All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ryder Lee <ryder.lee@mediatek.com>
To: Felix Fietkau <nbd@nbd.name>, <linux-wireless@vger.kernel.org>
Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>,
	Shayne Chen <shayne.chen@mediatek.com>,
	Evelyn Tsai <evelyn.tsai@mediatek.com>,
	<linux-mediatek@lists.infradead.org>,
	Bo Jiao <bo.jiao@mediatek.com>,
	Ryder Lee <ryder.lee@mediatek.com>
Subject: [PATCH v2 2/4] wifi: mt76: mt7915: enable full system reset support
Date: Wed, 9 Nov 2022 07:29:42 +0800	[thread overview]
Message-ID: <d43792ee229994c304f7a14271cd871bddec73da.1667949443.git.ryder.lee@mediatek.com> (raw)
In-Reply-To: <26aefa69d1002616412c4b00bf2e779f71ca3289.1667949443.git.ryder.lee@mediatek.com>

From: Bo Jiao <bo.jiao@mediatek.com>

Add mt7915_reset() and refactor mt7915_mac_reset_work() to support
full system recovery.

Co-developed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Bo Jiao <bo.jiao@mediatek.com>
---
change since v2 - change dev_info to make it easier to see that firmware crashed while looking at dmesg.
---
 .../net/wireless/mediatek/mt76/mt7915/init.c  |  11 +-
 .../net/wireless/mediatek/mt76/mt7915/mac.c   | 214 +++++++++++++++++-
 .../net/wireless/mediatek/mt76/mt7915/main.c  |  18 +-
 .../net/wireless/mediatek/mt76/mt7915/mcu.c   |  24 +-
 .../net/wireless/mediatek/mt76/mt7915/mmio.c  |   7 +-
 .../wireless/mediatek/mt76/mt7915/mt7915.h    |  15 +-
 .../net/wireless/mediatek/mt76/mt7915/regs.h  |   4 +
 7 files changed, 267 insertions(+), 26 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index 324db5291c85..1f39aa3e3f3d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -262,9 +262,8 @@ static void mt7915_led_set_brightness(struct led_classdev *led_cdev,
 		mt7915_led_set_config(led_cdev, 0xff, 0);
 }
 
-static void
-mt7915_init_txpower(struct mt7915_dev *dev,
-		    struct ieee80211_supported_band *sband)
+void mt7915_init_txpower(struct mt7915_dev *dev,
+			 struct ieee80211_supported_band *sband)
 {
 	int i, n_chains = hweight8(dev->mphy.antenna_mask);
 	int nss_delta = mt76_tx_power_nss_delta(n_chains);
@@ -446,7 +445,7 @@ mt7915_mac_init_band(struct mt7915_dev *dev, u8 band)
 	mt76_clear(dev, MT_DMA_DCR0(band), MT_DMA_DCR0_RXD_G5_EN);
 }
 
-static void mt7915_mac_init(struct mt7915_dev *dev)
+void mt7915_mac_init(struct mt7915_dev *dev)
 {
 	int i;
 	u32 rx_len = is_mt7915(&dev->mt76) ? 0x400 : 0x680;
@@ -476,7 +475,7 @@ static void mt7915_mac_init(struct mt7915_dev *dev)
 	}
 }
 
-static int mt7915_txbf_init(struct mt7915_dev *dev)
+int mt7915_txbf_init(struct mt7915_dev *dev)
 {
 	int ret;
 
@@ -1117,6 +1116,8 @@ int mt7915_register_device(struct mt7915_dev *dev)
 			goto unreg_thermal;
 	}
 
+	dev->recovery.hw_init_done = true;
+
 	mt7915_init_debugfs(&dev->phy);
 
 	return 0;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index 3b1259f14de6..69ce3b39aa53 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -1265,7 +1265,7 @@ mt7915_wait_reset_state(struct mt7915_dev *dev, u32 state)
 	bool ret;
 
 	ret = wait_event_timeout(dev->reset_wait,
-				 (READ_ONCE(dev->reset_state) & state),
+				 (READ_ONCE(dev->recovery.state) & state),
 				 MT7915_RESET_TIMEOUT);
 
 	WARN(!ret, "Timeout waiting for MCU reset state %x\n", state);
@@ -1320,6 +1320,171 @@ void mt7915_tx_token_put(struct mt7915_dev *dev)
 	idr_destroy(&dev->mt76.token);
 }
 
