Merge branch 'alx-msix'

Tobias Regnery says:

====================
alx: add msi-x support

This patchset adds msi-x support to the alx driver. It is a preparatory
series for multi queue support, which I am currently working on. As there
is no advantage over msi interrupts without multi queue support, msi-x
interrupts are disabled by default. In order to test for regressions, a
new module parameter is added to enable msi-x interrupts.

Based on information of the downstream driver at github.com/qca/alx
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/alx/alx.h

@@ -76,11 +76,19 @@ enum alx_device_quirks {
 	ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG = BIT(0),
 };
 
+#define ALX_FLAG_USING_MSIX	BIT(0)
+#define ALX_FLAG_USING_MSI	BIT(1)
+
 struct alx_priv {
 	struct net_device *dev;
 
 	struct alx_hw hw;
 
+	/* msi-x vectors */
+	int num_vec;
+	struct msix_entry *msix_entries;
+	char irq_lbl[IFNAMSIZ + 8];
+
 	/* all descriptor memory */
 	struct {
 		dma_addr_t dma;
@@ -105,7 +113,7 @@ struct alx_priv {
 
 	u16 msg_enable;
 
-	bool msi;
+	int flags;
 
 	/* protects hw.stats */
 	spinlock_t stats_lock;

drivers/net/ethernet/atheros/alx/hw.c

@@ -1031,6 +1031,20 @@ void alx_configure_basic(struct alx_hw *hw)
 	alx_write_mem32(hw, ALX_WRR, val);
 }
 
+void alx_mask_msix(struct alx_hw *hw, int index, bool mask)
+{
+	u32 reg, val;
+
+	reg = ALX_MSIX_ENTRY_BASE + index * PCI_MSIX_ENTRY_SIZE +
+		PCI_MSIX_ENTRY_VECTOR_CTRL;
+
+	val = mask ? PCI_MSIX_ENTRY_CTRL_MASKBIT : 0;
+
+	alx_write_mem32(hw, reg, val);
+	alx_post_write(hw);
+}
+
+
 bool alx_get_phy_info(struct alx_hw *hw)
 {
 	u16  devs1, devs2;

drivers/net/ethernet/atheros/alx/hw.h

@@ -562,6 +562,7 @@ int alx_reset_mac(struct alx_hw *hw);
 void alx_set_macaddr(struct alx_hw *hw, const u8 *addr);
 bool alx_phy_configured(struct alx_hw *hw);
 void alx_configure_basic(struct alx_hw *hw);
+void alx_mask_msix(struct alx_hw *hw, int index, bool mask);
 void alx_disable_rss(struct alx_hw *hw);
 bool alx_get_phy_info(struct alx_hw *hw);
 void alx_update_hw_stats(struct alx_hw *hw);

drivers/net/ethernet/atheros/alx/main.c

@@ -51,6 +51,9 @@
 
 const char alx_drv_name[] = "alx";
 
+static bool msix = false;
+module_param(msix, bool, 0);
+MODULE_PARM_DESC(msix, "Enable msi-x interrupt support");
 
 static void alx_free_txbuf(struct alx_priv *alx, int entry)
 {
@@ -292,32 +295,29 @@ static int alx_poll(struct napi_struct *napi, int budget)
 	napi_complete(&alx->napi);
 
 	/* enable interrupt */
-	spin_lock_irqsave(&alx->irq_lock, flags);
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
-	alx->int_mask |= ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0;
+		alx_mask_msix(hw, 1, false);
-	alx_write_mem32(hw, ALX_IMR, alx->int_mask);
+	} else {
-	spin_unlock_irqrestore(&alx->irq_lock, flags);
+		spin_lock_irqsave(&alx->irq_lock, flags);
+		alx->int_mask |= ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0;
+		alx_write_mem32(hw, ALX_IMR, alx->int_mask);
+		spin_unlock_irqrestore(&alx->irq_lock, flags);
+	}
 
 	alx_post_write(hw);
 
 	return work;
 }
 
-static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)
+static bool alx_intr_handle_misc(struct alx_priv *alx, u32 intr)
 {
 	struct alx_hw *hw = &alx->hw;
-	bool write_int_mask = false;
-
-	spin_lock(&alx->irq_lock);
-
-	/* ACK interrupt */
-	alx_write_mem32(hw, ALX_ISR, intr | ALX_ISR_DIS);
-	intr &= alx->int_mask;
 
 	if (intr & ALX_ISR_FATAL) {
 		netif_warn(alx, hw, alx->dev,
 			   "fatal interrupt 0x%x, resetting\n", intr);
 		alx_schedule_reset(alx);
-		goto out;
+		return true;
 	}
 
 	if (intr & ALX_ISR_ALERT)
@@ -329,19 +329,32 @@ static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)
 		 * is cleared, the interrupt status could be cleared.
 		 */
 		alx->int_mask &= ~ALX_ISR_PHY;
-		write_int_mask = true;
+		alx_write_mem32(hw, ALX_IMR, alx->int_mask);
 		alx_schedule_link_check(alx);
 	}
 
