PCI: endpoint: Add EPC 'deinit' event and dw_pcie_ep_linkdown() API

Currently dw_pcie_ep_init_notify() wrapper just calls pci_epc_init_notify() directly. So this wrapper provides no benefit to the glue drivers.

So let's remove it and call pci_epc_init_notify() directly from glue drivers.

Suggested-by Bjorn Helgaas <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

Currently dw_pcie_ep_init_notify() wrapper just calls pci_epc_init_notify() directly. So this wrapper provides no benefit to the glue drivers.

So let's remove it and call pci_epc_init_notify() directly from glue drivers.

Suggested-by Bjorn Helgaas <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
 drivers/pci/controller/dwc/pci-dra7xx.c           |  2 +-
 drivers/pci/controller/dwc/pci-imx6.c             |  2 +-
 drivers/pci/controller/dwc/pci-keystone.c         |  2 +-
 drivers/pci/controller/dwc/pci-layerscape-ep.c    |  2 +-
 drivers/pci/controller/dwc/pcie-artpec6.c         |  2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c   | 12 ------------
 drivers/pci/controller/dwc/pcie-designware-plat.c |  2 +-
 drivers/pci/controller/dwc/pcie-designware.h      |  5 -----
 drivers/pci/controller/dwc/pcie-keembay.c         |  2 +-
 drivers/pci/controller/dwc/pcie-qcom-ep.c         |  2 +-
 drivers/pci/controller/dwc/pcie-rcar-gen4.c       |  2 +-
 drivers/pci/controller/dwc/pcie-tegra194.c        |  2 +-
 drivers/pci/controller/dwc/pcie-uniphier-ep.c     |  2 +-
 13 files changed, 11 insertions(+), 28 deletions(-)

drivers/pci/controller/dwc/pci-dra7xx.c +1 -1

index d2d17d37d3e0..e491d0ff3962 100644
@@ -474,7 +474,7 @@ static int dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
 		return ret;
 	}
 
-	dw_pcie_ep_init_notify(ep);
+	pci_epc_init_notify(ep->epc);
 
 	return 0;
 }

drivers/pci/controller/dwc/pci-imx6.c +1 -1

index 917c69edee1d..a876b8e6e741 100644
@@ -1131,7 +1131,7 @@ static int imx6_add_pcie_ep(struct imx6_pcie *imx6_pcie,
 		return ret;
 	}
 
-	dw_pcie_ep_init_notify(ep);
+	pci_epc_init_notify(ep->epc);
 
 	/* Start LTSSM. */
 	imx6_pcie_ltssm_enable(dev);

drivers/pci/controller/dwc/pci-keystone.c +1 -1

index d3a7d14ee685..ca1054f5c79a 100644
@@ -1293,7 +1293,7 @@ static int ks_pcie_probe(struct platform_device *pdev)
 			goto err_ep_init;
 		}
 
-		dw_pcie_ep_init_notify(&pci->ep);
+		pci_epc_init_notify(pci->ep.epc);
 
 		break;
 	default:

drivers/pci/controller/dwc/pci-layerscape-ep.c +1 -1

index 7dde6d5fa4d8..35bb481564c7 100644
@@ -286,7 +286,7 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	dw_pcie_ep_init_notify(&pci->ep);
+	pci_epc_init_notify(pci->ep.epc);
 
 	return ls_pcie_ep_interrupt_init(pcie, pdev);
 }

drivers/pci/controller/dwc/pcie-artpec6.c +1 -1

index a4630b92489b..dc8dd7f27b78 100644
@@ -452,7 +452,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
 			return ret;
 		}
 
-		dw_pcie_ep_init_notify(&pci->ep);
+		pci_epc_init_notify(pci->ep.epc);
 
 		break;
 	default:

drivers/pci/controller/dwc/pcie-designware-ep.c +0 -12

index 47391d7d3a73..2e69f81baf99 100644
@@ -27,18 +27,6 @@ void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup);
 
-/**
- * dw_pcie_ep_init_notify - Notify EPF drivers about EPC initialization complete
- * @ep: DWC EP device
- */
-void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
-{
-	struct pci_epc *epc = ep->epc;
-
-	pci_epc_init_notify(epc);
-}
-EXPORT_SYMBOL_GPL(dw_pcie_ep_init_notify);
-
 /**
  * dw_pcie_ep_get_func_from_ep - Get the struct dw_pcie_ep_func corresponding to
  *				 the endpoint function

drivers/pci/controller/dwc/pcie-designware-plat.c +1 -1

index 8490c5d6ff9f..771b9d9be077 100644
@@ -154,7 +154,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
 			dw_pcie_ep_deinit(&pci->ep);
 		}
 
