[PATCH 2/5] PCI: endpoint: Add BME notifier support

[Manivannan Sadhasivam]

Add support to notify the EPF device about the Bus Master Enable (BME)
event received by the EPC device from the Root complex.

Usage:
======

EPC
---

```
static irqreturn_t pcie_ep_irq(int irq, void *data)
{
...
	case PCIE_EP_INT_BME:
		pci_epc_bme_notify(epc);
		break;
...
}
```

EPF
---

```
static int pci_epf_notifier(struct notifier_block *nb, unsigned long val,
			    void *data)
{
...
	case BME:
		/* Handle BME event */
		break;
...
}
```

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
 drivers/pci/endpoint/pci-epc-core.c | 17 +++++++++++++++++
 include/linux/pci-epc.h             |  1 +
 include/linux/pci-epf.h             |  1 +
 3 files changed, 19 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index f29d78c18438..7e42a83a4877 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -675,6 +675,23 @@ void pci_epc_init_notify(struct pci_epc *epc)
 }
 EXPORT_SYMBOL_GPL(pci_epc_init_notify);
 
+/**
+ * pci_epc_bme_notify() - Notify the EPF device that the EPC device has received
+ *			  the BME event from the Root complex
+ * @epc: the EPC device that received the BME event
+ *
+ * Invoke to Notify the EPF device that the EPC device has received the Bus
+ * Master Enable (BME) event from the Root complex
+ */
+void pci_epc_bme_notify(struct pci_epc *epc)
+{
+	if (!epc || IS_ERR(epc))
+		return;
+
+	atomic_notifier_call_chain(&epc->notifier, BME, NULL);
+}
+EXPORT_SYMBOL_GPL(pci_epc_bme_notify);
+
 /**
  * pci_epc_destroy() - destroy the EPC device
  * @epc: the EPC device that has to be destroyed
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 23590efc13e7..6c2cff33f670 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -204,6 +204,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
 void pci_epc_linkup(struct pci_epc *epc);
 void pci_epc_linkdown(struct pci_epc *epc);
 void pci_epc_init_notify(struct pci_epc *epc);
+void pci_epc_bme_notify(struct pci_epc *epc);
 void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
 			enum pci_epc_interface_type type);
 int pci_epc_write_header(struct pci_epc *epc, u8 func_no,
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index e9ad634b1575..063a59a58e3c 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -21,6 +21,7 @@ enum pci_notify_event {
 	CORE_INIT,
 	LINK_UP,
 	LINK_DOWN,
+	BME,
 };
 
 enum pci_barno {
-- 
2.25.1