hello On 10/23/24 17:32, Mathieu Poirier wrote: > 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. > FYI a PR exists in OpenAMP to use this configuration space to customize the size of the buffers [2]. This probably means we need something scalable for the configuration space. I guess your objective is to match the vring ID with the mailbox channel ID, right? We have a similar issue with the STM32MP1/2. It is hard-coded in the stm32_rproc driver[1], which is far from perfect because it is not simple to add a new vdev instance. I would have two other alternatives to highlight - An alternative could be to have a vendor resource in the resource table and use rproc_handle_rsc operations. This resource would define the match between the vrings IDs and the mailbox IDs. However, if several vendors are facing the same issue, perhaps better to find a generic solution. - another alternative already discussed several times in openAMP group would be to define a new version of the resource table. [1]https://elixir.bootlin.com/linux/v6.11/source/drivers/remoteproc/stm32_rproc.c#L328 [2] https://github.com/OpenAMP/open-amp/pull/155 Regards Arnaud > 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 >> >