[PATCH 01/14] show_progress: add system wide progress stage notifier

[Ahmad Fatoum]

Use case is e.g. board code that wants to register a client to light
status LEDs to indicate system state when no serial output is available.
This functionality doesn't increase code size due to linker GC when
CONFIG_PROGRESS_NOTIFIER is disabled.

There is a generic progress notifier provided that just logs the
status. This could be shared with the booted kernel via pstore or
the log as a whole written to a system setup USB drive.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 include/progress.h  | 43 +++++++++++++++++++++++++++++++++++++++++++
 lib/Kconfig         |  6 ++++++
 lib/show_progress.c | 28 ++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/include/progress.h b/include/progress.h
index 50b15fb12b4c..7230bd3a9bd5 100644
--- a/include/progress.h
+++ b/include/progress.h
@@ -3,6 +3,8 @@
 #define __PROGRSS_H
 
 #include <linux/types.h>
+#include <notifier.h>
+#include <errno.h>
 
 /* Initialize a progress bar. If max > 0 a one line progress
  * bar is printed where 'max' corresponds to 100%. If max == 0
@@ -15,4 +17,45 @@ void init_progression_bar(loff_t max);
  */
 void show_progress(loff_t now);
 
+extern struct notifier_head progress_notifier;
+
+enum progress_stage {
+	PROGRESS_UNSPECIFIED = 0,
+	PROGRESS_UPDATING,
+	PROGRESS_UPDATE_SUCCESS,
+	PROGRESS_UPDATE_FAIL,
+};
+
+/*
+ * Notifier list for code which wants to be called at progress
+ * This could use by board code to e.g. flash a LED during updates
+ */
+extern struct notifier_head progress_notifier_list;
+
+/* generic client that just logs the state */
+extern struct notifier_block progress_log_client;
+
+static inline int progress_register_client(struct notifier_block *nb)
+{
+	if (!IS_ENABLED(CONFIG_PROGRESS_NOTIFIER))
+		return -ENOSYS;
+	return notifier_chain_register(&progress_notifier_list, nb);
+}
+
+static inline int progress_unregister_client(struct notifier_block *nb)
+{
+	if (!IS_ENABLED(CONFIG_PROGRESS_NOTIFIER))
+		return -ENOSYS;
+	return notifier_chain_unregister(&progress_notifier_list, nb);
+}
+
+static inline int progress_notifier_call_chain(enum progress_stage stage, const char *prefix)
+{
+	if (!IS_ENABLED(CONFIG_PROGRESS_NOTIFIER))
+		return -ENOSYS;
+
+	/* clients should not modify the prefix */
+	return notifier_call_chain(&progress_notifier_list, stage, (char *)(prefix ?: ""));
+}
+
 #endif /*  __PROGRSS_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index e5831ecdb9a7..922710e106b3 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -154,6 +154,12 @@ source "lib/logo/Kconfig"
 
 source "lib/bootstrap/Kconfig"
 
+config PROGRESS_NOTIFIER
+	bool
+	help
+	  This is selected by boards that register a notifier to visualize
+	  progress, like blinking a LED during an update.
+
 config PRINTF_UUID
 	bool
 
diff --git a/lib/show_progress.c b/lib/show_progress.c
index 1be06ea7806e..1b624bcb9af8 100644
--- a/lib/show_progress.c
+++ b/lib/show_progress.c
@@ -57,3 +57,31 @@ void init_progression_bar(loff_t max)
 	else
 		printf("\t");
 }
+
+NOTIFIER_HEAD(progress_notifier_list);
+
+static int progress_logger(struct notifier_block *r, unsigned long stage, void *_prefix)
+{
+	const char *prefix = _prefix;
+
+	switch ((enum progress_stage)stage) {
+		case PROGRESS_UPDATING:
+			pr_info("%sSoftware update in progress\n", prefix);
+			break;
+		case PROGRESS_UPDATE_SUCCESS:
+			pr_info("%sSoftware update finished successfully\n", prefix);
+			break;
+		case PROGRESS_UPDATE_FAIL:
+			pr_info("%sSoftware update failed\n", prefix);
+			break;
+		case PROGRESS_UNSPECIFIED:
+			/* default state. This should not be reached */
+			break;
+	}
+
+	return 0;
+}
+
+struct notifier_block progress_log_client =  {
+	.notifier_call = progress_logger
+};
-- 
2.29.2