Re: [PATCH v2] commands: add new of_fixup command to list and disable DT fixups

[Sascha Hauer <sha@pengutronix.de>]

On Thu, Apr 20, 2023 at 10:32:19PM +0200, Ahmad Fatoum wrote:
> 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>
> ---
> v1 -> v2:
>   - extend commit message a bit
>   - fix typo (Sascha)
>   - drop CONFIG_OF_FIXUP_TOGGLE
>   - print warning message when all specified fixups are non-existent
> ---

Applied, thanks

Sascha

>  commands/Kconfig    | 14 +++++++
>  commands/Makefile   |  1 +
>  commands/of_fixup.c | 93 +++++++++++++++++++++++++++++++++++++++++++++
>  common/kallsyms.c   |  8 ++--
>  common/oftree.c     | 14 ++++---
>  include/kallsyms.h  |  4 ++
>  include/of.h        | 10 +++++
>  7 files changed, 134 insertions(+), 10 deletions(-)
>  create mode 100644 commands/of_fixup.c
> 
> diff --git a/commands/Kconfig b/commands/Kconfig
> index e4452cd42d45..3becc88129c1 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -2283,6 +2283,20 @@ 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 ec59137d7e12..0ac84076f83d 100644
> --- a/commands/Makefile
> +++ b/commands/Makefile
> @@ -88,6 +88,7 @@ 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 000000000000..d667afb5b107
> --- /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
> diff --git a/common/kallsyms.c b/common/kallsyms.c
> index a9b2b9368992..3c5904f8a833 100644
> --- a/common/kallsyms.c
> +++ b/common/kallsyms.c
> @@ -165,10 +165,10 @@ static unsigned long get_symbol_pos(unsigned long addr,
>   *   It resides in a module.
>   * - We also guarantee that modname will be valid until rescheduled.
>   */
> -static const char *kallsyms_lookup(unsigned long addr,
> -				   unsigned long *symbolsize,
> -				   unsigned long *offset,
> -				   char **modname, char *namebuf)
> +const char *kallsyms_lookup(unsigned long addr,
> +			    unsigned long *symbolsize,
> +			    unsigned long *offset,
> +			    char **modname, char *namebuf)
>  {
>  	namebuf[KSYM_NAME_LEN - 1] = 0;
>  	namebuf[0] = 0;
> diff --git a/common/oftree.c b/common/oftree.c
> index 4beadc5aaa89..1f751cc0ac89 100644
> --- a/common/oftree.c
> +++ b/common/oftree.c
> @@ -350,13 +350,12 @@ int of_register_set_status_fixup(const char *path, bool status)
>  	return of_register_fixup(of_fixup_status, (void *)data);
>  }
>  
> -struct of_fixup {
> -	int (*fixup)(struct device_node *, void *);
> -	void *context;
> -	struct list_head list;
> -};
> +LIST_HEAD(of_fixup_list);
>  
> -static LIST_HEAD(of_fixup_list);
> +static inline bool of_fixup_disabled(struct of_fixup *fixup)
> +{
> +    return fixup->disabled;
> +}
>  
>  int of_register_fixup(int (*fixup)(struct device_node *, void *), void *context)
>  {
> @@ -401,6 +400,9 @@ int of_fix_tree(struct device_node *node)
>  	of_overlay_load_firmware_clear();
>  
>  	list_for_each_entry(of_fixup, &of_fixup_list, list) {
> +		if (of_fixup_disabled(of_fixup))
> +			continue;
> +
>  		ret = of_fixup->fixup(node, of_fixup->context);
>  		if (ret)
>  			pr_warn("Failed to fixup node in %pS: %s\n",
> diff --git a/include/kallsyms.h b/include/kallsyms.h
> index e0b3ff7cd503..f61efc9e0c42 100644
> --- a/include/kallsyms.h
> +++ b/include/kallsyms.h
> @@ -6,6 +6,10 @@
>  #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
>  		2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
>  unsigned long kallsyms_lookup_name(const char *name);
> +const char *kallsyms_lookup(unsigned long addr,
> +			    unsigned long *symbolsize,
> +			    unsigned long *offset,
> +			    char **modname, char *namebuf);
>  
>  /* Look up a kernel symbol and return it in a text buffer. */
>  int sprint_symbol(char *buffer, unsigned long address);
> diff --git a/include/of.h b/include/of.h
> index 22358f5579ec..5cdea4329330 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -331,6 +331,16 @@ int of_find_path_by_node(struct device_node *node, char **outpath, unsigned flag
>  struct device_node *of_find_node_by_devpath(struct device_node *root, const char *path);
>  int of_register_fixup(int (*fixup)(struct device_node *, void *), void *context);
>  int of_unregister_fixup(int (*fixup)(struct device_node *, void *), void *context);
> +
> +struct of_fixup {
> +	int (*fixup)(struct device_node *, void *);
> +	void *context;
> +	struct list_head list;
> +	bool disabled;
> +};
> +
> +extern struct list_head of_fixup_list;
> +
>  int of_register_set_status_fixup(const char *node, bool status);
>  struct device_node *of_find_node_by_alias(struct device_node *root,
>  		const char *alias);
> -- 
> 2.39.2
> 
> 
> 

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