+static int
+mt7915_mac_restart(struct mt7915_dev *dev)
+{
+	struct mt7915_phy *phy2;
+	struct mt76_phy *ext_phy;
+	struct mt76_dev *mdev = &dev->mt76;
+	int i, ret;
+	u32 irq_mask;
+
+	ext_phy = dev->mt76.phys[MT_BAND1];
+	phy2 = ext_phy ? ext_phy->priv : NULL;
+
+	if (dev->hif2) {
+		mt76_wr(dev, MT_INT1_MASK_CSR, 0x0);
+		mt76_wr(dev, MT_INT1_SOURCE_CSR, ~0);
+	}
+
+	if (dev_is_pci(mdev->dev)) {
+		mt76_wr(dev, MT_PCIE_MAC_INT_ENABLE, 0x0);
+		if (dev->hif2)
+			mt76_wr(dev, MT_PCIE1_MAC_INT_ENABLE, 0x0);
+	}
+
+	set_bit(MT76_RESET, &dev->mphy.state);
+	set_bit(MT76_MCU_RESET, &dev->mphy.state);
+	wake_up(&dev->mt76.mcu.wait);
+	if (ext_phy) {
+		set_bit(MT76_RESET, &ext_phy->state);
+		set_bit(MT76_MCU_RESET, &ext_phy->state);
+	}
+
+	/* lock/unlock all queues to ensure that no tx is pending */
+	mt76_txq_schedule_all(&dev->mphy);
+	if (ext_phy)
+		mt76_txq_schedule_all(ext_phy);
+
+	/* disable all tx/rx napi */
+	mt76_worker_disable(&dev->mt76.tx_worker);
+	mt76_for_each_q_rx(mdev, i) {
+		if (mdev->q_rx[i].ndesc)
+			napi_disable(&dev->mt76.napi[i]);
+	}
+	napi_disable(&dev->mt76.tx_napi);
+
+	/* token reinit */
+	mt7915_tx_token_put(dev);
+	idr_init(&dev->mt76.token);
+
+	mt7915_dma_reset(dev, true);
+
+	local_bh_disable();
+	mt76_for_each_q_rx(mdev, i) {
+		if (mdev->q_rx[i].ndesc) {
+			napi_enable(&dev->mt76.napi[i]);
+			napi_schedule(&dev->mt76.napi[i]);
+		}
+	}
+	local_bh_enable();
+	clear_bit(MT76_MCU_RESET, &dev->mphy.state);
+	clear_bit(MT76_STATE_MCU_RUNNING, &dev->mphy.state);
+
+	mt76_wr(dev, MT_INT_MASK_CSR, dev->mt76.mmio.irqmask);
+	mt76_wr(dev, MT_INT_SOURCE_CSR, ~0);
+
+	if (dev->hif2) {
+		mt76_wr(dev, MT_INT1_MASK_CSR, irq_mask);
+		mt76_wr(dev, MT_INT1_SOURCE_CSR, ~0);
+	}
+	if (dev_is_pci(mdev->dev)) {
+		mt76_wr(dev, MT_PCIE_MAC_INT_ENABLE, 0xff);
+		if (dev->hif2)
+			mt76_wr(dev, MT_PCIE1_MAC_INT_ENABLE, 0xff);
+	}
+
+	/* load firmware */
+	ret = mt7915_mcu_init_firmware(dev);
+	if (ret)
+		goto out;
+
+	/* set the necessary init items */
+	ret = mt7915_mcu_set_eeprom(dev);
+	if (ret)
+		goto out;
+
+	mt7915_mac_init(dev);
+	mt7915_init_txpower(dev, &dev->mphy.sband_2g.sband);
+	mt7915_init_txpower(dev, &dev->mphy.sband_5g.sband);
+	ret = mt7915_txbf_init(dev);
+
+	if (test_bit(MT76_STATE_RUNNING, &dev->mphy.state)) {
+		ret = mt7915_run(dev->mphy.hw);
+		if (ret)
+			goto out;
+	}
+
+	if (ext_phy && test_bit(MT76_STATE_RUNNING, &ext_phy->state)) {
+		ret = mt7915_run(ext_phy->hw);
+		if (ret)
+			goto out;
+	}
+
+out:
+	/* reset done */
+	clear_bit(MT76_RESET, &dev->mphy.state);
+	if (phy2)
+		clear_bit(MT76_RESET, &phy2->mt76->state);
+
+	local_bh_disable();
+	napi_enable(&dev->mt76.tx_napi);
+	napi_schedule(&dev->mt76.tx_napi);
+	local_bh_enable();
+
+	mt76_worker_enable(&dev->mt76.tx_worker);
+
+	return ret;
+}
+
+static void
+mt7915_mac_full_reset(struct mt7915_dev *dev)
+{
+	struct mt7915_phy *phy2;
+	struct mt76_phy *ext_phy;
+	int i;
+
+	ext_phy = dev->mt76.phys[MT_BAND1];
+	phy2 = ext_phy ? ext_phy->priv : NULL;
+
+	dev->recovery.hw_full_reset = true;
+
+	wake_up(&dev->mt76.mcu.wait);
+	ieee80211_stop_queues(mt76_hw(dev));
+	if (ext_phy)
+		ieee80211_stop_queues(ext_phy->hw);
+
+	cancel_delayed_work_sync(&dev->mphy.mac_work);
+	if (ext_phy)
+		cancel_delayed_work_sync(&ext_phy->mac_work);
+
+	mutex_lock(&dev->mt76.mutex);
+	for (i = 0; i < 10; i++) {
+		if (!mt7915_mac_restart(dev))
+			break;
+	}
+	mutex_unlock(&dev->mt76.mutex);
+
+	if (i == 10)
+		dev_err(dev->mt76.dev, "chip full reset failed\n");
+
+	ieee80211_restart_hw(mt76_hw(dev));
+	if (ext_phy)
+		ieee80211_restart_hw(ext_phy->hw);
+
+	ieee80211_wake_queues(mt76_hw(dev));
+	if (ext_phy)
+		ieee80211_wake_queues(ext_phy->hw);
+
+	dev->recovery.hw_full_reset = false;
+	ieee80211_queue_delayed_work(mt76_hw(dev), &dev->mphy.mac_work,
+				     MT7915_WATCHDOG_TIME);
+	if (ext_phy)
+		ieee80211_queue_delayed_work(ext_phy->hw,
+					     &ext_phy->mac_work,
+					     MT7915_WATCHDOG_TIME);
+}
+
 /* system error recovery */
 void mt7915_mac_reset_work(struct work_struct *work)
 {
@@ -1332,7 +1497,28 @@ void mt7915_mac_reset_work(struct work_struct *work)
 	ext_phy = dev->mt76.phys[MT_BAND1];
 	phy2 = ext_phy ? ext_phy->priv : NULL;
 
