PCI: endpoint: Rename BME to Bus Master Enable

BME which stands for 'Bus Master Enable' is not defined in the PCIe base
spec even though it is commonly referred in many places (vendor docs).  To
align with the spec, rename it to its expansion 'Bus Master Enable'.

Suggested-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/linux-pci/20240430-pci-epf-rework-v4-3-22832d0d456f@linaro.org
Link: https://lore.kernel.org/linux-pci/20240430-pci-epf-rework-v4-4-22832d0d456f@linaro.org
Tested-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: squash removal of irrelevant 'Link is enabled']
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

Author: Mani-Sadhasivam

drivers/pci/controller/dwc/pcie-qcom-ep.c

@@ -642,10 +642,10 @@ static irqreturn_t qcom_pcie_ep_global_irq_thread(int irq, void *data)
 		pcie_ep->link_status = QCOM_PCIE_EP_LINK_DOWN;
 		pci_epc_linkdown(pci->ep.epc);
 	} else if (FIELD_GET(PARF_INT_ALL_BME, status)) {
-		dev_dbg(dev, "Received BME event. Link is enabled!\n");
+		dev_dbg(dev, "Received Bus Master Enable event\n");
 		pcie_ep->link_status = QCOM_PCIE_EP_LINK_ENABLED;
 		qcom_pcie_ep_icc_update(pcie_ep);
-		pci_epc_bme_notify(pci->ep.epc);
+		pci_epc_bus_master_enable_notify(pci->ep.epc);
 	} else if (FIELD_GET(PARF_INT_ALL_PM_TURNOFF, status)) {
 		dev_dbg(dev, "Received PM Turn-off event! Entering L23\n");
 		val = readl_relaxed(pcie_ep->parf + PARF_PM_CTRL);

drivers/pci/endpoint/functions/pci-epf-mhi.c

@@ -819,7 +819,7 @@ static int pci_epf_mhi_link_down(struct pci_epf *epf)
 	return 0;
 }
 
-static int pci_epf_mhi_bme(struct pci_epf *epf)
+static int pci_epf_mhi_bus_master_enable(struct pci_epf *epf)
 {
 	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
 	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
@@ -882,8 +882,8 @@ static void pci_epf_mhi_unbind(struct pci_epf *epf)
 
 	/*
 	 * Forcefully power down the MHI EP stack. Only way to bring the MHI EP
-	 * stack back to working state after successive bind is by getting BME
-	 * from host.
+	 * stack back to working state after successive bind is by getting Bus
+	 * Master Enable event from host.
 	 */
 	if (mhi_cntrl->mhi_dev) {
 		mhi_ep_power_down(mhi_cntrl);
@@ -900,7 +900,7 @@ static const struct pci_epc_event_ops pci_epf_mhi_event_ops = {
 	.epc_init = pci_epf_mhi_epc_init,
 	.link_up = pci_epf_mhi_link_up,
 	.link_down = pci_epf_mhi_link_down,
-	.bme = pci_epf_mhi_bme,
+	.bus_master_enable = pci_epf_mhi_bus_master_enable,
 };
 
 static int pci_epf_mhi_probe(struct pci_epf *epf,

drivers/pci/endpoint/pci-epc-core.c

@@ -775,14 +775,15 @@ void pci_epc_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf)
 EXPORT_SYMBOL_GPL(pci_epc_notify_pending_init);
 
 /**
- * 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
+ * pci_epc_bus_master_enable_notify() - Notify the EPF device that the EPC
+ *					device has received the Bus Master
+ *					Enable event from the Root complex
+ * @epc: the EPC device that received the Bus Master Enable event
  *
- * Invoke to Notify the EPF device that the EPC device has received the Bus
- * Master Enable (BME) event from the Root complex
+ * Notify the EPF device that the EPC device has generated the Bus Master Enable
+ * event due to host setting the Bus Master Enable bit in the Command register.
  */
-void pci_epc_bme_notify(struct pci_epc *epc)
+void pci_epc_bus_master_enable_notify(struct pci_epc *epc)
 {
 	struct pci_epf *epf;
 
@@ -792,13 +793,13 @@ void pci_epc_bme_notify(struct pci_epc *epc)
 	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->bme)
-			epf->event_ops->bme(epf);
+		if (epf->event_ops && epf->event_ops->bus_master_enable)
+			epf->event_ops->bus_master_enable(epf);
 		mutex_unlock(&epf->lock);
 	}
 	mutex_unlock(&epc->list_lock);
 }
-EXPORT_SYMBOL_GPL(pci_epc_bme_notify);
+EXPORT_SYMBOL_GPL(pci_epc_bus_master_enable_notify);
 
 /**
  * pci_epc_destroy() - destroy the EPC device

include/linux/pci-epc.h

@@ -226,7 +226,7 @@ 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_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf);
-void pci_epc_bme_notify(struct pci_epc *epc);
+void pci_epc_bus_master_enable_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, u8 vfunc_no,

include/linux/pci-epf.h

@@ -73,13 +73,13 @@ struct pci_epf_ops {
  * @epc_init: Callback for the EPC initialization complete event
  * @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
+ * @bus_master_enable: Callback for the EPC Bus Master Enable event
  */
 struct pci_epc_event_ops {
 	int (*epc_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 (*bus_master_enable)(struct pci_epf *epf);
 };
 
 /**