[PATCH 1/2] commands: devlookup: add support for cdev aliases

[PATCH 1/2] commands: devlookup: add support for cdev aliases

[Ahmad Fatoum]

To allow easier observability into the newly added cdev alias
functionality, extend devlookup to be able to resolve them.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 commands/Kconfig     |  2 +-
 commands/devlookup.c | 50 +++++++++++++++++++++++++++++++++++++-------
 include/stringlist.h |  6 ++++++
 3 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/commands/Kconfig b/commands/Kconfig
index ca3f13d7e0cc..7eff747ffdb6 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -92,7 +92,7 @@ config CMD_DEVLOOKUP
 	help
 	  Look up device behind device file and its parameters
 
-	  devlookup [-v VAR] /dev/DEVICE [parameter]
+	  devlookup [-v VAR] [-ka] /dev/DEVICE [parameter]
 
 	  Detects the device behind a device file and outputs it,
 	  unless a second argument is given. In that case the device
diff --git a/commands/devlookup.c b/commands/devlookup.c
index 0d4c6e808b60..5877d5f1b82c 100644
--- a/commands/devlookup.c
+++ b/commands/devlookup.c
@@ -9,17 +9,25 @@
 #include <linux/ctype.h>
 #include <environment.h>
 #include <block.h>
+#include <stringlist.h>
+
+static int devlookup_process(struct cdev *cdev, void *sl)
+{
+	string_list_add(sl, cdev->name);
+	return 1;
+}
 
 static int do_devlookup(int argc, char *argv[])
 {
 	const char *variable = NULL, *devicefile, *paramname;
-	struct cdev *cdev;
+	struct cdev *cdev = NULL;
 	int opt, ret;
-	bool kernelopt = false;
+	bool alias = false, kernelopt = false;
 	const char *val;
-	char *buf = NULL;
+	char *aliasbuf = NULL, *buf = NULL;
+	struct string_list sl;
 
-	while ((opt = getopt(argc, argv, "v:k")) > 0) {
+	while ((opt = getopt(argc, argv, "v:ka")) > 0) {
 		switch(opt) {
 		case 'v':
 			variable = optarg;
@@ -27,6 +35,9 @@ static int do_devlookup(int argc, char *argv[])
 		case 'k':
 			kernelopt = true;
 			break;
+		case 'a':
+			alias = true;
+			break;
 		}
 	}
 
@@ -39,12 +50,33 @@ static int do_devlookup(int argc, char *argv[])
 	devicefile = argv[0];
 	paramname  = argv[1];
 
+	string_list_init(&sl);
+
+	ret = cdev_alias_resolve_for_each(devicefile, devlookup_process, &sl);
+	if (ret < 0)
+		goto out;
+	else if (ret > 1) {
+		aliasbuf = string_list_join(&sl, " ");
+		if (string_list_count(&sl) > 1 && (kernelopt || paramname)) {
+			printf("Option not supported for multi cdev alias\n");
+			return COMMAND_ERROR;
+		}
+
+		if (alias) {
+			ret = cmd_export_val(variable, aliasbuf);
+			goto out;
+		}
+
+		devicefile = aliasbuf;
+	}
+
 	devicefile = devpath_to_name(devicefile);
 
 	cdev = cdev_open_by_name(devicefile, O_RDONLY);
 	if (!cdev) {
 		printf("devlookup: cdev %s not found\n", devicefile);
-		return -ENOENT;
+		ret = -ENOENT;
+		goto out;
 	}
 
 	if (!cdev->dev) {
@@ -62,8 +94,11 @@ static int do_devlookup(int argc, char *argv[])
 
 	ret = cmd_export_val(variable, val);
 out:
+	string_list_free(&sl);
+	free(aliasbuf);
 	free(buf);
-	cdev_close(cdev);
+	if (cdev)
+		cdev_close(cdev);
 
 	return ret;
 }
@@ -76,12 +111,13 @@ BAREBOX_CMD_HELP_TEXT("")
 BAREBOX_CMD_HELP_TEXT("Options:")
 BAREBOX_CMD_HELP_OPT ("-v",  "write output to VARIABLE instead of printing it")
 BAREBOX_CMD_HELP_OPT ("-k",  "output kernel rootarg line")
+BAREBOX_CMD_HELP_OPT ("-a",  "output resolution of cdev alias")
 BAREBOX_CMD_HELP_END
 
 BAREBOX_CMD_START(devlookup)
 	.cmd		= do_devlookup,
 	BAREBOX_CMD_DESC("look up device behind device file and its parameters")
-	BAREBOX_CMD_OPTS("[-v VAR] [-k] /dev/DEVICE [parameter]")
+	BAREBOX_CMD_OPTS("[-v VAR] [-ka] /dev/DEVICE [parameter]")
 	BAREBOX_CMD_GROUP(CMD_GRP_SCRIPT)
 	BAREBOX_CMD_HELP(cmd_devlookup_help)
 BAREBOX_CMD_END
diff --git a/include/stringlist.h b/include/stringlist.h
index dcfd33c6e064..b964fabd2320 100644
--- a/include/stringlist.h
+++ b/include/stringlist.h
@@ -3,6 +3,7 @@
 #define __STRINGLIST_H
 
 #include <linux/list.h>
+#include <linux/string.h>
 #include <malloc.h>
 
 struct string_list {
@@ -24,6 +25,11 @@ static inline void string_list_init(struct string_list *sl)
 	sl->str = NULL;
 }
 
+static inline size_t string_list_count(struct string_list *sl)
+{
+	return list_count_nodes(&sl->list);
+}
+
 static inline void string_list_free(struct string_list *sl)
 {
 	struct string_list *entry, *safe;
-- 
2.39.5

[PATCH 2/2] common: bootdef: output resolution at info log level

[Ahmad Fatoum]

To make it easier to follow how bootsource target is resolved, print out
the resolution as well as the concrete name of the target on error.

The latter is especially useful when specifying partitions, e.g.
bootsource.2.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 common/bootdef.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/common/bootdef.c b/common/bootdef.c
index 254228580191..e8140d3a6bce 100644
--- a/common/bootdef.c
+++ b/common/bootdef.c
@@ -13,6 +13,7 @@
 
 static int bootdev_process(struct cdev *cdev, void *entries)
 {
+	pr_info("resolved to %s\n", cdev->name);
 	return bootentry_create_from_name(entries, cdev->name);
 }
 
@@ -22,7 +23,7 @@ static int bootdef_add_entry(struct bootentries *entries, const char *name)
 
 	ret = cdev_alias_resolve_for_each(name, bootdev_process, entries);
 	if (ret == -ENODEV) {
-		pr_info("Could not autodetect bootsource device\n");
+		pr_info("Could not autodetect %s device\n", name);
 		return 0;
 	}
 
-- 
2.39.5

Re: [PATCH 1/2] commands: devlookup: add support for cdev aliases

[Sascha Hauer]

On Mon, 14 Apr 2025 08:25:29 +0200, Ahmad Fatoum wrote:
> To allow easier observability into the newly added cdev alias
> functionality, extend devlookup to be able to resolve them.
> 
> 

Applied, thanks!

[1/2] commands: devlookup: add support for cdev aliases
      https://git.pengutronix.de/cgit/barebox/commit/?id=b00cd7d3ceb7 (link may not be stable)
[2/2] common: bootdef: output resolution at info log level
      https://git.pengutronix.de/cgit/barebox/commit/?id=35d4ff56ee19 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>