-	if (!(READ_ONCE(dev->reset_state) & MT_MCU_CMD_STOP_DMA))
+	/* chip full reset */
+	if (dev->recovery.restart) {
+		/* disable WA/WM WDT */
+		mt76_clear(dev, MT_WFDMA0_MCU_HOST_INT_ENA,
+			   MT_MCU_CMD_WDT_MASK);
+
+		mt7915_mac_full_reset(dev);
+
+		/* enable mcu irq */
+		mt7915_irq_enable(dev, MT_INT_MCU_CMD);
+		mt7915_irq_disable(dev, 0);
+
+		/* enable WA/WM WDT */
+		mt76_set(dev, MT_WFDMA0_MCU_HOST_INT_ENA, MT_MCU_CMD_WDT_MASK);
+
+		dev->recovery.state = MT_MCU_CMD_NORMAL_STATE;
+		dev->recovery.restart = false;
+		return;
+	}
+
+	/* chip partial reset */
+	if (!(READ_ONCE(dev->recovery.state) & MT_MCU_CMD_STOP_DMA))
 		return;
 
 	ieee80211_stop_queues(mt76_hw(dev));
@@ -1406,6 +1592,30 @@ void mt7915_mac_reset_work(struct work_struct *work)
 					     MT7915_WATCHDOG_TIME);
 }
 
