NTB: Disable interrupts and poll under high load

[linux-drm-fsl-dcu.git] / drivers / ntb / ntb_hw.c

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index 80505aeecf9e13b40b225048f0630e3e239c0edf..170e8e60cdb7fe3d47307d4b9146039e3af7f3a8 100644 (file)
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -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;
 }
 
@@ -955,12 +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.
@@ -976,12 +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