Hello Daniel,
On Fri, Oct 18, 2024 at 02:09:29PM +0300, Daniel Baluta wrote:
> Currently we generate notifyids in the linux kernel and override
> those found in rsc_table.
>
> This doesn't play well with users expecting to use the exact ids
> from rsc_table.
>
> So, use predefined notifyids found in rsc_table if any. Otherwise,
> let Linux generate the ids as before.
>
> Keypoint is we also define an invalid notifid as 0xFFFFFFFFU. This
> should be placed as notifids if users want Linux to generate the ids.
>
> Signed-off-by: Alexandru Lastur <alexandru.lastur@xxxxxxx>
> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxx>
> ---
> drivers/remoteproc/remoteproc_core.c | 14 ++++++++++++--
> include/linux/remoteproc.h | 1 +
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index f276956f2c5c..9f00fe16da38 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -332,6 +332,7 @@ int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
> int ret, notifyid;
> struct rproc_mem_entry *mem;
> size_t size;
> + int start, end;
>
> /* actual size of vring (in bytes) */
> size = PAGE_ALIGN(vring_size(rvring->num, rvring->align));
> @@ -363,9 +364,18 @@ int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
> /*
> * Assign an rproc-wide unique index for this vring
> * TODO: assign a notifyid for rvdev updates as well
> - * TODO: support predefined notifyids (via resource table)
> */
> - ret = idr_alloc(&rproc->notifyids, rvring, 0, 0, GFP_KERNEL);
> +
> + start = 0;
> + end = 0;
> +
> + /* use id if specified in rsc table */
> + if (rsc->vring[i].notifyid != RSC_INVALID_NOTIFYID) {
> + start = rsc->vring[i].notifyid;
> + end = start + 1;
> + }
This will likely introduce a backward compatibility issue where anyone that
has more than one vring and set their notifyids to anything else than 0xFFFFFFFF
in the resource table will see a boot failure.
A while back the openAMP group started discussions on using the configuration
space of a virtio device to enhance device discovery, with exactly this kind of
use case in mind. I think it is the only way to move forward with this
feature, though it is a big job that requires a lot of community interactions.
Regards,
Mathieu
> +
> + ret = idr_alloc(&rproc->notifyids, rvring, start, end, GFP_KERNEL);
> if (ret < 0) {
> dev_err(dev, "idr_alloc failed: %d\n", ret);
> return ret;
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index b4795698d8c2..98c3e181086e 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -238,6 +238,7 @@ struct fw_rsc_trace {
> u8 name[32];
> } __packed;
>
> +#define RSC_INVALID_NOTIFYID 0xFFFFFFFFU
> /**
> * struct fw_rsc_vdev_vring - vring descriptor entry
> * @da: device address
> --
> 2.43.0
>