+	return false;
+}
+
+static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)
+{
+	struct alx_hw *hw = &alx->hw;
+
+	spin_lock(&alx->irq_lock);
+
+	/* ACK interrupt */
+	alx_write_mem32(hw, ALX_ISR, intr | ALX_ISR_DIS);
+	intr &= alx->int_mask;
+
+	if (alx_intr_handle_misc(alx, intr))
+		goto out;
+
 	if (intr & (ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0)) {
 		napi_schedule(&alx->napi);
 		/* mask rx/tx interrupt, enable them when napi complete */
 		alx->int_mask &= ~ALX_ISR_ALL_QUEUES;
-		write_int_mask = true;
-	}
-
-	if (write_int_mask)
 		alx_write_mem32(hw, ALX_IMR, alx->int_mask);
+	}
 
 	alx_write_mem32(hw, ALX_ISR, 0);
 
@@ -350,6 +363,46 @@ static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t alx_intr_msix_ring(int irq, void *data)
+{
+	struct alx_priv *alx = data;
+	struct alx_hw *hw = &alx->hw;
+
+	/* mask interrupt to ACK chip */
+	alx_mask_msix(hw, 1, true);
+	/* clear interrupt status */
+	alx_write_mem32(hw, ALX_ISR, (ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0));
+
+	napi_schedule(&alx->napi);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t alx_intr_msix_misc(int irq, void *data)
+{
+	struct alx_priv *alx = data;
+	struct alx_hw *hw = &alx->hw;
+	u32 intr;
+
+	/* mask interrupt to ACK chip */
+	alx_mask_msix(hw, 0, true);
+
+	/* read interrupt status */
+	intr = alx_read_mem32(hw, ALX_ISR);
+	intr &= (alx->int_mask & ~ALX_ISR_ALL_QUEUES);
+
+	if (alx_intr_handle_misc(alx, intr))
+		return IRQ_HANDLED;
+
+	/* clear interrupt status */
+	alx_write_mem32(hw, ALX_ISR, intr);
+
+	/* enable interrupt again */
+	alx_mask_msix(hw, 0, false);
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t alx_intr_msi(int irq, void *data)
 {
 	struct alx_priv *alx = data;
@@ -614,31 +667,136 @@ static void alx_free_rings(struct alx_priv *alx)
 static void alx_config_vector_mapping(struct alx_priv *alx)
 {
 	struct alx_hw *hw = &alx->hw;
+	u32 tbl = 0;
 
-	alx_write_mem32(hw, ALX_MSI_MAP_TBL1, 0);
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
+		tbl |= 1 << ALX_MSI_MAP_TBL1_TXQ0_SHIFT;
+		tbl |= 1 << ALX_MSI_MAP_TBL1_RXQ0_SHIFT;
+	}
+
+	alx_write_mem32(hw, ALX_MSI_MAP_TBL1, tbl);
 	alx_write_mem32(hw, ALX_MSI_MAP_TBL2, 0);
 	alx_write_mem32(hw, ALX_MSI_ID_MAP, 0);
 }
 
+static bool alx_enable_msix(struct alx_priv *alx)
+{
+	int i, err, num_vec = 2;
+
+	alx->msix_entries = kcalloc(num_vec, sizeof(struct msix_entry),
+				    GFP_KERNEL);
+	if (!alx->msix_entries) {
+		netdev_warn(alx->dev, "Allocation of msix entries failed!\n");
+		return false;
+	}
+
+	for (i = 0; i < num_vec; i++)
+		alx->msix_entries[i].entry = i;
+
+	err = pci_enable_msix(alx->hw.pdev, alx->msix_entries, num_vec);
+	if (err) {
+		kfree(alx->msix_entries);
+		netdev_warn(alx->dev, "Enabling MSI-X interrupts failed!\n");
+		return false;
+	}
+
+	alx->num_vec = num_vec;
+	return true;
+}
+
+static int alx_request_msix(struct alx_priv *alx)
+{
+	struct net_device *netdev = alx->dev;
+	int i, err, vector = 0, free_vector = 0;
+
+	err = request_irq(alx->msix_entries[0].vector, alx_intr_msix_misc,
+			  0, netdev->name, alx);
+	if (err)
+		goto out_err;
+
+	vector++;
+	sprintf(alx->irq_lbl, "%s-TxRx-0", netdev->name);
+
+	err = request_irq(alx->msix_entries[vector].vector,
+			  alx_intr_msix_ring, 0, alx->irq_lbl, alx);
+		if (err)
+			goto out_free;
+
+	return 0;
+
+out_free:
+	free_irq(alx->msix_entries[free_vector++].vector, alx);
+
+	vector--;
+	for (i = 0; i < vector; i++)
+		free_irq(alx->msix_entries[free_vector++].vector, alx);
+
+out_err:
+	return err;
+}
+
+static void alx_init_intr(struct alx_priv *alx, bool msix)
+{
+	if (msix) {
+		if (alx_enable_msix(alx))
+			alx->flags |= ALX_FLAG_USING_MSIX;
+	}
+
+	if (!(alx->flags & ALX_FLAG_USING_MSIX)) {
+		alx->num_vec = 1;
+
+		if (!pci_enable_msi(alx->hw.pdev))
+			alx->flags |= ALX_FLAG_USING_MSI;
+	}
+}
+
+static void alx_disable_advanced_intr(struct alx_priv *alx)
+{
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
+		kfree(alx->msix_entries);
+		pci_disable_msix(alx->hw.pdev);
+		alx->flags &= ~ALX_FLAG_USING_MSIX;
+	}
+
+	if (alx->flags & ALX_FLAG_USING_MSI) {
+		pci_disable_msi(alx->hw.pdev);
+		alx->flags &= ~ALX_FLAG_USING_MSI;
+	}
+}
+
 static void alx_irq_enable(struct alx_priv *alx)
 {
 	struct alx_hw *hw = &alx->hw;
+	int i;
 
