wifi: iwlwifi: dbg-tlv: clear FW debug memory on init

When we restart the firmware, we shouldn't keep old debug data
around. Since the "allocate" function might not reallocate the
memory blocks (they're only freed when we unbind from the device),
clear the memory to have a clean slate for debug data.

This is a bit more complex since we normally don't enter into
the allocation function, but duplicating the logic didn't seem
enticing either, so rework the allocation a bit to always go
into the individual block allocation, but there clear if it's
already allocated, rather than allocating again.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230613155501.30b82881cfbf.I39520aff8ac95ee64d39dc5913525a1efd7995fa@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c

@@ -586,8 +586,14 @@ static int iwl_dbg_tlv_alloc_fragments(struct iwl_fw_runtime *fwrt,
 	fw_mon_cfg = &fwrt->trans->dbg.fw_mon_cfg[alloc_id];
 	fw_mon = &fwrt->trans->dbg.fw_mon_ini[alloc_id];
 
-	if (fw_mon->num_frags ||
-	    fw_mon_cfg->buf_location !=
+	if (fw_mon->num_frags) {
+		for (i = 0; i < fw_mon->num_frags; i++)
+			memset(fw_mon->frags[i].block, 0,
+			       fw_mon->frags[i].size);
+		return 0;
+	}
+
+	if (fw_mon_cfg->buf_location !=
 	    cpu_to_le32(IWL_FW_INI_LOCATION_DRAM_PATH))
 		return 0;
 
@@ -1272,18 +1278,23 @@ static void iwl_dbg_tlv_init_cfg(struct iwl_fw_runtime *fwrt)
 	int ret, i;
 	u32 failed_alloc = 0;
 
-	if (*ini_dest != IWL_FW_INI_LOCATION_INVALID)
-		return;
-
-	IWL_DEBUG_FW(fwrt,
-		     "WRT: Generating active triggers list, domain 0x%x\n",
-		     fwrt->trans->dbg.domains_bitmap);
+	if (*ini_dest == IWL_FW_INI_LOCATION_INVALID) {
+		IWL_DEBUG_FW(fwrt,
+			     "WRT: Generating active triggers list, domain 0x%x\n",
+			     fwrt->trans->dbg.domains_bitmap);
 
-	for (i = 0; i < ARRAY_SIZE(fwrt->trans->dbg.time_point); i++) {
-		struct iwl_dbg_tlv_time_point_data *tp =
-			&fwrt->trans->dbg.time_point[i];
+		for (i = 0; i < ARRAY_SIZE(fwrt->trans->dbg.time_point); i++) {
+			struct iwl_dbg_tlv_time_point_data *tp =
+				&fwrt->trans->dbg.time_point[i];
 
-		iwl_dbg_tlv_gen_active_trig_list(fwrt, tp);
+			iwl_dbg_tlv_gen_active_trig_list(fwrt, tp);
+		}
+	} else if (*ini_dest != IWL_FW_INI_LOCATION_DRAM_PATH) {
+		/* For DRAM, go through the loop below to clear all the buffers
+		 * properly on restart, otherwise garbage may be left there and
+		 * leak into new debug dumps.
+		 */
+		return;
 	}
 
 	*ini_dest = IWL_FW_INI_LOCATION_INVALID;