+void mt7915_reset(struct mt7915_dev *dev)
+{
+	if (!dev->recovery.hw_init_done)
+		return;
+
+	if (dev->recovery.hw_full_reset)
+		return;
+
+	/* wm/wa exception: do full recovery */
+	if (READ_ONCE(dev->recovery.state) & MT_MCU_CMD_WDT_MASK) {
+		dev->recovery.restart = true;
+		dev_info(dev->mt76.dev,
+			 "%s indicated firmware crash, attempting recovery\n",
+			 wiphy_name(dev->mt76.hw->wiphy));
+
+		mt7915_irq_disable(dev, MT_INT_MCU_CMD);
+		queue_work(dev->mt76.wq, &dev->reset_work);
+		return;
+	}
+
+	queue_work(dev->mt76.wq, &dev->reset_work);
+	wake_up(&dev->reset_wait);
+}
+
 void mt7915_mac_update_stats(struct mt7915_phy *phy)
 {
 	struct mt7915_dev *dev = phy->dev;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/main.c b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
index 6de49b93387e..32c362965dc4 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
@@ -20,17 +20,13 @@ static bool mt7915_dev_running(struct mt7915_dev *dev)
 	return phy && test_bit(MT76_STATE_RUNNING, &phy->mt76->state);
 }
 
-static int mt7915_start(struct ieee80211_hw *hw)
+int mt7915_run(struct ieee80211_hw *hw)
 {
 	struct mt7915_dev *dev = mt7915_hw_dev(hw);
 	struct mt7915_phy *phy = mt7915_hw_phy(hw);
 	bool running;
 	int ret;
 
-	flush_work(&dev->init_work);
-
-	mutex_lock(&dev->mt76.mutex);
-
 	running = mt7915_dev_running(dev);
 
 	if (!running) {
@@ -80,6 +76,18 @@ static int mt7915_start(struct ieee80211_hw *hw)
 		mt7915_mac_reset_counters(phy);
 
 out:
+	return ret;
+}
+
+static int mt7915_start(struct ieee80211_hw *hw)
+{
+	struct mt7915_dev *dev = mt7915_hw_dev(hw);
+	int ret;
+
+	flush_work(&dev->init_work);
+
+	mutex_lock(&dev->mt76.mutex);
+	ret = mt7915_run(hw);
 	mutex_unlock(&dev->mt76.mutex);
 
 	return ret;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index 65ae959859e7..17fe29d8fd71 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -2249,18 +2249,10 @@ mt7915_mcu_init_rx_airtime(struct mt7915_dev *dev)
 				 sizeof(req), true);
 }
 
-int mt7915_mcu_init(struct mt7915_dev *dev)
+int mt7915_mcu_init_firmware(struct mt7915_dev *dev)
 {
-	static const struct mt76_mcu_ops mt7915_mcu_ops = {
-		.headroom = sizeof(struct mt76_connac2_mcu_txd),
-		.mcu_skb_send_msg = mt7915_mcu_send_message,
-		.mcu_parse_response = mt7915_mcu_parse_response,
-		.mcu_restart = mt76_connac_mcu_restart,
-	};
 	int ret;
 
-	dev->mt76.mcu_ops = &mt7915_mcu_ops;
-
 	/* force firmware operation mode into normal state,
 	 * which should be set before firmware download stage.
 	 */
@@ -2309,6 +2301,20 @@ int mt7915_mcu_init(struct mt7915_dev *dev)
 				 MCU_WA_PARAM_RED, 0, 0);
 }
 
+int mt7915_mcu_init(struct mt7915_dev *dev)
+{
+	static const struct mt76_mcu_ops mt7915_mcu_ops = {
+		.headroom = sizeof(struct mt76_connac2_mcu_txd),
+		.mcu_skb_send_msg = mt7915_mcu_send_message,
+		.mcu_parse_response = mt7915_mcu_parse_response,
+		.mcu_restart = mt76_connac_mcu_restart,
+	};
+
+	dev->mt76.mcu_ops = &mt7915_mcu_ops;
+
+	return mt7915_mcu_init_firmware(dev);
+}
+
 void mt7915_mcu_exit(struct mt7915_dev *dev)
 {
 	__mt76_mcu_restart(&dev->mt76);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
index be1b8ea711c7..032af46289af 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
@@ -746,10 +746,9 @@ static void mt7915_irq_tasklet(struct tasklet_struct *t)
 		u32 val = mt76_rr(dev, MT_MCU_CMD);
 
 		mt76_wr(dev, MT_MCU_CMD, val);
-		if (val & MT_MCU_CMD_ERROR_MASK) {
-			dev->reset_state = val;
-			queue_work(dev->mt76.wq, &dev->reset_work);
-			wake_up(&dev->reset_wait);
+		if (val & (MT_MCU_CMD_ERROR_MASK | MT_MCU_CMD_WDT_MASK)) {
+			dev->recovery.state = val;
+			mt7915_reset(dev);
 		}
 	}
 }
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h b/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
index 5af26e60e902..49caf7b21a20 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
@@ -303,7 +303,13 @@ struct mt7915_dev {
 	struct work_struct rc_work;
 	struct work_struct reset_work;
 	wait_queue_head_t reset_wait;
-	u32 reset_state;
+
+	struct {
+		u32 state;
+		bool hw_full_reset:1;
+		bool hw_init_done:1;
+		bool restart:1;
+	} recovery;
 
