iwlwifi: fix access to prph when transport is stopped

sara-s · lucacoelho · commit 0232d2cd7aa8 · 2017-11-25T17:12:56.000+02:00
When getting HW rfkill we get stop_device being called from two paths. One path is the IRQ calling stop device, and updating op mode and stack. As a result, cfg80211 is running rfkill sync work that shuts down all devices (second path). In the second path, we eventually get to iwl_mvm_stop_device which calls iwl_fw_dump_conf_clear->iwl_fw_dbg_stop_recording, that access periphery registers. The device may be stopped at this point from the first path, which will result with a failure to access those registers. Simply checking for the trans status is insufficient, since the race will still exist, only minimized. Instead, move the stop from iwl_fw_dump_conf_clear (which is getting called only from stop path) to the transport stop device function, where the access is always safe. This has the added value, of actually stopping dbgc before stopping device even when the stop is initiated from the transport. Fixes: 1efc384 ("iwlwifi: stop dbgc recording before stopping DMA") Signed-off-by: Sara Sharon <sara.sharon@intel.com> Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/dbg.h b/drivers/net/wireless/intel/iwlwifi/fw/dbg.h
@@ -209,8 +209,6 @@ static inline void iwl_fw_dbg_stop_recording(struct iwl_fw_runtime *fwrt)
 
 static inline void iwl_fw_dump_conf_clear(struct iwl_fw_runtime *fwrt)
 {
-	iwl_fw_dbg_stop_recording(fwrt);
-
 	fwrt->dump.conf = FW_DBG_INVALID;
 }
 
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
@@ -49,6 +49,7 @@
  *
  *****************************************************************************/
 #include "iwl-trans.h"
+#include "iwl-prph.h"
 #include "iwl-context-info.h"
 #include "internal.h"
 
@@ -156,6 +157,11 @@ void _iwl_trans_pcie_gen2_stop_device(struct iwl_trans *trans, bool low_power)
 
 	trans_pcie->is_down = true;
 
+	/* Stop dbgc before stopping device */
+	iwl_write_prph(trans, DBGC_IN_SAMPLE, 0);
+	udelay(100);
+	iwl_write_prph(trans, DBGC_OUT_CTRL, 0);
+
 	/* tell the device to stop sending interrupts */
 	iwl_disable_interrupts(trans);
 
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1227,6 +1227,15 @@ static void _iwl_trans_pcie_stop_device(struct iwl_trans *trans, bool low_power)
 
 	trans_pcie->is_down = true;
 
+	/* Stop dbgc before stopping device */
+	if (trans->cfg->device_family == IWL_DEVICE_FAMILY_7000) {
+		iwl_set_bits_prph(trans, MON_BUFF_SAMPLE_CTL, 0x100);
+	} else {
+		iwl_write_prph(trans, DBGC_IN_SAMPLE, 0);
+		udelay(100);
+		iwl_write_prph(trans, DBGC_OUT_CTRL, 0);
+	}
+
 	/* tell the device to stop sending interrupts */
 	iwl_disable_interrupts(trans);
 

Original file line number	Diff line number	Diff line change
`@@ -209,8 +209,6 @@ static inline void iwl_fw_dbg_stop_recording(struct iwl_fw_runtime *fwrt)`
`209`	`209`
`210`	`210`	`static inline void iwl_fw_dump_conf_clear(struct iwl_fw_runtime *fwrt)`
`211`	`211`	`{`
`212`		`- iwl_fw_dbg_stop_recording(fwrt);`
`213`		`-`
`214`	`212`	`fwrt->dump.conf = FW_DBG_INVALID;`
`215`	`213`	`}`
`216`	`214`