commands: add new of_fixup command to list and disable DT fixups

barebox can already dry run fixups with of_diff - +, but there's no way
to selectively disable a fixup to rule out it causing issues.

For platforms supporting kallsyms, we can readily allow enabling
and disabling fixups by name, so let's add a command that does just that
to aid in debugging.

Suggested-by: Daniel Brát <danek.brat@gmail.com>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20230420203219.2255564-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 108 insertions, 0 deletions

diff --git a/commands/Kconfig b/commands/Kconfig
index 76dfca2dfd..c72c2b7758 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -2255,6 +2255,20 @@ config CMD_OF_DISPLAY_TIMINGS
 		  -s path	select display-timings and register oftree fixup
 		  -f dtb	work on dtb. Has no effect on -s option
 
+config CMD_OF_FIXUP
+	tristate
+	select OFTREE
+	depends on KALLSYMS
+	prompt "of_fixup"
+	help
+	  List and enable/disable fixups
+
+	  Usage: of_fixup [-de] [fixups...]
+
+	  Options:
+		-d		disable fixup
+	  	-e		re-enable fixup
+
 config CMD_OF_FIXUP_STATUS
 	tristate
 	select OFTREE
diff --git a/commands/Makefile b/commands/Makefile
index cac1d4f253..98625a0373 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_CMD_OF_PROPERTY)	+= of_property.o
 obj-$(CONFIG_CMD_OF_NODE)	+= of_node.o
 obj-$(CONFIG_CMD_OF_DUMP)	+= of_dump.o
 obj-$(CONFIG_CMD_OF_DISPLAY_TIMINGS)	+= of_display_timings.o
+obj-$(CONFIG_CMD_OF_FIXUP)	+= of_fixup.o
 obj-$(CONFIG_CMD_OF_FIXUP_STATUS)	+= of_fixup_status.o
 obj-$(CONFIG_CMD_OF_OVERLAY)	+= of_overlay.o
 obj-$(CONFIG_CMD_MAGICVAR)	+= magicvar.o
diff --git a/commands/of_fixup.c b/commands/of_fixup.c
new file mode 100644
index 0000000000..d667afb5b1
--- /dev/null
+++ b/commands/of_fixup.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * of_fixup.c - List and remove OF fixups
+ */
+
+#include <common.h>
+#include <kallsyms.h>
+#include <of.h>
+#include <command.h>
+#include <malloc.h>
+#include <complete.h>
+#include <getopt.h>
+#include <string.h>
+
+static int do_of_fixup(int argc, char *argv[])
+{
+	struct of_fixup *of_fixup;
+	int opt, enable = -1;
+	bool did_fixup = false;
+
+	while ((opt = getopt(argc, argv, "ed")) > 0) {
+		switch (opt) {
+		case 'e':
+			enable = 1;
+			break;
+		case 'd':
+			enable = 0;
+			break;
+		default:
+			return COMMAND_ERROR_USAGE;
+		}
+	}
+
+	argv += optind;
+	argc -= optind;
+
+	if ((enable < 0 && argc > 0) || (enable >= 0 && argc == 0))
+		return COMMAND_ERROR_USAGE;
+
+	list_for_each_entry(of_fixup, &of_fixup_list, list) {
+		int i;
+		ulong addr = (ulong)of_fixup->fixup;
+		char sym[KSYM_SYMBOL_LEN];
+		const char *name;
+
+		name = kallsyms_lookup(addr, NULL, NULL, NULL, sym);
+		if (!name) {
+			sprintf(sym, "<0x%lx>", addr);
+			name = sym;
+		}
+
+		if (enable == -1) {
+			printf("%s(0x%p)%s\n", name, of_fixup->context,
+			       of_fixup->disabled ? " [DISABLED]" : "");
+			continue;
+		}
+
+		for (i = 0; i < argc; i++) {
+			if (strcmp(name, argv[i]) != 0)
+				continue;
+
+			of_fixup->disabled = !enable;
+			did_fixup = true;
+		}
+	}
+
+	if (argc && !did_fixup) {
+		printf("none of the specified fixups found\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+BAREBOX_CMD_HELP_START(of_fixup)
+BAREBOX_CMD_HELP_TEXT("Disable or re-enable an already registered fixup for the device tree.")
+BAREBOX_CMD_HELP_TEXT("Call without arguments to list all fixups")
+BAREBOX_CMD_HELP_TEXT("")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT("-d",  "disable fixup")
+BAREBOX_CMD_HELP_OPT("-e",  "re-enable fixup")
+BAREBOX_CMD_HELP_OPT("fixups",  "List of fixups to enable or disable")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(of_fixup)
+	.cmd	= do_of_fixup,
+	BAREBOX_CMD_DESC("list and enable/disable fixups")
+	BAREBOX_CMD_OPTS("[-de] [fixups...]")
+	BAREBOX_CMD_GROUP(CMD_GRP_MISC)
+	BAREBOX_CMD_COMPLETE(empty_complete)
+	BAREBOX_CMD_HELP(cmd_of_fixup_help)
+BAREBOX_CMD_END