powernv/eeh: Update the EEH code to use the opal irq domain

The eeh code currently uses the old notifier method to get eeh events
from OPAL. It also contains some logic to filter opal events which has
been moved into the virtual irqchip. This patch converts the eeh code
to the new event interface which simplifies event handling.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/eeh-powernv.c

@@ -16,6 +16,7 @@
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/msi.h>
 #include <linux/of.h>
@@ -40,6 +41,7 @@
 #include "pci.h"
 
 static bool pnv_eeh_nb_init = false;
+static int eeh_event_irq = -EINVAL;
 
 /**
  * pnv_eeh_init - EEH platform dependent initialization
@@ -88,34 +90,22 @@ static int pnv_eeh_init(void)
 	return 0;
 }
 
-static int pnv_eeh_event(struct notifier_block *nb,
-			 unsigned long events, void *change)
+static irqreturn_t pnv_eeh_event(int irq, void *data)
 {
-	uint64_t changed_evts = (uint64_t)change;
-
 	/*
-	 * We simply send special EEH event if EEH has
-	 * been enabled, or clear pending events in
-	 * case that we enable EEH soon
+	 * We simply send a special EEH event if EEH has been
+	 * enabled. We don't care about EEH events until we've
+	 * finished processing the outstanding ones. Event processing
+	 * gets unmasked in next_error() if EEH is enabled.
 	 */
-	if (!(changed_evts & OPAL_EVENT_PCI_ERROR) ||
-	    !(events & OPAL_EVENT_PCI_ERROR))
-		return 0;
+	disable_irq_nosync(irq);
 
 	if (eeh_enabled())
 		eeh_send_failure_event(NULL);
-	else
-		opal_notifier_update_evt(OPAL_EVENT_PCI_ERROR, 0x0ul);
 
-	return 0;
+	return IRQ_HANDLED;
 }
 
-static struct notifier_block pnv_eeh_nb = {
-	.notifier_call	= pnv_eeh_event,
-	.next		= NULL,
-	.priority	= 0
-};
-
 #ifdef CONFIG_DEBUG_FS
 static ssize_t pnv_eeh_ei_write(struct file *filp,
 				const char __user *user_buf,
@@ -237,16 +227,28 @@ static int pnv_eeh_post_init(void)
 
 	/* Register OPAL event notifier */
 	if (!pnv_eeh_nb_init) {
-		ret = opal_notifier_register(&pnv_eeh_nb);
-		if (ret) {
-			pr_warn("%s: Can't register OPAL event notifier (%d)\n",
-				__func__, ret);
+		eeh_event_irq = opal_event_request(ilog2(OPAL_EVENT_PCI_ERROR));
+		if (eeh_event_irq < 0) {
+			pr_err("%s: Can't register OPAL event interrupt (%d)\n",
+			       __func__, eeh_event_irq);
+			return eeh_event_irq;
+		}
+
+		ret = request_irq(eeh_event_irq, pnv_eeh_event,
+				IRQ_TYPE_LEVEL_HIGH, "opal-eeh", NULL);
+		if (ret < 0) {
+			irq_dispose_mapping(eeh_event_irq);
+			pr_err("%s: Can't request OPAL event interrupt (%d)\n",
+			       __func__, eeh_event_irq);
 			return ret;
 		}
 
 		pnv_eeh_nb_init = true;
 	}
 
+	if (!eeh_enabled())
+		disable_irq(eeh_event_irq);
+
 	list_for_each_entry(hose, &hose_list, list_node) {
 		phb = hose->private_data;
 
@@ -1303,12 +1305,10 @@ static int pnv_eeh_next_error(struct eeh_pe **pe)
 	int state, ret = EEH_NEXT_ERR_NONE;
 
 	/*
-	 * While running here, it's safe to purge the event queue.
-	 * And we should keep the cached OPAL notifier event sychronized
-	 * between the kernel and firmware.
+	 * While running here, it's safe to purge the event queue. The
+	 * event should still be masked.
 	 */
 	eeh_remove_event(NULL, false);
-	opal_notifier_update_evt(OPAL_EVENT_PCI_ERROR, 0x0ul);
 
 	list_for_each_entry(hose, &hose_list, list_node) {
 		/*
@@ -1477,6 +1477,10 @@ static int pnv_eeh_next_error(struct eeh_pe **pe)
 			break;
 	}
 
+	/* Unmask the event */
+	if (eeh_enabled())
+		enable_irq(eeh_event_irq);
+
 	return ret;
 }