Hi Heinrich, On Mon, 11 Oct 2021 at 09:31, Heinrich Schuchardt <xypron.g...@gmx.de> wrote: > > > > On 10/11/21 16:54, Simon Glass wrote: > > Hi Takahiro, > > > > On Mon, 11 Oct 2021 at 00:43, AKASHI Takahiro > > <takahiro.aka...@linaro.org> wrote: > >> > >> Simon, > >> > >> On Sun, Oct 10, 2021 at 08:14:18AM -0600, Simon Glass wrote: > >>> Hi Takahiro, > >>> > >>> On Thu, 30 Sept 2021 at 23:04, AKASHI Takahiro > >>> <takahiro.aka...@linaro.org> wrote: > >>>> > >>>> This member field in udevice will be used to dereference from udevice > >>>> to efi_object (or efi_handle). > >>>> > >>>> Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org> > >>>> --- > >>>> include/dm/device.h | 4 ++++ > >>>> 1 file changed, 4 insertions(+) > >>> > >>> I think this should be generalised. > >>> > >>> Can we add a simple API for attaching things to devices? Something like: > >> > >> Ok. > >> > >> > >>> config DM_TAG > >>> bool "Support tags attached to devices" > >>> > >>> enum dm_tag_t { > >>> DM_TAG_EFI = 0, > >>> > >>> DM_TAG_COUNT, > >>> }; > >>> > >>> ret = dev_tag_set_ptr(dev, DM_TAG_EFI, ptr); > >>> > >>> void *ptr = dev_tag_get_ptr(dev, DM_TAG_EFI); > >>> > >>> ulong val = dev_tag_get_val(dev, DM_TAG_EFI); > >>> > >>> Under the hood I think for now we could have a simple list of tags for > >>> all of DM: > >>> > >>> struct dmtag_node { > >>> struct list_head sibling; > >>> struct udevice *dev; > >>> enum dm_tag_t tag; > >>> union { > >>> void *ptr; > >>> ulong val; > >>> }; > >>> }; > >> > >> Just let me make sure; Do you intend that we have a *single* list of tags > >> in the system instead of maintaining a list *per udevice*? > > > > Yes I would prefer not to have a list per udevice, although the API > > could be adjusted to iterate through all tags for a particular > > udevice, if that is needed (dev_tag_first...() dev_tag_next...(). > > There will never be more than one UEFI handle for one udevice. > We need a single field that points to the the handle if such a handle > exists. But there will be devices for which UEFI protocols don't exist > and where we need no handle. In this case the value can be NULL. > > Why should we complicate the picture with a list of tags?
Let's not talk about complexity while we are discussing UEFI :-) There are other cases where we need to add info to a device. We cover almost all the cases with the uclass-private, plat and priv data attached to each device. But in some cases that is not enough, as with EFI. I have hit this before in a few other places but have tried to work around it rather than extending driver model and adding to the already-large struct udevice. But I think we are at the end of the road on that. I'd also like to look at how much (for example) uclass-plat data is used for devices, in case it would be more efficient to move it to a tag model. I should also point out you are talking about the implementation rather than the API. We can always change the impl later, so long as we have a suitable API. > > > > Looking at some of your other patches I think you might need to > > support multiple tags for EFI, if there are different things. But > > perhaps a list is necesary. > > > >> > >> -Takahiro Akashi > >> > >> > >>> This can be useful in other situations, for example I think we need to > >>> be able to send an event when a device is probed so that other devices > >>> (with tags attached) can take action. But in any case, it makes the > >>> API separate from the data structure, so aids refactoring later. > >>> > >>> If we find that this is slow we can change the impl, but I doubt it > >>> will matter fornow. > >>> Regards, Simon