iwlwifi: mvm: send udev event upon firmware error to dump logs

When the firmware asserts, the driver will dump the firmware
state to an internal buffer. This buffer is kept aside until
it is dumped through debugfs. Once an external application
fetched the data, the buffer is freed and a new buffer can
be allocated in case another assert occurs.

A udev event is sent to trigger an external application.

A simple rule like:
DRIVER=="iwlwifi", ACTION=="change", RUN+="/sbin/dump_sram.sh"

can fetch the data from debugfs.

Here is my dump_sram.sh:

phyname=$(basename ${DEVPATH})
date=$(date +%F_%H_%M)
filename=/var/log/iwl-sram-${phyname}-${date}.bin
cat /sys/kernel/debug/ieee80211/${phyname}/iwlwifi/iwlmvm/fw_error_dump > ${filename}

The current SRAM size is 80KB so, currently:
$ ls -lh iwl-sram-phy0-2014-03-16_13_14.bin
-rw-r--r-- 1 emmanuel emmanuel 81K Mar 16 13:15 iwl-sram-phy0-2014-03-16_13_14.bin

and after compression:
$ ls -lh iwl-sram-phy0-2014-03-16_13_14.bin.xz
-rw-r--r-- 1 emmanuel emmanuel 13K Mar 16 13:15 iwl-sram-phy0-2014-03-16_13_14.bin.xz

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index 48a8e67..8414c03 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -607,6 +607,15 @@ static void iwl_mvm_cleanup_iterator(void *data, u8 *mac,
 
 static void iwl_mvm_restart_cleanup(struct iwl_mvm *mvm)
 {
+#ifdef CONFIG_IWLWIFI_DEBUGFS
+	static char *env[] = { "DRIVER=iwlwifi", "EVENT=error_dump", NULL };
+
+	iwl_mvm_fw_error_dump(mvm);
+
+	/* notify the userspace about the error we had */
+	kobject_uevent_env(&mvm->hw->wiphy->dev.kobj, KOBJ_CHANGE, env);
+#endif
+
 	iwl_trans_stop_device(mvm->trans);
 
 	mvm->scan_status = IWL_MVM_SCAN_NONE;