 	/* level-1 interrupt switch */
 	alx_write_mem32(hw, ALX_ISR, 0);
 	alx_write_mem32(hw, ALX_IMR, alx->int_mask);
 	alx_post_write(hw);
+
+	if (alx->flags & ALX_FLAG_USING_MSIX)
+		/* enable all msix irqs */
+		for (i = 0; i < alx->num_vec; i++)
+			alx_mask_msix(hw, i, false);
 }
 
 static void alx_irq_disable(struct alx_priv *alx)
 {
 	struct alx_hw *hw = &alx->hw;
+	int i;
 
 	alx_write_mem32(hw, ALX_ISR, ALX_ISR_DIS);
 	alx_write_mem32(hw, ALX_IMR, 0);
 	alx_post_write(hw);
 
-	synchronize_irq(alx->hw.pdev->irq);
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
+		for (i = 0; i < alx->num_vec; i++) {
+			alx_mask_msix(hw, i, true);
+			synchronize_irq(alx->msix_entries[i].vector);
+		}
+	} else {
+		synchronize_irq(alx->hw.pdev->irq);
+	}
 }
 
 static int alx_request_irq(struct alx_priv *alx)
@@ -650,9 +808,18 @@ static int alx_request_irq(struct alx_priv *alx)
 
 	msi_ctrl = (hw->imt >> 1) << ALX_MSI_RETRANS_TM_SHIFT;
 
-	if (!pci_enable_msi(alx->hw.pdev)) {
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
-		alx->msi = true;
+		alx_write_mem32(hw, ALX_MSI_RETRANS_TIMER, msi_ctrl);
+		err = alx_request_msix(alx);
+		if (!err)
+			goto out;
 
+		/* msix request failed, realloc resources */
+		alx_disable_advanced_intr(alx);
+		alx_init_intr(alx, false);
+	}
+
+	if (alx->flags & ALX_FLAG_USING_MSI) {
 		alx_write_mem32(hw, ALX_MSI_RETRANS_TIMER,
 				msi_ctrl | ALX_MSI_MASK_SEL_LINE);
 		err = request_irq(pdev->irq, alx_intr_msi, 0,
@@ -660,6 +827,7 @@ static int alx_request_irq(struct alx_priv *alx)
 		if (!err)
 			goto out;
 		/* fall back to legacy interrupt */
+		alx->flags &= ~ALX_FLAG_USING_MSI;
 		pci_disable_msi(alx->hw.pdev);
 	}
 
@@ -669,19 +837,25 @@ static int alx_request_irq(struct alx_priv *alx)
 out:
 	if (!err)
 		alx_config_vector_mapping(alx);
+	else
+		netdev_err(alx->dev, "IRQ registration failed!\n");
 	return err;
 }
 
 static void alx_free_irq(struct alx_priv *alx)
 {
 	struct pci_dev *pdev = alx->hw.pdev;
+	int i;
 
-	free_irq(pdev->irq, alx);
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
-
+		/* we have only 2 vectors without multi queue support */
-	if (alx->msi) {
+		for (i = 0; i < 2; i++)
-		pci_disable_msi(alx->hw.pdev);
+			free_irq(alx->msix_entries[i].vector, alx);
-		alx->msi = false;
+	} else {
+		free_irq(pdev->irq, alx);
 	}
+
+	alx_disable_advanced_intr(alx);
 }
 
 static int alx_identify_hw(struct alx_priv *alx)
@@ -847,6 +1021,8 @@ static int __alx_open(struct alx_priv *alx, bool resume)
 {
 	int err;
 
+	alx_init_intr(alx, msix);
+
 	if (!resume)
 		netif_carrier_off(alx->dev);
 
@@ -1236,7 +1412,10 @@ static void alx_poll_controller(struct net_device *netdev)
 {
 	struct alx_priv *alx = netdev_priv(netdev);
 
-	if (alx->msi)
+	if (alx->flags & ALX_FLAG_USING_MSIX) {
+		alx_intr_msix_misc(0, alx);
+		alx_intr_msix_ring(0, alx);
+	} else if (alx->flags & ALX_FLAG_USING_MSI)
 		alx_intr_msi(0, alx);
 	else
 		alx_intr_legacy(0, alx);