PCI: endpoint: Use notification chain mechanism to notify EPC events to EPF

Use atomic_notifier_call_chain() to notify EPC events like linkup to EPF
driver instead of using linkup ops in EPF driver. This is in preparation
for adding proper locking mechanism to EPF ops. This will also enable to
add more events (in addition to linkup) in the future.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Vidya Sagar <vidyas@nvidia.com>

3 files changed, 13 insertions, 31 deletions

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 5d74f81ddfe4..bddff15052cc 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -360,12 +360,16 @@ reset_handler:
 			   msecs_to_jiffies(1));
 }
 
-static void pci_epf_test_linkup(struct pci_epf *epf)
+static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val,
+				 void *data)
 {
+	struct pci_epf *epf = container_of(nb, struct pci_epf, nb);
 	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
 
 	queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
 			   msecs_to_jiffies(1));
+
+	return NOTIFY_OK;
 }
 
 static void pci_epf_test_unbind(struct pci_epf *epf)
@@ -546,8 +550,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 		}
 	}
 
-	if (!linkup_notifier)
+	if (linkup_notifier) {
+		epf->nb.notifier_call = pci_epf_test_notifier;
+		pci_epc_register_notifier(epc, &epf->nb);
+	} else {
 		queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
+	}
 
 	return 0;
 }
@@ -580,7 +588,6 @@ static int pci_epf_test_probe(struct pci_epf *epf)
 static struct pci_epf_ops ops = {
 	.unbind	= pci_epf_test_unbind,
 	.bind	= pci_epf_test_bind,
-	.linkup = pci_epf_test_linkup,
 };
 
 static struct pci_epf_driver test_driver = {
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 2091508c1620..2f6436599fcb 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -539,16 +539,10 @@ EXPORT_SYMBOL_GPL(pci_epc_remove_epf);
  */
 void pci_epc_linkup(struct pci_epc *epc)
 {
-	unsigned long flags;
-	struct pci_epf *epf;
-
 	if (!epc || IS_ERR(epc))
 		return;
 
-	spin_lock_irqsave(&epc->lock, flags);
-	list_for_each_entry(epf, &epc->pci_epf, list)
-		pci_epf_linkup(epf);
-	spin_unlock_irqrestore(&epc->lock, flags);
+	atomic_notifier_call_chain(&epc->notifier, 0, NULL);
 }
 EXPORT_SYMBOL_GPL(pci_epc_linkup);
 
@@ -612,6 +606,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 
 	spin_lock_init(&epc->lock);
 	INIT_LIST_HEAD(&epc->pci_epf);
+	ATOMIC_INIT_NOTIFIER_HEAD(&epc->notifier);
 
 	device_initialize(&epc->dev);
 	epc->dev.class = pci_epc_class;
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index fb1306de8f40..93f28c65ace0 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -21,26 +21,6 @@ static struct bus_type pci_epf_bus_type;
 static const struct device_type pci_epf_type;
 
 /**
- * pci_epf_linkup() - Notify the function driver that EPC device has
- *		      established a connection with the Root Complex.
- * @epf: the EPF device bound to the EPC device which has established
- *	 the connection with the host
- *
- * Invoke to notify the function driver that EPC device has established
- * a connection with the Root Complex.
- */
-void pci_epf_linkup(struct pci_epf *epf)
-{
-	if (!epf->driver) {
-		dev_WARN(&epf->dev, "epf device not bound to driver\n");
-		return;
-	}
-
-	epf->driver->ops->linkup(epf);
-}
-EXPORT_SYMBOL_GPL(pci_epf_linkup);
-
-/**
  * pci_epf_unbind() - Notify the function driver that the binding between the
  *		      EPF device and EPC device has been lost
  * @epf: the EPF device which has lost the binding with the EPC device
@@ -214,7 +194,7 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
 	if (!driver->ops)
 		return -EINVAL;
 
-	if (!driver->ops->bind || !driver->ops->unbind || !driver->ops->linkup)
+	if (!driver->ops->bind || !driver->ops->unbind)
 		return -EINVAL;
 
 	driver->driver.bus = &pci_epf_bus_type;