 	struct list_head sta_rc_list;
 	struct list_head sta_poll_list;
@@ -444,7 +450,13 @@ int mt7915_dma_init(struct mt7915_dev *dev, struct mt7915_phy *phy2);
 void mt7915_dma_prefetch(struct mt7915_dev *dev);
 void mt7915_dma_cleanup(struct mt7915_dev *dev);
 int mt7915_dma_reset(struct mt7915_dev *dev, bool force);
+int mt7915_txbf_init(struct mt7915_dev *dev);
+void mt7915_init_txpower(struct mt7915_dev *dev,
+			 struct ieee80211_supported_band *sband);
+void mt7915_reset(struct mt7915_dev *dev);
+int mt7915_run(struct ieee80211_hw *hw);
 int mt7915_mcu_init(struct mt7915_dev *dev);
+int mt7915_mcu_init_firmware(struct mt7915_dev *dev);
 int mt7915_mcu_twt_agrt_update(struct mt7915_dev *dev,
 			       struct mt7915_vif *mvif,
 			       struct mt7915_twt_flow *flow,
@@ -544,6 +556,7 @@ static inline void mt7915_irq_disable(struct mt7915_dev *dev, u32 mask)
 		mt76_set_irq_mask(&dev->mt76, MT_INT_MASK_CSR, mask, 0);
 }
 
+void mt7915_mac_init(struct mt7915_dev *dev);
 u32 mt7915_mac_wtbl_lmac_addr(struct mt7915_dev *dev, u16 wcid, u8 dw);
 bool mt7915_mac_wtbl_update(struct mt7915_dev *dev, int idx, u32 mask);
 void mt7915_mac_reset_counters(struct mt7915_phy *phy);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/regs.h b/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
index 5180dd931835..9120380d74c6 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
@@ -541,6 +541,8 @@ enum offs_rev {
 #define MT_WFDMA0_BUSY_ENA_TX_FIFO1	BIT(1)
 #define MT_WFDMA0_BUSY_ENA_RX_FIFO	BIT(2)
 
+#define MT_WFDMA0_MCU_HOST_INT_ENA	MT_WFDMA0(0x1f4)
+
 #define MT_WFDMA0_GLO_CFG		MT_WFDMA0(0x208)
 #define MT_WFDMA0_GLO_CFG_TX_DMA_EN	BIT(0)
 #define MT_WFDMA0_GLO_CFG_RX_DMA_EN	BIT(2)
@@ -709,6 +711,8 @@ enum offs_rev {
 #define MT_MCU_CMD_NORMAL_STATE		BIT(5)
 #define MT_MCU_CMD_ERROR_MASK		GENMASK(5, 1)
 
+#define MT_MCU_CMD_WDT_MASK		GENMASK(31, 30)
+
 /* TOP RGU */
 #define MT_TOP_RGU_BASE			0x18000000
 #define MT_TOP_PWR_CTRL			(MT_TOP_RGU_BASE + (0x0))
-- 
2.36.1


  reply	other threads:[~2022-11-08 23:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-08 23:29 [PATCH v2 1/4] wifi: mt76: mt7915: rework mt7915_dma_reset() Ryder Lee
2022-11-08 23:29 ` Ryder Lee [this message]
2022-11-08 23:29 ` [PATCH v2 3/4] wifi: mt76: mt7915: add full system reset into debugfs Ryder Lee
2022-11-08 23:29 ` [PATCH v2 4/4] wifi: mt76: mt7915: enable coredump support Ryder Lee
2022-11-09 19:32 ` [PATCH v2 1/4] wifi: mt76: mt7915: rework mt7915_dma_reset() Lorenzo Bianconi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d43792ee229994c304f7a14271cd871bddec73da.1667949443.git.ryder.lee@mediatek.com \
    --to=ryder.lee@mediatek.com \
    --cc=bo.jiao@mediatek.com \
    --cc=evelyn.tsai@mediatek.com \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=lorenzo.bianconi@redhat.com \
    --cc=nbd@nbd.name \
    --cc=shayne.chen@mediatek.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.