[PATCH] htirq: allow buggy drivers of buggy hardware to write the registers

This patch adds a variant of ht_create_irq __ht_create_irq that takes an
aditional parameter update that is a function that is called whenever we want
to write to a drivers htirq configuration registers.

This is needed to support the ipath_iba6110 because it's registers in the
proper location are not actually conected to the hardware that controlls
interrupt delivery.

[[e-mail]: fixes]
Signed-off-by: Eric W. Biederman <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: <[e-mail]>
Cc: Roland Dreier <[e-mail]>
Signed-off-by: Bryan O'Sullivan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/pci/htirq.c

···
 
 struct ht_irq_cfg {
 	struct pci_dev *dev;
+	 /* Update callback used to cope with buggy hardware */
+	ht_irq_update_t *update;
 	unsigned pos;
 	unsigned idx;
 	struct ht_irq_msg msg;
···
 		pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
 		pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_hi);
 	}
+	if (cfg->update)
+		cfg->update(cfg->dev, irq, msg);
 	spin_unlock_irqrestore(&ht_irq_lock, flags);
 	cfg->msg = *msg;
 }
···
 }
 
 /**
- * ht_create_irq - create an irq and attach it to a device.
+ * __ht_create_irq - create an irq and attach it to a device.
  * @dev: The hypertransport device to find the irq capability on.
  * @idx: Which of the possible irqs to attach to.
- *
- * ht_create_irq is needs to be called for all hypertransport devices
- * that generate irqs.
+ * @update: Function to be called when changing the htirq message
  *
  * The irq number of the new irq or a negative error value is returned.
  */
-int ht_create_irq(struct pci_dev *dev, int idx)
+int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
 {
 	struct ht_irq_cfg *cfg;
 	unsigned long flags;
···
 		return -ENOMEM;
 
 	cfg->dev = dev;
+	cfg->update = update;
 	cfg->pos = pos;
 	cfg->idx = 0x10 + (idx * 2);
 	/* Initialize msg to a value that will never match the first write. */
···
 }
 
 /**
+ * ht_create_irq - create an irq and attach it to a device.
+ * @dev: The hypertransport device to find the irq capability on.
+ * @idx: Which of the possible irqs to attach to.
+ *
+ * ht_create_irq needs to be called for all hypertransport devices
+ * that generate irqs.
+ *
+ * The irq number of the new irq or a negative error value is returned.
+ */
+int ht_create_irq(struct pci_dev *dev, int idx)
+{
+	return __ht_create_irq(dev, idx, NULL);
+}
+
+/**
  * ht_destroy_irq - destroy an irq created with ht_create_irq
  *
  * This reverses ht_create_irq removing the specified irq from
···
 	kfree(cfg);
 }
 
+EXPORT_SYMBOL(__ht_create_irq);
 EXPORT_SYMBOL(ht_create_irq);
 EXPORT_SYMBOL(ht_destroy_irq);

include/linux/htirq.h

···
 /* The arch hook for getting things started */
 int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev);
 
+/* For drivers of buggy hardware */
+typedef void (ht_irq_update_t)(struct pci_dev *dev, int irq,
+			       struct ht_irq_msg *msg);
+int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update);
+
 #endif /* LINUX_HTIRQ_H */