5 files changed, 110 insertions, 23 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
index f131ef0ec5b3..ac9787c09248 100644
--- a/drivers/net/wireless/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
@@ -830,8 +830,14 @@ static ssize_t iwl_dbgfs_fw_restart_write(struct iwl_mvm *mvm, char *buf,
 static ssize_t iwl_dbgfs_fw_nmi_write(struct iwl_mvm *mvm, char *buf,
 				      size_t count, loff_t *ppos)
 {
+	int ret = iwl_mvm_ref_sync(mvm, IWL_MVM_REF_NMI);
+	if (ret)
+		return ret;
+
 	iwl_force_nmi(mvm->trans);
 
+	iwl_mvm_unref(mvm, IWL_MVM_REF_NMI);
+
 	return count;
 }
 
@@ -1115,11 +1121,11 @@ static ssize_t iwl_dbgfs_d3_sram_read(struct file *file, char __user *user_buf,
 }
 #endif
 
-#define PRINT_MVM_REF(ref) do {					\
-	if (test_bit(ref, mvm->ref_bitmap))			\
-		pos += scnprintf(buf + pos, bufsz - pos,	\
-				 "\t(0x%lx) %s\n",		\
-				 BIT(ref), #ref);		\
+#define PRINT_MVM_REF(ref) do {						\
+	if (mvm->refs[ref])						\
+		pos += scnprintf(buf + pos, bufsz - pos,		\
+				 "\t(0x%lx): %d %s\n",			\
+				 BIT(ref), mvm->refs[ref], #ref);	\
 } while (0)
 
 static ssize_t iwl_dbgfs_d0i3_refs_read(struct file *file,
@@ -1127,12 +1133,17 @@ static ssize_t iwl_dbgfs_d0i3_refs_read(struct file *file,
 					size_t count, loff_t *ppos)
 {
 	struct iwl_mvm *mvm = file->private_data;
-	int pos = 0;
+	int i, pos = 0;
 	char buf[256];
 	const size_t bufsz = sizeof(buf);
+	u32 refs = 0;
+
+	for (i = 0; i < IWL_MVM_REF_COUNT; i++)
+		if (mvm->refs[i])
+			refs |= BIT(i);
 
-	pos += scnprintf(buf + pos, bufsz - pos, "taken mvm refs: 0x%lx\n",
-			 mvm->ref_bitmap[0]);
+	pos += scnprintf(buf + pos, bufsz - pos, "taken mvm refs: 0x%x\n",
+			 refs);
 
 	PRINT_MVM_REF(IWL_MVM_REF_UCODE_DOWN);
 	PRINT_MVM_REF(IWL_MVM_REF_SCAN);
@@ -1158,7 +1169,7 @@ static ssize_t iwl_dbgfs_d0i3_refs_write(struct iwl_mvm *mvm, char *buf,
 
 	mutex_lock(&mvm->mutex);
 
-	taken = test_bit(IWL_MVM_REF_USER, mvm->ref_bitmap);
+	taken = mvm->refs[IWL_MVM_REF_USER];
 	if (value == 1 && !taken)
 		iwl_mvm_ref(mvm, IWL_MVM_REF_USER);
 	else if (value == 0 && taken)
@@ -1194,14 +1205,21 @@ iwl_dbgfs_prph_reg_read(struct file *file,
 	int pos = 0;
 	char buf[32];
 	const size_t bufsz = sizeof(buf);
+	int ret;
 
 	if (!mvm->dbgfs_prph_reg_addr)
 		return -EINVAL;
 
+	ret = iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PRPH_READ);
+	if (ret)
+		return ret;
+
 	pos += scnprintf(buf + pos, bufsz - pos, "Reg 0x%x: (0x%x)\n",
 		mvm->dbgfs_prph_reg_addr,
 		iwl_read_prph(mvm->trans, mvm->dbgfs_prph_reg_addr));
 
+	iwl_mvm_unref(mvm, IWL_MVM_REF_PRPH_READ);
+
 	return simple_read_from_buffer(user_buf, count, ppos, buf, pos);
 }
 
@@ -1211,6 +1229,7 @@ iwl_dbgfs_prph_reg_write(struct iwl_mvm *mvm, char *buf,
 {
 	u8 args;
 	u32 value;
+	int ret;
 
 	args = sscanf(buf, "%i %i", &mvm->dbgfs_prph_reg_addr, &value);
 	/* if we only want to set the reg address - nothing more to do */
@@ -1221,7 +1240,13 @@ iwl_dbgfs_prph_reg_write(struct iwl_mvm *mvm, char *buf,
 	if (args != 2)
 		return -EINVAL;
 
+	ret = iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PRPH_WRITE);
+	if (ret)
+		return ret;
+
 	iwl_write_prph(mvm->trans, mvm->dbgfs_prph_reg_addr, value);
+
+	iwl_mvm_unref(mvm, IWL_MVM_REF_PRPH_WRITE);
 out:
 	return count;
 }
diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index 2eb6ebee4467..12a9aed7a5d3 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -211,7 +211,9 @@ void iwl_mvm_ref(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type)
 		return;
 
