PCI: endpoint: Remove "core_init_notifier" flag

"core_init_notifier" flag is set by the glue drivers requiring refclk from
the host to complete the DWC core initialization. Also, those drivers will
send a notification to the EPF drivers once the initialization is fully
completed using the pci_epc_init_notify() API. Only then, the EPF drivers
will start functioning.

For the rest of the drivers generating refclk locally, EPF drivers will
start functioning post binding with them. EPF drivers rely on the
'core_init_notifier' flag to differentiate between the drivers.
Unfortunately, this creates two different flows for the EPF drivers.

So to avoid that, let's get rid of the "core_init_notifier" flag and follow
a single initialization flow for the EPF drivers. This is done by calling
the dw_pcie_ep_init_notify() from all glue drivers after the completion of
dw_pcie_ep_init_registers() API. This will allow all the glue drivers to
send the notification to the EPF drivers once the initialization is fully
completed.

Only difference here is that, the drivers requiring refclk from host will
send the notification once refclk is received, while others will send it
during probe time itself.

But this also requires the EPC core driver to deliver the notification
after EPF driver bind. Because, the glue driver can send the notification
before the EPF drivers bind() and in those cases the EPF drivers will miss
the event. To accommodate this, EPC core is now caching the state of the
EPC initialization in 'init_complete' flag and pci-ep-cfs driver sends the
notification to EPF drivers based on that after each EPF driver bind.

Link: https://lore.kernel.org/linux-pci/20240327-pci-dbi-rework-v12-8-082625472414@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>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

3 files changed, 36 insertions, 13 deletions

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index cd4ffb39dcdc..212fc303fb63 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -753,6 +753,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
 	const struct pci_epc_features *epc_features;
 	struct pci_epc *epc = epf->epc;
 	struct device *dev = &epf->dev;
+	bool linkup_notifier = false;
 	bool msix_capable = false;
 	bool msi_capable = true;
 	int ret;
@@ -795,6 +796,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
 		}
 	}
 
+	linkup_notifier = epc_features->linkup_notifier;
+	if (!linkup_notifier)
+		queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
+
 	return 0;
 }
 
@@ -890,8 +895,6 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 	const struct pci_epc_features *epc_features;
 	enum pci_barno test_reg_bar = BAR_0;
 	struct pci_epc *epc = epf->epc;
-	bool linkup_notifier = false;
-	bool core_init_notifier = false;
 
 	if (WARN_ON_ONCE(!epc))
 		return -EINVAL;
@@ -902,8 +905,6 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 		return -EOPNOTSUPP;
 	}
 
-	linkup_notifier = epc_features->linkup_notifier;
-	core_init_notifier = epc_features->core_init_notifier;
 	test_reg_bar = pci_epc_get_first_free_bar(epc_features);
 	if (test_reg_bar < 0)
 		return -EINVAL;
@@ -916,21 +917,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 	if (ret)
 		return ret;
 
-	if (!core_init_notifier) {
-		ret = pci_epf_test_core_init(epf);
-		if (ret)
-			return ret;
-	}
-
 	epf_test->dma_supported = true;
 
 	ret = pci_epf_test_init_dma_chan(epf_test);
 	if (ret)
 		epf_test->dma_supported = false;
 
-	if (!linkup_notifier && !core_init_notifier)
-		queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
-
 	return 0;
 }
 
diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 0ea64e24ed61..3b21e28f9b59 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -64,6 +64,9 @@ static int pci_secondary_epc_epf_link(struct config_item *epf_item,
 		return ret;
 	}
 
+	/* Send any pending EPC initialization complete to the EPF driver */
+	pci_epc_notify_pending_init(epc, epf);
+
 	return 0;
 }
 
@@ -125,6 +128,9 @@ static int pci_primary_epc_epf_link(struct config_item *epf_item,
 		return ret;
 	}
 
+	/* Send any pending EPC initialization complete to the EPF driver */
+	pci_epc_notify_pending_init(epc, epf);
+
 	return 0;
 }
 
@@ -230,6 +236,9 @@ static int pci_epc_epf_link(struct config_item *epc_item,
 		return ret;
 	}
 
+	/* Send any pending EPC initialization complete to the EPF driver */
+	pci_epc_notify_pending_init(epc, epf);
+
 	return 0;
 }
 
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index da3fc0795b0b..47d27ec7439d 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -748,11 +748,33 @@ void pci_epc_init_notify(struct pci_epc *epc)
 			epf->event_ops->core_init(epf);
 		mutex_unlock(&epf->lock);
 	}
+	epc->init_complete = true;
 	mutex_unlock(&epc->list_lock);
 }
 EXPORT_SYMBOL_GPL(pci_epc_init_notify);
 
 /**
+ * pci_epc_notify_pending_init() - Notify the pending EPC device initialization
+ *                                 complete to the EPF device
+ * @epc: the EPC device whose core initialization is pending to be notified
+ * @epf: the EPF device to be notified
+ *
+ * Invoke to notify the pending EPC device initialization complete to the EPF
+ * device. This is used to deliver the notification if the EPC initialization
+ * got completed before the EPF driver bind.
+ */
+void pci_epc_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf)
+{
+	if (epc->init_complete) {
+		mutex_lock(&epf->lock);
+		if (epf->event_ops && epf->event_ops->core_init)
+			epf->event_ops->core_init(epf);
+		mutex_unlock(&epf->lock);
+	}
+}
+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