Re: [PATCH V2 net 08/20] net/ena: add hardware hints capability to the driver

In case the device does not support this capability, the driver
will use its own defines.

Signed-off-by: Netanel Belgazal <redacted>
---
 drivers/net/ethernet/amazon/ena/ena_admin_defs.h | 31 +++++++++
 drivers/net/ethernet/amazon/ena/ena_com.c        | 41 ++++++++---
 drivers/net/ethernet/amazon/ena/ena_com.h        |  5 ++
 drivers/net/ethernet/amazon/ena/ena_ethtool.c    |  1 -
 drivers/net/ethernet/amazon/ena/ena_netdev.c     | 86 +++++++++++++++++++-----
 drivers/net/ethernet/amazon/ena/ena_netdev.h     | 19 +++++-
 drivers/net/ethernet/amazon/ena/ena_regs_defs.h  |  2 +
 7 files changed, 157 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
index 6d70bf5..35ae511 100644
--- a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
+++ b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h

@@ -70,6 +70,8 @@ enum ena_admin_aq_feature_id {
 
 	ENA_ADMIN_MAX_QUEUES_NUM		= 2,
 
+	ENA_ADMIN_HW_HINTS			= 3,
+
 	ENA_ADMIN_RSS_HASH_FUNCTION		= 10,
 
 	ENA_ADMIN_STATELESS_OFFLOAD_CONFIG	= 11,

@@ -749,6 +751,31 @@ struct ena_admin_feature_rss_ind_table {
 	struct ena_admin_rss_ind_table_entry inline_entry;
 };
 
+/* When hint value is 0, driver should use it's own predefined value */
+struct ena_admin_ena_hw_hints {
+	/* value in ms */
+	u16 mmio_read_timeout;
+
+	/* value in ms */
+	u16 driver_watchdog_timeout;
+
+	/* Per packet tx completion timeout. value in ms */
+	u16 missing_tx_completion_timeout;
+
+	u16 missed_tx_completion_count_threshold_to_reset;
+
+	/* value in ms */
+	u16 admin_completion_tx_timeout;
+
+	u16 netdev_wd_timeout;
+
+	u16 max_tx_sgl_size;
+
+	u16 max_rx_sgl_size;
+
+	u16 reserved[8];
+};
+
 struct ena_admin_get_feat_cmd {
 	struct ena_admin_aq_common_desc aq_common_descriptor;
 

@@ -782,6 +809,8 @@ struct ena_admin_get_feat_resp {
 		struct ena_admin_feature_rss_ind_table ind_table;
 
 		struct ena_admin_feature_intr_moder_desc intr_moderation;
+
+		struct ena_admin_ena_hw_hints hw_hints;
 	} u;
 };
 

@@ -857,6 +886,8 @@ enum ena_admin_aenq_notification_syndrom {
 	ENA_ADMIN_SUSPEND	= 0,
 
 	ENA_ADMIN_RESUME	= 1,
+
+	ENA_ADMIN_UPDATE_HINTS	= 2,
 };
 
 struct ena_admin_aenq_entry {

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c
index 46aad3a..f1e4f04 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c

@@ -508,15 +508,13 @@ static int ena_com_comp_status_to_errno(u8 comp_status)
 static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_ctx,
 						     struct ena_com_admin_queue *admin_queue)
 {
-	unsigned long flags;
-	u32 start_time;
+	unsigned long flags, timeout;
 	int ret;
 
-	start_time = ((u32)jiffies_to_usecs(jiffies));
+	timeout = jiffies + usecs_to_jiffies(admin_queue->completion_timeout);
 
 	while (comp_ctx->status == ENA_CMD_SUBMITTED) {
-		if ((((u32)jiffies_to_usecs(jiffies)) - start_time) >
-		    ADMIN_CMD_TIMEOUT_US) {
+		if (time_is_before_jiffies(timeout)) {
 			pr_err("Wait for completion (polling) timeout\n");
 			/* ENA didn't have any completion */
 			spin_lock_irqsave(&admin_queue->q_lock, flags);

