[PATCH v3 16/23] cmd: log: Add commands to list categories and drivers

[Sean Anderson <seanga2@gmail.com>]

This allows users to query which categories and drivers are available on
their system. This allows them to construct filter-add commands without
(e.g.) adjusting the log format to show categories and drivers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v3:
- Document assumption that erroneous results from log_get_cat_name begin with
  '<'

Changes in v2:
- New

 cmd/log.c     | 35 +++++++++++++++++++++++++++++++++++
 common/log.c  |  1 +
 include/log.h |  5 +++--
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/cmd/log.c b/cmd/log.c
index 651e50358c..8d8d8a8172 100644
--- a/cmd/log.c
+++ b/cmd/log.c
@@ -47,6 +47,37 @@ static int do_log_level(struct cmd_tbl *cmdtp, int flag, int argc,
 	return CMD_RET_SUCCESS;
 }
 
+static int do_log_categories(struct cmd_tbl *cmdtp, int flag, int argc,
+			     char *const argv[])
+{
+	enum log_category_t cat;
+	const char *name;
+
+	for (cat = LOGC_FIRST; cat < LOGC_COUNT; cat++) {
+		name = log_get_cat_name(cat);
+		/*
+		 * Invalid category names (e.g. <invalid> or <missing>) begin
+		 * with '<'.
+		 */
+		if (name[0] == '<')
+			continue;
+		printf("%s\n", name);
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
+static int do_log_drivers(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	struct log_device *ldev;
+
+	list_for_each_entry(ldev, &gd->log_head, sibling_node)
+		printf("%s\n", ldev->drv->name);
+
+	return CMD_RET_SUCCESS;
+}
+
 static int do_log_format(struct cmd_tbl *cmdtp, int flag, int argc,
 			 char *const argv[])
 {
@@ -123,6 +154,8 @@ static int do_log_rec(struct cmd_tbl *cmdtp, int flag, int argc,
 #ifdef CONFIG_SYS_LONGHELP
 static char log_help_text[] =
 	"level - get/set log level\n"
+	"categories - list log categories\n"
+	"drivers - list log drivers\n"
 	"log format <fmt> - set log output format. <fmt> is a string where\n"
 	"\teach letter indicates something that should be displayed:\n"
 	"\tc=category, l=level, F=file, L=line number, f=function, m=msg\n"
@@ -134,6 +167,8 @@ static char log_help_text[] =
 
 U_BOOT_CMD_WITH_SUBCMDS(log, "log system", log_help_text,
 	U_BOOT_SUBCMD_MKENT(level, 2, 1, do_log_level),
+	U_BOOT_SUBCMD_MKENT(categories, 1, 1, do_log_categories),
+	U_BOOT_SUBCMD_MKENT(drivers, 1, 1, do_log_drivers),
 	U_BOOT_SUBCMD_MKENT(format, 2, 1, do_log_format),
 	U_BOOT_SUBCMD_MKENT(rec, 7, 1, do_log_rec),
 );
diff --git a/common/log.c b/common/log.c
index 259d922987..c4a14e191a 100644
--- a/common/log.c
+++ b/common/log.c
@@ -41,6 +41,7 @@ static const char *const log_level_name[LOGL_COUNT] = {
 	"IO",
 };
 
+/* All error responses MUST begin with '<' */
 const char *log_get_cat_name(enum log_category_t cat)
 {
 	const char *name;
diff --git a/include/log.h b/include/log.h
index d5e09a838f..9f57957aae 100644
--- a/include/log.h
+++ b/include/log.h
@@ -407,8 +407,9 @@ struct log_filter {
  * log_get_cat_name() - Get the name of a category
  *
  * @cat: Category to look up
- * @return category name (which may be a uclass driver name) if found, or
- *	 "<invalid>" if invalid, or "<missing>" if not found
+ * @return: category name (which may be a uclass driver name) if found, or
+ *	   "<invalid>" if invalid, or "<missing>" if not found. All error
+ *	   responses begin with '<'.
  */
 const char *log_get_cat_name(enum log_category_t cat);
 
-- 
2.28.0