev function
> >> remoteproc: Move rproc_vdev management to remoteproc_virtio.c
> >> remoteproc: virtio: Create platform device for the
> >> remoteproc_virtio
> >>
> >> drivers/remoteproc/remoteproc_core.c | 159 +++----------------
> >> drivers/remoteproc/remoteproc_internal.h | 33 +++-
> >> drivers/remoteproc/remoteproc_virtio.c | 193
> >> ++++++++++++++++++++---
> >> include/linux/remoteproc.h | 6 +-
> >> 4 files changed, 227 insertions(+), 164 deletions(-)
> >>
> >> --
> >> 2.25.1
> >