@@ -560,7 +558,8 @@ static int ena_com_wait_and_process_admin_cq_interrupts(struct ena_comp_ctx *com
 	int ret;
 
 	wait_for_completion_timeout(&comp_ctx->wait_event,
-				    usecs_to_jiffies(ADMIN_CMD_TIMEOUT_US));
+				    usecs_to_jiffies(
+					    admin_queue->completion_timeout));
 
 	/* In case the command wasn't completed find out the root cause.
 	 * There might be 2 kinds of errors

@@ -600,12 +599,14 @@ static u32 ena_com_reg_bar_read32(struct ena_com_dev *ena_dev, u16 offset)
 	struct ena_com_mmio_read *mmio_read = &ena_dev->mmio_read;
 	volatile struct ena_admin_ena_mmio_req_read_less_resp *read_resp =
 		mmio_read->read_resp;
-	u32 mmio_read_reg, ret;
+	u32 mmio_read_reg, timeout, ret;
 	unsigned long flags;
 	int i;
 
 	might_sleep();
 
+	timeout = mmio_read->reg_read_to ? : ENA_REG_READ_TIMEOUT;
+
 	/* If readless is disabled, perform regular read */
 	if (!mmio_read->readless_supported)
 		return readl(ena_dev->reg_bar + offset);

@@ -626,14 +627,14 @@ static u32 ena_com_reg_bar_read32(struct ena_com_dev *ena_dev, u16 offset)
 
 	writel(mmio_read_reg, ena_dev->reg_bar + ENA_REGS_MMIO_REG_READ_OFF);
 
-	for (i = 0; i < ENA_REG_READ_TIMEOUT; i++) {
+	for (i = 0; i < timeout; i++) {
 		if (read_resp->req_id == mmio_read->seq_num)
 			break;
 
 		udelay(1);
 	}
 
-	if (unlikely(i == ENA_REG_READ_TIMEOUT)) {
+	if (unlikely(i == timeout)) {
 		pr_err("reading reg failed for timeout. expected: req id[%hu] offset[%hu] actual: req id[%hu] offset[%hu]\n",
 		       mmio_read->seq_num, offset, read_resp->req_id,
 		       read_resp->reg_off);

@@ -1717,6 +1718,20 @@ int ena_com_get_dev_attr_feat(struct ena_com_dev *ena_dev,
 	memcpy(&get_feat_ctx->offload, &get_resp.u.offload,
 	       sizeof(get_resp.u.offload));
 
+	/* Driver hints isn't mandatory admin command. So in case the
+	 * command isn't supported set driver hints to 0
+	 */
+	rc = ena_com_get_feature(ena_dev, &get_resp, ENA_ADMIN_HW_HINTS);
+
+	if (!rc)
+		memcpy(&get_feat_ctx->hw_hints, &get_resp.u.hw_hints,
+		       sizeof(get_resp.u.hw_hints));
+	else if (rc == -EPERM)
+		memset(&get_feat_ctx->hw_hints, 0x0,
+		       sizeof(get_feat_ctx->hw_hints));
+	else
+		return rc;
+
 	return 0;
 }
 

@@ -1842,6 +1857,14 @@ int ena_com_dev_reset(struct ena_com_dev *ena_dev)
 		return rc;
 	}
 
+	timeout = (cap & ENA_REGS_CAPS_ADMIN_CMD_TO_MASK) >>
+		ENA_REGS_CAPS_ADMIN_CMD_TO_SHIFT;
+	if (timeout)
+		/* the resolution of timeout reg is 100ms */
+		ena_dev->admin_queue.completion_timeout = timeout * 100000;
+	else
+		ena_dev->admin_queue.completion_timeout = ADMIN_CMD_TIMEOUT_US;
+
 	return 0;
 }
 

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.h b/drivers/net/ethernet/amazon/ena/ena_com.h
index 509d7b8..6883ee5 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h

@@ -96,6 +96,8 @@
 #define ENA_INTR_MODER_LEVEL_STRIDE			2
 #define ENA_INTR_BYTE_COUNT_NOT_SUPPORTED		0xFFFFFF
 
+#define ENA_HW_HINTS_NO_TIMEOUT				0xFFFF
+
 enum ena_intr_moder_level {
 	ENA_INTR_MODER_LOWEST = 0,
 	ENA_INTR_MODER_LOW,

@@ -232,6 +234,7 @@ struct ena_com_admin_queue {
 	void *q_dmadev;
 	spinlock_t q_lock; /* spinlock for the admin queue */
 	struct ena_comp_ctx *comp_ctx;
+	u32 completion_timeout;
 	u16 q_depth;
 	struct ena_com_admin_cq cq;
 	struct ena_com_admin_sq sq;

@@ -266,6 +269,7 @@ struct ena_com_aenq {
 struct ena_com_mmio_read {
 	struct ena_admin_ena_mmio_req_read_less_resp *read_resp;
 	dma_addr_t read_resp_dma_addr;
+	u32 reg_read_to; /* in us */
 	u16 seq_num;
 	bool readless_supported;
 	/* spin lock to ensure a single outstanding read */

@@ -335,6 +339,7 @@ struct ena_com_dev_get_features_ctx {
 	struct ena_admin_device_attr_feature_desc dev_attr;
 	struct ena_admin_feature_aenq_desc aenq;
 	struct ena_admin_feature_offload_desc offload;
+	struct ena_admin_ena_hw_hints hw_hints;
 };
 
 struct ena_com_create_io_ctx {

diff --git a/drivers/net/ethernet/amazon/ena/ena_ethtool.c b/drivers/net/ethernet/amazon/ena/ena_ethtool.c
index 67b2338f..a1fbfc2 100644
--- a/drivers/net/ethernet/amazon/ena/ena_ethtool.c
+++ b/drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -80,7 +80,6 @@ static const struct ena_stats ena_stats_tx_strings[] = {
 	ENA_STAT_TX_ENTRY(tx_poll),
 	ENA_STAT_TX_ENTRY(doorbells),
 	ENA_STAT_TX_ENTRY(prepare_ctx_err),
-	ENA_STAT_TX_ENTRY(missing_tx_comp),
 	ENA_STAT_TX_ENTRY(bad_req_id),
 };
 

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 962ffb5..0b718ee 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -1981,6 +1981,7 @@ static netdev_tx_t ena_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	tx_info->tx_descs = nb_hw_desc;
 	tx_info->last_jiffies = jiffies;
+	tx_info->print_once = 0;
 
 	tx_ring->next_to_use = ENA_TX_RING_IDX_NEXT(next_to_use,
 		tx_ring->ring_size);

@@ -2554,33 +2555,34 @@ static void check_for_missing_tx_completions(struct ena_adapter *adapter)
 	if (!test_bit(ENA_FLAG_DEV_UP, &adapter->flags))
 		return;
 
+	if (adapter->missing_tx_completion_to == ENA_HW_HINTS_NO_TIMEOUT)
+		return;
+
 	budget = ENA_MONITORED_TX_QUEUES;
 
 	for (i = adapter->last_monitored_tx_qid; i < adapter->num_queues; i++) {
 		tx_ring = &adapter->tx_ring[i];
 
+		missed_tx = 0;
+
 		for (j = 0; j < tx_ring->ring_size; j++) {
 			tx_buf = &tx_ring->tx_buffer_info[j];
 			last_jiffies = tx_buf->last_jiffies;
-			if (unlikely(last_jiffies && time_is_before_jiffies(last_jiffies + TX_TIMEOUT))) {
-				netif_notice(adapter, tx_err, adapter->netdev,
-					     "Found a Tx that wasn't completed on time, qid %d, index %d.\n",
-					     tx_ring->qid, j);
+			if (unlikely(last_jiffies && time_is_before_jiffies(last_jiffies + adapter->missing_tx_completion_to))) {
+				if (!tx_buf->print_once)
+					netif_notice(adapter, tx_err, adapter->netdev,
+						     "Found a Tx that wasn't completed on time, qid %d, index %d.\n",
+						     tx_ring->qid, j);
 
-				u64_stats_update_begin(&tx_ring->syncp);
-				missed_tx = tx_ring->tx_stats.missing_tx_comp++;
-				u64_stats_update_end(&tx_ring->syncp);
+				tx_buf->print_once = 1;
+				missed_tx++;
 
-				/* Clear last jiffies so the lost buffer won't
-				 * be counted twice.
-				 */
-				tx_buf->last_jiffies = 0;
-
-				if (unlikely(missed_tx > MAX_NUM_OF_TIMEOUTED_PACKETS)) {
+				if (unlikely(missed_tx > adapter->missing_tx_completion_threshold)) {
 					netif_err(adapter, tx_err, adapter->netdev,
 						  "The number of lost tx completion is above the threshold (%d > %d). Reset the device\n",
-						  missed_tx, MAX_NUM_OF_TIMEOUTED_PACKETS);
+						  missed_tx, adapter->missing_tx_completion_threshold);
 					set_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags);
+					return;
 				}
 			}
 		}

@@ -2601,8 +2603,11 @@ static void check_for_missing_keep_alive(struct ena_adapter *adapter)
 	if (!adapter->wd_state)
 		return;
 
-	keep_alive_expired = round_jiffies(adapter->last_keep_alive_jiffies
-					   + ENA_DEVICE_KALIVE_TIMEOUT);
+	if (adapter->keep_alive_timeout == ENA_HW_HINTS_NO_TIMEOUT)
+		return;
+
+	keep_alive_expired = round_jiffies(adapter->last_keep_alive_jiffies +
+					   adapter->keep_alive_timeout);
 	if (unlikely(time_is_before_jiffies(keep_alive_expired))) {
 		netif_err(adapter, drv, adapter->netdev,
 			  "Keep alive watchdog timeout.\n");

@@ -2625,6 +2630,44 @@ static void check_for_admin_com_state(struct ena_adapter *adapter)
 	}
 }
 
+static void ena_update_hints(struct ena_adapter *adapter,
+			     struct ena_admin_ena_hw_hints *hints)
+{
+	struct net_device *netdev = adapter->netdev;
+
+	if (hints->admin_completion_tx_timeout)
+		adapter->ena_dev->admin_queue.completion_timeout =
+			hints->admin_completion_tx_timeout * 1000;
+
+	if (hints->mmio_read_timeout)
+		/* convert to usec */
+		adapter->ena_dev->mmio_read.reg_read_to =
+			hints->mmio_read_timeout * 1000;
+
+	if (hints->missed_tx_completion_count_threshold_to_reset)
+		adapter->missing_tx_completion_threshold =
+			hints->missed_tx_completion_count_threshold_to_reset;
+
+	if (hints->missing_tx_completion_timeout) {
+		if (hints->missing_tx_completion_timeout == ENA_HW_HINTS_NO_TIMEOUT)
+			adapter->missing_tx_completion_to = ENA_HW_HINTS_NO_TIMEOUT;
+		else
+			adapter->missing_tx_completion_to =
+				msecs_to_jiffies(hints->missing_tx_completion_timeout);
+	}
+
+	if (hints->netdev_wd_timeout)
+		netdev->watchdog_timeo = msecs_to_jiffies(hints->netdev_wd_timeout);
+
+	if (hints->driver_watchdog_timeout) {
+		if (hints->driver_watchdog_timeout == ENA_HW_HINTS_NO_TIMEOUT)
+			adapter->keep_alive_timeout = ENA_HW_HINTS_NO_TIMEOUT;
+		else
+			adapter->keep_alive_timeout =
+				msecs_to_jiffies(hints->driver_watchdog_timeout);
+	}
+}
+
 static void ena_update_host_info(struct ena_admin_host_info *host_info,
 				 struct net_device *netdev)
 {

@@ -3036,6 +3079,11 @@ static int ena_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	INIT_WORK(&adapter->reset_task, ena_fw_reset_device);
 
 	adapter->last_keep_alive_jiffies = jiffies;
+	adapter->keep_alive_timeout = ENA_DEVICE_KALIVE_TIMEOUT;
+	adapter->missing_tx_completion_to = TX_TIMEOUT;
+	adapter->missing_tx_completion_threshold = MAX_NUM_OF_TIMEOUTED_PACKETS;
+
+	ena_update_hints(adapter, &get_feat_ctx.hw_hints);
 
 	init_timer(&adapter->timer_service);
 	adapter->timer_service.expires = round_jiffies(jiffies + HZ);

