On Sat, 26 Aug 2023 at 16:09, Heinrich Schuchardt <xypron.g...@gmx.de> wrote:
>
> On 8/26/23 11:06, Sughosh Ganu wrote:
> > Add a function which is registered to spy for a EVT_FT_FIXUP event,
> > and removes the non upstreamed nodes and properties from the
> > devicetree before it gets passed to the OS.
> >
> > This allows removing entire nodes, or specific properties under nodes
> > from the devicetree. The required nodes and properties can be
> > registered for removal through the DT_NON_COMPLIANT_PURGE and
> > DT_NON_COMPLIANT_PURGE_LIST macros.
> >
> > Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
> > ---
> > include/dt-structs.h | 11 +++++++
> > lib/Makefile | 1 +
> > lib/dt_purge.c | 73 ++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 85 insertions(+)
> > create mode 100644 lib/dt_purge.c
> >
> > diff --git a/include/dt-structs.h b/include/dt-structs.h
> > index fa1622cb1d..f535c60471 100644
> > --- a/include/dt-structs.h
> > +++ b/include/dt-structs.h
> > @@ -57,3 +57,14 @@ struct phandle_2_arg {
> > #endif
> >
> > #endif
> > +
> > +struct dt_non_compliant_purge {
> > + const char *node_path;
> > + const char *prop;
> > +};
> > +
> > +#define DT_NON_COMPLIANT_PURGE(__name) \
> > + ll_entry_declare(struct dt_non_compliant_purge, __name, dt_purge)
> > +
> > +#define DT_NON_COMPLIANT_PURGE_LIST(__name) \
> > + ll_entry_declare_list(struct dt_non_compliant_purge, __name, dt_purge)
> > diff --git a/lib/Makefile b/lib/Makefile
> > index 8d8ccc8bbc..82a906daa0 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -37,6 +37,7 @@ endif
> > obj-y += crc8.o
> > obj-y += crc16.o
> > obj-y += crc16-ccitt.o
> > +obj-y += dt_purge.o
>
> SPL can be the last boot stage (e.g. for Falcon Mode). So placing this
> under 'ifndef CONFIG_SPL_BUILD' is not correct.
>
> You need some logic that identifies into which boot stage this code
> belongs, e.g. use obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT).
Okay. Will check and add this under the suggested config symbol.
-sughosh
>
> Best regards
>
> Heinrich
>
> > obj-$(CONFIG_ERRNO_STR) += errno_str.o
> > obj-$(CONFIG_FIT) += fdtdec_common.o
> > obj-$(CONFIG_TEST_FDTDEC) += fdtdec_test.o
> > diff --git a/lib/dt_purge.c b/lib/dt_purge.c
> > new file mode 100644
> > index 0000000000..f893ba9796
> > --- /dev/null
> > +++ b/lib/dt_purge.c
> > @@ -0,0 +1,73 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright (c) 2023, Linaro Limited
> > + */
> > +
> > +#include <dt-structs.h>
> > +#include <event.h>
> > +#include <linker_lists.h>
> > +
> > +#include <linux/libfdt.h>
> > +
> > +/**
> > + * dt_non_compliant_purge() - Remove non-upstreamed nodes and
> > properties
> > + * from the DT
> > + * @ctx: Context for event
> > + * @event: Event to process
> > + *
> > + * Iterate through an array of DT nodes and properties, and remove them
> > + * from the device-tree before the DT gets handed over to the kernel.
> > + * These are nodes and properties which do not have upstream bindings
> > + * and need to be purged before being handed over to the kernel.
> > + *
> > + * If both the node and property are specified, delete the property. If
> > + * only the node is specified, delete the entire node, including it's
> > + * subnodes, if any.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + */
> > +static int dt_non_compliant_purge(void *ctx, struct event *event)
> > +{
> > + int nodeoff = 0;
> > + int err = 0;
> > + void *fdt;
> > + const struct event_ft_fixup *fixup = &event->data.ft_fixup;
> > + struct dt_non_compliant_purge *purge_entry;
> > + struct dt_non_compliant_purge *purge_start =
> > + ll_entry_start(struct dt_non_compliant_purge, dt_purge);
> > + int nentries = ll_entry_count(struct dt_non_compliant_purge,
> > dt_purge);
> > +
> > + if (fixup->images)
> > + return 0;
> > +
> > + fdt = fixup->tree.fdt;
> > + for (purge_entry = purge_start; purge_entry != purge_start + nentries;
> > + purge_entry++) {
> > + nodeoff = fdt_path_offset(fdt, purge_entry->node_path);
> > + if (nodeoff < 0) {
> > + log_debug("Error (%d) getting node offset for %s\n",
> > + nodeoff, purge_entry->node_path);
> > + continue;
> > + }
> > +
> > + if (purge_entry->prop) {
> > + err = fdt_delprop(fdt, nodeoff, purge_entry->prop);
> > + if (err < 0 && err != -FDT_ERR_NOTFOUND) {
> > + log_debug("Error (%d) deleting %s\n",
> > + err, purge_entry->prop);
> > + goto out;
> > + }
> > + } else {
> > + err = fdt_del_node(fdt, nodeoff);
> > + if (err) {
> > + log_debug("Error (%d) trying to delete node
> > %s\n",
> > + err, purge_entry->node_path);
> > + goto out;
> > + }
> > + }
> > + }
> > +
> > +out:
> > + return err;
> > +}
> > +EVENT_SPY(EVT_FT_FIXUP, dt_non_compliant_purge);
>
