[PATCH v6 1/4] PCI: endpoint: Add D-state change notifier support

[Krishna chaitanya chundru <quic_krichai@quicinc.com>]

Add support to notify the EPF device about the D-state change event
from the EPC device.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 Documentation/PCI/endpoint/pci-endpoint.rst |  4 ++++
 drivers/pci/endpoint/pci-epc-core.c         | 24 ++++++++++++++++++++++++
 include/linux/pci-epc.h                     |  1 +
 include/linux/pci-epf.h                     |  2 ++
 4 files changed, 31 insertions(+)

diff --git a/Documentation/PCI/endpoint/pci-endpoint.rst b/Documentation/PCI/endpoint/pci-endpoint.rst
index 4f5622a65555..a1d610f612b4 100644
--- a/Documentation/PCI/endpoint/pci-endpoint.rst
+++ b/Documentation/PCI/endpoint/pci-endpoint.rst
@@ -78,6 +78,10 @@ by the PCI controller driver.
    Cleanup the pci_epc_mem structure allocated during pci_epc_mem_init().
 
 
+* pci_epc_dstate_notify()
+
+   Notify all the function drivers that the EPC device has changed its D-state.
+
 EPC APIs for the PCI Endpoint Function Driver
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 5a4a8b0be626..4d589a5c96f0 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -783,6 +783,30 @@ void pci_epc_bme_notify(struct pci_epc *epc)
 }
 EXPORT_SYMBOL_GPL(pci_epc_bme_notify);
 
+/**
+ * pci_epc_dstate_notify() - Notify the EPF driver that EPC device D-state
+ *			has changed
+ * @epc: the EPC device which has change in D-state
+ * @state: the changed D-state
+ *
+ * Invoke to Notify the EPF device that the EPC device D-state has
+ * changed.
+ */
+void pci_epc_dstate_notify(struct pci_epc *epc, pci_power_t state)
+{
+	struct pci_epf *epf;
+
+	mutex_lock(&epc->list_lock);
+	list_for_each_entry(epf, &epc->pci_epf, list) {
+		mutex_lock(&epf->lock);
+		if (epf->event_ops && epf->event_ops->dstate_notify)
+			epf->event_ops->dstate_notify(epf, state);
+		mutex_unlock(&epf->lock);
+	}
+	mutex_unlock(&epc->list_lock);
+}
+EXPORT_SYMBOL_GPL(pci_epc_dstate_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 5cb694031072..225a5a88627f 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -251,4 +251,5 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
 				     phys_addr_t *phys_addr, size_t size);
 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
 			   void __iomem *virt_addr, size_t size);
+void pci_epc_dstate_notify(struct pci_epc *epc, pci_power_t state);
 #endif /* __LINUX_PCI_EPC_H */
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 3f44b6aec477..b2178bb0e976 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -73,12 +73,14 @@ struct pci_epf_ops {
  * @link_up: Callback for the EPC link up event
  * @link_down: Callback for the EPC link down event
  * @bme: Callback for the EPC BME (Bus Master Enable) event
+ * @dstate_notify: Callback for the EPC D-state change event
  */
 struct pci_epc_event_ops {
 	int (*core_init)(struct pci_epf *epf);
 	int (*link_up)(struct pci_epf *epf);
 	int (*link_down)(struct pci_epf *epf);
 	int (*bme)(struct pci_epf *epf);
+	int (*dstate_notify)(struct pci_epf *epf, pci_power_t state);
 };
 
 /**

-- 
2.42.0