 	IWL_DEBUG_RPM(mvm, "Take mvm reference - type %d\n", ref_type);
-	WARN_ON(test_and_set_bit(ref_type, mvm->ref_bitmap));
+	spin_lock_bh(&mvm->refs_lock);
+	mvm->refs[ref_type]++;
+	spin_unlock_bh(&mvm->refs_lock);
 	iwl_trans_ref(mvm->trans);
 }
 
@@ -221,29 +223,35 @@ void iwl_mvm_unref(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type)
 		return;
 
 	IWL_DEBUG_RPM(mvm, "Leave mvm reference - type %d\n", ref_type);
-	WARN_ON(!test_and_clear_bit(ref_type, mvm->ref_bitmap));
+	spin_lock_bh(&mvm->refs_lock);
+	WARN_ON(!mvm->refs[ref_type]--);
+	spin_unlock_bh(&mvm->refs_lock);
 	iwl_trans_unref(mvm->trans);
 }
 
-static void
-iwl_mvm_unref_all_except(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref)
+static void iwl_mvm_unref_all_except(struct iwl_mvm *mvm,
+				     enum iwl_mvm_ref_type except_ref)
 {
-	int i;
+	int i, j;
 
 	if (!iwl_mvm_is_d0i3_supported(mvm))
 		return;
 
-	for_each_set_bit(i, mvm->ref_bitmap, IWL_MVM_REF_COUNT) {
-		if (ref == i)
+	spin_lock_bh(&mvm->refs_lock);
+	for (i = 0; i < IWL_MVM_REF_COUNT; i++) {
+		if (except_ref == i || !mvm->refs[i])
 			continue;
 
-		IWL_DEBUG_RPM(mvm, "Cleanup: remove mvm ref type %d\n", i);
-		clear_bit(i, mvm->ref_bitmap);
-		iwl_trans_unref(mvm->trans);
+		IWL_DEBUG_RPM(mvm, "Cleanup: remove mvm ref type %d (%d)\n",
+			      i, mvm->refs[i]);
+		for (j = 0; j < mvm->refs[i]; j++)
+			iwl_trans_unref(mvm->trans);
+		mvm->refs[i] = 0;
 	}
+	spin_unlock_bh(&mvm->refs_lock);
 }
 
-static int iwl_mvm_ref_sync(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type)
+int iwl_mvm_ref_sync(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type)
 {
 	iwl_mvm_ref(mvm, ref_type);
 
@@ -1533,6 +1541,14 @@ static int iwl_mvm_start_ap_ibss(struct ieee80211_hw *hw,
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
 	int ret;
 
+	/*
+	 * iwl_mvm_mac_ctxt_add() might read directly from the device
+	 * (the system time), so make sure it is available.
+	 */
+	ret = iwl_mvm_ref_sync(mvm, IWL_MVM_REF_START_AP);
+	if (ret)
+		return ret;
+
 	mutex_lock(&mvm->mutex);
 
 	/* Send the beacon template */
@@ -1594,6 +1610,7 @@ out_remove:
 	iwl_mvm_mac_ctxt_remove(mvm, vif);
 out_unlock:
 	mutex_unlock(&mvm->mutex);
+	iwl_mvm_unref(mvm, IWL_MVM_REF_START_AP);
 	return ret;
 }
 
@@ -1671,6 +1688,14 @@ static void iwl_mvm_bss_info_changed(struct ieee80211_hw *hw,
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 
+	/*
+	 * iwl_mvm_bss_info_changed_station() might call
+	 * iwl_mvm_protect_session(), which reads directly from
+	 * the device (the system time), so make sure it is available.
+	 */
+	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_BSS_CHANGED))
+		return;
+
 	mutex_lock(&mvm->mutex);
 
 	if (changes & BSS_CHANGED_IDLE && !bss_conf->idle)
@@ -1690,6 +1715,7 @@ static void iwl_mvm_bss_info_changed(struct ieee80211_hw *hw,
 	}
 
 	mutex_unlock(&mvm->mutex);
+	iwl_mvm_unref(mvm, IWL_MVM_REF_BSS_CHANGED);
 }
 
 static int iwl_mvm_mac_hw_scan(struct ieee80211_hw *hw,
@@ -2065,10 +2091,19 @@ static void iwl_mvm_mac_mgd_prepare_tx(struct ieee80211_hw *hw,
 	if (WARN_ON_ONCE(vif->bss_conf.assoc))
 		return;
 
+	/*
+	 * iwl_mvm_protect_session() reads directly from the device
+	 * (the system time), so make sure it is available.
+	 */
+	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PREPARE_TX))
+		return;
+
 	mutex_lock(&mvm->mutex);
 	/* Try really hard to protect the session and hear a beacon */
 	iwl_mvm_protect_session(mvm, vif, duration, min_duration, 500);
 	mutex_unlock(&mvm->mutex);
+
+	iwl_mvm_unref(mvm, IWL_MVM_REF_PREPARE_TX);
 }
 
 static void iwl_mvm_mac_mgd_protect_tdls_discover(struct ieee80211_hw *hw,
@@ -2077,10 +2112,19 @@ static void iwl_mvm_mac_mgd_protect_tdls_discover(struct ieee80211_hw *hw,
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 	u32 duration = 2 * vif->bss_conf.dtim_period * vif->bss_conf.beacon_int;
 
