On Wed, Jan 26, 2022 at 11:15:24AM +0100, Sascha Hauer wrote: > On Wed, Jan 26, 2022 at 10:35:13AM +0100, Michael Olbrich wrote: > > On Wed, Jan 26, 2022 at 08:57:27AM +0100, Sascha Hauer wrote: > > > On Mon, Jan 24, 2022 at 11:04:58AM +0100, Michael Olbrich wrote: > > > > On some platforms (e.g. EFI on x86_64) the state backend can only be > > > > selected by a partiton UUID. On existing devices with a DOS partition > > > > table, there may be no spare partition available for state. > > > > > > > > This makes it possible to select the disk via UUID. The exact position is > > > > defined by an explicitly specified offset. > > > > > > > > Signed-off-by: Michael Olbrich <m.olbrich@xxxxxxxxxxxxxx> > > > > --- > > > > > > > > I wasn't sure where to add the helper function. Is include/fs.h ok or > > > > should I put it somewhere else? > > > > > > > > I'll implement the same helper for dt-utils, so we can avoid additional > > > > #ifdef here. > > > > > > > > common/state/state.c | 55 +++++++++++++++++++++++++++++--------------- > > > > include/fs.h | 12 ++++++++++ > > > > 2 files changed, 49 insertions(+), 18 deletions(-) > > > > > > > > diff --git a/common/state/state.c b/common/state/state.c > > > > index 8c34ae83e52b..2a8b12d20c5a 100644 > > > > --- a/common/state/state.c > > > > +++ b/common/state/state.c > > > > @@ -592,6 +592,7 @@ struct state *state_new_from_node(struct device_node *node, bool readonly) > > > > const char *backend_type; > > > > const char *storage_type = NULL; > > > > const char *alias; > > > > + const char *diskuuid; > > > > uint32_t stridesize; > > > > struct device_node *partition_node; > > > > off_t offset = 0; > > > > @@ -607,30 +608,48 @@ struct state *state_new_from_node(struct device_node *node, bool readonly) > > > > if (IS_ERR(state)) > > > > return state; > > > > > > > > - partition_node = of_parse_phandle(node, "backend", 0); > > > > - if (!partition_node) { > > > > - dev_err(&state->dev, "Cannot resolve \"backend\" phandle\n"); > > > > - ret = -EINVAL; > > > > - goto out_release_state; > > > > - } > > > > + ret = of_property_read_string(node, "backend-diskuuid", &diskuuid); > > > > > > This needs some documentation in > > > Documentation/devicetree/bindings/barebox/barebox,state.rst. > > > > I can do that. > > > > > > + if (ret == 0) { > > > > + u64 off; > > > > + > > > > + ret = devpath_from_diskuuid(diskuuid, &state->backend_path); > > > > + if (ret) { > > > > + dev_err(&state->dev, "state failed find backend device for diskuuid='%s'\n", > > > > + diskuuid); > > > > + goto out_release_state; > > > > + } > > > > + ret = of_property_read_u64(node, "backend-offset", &off); > > > > > > I stumbled upon this because you have to use a 64bit type here instead > > > of using 'offset' directly. I think 'offset' should be 64bit instead so > > > that larger offsets can be used. > > > > It's not that simple. 'offset' used as a 'off_t' and 'ssize_t' all over the > > place in the state framework. On 32bit architecture both are defined as > > 'long' or 'int'. Both are 32 bit types so changing 'offset' to a 64bit type > > here doesn't really help. > > Of course not, we would have to replace all variables which are used as > offset into a device to 64bit types. That's a separate topic which > doesn't have to be solved as part of this series. So what should I do here? - use 'u64' for 'offset' and remove the separate variable - use 'loff_t' for 'offset' - keep it as it is - something else? > > > > + } > > > > + offset = off; > > > > > > What about the size of the state partition? This is not set anywhere in > > > this case so it's still zero. It should be specified the in device tree > > > as well. At the same time I'm a bit nervous that it apparently still > > > works with size zero. > > > > The code explicitly checks if the size is specified and skips any range > > checks if it's not. From what I can tell, it has been like that from the > > beginning. > > That's likely ok for real partitions. When reading/writing them past the end > we'll get an error from the lower layers which can be handled, but not > so in this case where size is potentially the rest of the whole disk. > > > > > If that's not ok, then I could add a 'backend-size' property, or do you > > have something else in mind? > > Yes, that's what I had in mind. And I think it should be mandatory. So, if we add a size, then it should also be validated in some way, right? Maybe ensure that it does not overlap with existing partitions? Michael -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox