Re: [PATCH net-next v11 3/7] r8169: add support for new interrupt mapping

From: Javen Xu <redacted>

To support RSS, the number of hardware interrupt bits should match the
interrupt of software. So we add support for new interrupt mapping here.
ISR_VEC_MAP_REG is the hardware register to indicate interrupt status.
IMR_SET_VEC_MAP_REG is interrupt mask which is set to enable irq.

Signed-off-by: Javen Xu <redacted>
---
Changes in v2:
  - no changes

Changes in v3:
  - init index in napi_struct and get message_id from index
  - move rtl8169_disable_hw_interrupt_msix directly before the call to
    napi_schedule()
  - change the condition in rtl8169_request_irq when RTL_VEC_MAP_ENABLE
    enabled, use rtl8169_interrupt_msix

Changes in v4:
  - remove flag tp->feature, replace tp->features & RTL_VEC_MAP_ENABLE
    with tp->irq_nvecs > 1, they are equivalent.
  - follow reverse xmas tree, in rtl8169_interrupt_msix(),
    rtl8169_poll_msix_rx(), rtl8169_poll_msix_tx(),
    rtl8169_poll_msix_other()
  - use napi->index in rtl8169_poll_msix_other()
  - add a comment to describe RTL8127 MSI-X vector layout
  - simplify r8169_init_napi()

Changes in v5:
  - replace magic number in rtl8169_poll_msix_tx()

Changes in v6:
  - when irq_nvecs <= 1, use register IntrMask_8125, else using vec map
  - fix irq sequence in rtl8169_interrupt_msix(), disable interrupts
    before clean it
  - remove dead code in rtl8169_poll_msix_tx()

Changes in v7:
  - remove recheck_desc_ownbit
  - change return value of rtl_tx
  - remove message_id which only used once

Changes in v8:
  - fix rtl8169_netpoll()
  - remove tx_done

Changes in v9:
  - change the way of getting message_id of napi

Changes in v10:
  - no changes

Changes in v11:
  - add comment on rtl8169_poll_msix_tx, only use 1 tx
  - remove napi for other. Separate napi only for datapath, control path
    like linkchg is handled in interrupt function, which will not call
    napi any more.
---
  drivers/net/ethernet/realtek/r8169_main.c | 213 +++++++++++++++++++---
  1 file changed, 187 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 9311a0cab4eb..b30f0a31d7c7 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c

@@ -84,6 +84,7 @@
  #define R8169_RX_RING_BYTES	((NUM_RX_DESC + 1) * sizeof(struct RxDesc))
  #define R8169_TX_STOP_THRS	(MAX_SKB_FRAGS + 1)
  #define R8169_TX_START_THRS	(2 * R8169_TX_STOP_THRS)
+#define R8169_MAX_QUEUES	16
  #define R8169_MAX_RX_QUEUES	8
  #define R8169_DEFAULT_RX_QUEUES	1
  #define R8169_MAX_TX_QUEUES	1

@@ -455,8 +456,12 @@ enum rtl8125_registers {
  	RSS_CTRL_8125		= 0x4500,
  	Q_NUM_CTRL_8125		= 0x4800,
  	EEE_TXIDLE_TIMER_8125	= 0x6048,
+	IMR_CLEAR_VEC_MAP_REG	= 0x0d00,
+	ISR_VEC_MAP_REG		= 0x0d04,
+	IMR_SET_VEC_MAP_REG	= 0x0d0c,
  };
  
+#define MSIX_ID_VEC_MAP_LINKCHG	29
  #define LEDSEL_MASK_8125	0x23f
  
  #define RX_VLAN_INNER_8125	BIT(22)

@@ -587,6 +592,9 @@ enum rtl_register_content {
  
  	/* magic enable v2 */
  	MagicPacket_v2	= (1 << 16),	/* Wake up when receives a Magic Packet */
+#define	ISRIMR_LINKCHG	BIT(29)
+#define	ISRIMR_TOK_Q0	BIT(8)
+#define	ISRIMR_ROK_Q0	BIT(0)
  };
  
  enum rtl_desc_bit {

@@ -1663,26 +1671,38 @@ static u32 rtl_get_events(struct rtl8169_private *tp)
  
  static void rtl_ack_events(struct rtl8169_private *tp, u32 bits)
  {
-	if (rtl_is_8125(tp))
-		RTL_W32(tp, IntrStatus_8125, bits);
-	else
+	if (rtl_is_8125(tp)) {
+		if (tp->irq_nvecs > 1)
+			RTL_W32(tp, ISR_VEC_MAP_REG, bits);
+		else
+			RTL_W32(tp, IntrStatus_8125, bits);
+	} else {
  		RTL_W16(tp, IntrStatus, bits);
+	}
  }
  
  static void rtl_irq_disable(struct rtl8169_private *tp)
  {
-	if (rtl_is_8125(tp))
-		RTL_W32(tp, IntrMask_8125, 0);
-	else
+	if (rtl_is_8125(tp)) {
+		if (tp->irq_nvecs > 1)
+			RTL_W32(tp, IMR_CLEAR_VEC_MAP_REG, 0xffffffff);
+		else
+			RTL_W32(tp, IntrMask_8125, 0);
+	} else {
  		RTL_W16(tp, IntrMask, 0);
+	}
  }
  
  static void rtl_irq_enable(struct rtl8169_private *tp)
  {
-	if (rtl_is_8125(tp))
-		RTL_W32(tp, IntrMask_8125, tp->irq_mask);
-	else
+	if (rtl_is_8125(tp)) {
+		if (tp->irq_nvecs > 1)
+			RTL_W32(tp, IMR_SET_VEC_MAP_REG, tp->irq_mask);
+		else
+			RTL_W32(tp, IntrMask_8125, tp->irq_mask);
+	} else {
  		RTL_W16(tp, IntrMask, tp->irq_mask);
+	}
  }
  
  static void rtl8169_irq_mask_and_ack(struct rtl8169_private *tp)

@@ -4382,13 +4402,17 @@ static void rtl8169_tx_clear(struct rtl8169_private *tp)
  
  static void rtl8169_napi_disable(struct rtl8169_private *tp)
  {
-	for (int i = 0; i < tp->irq_nvecs; i++)
+	int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
+
+	for (int i = 0; i < napi_num; i++)
  		napi_disable(&tp->rtl8169_napi[i]);
  }
  
  static void rtl8169_napi_enable(struct rtl8169_private *tp)
  {
-	for (int i = 0; i < tp->irq_nvecs; i++)
+	int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
+
+	for (int i = 0; i < napi_num; i++)
  		napi_enable(&tp->rtl8169_napi[i]);
  }
  

@@ -5030,13 +5054,66 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
  	return IRQ_HANDLED;
  }
  
+static void rtl8169_free_one_irq(struct rtl8169_private *tp, int i)
+{
+	if (tp->irq_nvecs > 1) {
+		if (i < R8169_MAX_QUEUES)
+			pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
+		else if (i == MSIX_ID_VEC_MAP_LINKCHG)
+			pci_free_irq(tp->pci_dev, i, tp);
+	} else {
+		pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
+	}
+}
+
  static void rtl8169_free_irq(struct rtl8169_private *tp)
  {
-	for (int i = 0; i < tp->irq_nvecs; i++) {
-		struct napi_struct *napi = &tp->rtl8169_napi[i];
+	for (int i = 0; i < tp->irq_nvecs; i++)
+		rtl8169_free_one_irq(tp, i);
+}
  
-		pci_free_irq(tp->pci_dev, i, napi);
-	}
+static void rtl8169_disable_hw_interrupt_msix(struct rtl8169_private *tp,
+					      int message_id)
+{
+	RTL_W32(tp, IMR_CLEAR_VEC_MAP_REG, BIT(message_id));
+}
+
+static void rtl8169_clear_hw_isr(struct rtl8169_private *tp, int message_id)
+{
+	RTL_W32(tp, ISR_VEC_MAP_REG, BIT(message_id));
+}
+
+static void rtl8169_enable_hw_interrupt_msix(struct rtl8169_private *tp,
+					     int message_id)
+{
+	RTL_W32(tp, IMR_SET_VEC_MAP_REG, BIT(message_id));
+}
+
+static irqreturn_t rtl8169_interrupt_msix(int irq, void *dev_instance)
+{
+	struct napi_struct *napi = dev_instance;
+	struct net_device *dev = napi->dev;
+	struct rtl8169_private *tp;
+	int message_id;
+
+	tp = netdev_priv(dev);
+	message_id = napi - tp->rtl8169_napi;
+
+	rtl8169_disable_hw_interrupt_msix(tp, message_id);
+	rtl8169_clear_hw_isr(tp, message_id);
+
+	napi_schedule(napi);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t rtl8169_interrupt_other(int irq, void *dev_instance)
+{
+	struct rtl8169_private *tp = dev_instance;
+
+	rtl8169_clear_hw_isr(tp, MSIX_ID_VEC_MAP_LINKCHG);
+	phy_mac_interrupt(tp->phydev);
+	return IRQ_HANDLED;
  }
  
  static int rtl8169_request_irq(struct rtl8169_private *tp)

@@ -5047,8 +5124,26 @@ static int rtl8169_request_irq(struct rtl8169_private *tp)
  
  	for (i = 0; i < tp->irq_nvecs; i++) {
  		napi = &tp->rtl8169_napi[i];
-		rc = pci_request_irq(tp->pci_dev, i, rtl8169_interrupt,
-				     NULL, napi, "%s-%d", dev->name, i);
+		if (tp->irq_nvecs > 1) {
+			if (i < R8169_MAX_QUEUES)
+				rc = pci_request_irq(tp->pci_dev, i,
+						     rtl8169_interrupt_msix,
+						     NULL, napi, "%s-%d",
+						     dev->name, i);
+			else if (i == MSIX_ID_VEC_MAP_LINKCHG)
+				rc = pci_request_irq(tp->pci_dev, i,
+						     rtl8169_interrupt_other,
+						     NULL, tp, "%s-%d",
+						     dev->name, i);
+			else
+				continue;
+		} else {
+			rc = pci_request_irq(tp->pci_dev, i,
+					     rtl8169_interrupt,
+					     NULL, napi, "%s-%d",
+					     dev->name, i);
+		}
+
  		if (rc)
  			goto free_irq;
  	}

@@ -5056,7 +5151,7 @@ static int rtl8169_request_irq(struct rtl8169_private *tp)
  
  free_irq:
  	while (--i >= 0)
-		pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
+		rtl8169_free_one_irq(tp, i);
  	return rc;
  }
  

@@ -5255,8 +5350,12 @@ static void rtl8169_netpoll(struct net_device *dev)
  	struct rtl8169_private *tp = netdev_priv(dev);
  
  	for (int i = 0; i < tp->irq_nvecs; i++) {

-		rtl8169_interrupt(pci_irq_vector(tp->pci_dev, i),
-				  &tp->rtl8169_napi[i]);
+		if (tp->irq_nvecs > 1)
+			rtl8169_interrupt_msix(pci_irq_vector(tp->pci_dev, i),
+					       &tp->rtl8169_napi[i]);
+		else
+			rtl8169_interrupt(pci_irq_vector(tp->pci_dev, i),
+					  &tp->rtl8169_napi[i]);
  	}
  }
  #endif

@@ -5454,7 +5553,9 @@ static void rtl_shutdown(struct pci_dev *pdev)
  
  static void r8169_free_napi(struct rtl8169_private *tp)
  {
-	for (int i = 0; i < tp->irq_nvecs; i++)
+	int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
+
+	for (int i = 0; i < napi_num; i++)
  		netif_napi_del(&tp->rtl8169_napi[i]);
  
  	kfree(tp->rtl8169_napi);

@@ -5508,10 +5609,16 @@ static const struct net_device_ops rtl_netdev_ops = {
  
  static void rtl_set_irq_mask(struct rtl8169_private *tp)
  {
-	tp->irq_mask = RxOK | RxErr | TxOK | TxErr | LinkChg;
+	if (tp->irq_nvecs > 1) {
+		tp->irq_mask = ISRIMR_LINKCHG | ISRIMR_TOK_Q0;
+		for (int i = 0; i < tp->num_rx_rings; i++)
+			tp->irq_mask |= ISRIMR_ROK_Q0 << i;
+	} else {
+		tp->irq_mask = RxOK | RxErr | TxOK | TxErr | LinkChg;
  
-	if (tp->mac_version <= RTL_GIGA_MAC_VER_06)
-		tp->irq_mask |= SYSErr | RxFIFOOver;
+		if (tp->mac_version <= RTL_GIGA_MAC_VER_06)
+			tp->irq_mask |= SYSErr | RxFIFOOver;
+	}
  }
  
  static int rtl_alloc_irq(struct rtl8169_private *tp)

@@ -5796,10 +5903,64 @@ static bool rtl_aspm_is_safe(struct rtl8169_private *tp)
  	return false;
  }
  
+static int rtl8169_poll_msix_rx(struct napi_struct *napi, int budget)
+{
+	struct net_device *dev = napi->dev;
+	struct rtl8169_private *tp;
+	int work_done = 0;
+	int message_id;
+
+	tp = netdev_priv(dev);
+	message_id = napi - tp->rtl8169_napi;
+
+	if (message_id < tp->num_rx_rings)
+		work_done += rtl_rx(dev, tp, &tp->rx_ring[message_id],
+				    budget, napi);
+
+	if (work_done < budget && napi_complete_done(napi, work_done))
+		rtl8169_enable_hw_interrupt_msix(tp, message_id);
+
+	return work_done;
+}
+
+static int rtl8169_poll_msix_tx(struct napi_struct *napi, int budget)
+{
+	struct net_device *dev = napi->dev;
+	struct rtl8169_private *tp;
+
+	tp = netdev_priv(dev);
+
+	/* Currently r8169 only supports a single Tx ring.
+	 * Therefore, we don't need a per-ring Tx processing loop here.
+	 */
+	rtl_tx(dev, tp, budget);
+
+	if (napi_complete_done(napi, 0))
+		rtl8169_enable_hw_interrupt_msix(tp, (int)(napi - tp->rtl8169_napi));
+
+	return 0;
+}
+
+/* RTL8127 MSI-X vector layout:
+ * Vectors 0 .. (RxQs - 1)		: Rx Queues
+ * Vectors RxQs .. (RxQs + TxQs - 1)	: Tx Queues
+ * NAPI is only allocated for data path
+ */
  static void r8169_init_napi(struct rtl8169_private *tp)
  {
-	for (int i = 0; i < tp->irq_nvecs; i++)
-		netif_napi_add(tp->dev, &tp->rtl8169_napi[i], rtl8169_poll);
+	int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
+
+	for (int i = 0; i < napi_num; i++) {
+		int (*poll_fn)(struct napi_struct *, int) = rtl8169_poll;
+
+		if (tp->irq_nvecs > 1) {
+			if (i < R8169_MAX_RX_QUEUES)
+				poll_fn = rtl8169_poll_msix_rx;
+			else
+				poll_fn = rtl8169_poll_msix_tx;
+		}
+		netif_napi_add(tp->dev, &tp->rtl8169_napi[i], poll_fn);
+	}
  }
  
  static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)