+	/*
+	 * iwl_mvm_protect_session() reads directly from the device
+	 * (the system time), so make sure it is available.
+	 */
+	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PROTECT_TDLS))
+		return;
+
 	mutex_lock(&mvm->mutex);
 	/* Protect the session to hear the TDLS setup response on the channel */
 	iwl_mvm_protect_session(mvm, vif, duration, duration, 100);
 	mutex_unlock(&mvm->mutex);
+
+	iwl_mvm_unref(mvm, IWL_MVM_REF_PROTECT_TDLS);
 }
 
 static int iwl_mvm_mac_sched_scan_start(struct ieee80211_hw *hw,
diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index 785e5232c757..24c12c77d93a 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -249,6 +249,15 @@ enum iwl_mvm_ref_type {
 	IWL_MVM_REF_TX,
 	IWL_MVM_REF_TX_AGG,
 	IWL_MVM_REF_ADD_IF,
+	IWL_MVM_REF_START_AP,
+	IWL_MVM_REF_BSS_CHANGED,
+	IWL_MVM_REF_PREPARE_TX,
+	IWL_MVM_REF_PROTECT_TDLS,
+	IWL_MVM_REF_CHECK_CTKILL,
+	IWL_MVM_REF_PRPH_READ,
+	IWL_MVM_REF_PRPH_WRITE,
+	IWL_MVM_REF_NMI,
+	IWL_MVM_REF_TM_CMD,
 	IWL_MVM_REF_EXIT_WORK,
 
 	IWL_MVM_REF_COUNT,
@@ -606,8 +615,9 @@ struct iwl_mvm {
 	 */
 	unsigned long fw_key_table[BITS_TO_LONGS(STA_KEY_MAX_NUM)];
 
-	/* A bitmap of reference types taken by the driver. */
-	unsigned long ref_bitmap[BITS_TO_LONGS(IWL_MVM_REF_COUNT)];
+	/* references taken by the driver and spinlock protecting them */
+	spinlock_t refs_lock;
+	u8 refs[IWL_MVM_REF_COUNT];
 
 	u8 vif_count;
 
@@ -988,6 +998,7 @@ int iwl_mvm_send_proto_offload(struct iwl_mvm *mvm,
 /* D0i3 */
 void iwl_mvm_ref(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type);
 void iwl_mvm_unref(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type);
+int iwl_mvm_ref_sync(struct iwl_mvm *mvm, enum iwl_mvm_ref_type ref_type);
 void iwl_mvm_d0i3_enable_tx(struct iwl_mvm *mvm, __le16 *qos_seq);
 int _iwl_mvm_exit_d0i3(struct iwl_mvm *mvm);
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/ops.c b/drivers/net/wireless/iwlwifi/mvm/ops.c
index 7f0e9afe8f25..19a66b590277 100644
--- a/drivers/net/wireless/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/iwlwifi/mvm/ops.c
@@ -428,6 +428,7 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	INIT_WORK(&mvm->d0i3_exit_work, iwl_mvm_d0i3_exit_work);
 
 	spin_lock_init(&mvm->d0i3_tx_lock);
+	spin_lock_init(&mvm->refs_lock);
 	skb_queue_head_init(&mvm->d0i3_tx);
 	init_waitqueue_head(&mvm->d0i3_exit_waitq);
 
@@ -542,7 +543,7 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	memset(&mvm->rx_stats, 0, sizeof(struct mvm_statistics_rx));
 
 	/* rpm starts with a taken ref. only set the appropriate bit here. */
-	set_bit(IWL_MVM_REF_UCODE_DOWN, mvm->ref_bitmap);
+	mvm->refs[IWL_MVM_REF_UCODE_DOWN] = 1;
 
 	return op_mode;
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/tt.c b/drivers/net/wireless/iwlwifi/mvm/tt.c
index 0c4ff3a57ade..0464599c111e 100644
--- a/drivers/net/wireless/iwlwifi/mvm/tt.c
+++ b/drivers/net/wireless/iwlwifi/mvm/tt.c
@@ -338,10 +338,16 @@ static void check_exit_ctkill(struct work_struct *work)
 
 	duration = tt->params->ct_kill_duration;
 
+	/* make sure the device is available for direct read/writes */
+	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_CHECK_CTKILL))
+		goto reschedule;
+
 	iwl_trans_start_hw(mvm->trans);
 	temp = check_nic_temperature(mvm);
 	iwl_trans_stop_device(mvm->trans);
 
+	iwl_mvm_unref(mvm, IWL_MVM_REF_CHECK_CTKILL);
+
 	if (temp < MIN_TEMPERATURE || temp > MAX_TEMPERATURE) {
 		IWL_DEBUG_TEMP(mvm, "Failed to measure NIC temperature\n");
 		goto reschedule;