generic: platform/mikrotik: use MTD notifier

If the SPI probe is sufficiently delayed, the routerboot driver may fail
to init as the routerboot partitions are not yet available.

Register an MTD user notifier instead of doing straight init so that the
init subroutines are only executed when the target MTD partitions are
present.

Because the init/exit routines can now be called outside of the kernel
normal init/exit calls, they cannot be jettisoned and must always be
available: the __init and __exit qualifiers are thus removed.

Reported-by: Denis Kalashnikov <denis281089@gmail.com>
Signed-off-by: Denis Kalashnikov <denis281089@gmail.com>
Signed-off-by: Thibaut VARÈNE <hacks@slashdirt.org>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
[bump hardconfig/softconfig versions]
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>

1 files changed, 39 insertions, 6 deletions

diff --git a/target/linux/generic/files/drivers/platform/mikrotik/routerboot.c b/target/linux/generic/files/drivers/platform/mikrotik/routerboot.c
index 4c8c0bfac5..96f2460916 100644
--- a/target/linux/generic/files/drivers/platform/mikrotik/routerboot.c
+++ b/target/linux/generic/files/drivers/platform/mikrotik/routerboot.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/sysfs.h>
+#include <linux/mtd/mtd.h>
 
 #include "routerboot.h"
 
@@ -160,25 +161,57 @@ fail:
 	return ret;
 }
 
-static int __init routerboot_init(void)
+static void routerboot_mtd_notifier_add(struct mtd_info *mtd)
 {
-	rb_kobj = kobject_create_and_add("mikrotik", firmware_kobj);
-	if (!rb_kobj)
-		return -ENOMEM;
+	/* Currently routerboot is only known to live on NOR flash */
+	if (mtd->type != MTD_NORFLASH)
+		return;
 
 	/*
 	 * We ignore the following return values and always register.
 	 * These init() routines are designed so that their failed state is
 	 * always manageable by the corresponding exit() calls.
+	 * Notifier is called with MTD mutex held: use __get/__put variants.
+	 * TODO: allow partition names override
 	 */
-	rb_hardconfig_init(rb_kobj);
-	rb_softconfig_init(rb_kobj);
+	if (!strcmp(mtd->name, RB_MTD_HARD_CONFIG))
+		rb_hardconfig_init(rb_kobj, mtd);
+	else if (!strcmp(mtd->name, RB_MTD_SOFT_CONFIG))
+		rb_softconfig_init(rb_kobj, mtd);
+}
+
+static void routerboot_mtd_notifier_remove(struct mtd_info *mtd)
+{
+	if (mtd->type != MTD_NORFLASH)
+		return;
+
+	if (!strcmp(mtd->name, RB_MTD_HARD_CONFIG))
+		rb_hardconfig_exit();
+	else if (!strcmp(mtd->name, RB_MTD_SOFT_CONFIG))
+		rb_softconfig_exit();
+}
+
+/* Note: using a notifier prevents qualifying init()/exit() functions with __init/__exit */
+static struct mtd_notifier routerboot_mtd_notifier = {
+	.add = routerboot_mtd_notifier_add,
+	.remove = routerboot_mtd_notifier_remove,
+};
+
+static int __init routerboot_init(void)
+{
+	rb_kobj = kobject_create_and_add("mikrotik", firmware_kobj);
+	if (!rb_kobj)
+		return -ENOMEM;
+
+	register_mtd_user(&routerboot_mtd_notifier);
 
 	return 0;
 }
 
 static void __exit routerboot_exit(void)
 {
+	unregister_mtd_user(&routerboot_mtd_notifier);
+	/* Exit routines are idempotent */
 	rb_softconfig_exit();
 	rb_hardconfig_exit();
 	kobject_put(rb_kobj);	// recursive afaict