@@ -3256,6 +3304,7 @@ static void ena_notification(void *adapter_data,
 			     struct ena_admin_aenq_entry *aenq_e)
 {
 	struct ena_adapter *adapter = (struct ena_adapter *)adapter_data;
+	struct ena_admin_ena_hw_hints *hints;
 
 	WARN(aenq_e->aenq_common_desc.group != ENA_ADMIN_NOTIFICATION,
 	     "Invalid group(%x) expected %x\n",

@@ -3273,6 +3322,11 @@ static void ena_notification(void *adapter_data,
 	case ENA_ADMIN_RESUME:
 		queue_work(ena_wq, &adapter->resume_io_task);
 		break;
+	case ENA_ADMIN_UPDATE_HINTS:
+		hints = (struct ena_admin_ena_hw_hints *)
+			(&aenq_e->inline_data_w4);
+		ena_update_hints(adapter, hints);
+		break;
 	default:
 		netif_err(adapter, drv, adapter->netdev,
 			  "Invalid aenq notification link state %d\n",

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h
index f0ddc11..2897fab 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h

@@ -146,7 +146,18 @@ struct ena_tx_buffer {
 	u32 tx_descs;
 	/* num of buffers used by this skb */
 	u32 num_of_bufs;
-	/* Save the last jiffies to detect missing tx packets */
+
+	/* Used for detect missing tx packets to limit the number of prints */
+	u32 print_once;
+	/* Save the last jiffies to detect missing tx packets
+	 *
+	 * sets to non zero value on ena_start_xmit and set to zero on
+	 * napi and timer_Service_routine.
+	 *
+	 * while this value is not protected by lock,
+	 * a given packet is not expected to be handled by ena_start_xmit
+	 * and by napi/timer_service at the same time.
+	 */
 	unsigned long last_jiffies;
 	struct ena_com_buf bufs[ENA_PKT_MAX_BUFS];
 } ____cacheline_aligned;

@@ -170,7 +181,6 @@ struct ena_stats_tx {
 	u64 napi_comp;
 	u64 tx_poll;
 	u64 doorbells;
-	u64 missing_tx_comp;
 	u64 bad_req_id;
 };
 

@@ -270,6 +280,8 @@ struct ena_adapter {
 	struct msix_entry *msix_entries;
 	int msix_vecs;
 
+	u32 missing_tx_completion_threshold;
+
 	u32 tx_usecs, rx_usecs; /* interrupt moderation */
 	u32 tx_frames, rx_frames; /* interrupt moderation */
 

@@ -283,6 +295,9 @@ struct ena_adapter {
 
 	u8 mac_addr[ETH_ALEN];
 
+	unsigned long keep_alive_timeout;
+	unsigned long missing_tx_completion_to;
+
 	char name[ENA_NAME_MAX_LEN];
 
 	unsigned long flags;

diff --git a/drivers/net/ethernet/amazon/ena/ena_regs_defs.h b/drivers/net/ethernet/amazon/ena/ena_regs_defs.h
index 26097a2..c3891c5 100644
--- a/drivers/net/ethernet/amazon/ena/ena_regs_defs.h
+++ b/drivers/net/ethernet/amazon/ena/ena_regs_defs.h

@@ -78,6 +78,8 @@
 #define ENA_REGS_CAPS_RESET_TIMEOUT_MASK		0x3e
 #define ENA_REGS_CAPS_DMA_ADDR_WIDTH_SHIFT		8
 #define ENA_REGS_CAPS_DMA_ADDR_WIDTH_MASK		0xff00
+#define ENA_REGS_CAPS_ADMIN_CMD_TO_SHIFT		16
+#define ENA_REGS_CAPS_ADMIN_CMD_TO_MASK		0xf0000
 
 /* aq_caps register */
 #define ENA_REGS_AQ_CAPS_AQ_DEPTH_MASK		0xffff