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, 45 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/ops.c b/drivers/net/wireless/iwlwifi/mvm/ops.c
index 10846b6..9545d7f 100644
--- a/drivers/net/wireless/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/iwlwifi/mvm/ops.c
@@ -61,6 +61,7 @@
  *
  *****************************************************************************/
 #include <linux/module.h>
+#include <linux/vmalloc.h>
 #include <net/mac80211.h>
 
 #include "iwl-notif-wait.h"
@@ -78,6 +79,7 @@
 #include "iwl-prph.h"
 #include "rs.h"
 #include "fw-api-scan.h"
+#include "fw-error-dump.h"
 #include "time-event.h"
 
 /*
@@ -534,6 +536,8 @@ static void iwl_op_mode_mvm_stop(struct iwl_op_mode *op_mode)
 	ieee80211_unregister_hw(mvm->hw);
 
 	kfree(mvm->scan_cmd);
+	vfree(mvm->fw_error_dump);
+	kfree(mvm->fw_error_sram);
 	kfree(mvm->mcast_filter_cmd);
 	mvm->mcast_filter_cmd = NULL;
 
@@ -804,13 +808,52 @@ static void iwl_mvm_nic_restart(struct iwl_mvm *mvm)
 	}
 }
 
+#ifdef CONFIG_IWLWIFI_DEBUGFS
+void iwl_mvm_fw_error_dump(struct iwl_mvm *mvm)
+{
+	struct iwl_fw_error_dump_file *dump_file;
+	struct iwl_fw_error_dump_data *dump_data;
+	u32 file_len;
+
+	lockdep_assert_held(&mvm->mutex);
+
+	if (mvm->fw_error_dump)
+		return;
+
+	file_len = mvm->fw_error_sram_len +
+		   sizeof(*dump_file) +
+		   sizeof(*dump_data);
+
+	dump_file = vmalloc(file_len);
+	if (!dump_file)
+		return;
+
+	mvm->fw_error_dump = dump_file;
+
+	dump_file->barker = cpu_to_le32(IWL_FW_ERROR_DUMP_BARKER);
+	dump_file->file_len = cpu_to_le32(file_len);
+	dump_data = (void *)dump_file->data;
+	dump_data->type = IWL_FW_ERROR_DUMP_SRAM;
+	dump_data->len = cpu_to_le32(mvm->fw_error_sram_len);
+
+	/*
+	 * No need for lock since at the stage the FW isn't loaded. So it
+	 * can't assert - we are the only one who can possibly be accessing
+	 * mvm->fw_error_sram right now.
+	 */
+	memcpy(dump_data->data, mvm->fw_error_sram, mvm->fw_error_sram_len);
+}
+#endif
+
 static void iwl_mvm_nic_error(struct iwl_op_mode *op_mode)
 {
 	struct iwl_mvm *mvm = IWL_OP_MODE_GET_MVM(op_mode);
 
 	iwl_mvm_dump_nic_error_log(mvm);
-	if (!mvm->restart_fw)
-		iwl_mvm_dump_sram(mvm);
+
+#ifdef CONFIG_IWLWIFI_DEBUGFS
+	iwl_mvm_fw_error_sram_dump(mvm);
+#endif
 
 	iwl_mvm_nic_restart(mvm);
 }