NTB: Disable interrupts and poll under high load
[linux-drm-fsl-dcu.git] / drivers / ntb / ntb_hw.c
index 1cb6e51e6bda97aadb4ba88bd46123544dcc4140..170e8e60cdb7fe3d47307d4b9146039e3af7f3a8 100644 (file)
@@ -141,6 +141,24 @@ void ntb_unregister_event_callback(struct ntb_device *ndev)
        ndev->event_cb = NULL;
 }
 
+static void ntb_irq_work(unsigned long data)
+{
+       struct ntb_db_cb *db_cb = (struct ntb_db_cb *)data;
+       int rc;
+
+       rc = db_cb->callback(db_cb->data, db_cb->db_num);
+       if (rc)
+               tasklet_schedule(&db_cb->irq_work);
+       else {
+               struct ntb_device *ndev = db_cb->ndev;
+               unsigned long mask;
+
+               mask = readw(ndev->reg_ofs.ldb_mask);
+               clear_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+               writew(mask, ndev->reg_ofs.ldb_mask);
+       }
+}
+
 /**
  * ntb_register_db_callback() - register a callback for doorbell interrupt
  * @ndev: pointer to ntb_device instance
@@ -155,7 +173,7 @@ void ntb_unregister_event_callback(struct ntb_device *ndev)
  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
  */
 int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
-                            void *data, void (*func)(void *data, int db_num))
+                            void *data, int (*func)(void *data, int db_num))
 {
        unsigned long mask;
 
@@ -166,6 +184,10 @@ int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
 
        ndev->db_cb[idx].callback = func;
        ndev->db_cb[idx].data = data;
+       ndev->db_cb[idx].ndev = ndev;
+
+       tasklet_init(&ndev->db_cb[idx].irq_work, ntb_irq_work,
+                    (unsigned long) &ndev->db_cb[idx]);
 
        /* unmask interrupt */
        mask = readw(ndev->reg_ofs.ldb_mask);
@@ -194,6 +216,8 @@ void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx)
        set_bit(idx * ndev->bits_per_vector, &mask);
        writew(mask, ndev->reg_ofs.ldb_mask);
 
+       tasklet_disable(&ndev->db_cb[idx].irq_work);
+
        ndev->db_cb[idx].callback = NULL;
 }
 
@@ -678,6 +702,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
                                return -EINVAL;
 
                        ndev->limits.max_mw = SNB_ERRATA_MAX_MW;
+                       ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
                        ndev->reg_ofs.spad_write = ndev->mw[1].vbase +
                                                   SNB_SPAD_OFFSET;
                        ndev->reg_ofs.rdb = ndev->mw[1].vbase +
@@ -688,8 +713,21 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
                         */
                        writeq(ndev->mw[1].bar_sz + 0x1000, ndev->reg_base +
                               SNB_PBAR4LMT_OFFSET);
+                       /* HW errata on the Limit registers.  They can only be
+                        * written when the base register is 4GB aligned and
+                        * < 32bit.  This should already be the case based on the
+                        * driver defaults, but write the Limit registers first
+                        * just in case.
+                        */
                } else {
                        ndev->limits.max_mw = SNB_MAX_MW;
+
+                       /* HW Errata on bit 14 of b2bdoorbell register.  Writes
+                        * will not be mirrored to the remote system.  Shrink
+                        * the number of bits by one, since bit 14 is the last
+                        * bit.
+                        */
+                       ndev->limits.max_db_bits = SNB_MAX_DB_BITS - 1;
                        ndev->reg_ofs.spad_write = ndev->reg_base +
                                                   SNB_B2B_SPAD_OFFSET;
                        ndev->reg_ofs.rdb = ndev->reg_base +
@@ -699,6 +737,12 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
                         * something silly
                         */
                        writeq(0, ndev->reg_base + SNB_PBAR4LMT_OFFSET);
+                       /* HW errata on the Limit registers.  They can only be
+                        * written when the base register is 4GB aligned and
+                        * < 32bit.  This should already be the case based on the
+                        * driver defaults, but write the Limit registers first
+                        * just in case.
+                        */
                }
 
                /* The Xeon errata workaround requires setting SBAR Base
@@ -769,6 +813,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
                 * have an equal amount.
                 */
                ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+               ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
                /* Note: The SDOORBELL is the cause of the errata.  You REALLY
                 * don't want to touch it.
                 */
@@ -793,6 +838,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
                 * have an equal amount.
                 */
                ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+               ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
                ndev->reg_ofs.rdb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
                ndev->reg_ofs.ldb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
                ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_SDBMSK_OFFSET;
@@ -819,7 +865,6 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
        ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_SLINK_STATUS_OFFSET;
        ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;
 
-       ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
        ndev->limits.msix_cnt = SNB_MSIX_CNT;
        ndev->bits_per_vector = SNB_DB_BITS_PER_VEC;
 
