[LEDE-DEV] [PATCH v1 1/2] base-files, mac80211, broadcom-wl: plug-and-play wifi detection

[Christian Lamparter]

Currently, the wifi detection script is executed as part of
the (early) boot process. Pluggable wifi USB devices, which
are inserted at a later time are not automatically
detected and therefore they don't show up in LuCI.

A user has to deal with wifi detection manually, or restart
the router.

However, the current "sleep 1" window - which the boot
process waits for wifi devices to "settle down" - is too
short to detect wifi devices for some routers.

For example, this can happen with USB WLAN devices on the
WNDR4700. This is because the usb controller needs to load
its firmware from UBI and initialize, before it can operate.

The issue can be seen on a BT HomeHub 5A as well as soon as
the caldata are on an ubi volume. This is because the ath9k
card has to be initialized by owl-loader first. Which has to
wait for the firmware extraction script to retrieve the pci
initialization values inside the caldata.

This patch moves the wifi detection to hotplug scripts.
For mac80211, the wifi detection will now automatically
run any time a "ieee80211" device is added. Likewise
broadcom-wl's script checks for new "net" devices.

As for potential problems:
- For devices with more than one wifi device, these scripts
  will run multiple times during boot (concurrently).
  For this reason, the script uses file locking to prevent
  races during discovery. (i.e duplicated radio instances).

- The broadcom-wl hotplug script is suboptimal.
  As it will run for any net devices (ethernet).

(- There might be non-wifi drivers that needed this delay)

All changes to base-files, mac80211 and broadcom-wl packages
have been integrated into a single patch to play nice with
git bisect.

Thanks to Martin Blumenstingl for helping with the implementation
and testing of the patch.

Signed-off-by: Mathias Kresin <dev at kresin.me>
Signed-off-by: Christian Lamparter <chunkeey at gmail.com>
---
We would like to hear, if these changes work with broadcom-wl.
(Felix removed the hostap, so this isn't included anymore).

trap and lock are part of the default busybox setup.
---
 package/base-files/files/etc/init.d/boot                 |  9 ---------
 .../files/etc/hotplug.d/net/00-broadcom-wifi-detect      | 16 ++++++++++++++++
 package/kernel/mac80211/Makefile                         |  2 ++
 package/kernel/mac80211/files/mac80211.hotplug           | 16 ++++++++++++++++
 4 files changed, 34 insertions(+), 9 deletions(-)
 create mode 100644 package/kernel/broadcom-wl/files/etc/hotplug.d/net/00-broadcom-wifi-detect
 create mode 100644 package/kernel/mac80211/files/mac80211.hotplug

diff --git a/package/base-files/files/etc/init.d/boot b/package/base-files/files/etc/init.d/boot
index 904f7db..1d61f2f 100755
--- a/package/base-files/files/etc/init.d/boot
+++ b/package/base-files/files/etc/init.d/boot
@@ -38,15 +38,6 @@ boot() {
 
 	/sbin/kmodloader
 
-	# allow wifi modules time to settle
-	sleep 1
-
-	/sbin/wifi detect > /tmp/wireless.tmp
-	[ -s /tmp/wireless.tmp ] && {
-		cat /tmp/wireless.tmp >> /etc/config/wireless
-	}
-	rm -f /tmp/wireless.tmp
-
 	/bin/config_generate
 	uci_apply_defaults
 	
diff --git a/package/kernel/broadcom-wl/files/etc/hotplug.d/net/00-broadcom-wifi-detect b/package/kernel/broadcom-wl/files/etc/hotplug.d/net/00-broadcom-wifi-detect
new file mode 100644
index 0000000..cd7af8b
--- /dev/null
+++ b/package/kernel/broadcom-wl/files/etc/hotplug.d/net/00-broadcom-wifi-detect
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+unlock() {
+	lock -u /tmp/wireless.lock
+}
+
+[ "${ACTION}" = "add" ] && {
+	trap unlock EXIT
+	lock /tmp/wireless.lock
+
+	/sbin/wifi detect > /tmp/wireless.tmp
+
+	[ -s /tmp/wireless.tmp ] && cat /tmp/wireless.tmp >> /etc/config/wireless
+
+	rm -f /tmp/wireless.tmp
+}
diff --git a/package/kernel/mac80211/Makefile b/package/kernel/mac80211/Makefile
index 91c9362..f320326 100644
--- a/package/kernel/mac80211/Makefile
+++ b/package/kernel/mac80211/Makefile
@@ -1732,6 +1732,8 @@ define KernelPackage/cfg80211/install
 	$(INSTALL_DIR) $(1)/lib/wifi $(1)/lib/netifd/wireless
 	$(INSTALL_DATA) ./files/lib/wifi/mac80211.sh $(1)/lib/wifi
 	$(INSTALL_BIN) ./files/lib/netifd/wireless/mac80211.sh $(1)/lib/netifd/wireless
+	$(INSTALL_DIR) $(1)/etc/hotplug.d/ieee80211
+	$(INSTALL_DATA) ./files/mac80211.hotplug $(1)/etc/hotplug.d/ieee80211/00-wifi-detect
 endef
 
 define KernelPackage/ipw2100/install
diff --git a/package/kernel/mac80211/files/mac80211.hotplug b/package/kernel/mac80211/files/mac80211.hotplug
new file mode 100644
index 0000000..cd7af8b
--- /dev/null
+++ b/package/kernel/mac80211/files/mac80211.hotplug
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+unlock() {
+	lock -u /tmp/wireless.lock
+}
+
+[ "${ACTION}" = "add" ] && {
+	trap unlock EXIT
+	lock /tmp/wireless.lock
+
+	/sbin/wifi detect > /tmp/wireless.tmp
+
+	[ -s /tmp/wireless.tmp ] && cat /tmp/wireless.tmp >> /etc/config/wireless
+
+	rm -f /tmp/wireless.tmp
+}
-- 
2.9.3