@@ -934,12 +979,16 @@ static irqreturn_t bwd_callback_msix_irq(int irq, void *data)
 {
        struct ntb_db_cb *db_cb = data;
        struct ntb_device *ndev = db_cb->ndev;
+       unsigned long mask;
 
        dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
                db_cb->db_num);
 
-       if (db_cb->callback)
-               db_cb->callback(db_cb->data, db_cb->db_num);
+       mask = readw(ndev->reg_ofs.ldb_mask);
+       set_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+       writew(mask, ndev->reg_ofs.ldb_mask);
+
+       tasklet_schedule(&db_cb->irq_work);
 
        /* No need to check for the specific HB irq, any interrupt means
         * we're connected.
@@ -955,12 +1004,16 @@ static irqreturn_t xeon_callback_msix_irq(int irq, void *data)
 {
        struct ntb_db_cb *db_cb = data;
        struct ntb_device *ndev = db_cb->ndev;
+       unsigned long mask;
 
        dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
                db_cb->db_num);
 
-       if (db_cb->callback)
-               db_cb->callback(db_cb->data, db_cb->db_num);
+       mask = readw(ndev->reg_ofs.ldb_mask);
+       set_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+       writew(mask, ndev->reg_ofs.ldb_mask);
+
+       tasklet_schedule(&db_cb->irq_work);
 
        /* On Sandybridge, there are 16 bits in the interrupt register
         * but only 4 vectors.  So, 5 bits are assigned to the first 3
@@ -986,7 +1039,7 @@ static irqreturn_t xeon_event_msix_irq(int irq, void *dev)
                dev_err(&ndev->pdev->dev, "Error determining link status\n");
 
        /* bit 15 is always the link bit */
-       writew(1 << ndev->limits.max_db_bits, ndev->reg_ofs.ldb);
+       writew(1 << SNB_LINK_DB, ndev->reg_ofs.ldb);
 
        return IRQ_HANDLED;
 }
@@ -1075,6 +1128,10 @@ static int ntb_setup_msix(struct ntb_device *ndev)
                         "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
                         rc);
                msix_entries = rc;
+
+               rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
+               if (rc)
+                       goto err1;
        }
 
        for (i = 0; i < msix_entries; i++) {
@@ -1176,9 +1233,10 @@ static int ntb_setup_interrupts(struct ntb_device *ndev)
         */
        if (ndev->hw_type == BWD_HW)
                writeq(~0, ndev->reg_ofs.ldb_mask);
-       else
-               writew(~(1 << ndev->limits.max_db_bits),
-                      ndev->reg_ofs.ldb_mask);
+       else {
+               u16 var = 1 << SNB_LINK_DB;
+               writew(~var, ndev->reg_ofs.ldb_mask);
+       }
 
        rc = ntb_setup_msix(ndev);
        if (!rc)
@@ -1286,6 +1344,39 @@ static void ntb_free_debugfs(struct ntb_device *ndev)
        }
 }
 
+static void ntb_hw_link_up(struct ntb_device *ndev)
+{
+       if (ndev->conn_type == NTB_CONN_TRANSPARENT)
+               ntb_link_event(ndev, NTB_LINK_UP);
+       else {
+               u32 ntb_cntl;
+
+               /* Let's bring the NTB link up */
+               ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+               ntb_cntl &= ~(NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK);
+               ntb_cntl |= NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP;
+               ntb_cntl |= NTB_CNTL_P2S_BAR45_SNOOP | NTB_CNTL_S2P_BAR45_SNOOP;
+               writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+       }
+}
+
+static void ntb_hw_link_down(struct ntb_device *ndev)
+{
+       u32 ntb_cntl;
+
+       if (ndev->conn_type == NTB_CONN_TRANSPARENT) {
+               ntb_link_event(ndev, NTB_LINK_DOWN);
+               return;
+       }
+
+       /* Bring NTB link down */
+       ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+       ntb_cntl &= ~(NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP);
+       ntb_cntl &= ~(NTB_CNTL_P2S_BAR45_SNOOP | NTB_CNTL_S2P_BAR45_SNOOP);
+       ntb_cntl |= NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK;
+       writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+}
+
 static int ntb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
        struct ntb_device *ndev;
@@ -1374,9 +1465,7 @@ static int ntb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (rc)
                goto err6;
 
-       /* Let's bring the NTB link up */
-       writel(NTB_CNTL_BAR23_SNOOP | NTB_CNTL_BAR45_SNOOP,
-              ndev->reg_ofs.lnk_cntl);
+       ntb_hw_link_up(ndev);
 
        return 0;
 
@@ -1406,12 +1495,8 @@ static void ntb_pci_remove(struct pci_dev *pdev)
 {
        struct ntb_device *ndev = pci_get_drvdata(pdev);
        int i;
-       u32 ntb_cntl;
 
-       /* Bring NTB link down */
-       ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
-       ntb_cntl |= NTB_CNTL_LINK_DISABLE;
-       writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+       ntb_hw_link_down(ndev);
 
        ntb_transport_free(ndev->ntb_transport);