-		dw_pcie_ep_init_notify(&pci->ep);
+		pci_epc_init_notify(pci->ep.epc);
 
 		break;
 	default:

drivers/pci/controller/dwc/pcie-designware.h +0 -5

index f8e5431a207b..49ae845a3662 100644
@@ -670,7 +670,6 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus,
 void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
 int dw_pcie_ep_init(struct dw_pcie_ep *ep);
 int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep);
-void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep);
 void dw_pcie_ep_deinit(struct dw_pcie_ep *ep);
 void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep);
 int dw_pcie_ep_raise_intx_irq(struct dw_pcie_ep *ep, u8 func_no);

@@ -698,10 +697,6 @@ static inline int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
 	return 0;
 }
 
-static inline void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
-{
-}
-
 static inline void dw_pcie_ep_deinit(struct dw_pcie_ep *ep)
 {
 }

drivers/pci/controller/dwc/pcie-keembay.c +1 -1

index 98bbc83182b4..278205db60a2 100644
@@ -442,7 +442,7 @@ static int keembay_pcie_probe(struct platform_device *pdev)
 			return ret;
 		}
 
-		dw_pcie_ep_init_notify(&pci->ep);
+		pci_epc_init_notify(pci->ep.epc);
 
 		break;
 	default:

drivers/pci/controller/dwc/pcie-qcom-ep.c +1 -1

index 1ecf602c225a..4d2d7457dcb3 100644
@@ -482,7 +482,7 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
 	val &= ~PARF_MSTR_AXI_CLK_EN;
 	writel_relaxed(val, pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
 
-	dw_pcie_ep_init_notify(&pcie_ep->pci.ep);
+	pci_epc_init_notify(pcie_ep->pci.ep.epc);
 
 	/* Enable LTSSM */
 	val = readl_relaxed(pcie_ep->parf + PARF_LTSSM);

drivers/pci/controller/dwc/pcie-rcar-gen4.c +1 -1

index cfeccc2f9ee1..237a6a8818de 100644
@@ -437,7 +437,7 @@ static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
 		rcar_gen4_pcie_ep_deinit(rcar);
 	}
 
-	dw_pcie_ep_init_notify(ep);
+	pci_epc_init_notify(ep->epc);
 
 	return ret;
 }

drivers/pci/controller/dwc/pcie-tegra194.c +1 -1

index 93f5433c5c55..432ed9d9a463 100644
@@ -1903,7 +1903,7 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 		goto fail_init_complete;
 	}
 
-	dw_pcie_ep_init_notify(ep);
+	pci_epc_init_notify(ep->epc);
 
 	/* Program the private control to allow sending LTR upstream */
 	if (pcie->of_data->has_ltr_req_fix) {

drivers/pci/controller/dwc/pcie-uniphier-ep.c +1 -1

index a2b844268e28..d6e73811216e 100644
@@ -410,7 +410,7 @@ static int uniphier_pcie_ep_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	dw_pcie_ep_init_notify(&priv->pci.ep);
+	pci_epc_init_notify(priv->pci.ep.epc);
 
 	return 0;
 }

Signature · 2 lines

-- 
2.25.1

Currently dw_pcie_ep_init_notify() wrapper just calls pci_epc_init_notify() directly. So this wrapper provides no benefit to the glue drivers.

So let's remove it and call pci_epc_init_notify() directly from glue drivers.

Suggested-by Bjorn Helgaas <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

---

As like the 'epc_init' event, that is used to signal the EPF drivers about the EPC initialization, let's introduce 'epc_deinit' event that is used to signal EPC deinitialization.

The EPC deinitialization applies only when any sort of fundamental reset is supported by the endpoint controller as per the PCIe spec.

Reference: PCIe Base spec v5.0, sections 4.2.4.9.1 and 6.6.1.

Currently, some EPC drivers like pcie-qcom-ep and pcie-tegra194 support PERST# as the fundamental reset. So the 'deinit' event will be notified to the EPF drivers when PERST# assert happens in the above mentioned EPC drivers.

The EPF drivers, on receiving the event through the epc_deinit() callback should reset the EPF state machine and also cleanup any configuration that got affected by the fundamental reset like BAR, DMA etc...

This change also warrants skipping the cleanups in unbind() if already done in epc_deinit().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

As like the 'epc_init' event, that is used to signal the EPF drivers about the EPC initialization, let's introduce 'epc_deinit' event that is used to signal EPC deinitialization.

The EPC deinitialization applies only when any sort of fundamental reset is supported by the endpoint controller as per the PCIe spec.

Reference: PCIe Base spec v5.0, sections 4.2.4.9.1 and 6.6.1.

Currently, some EPC drivers like pcie-qcom-ep and pcie-tegra194 support PERST# as the fundamental reset. So the 'deinit' event will be notified to the EPF drivers when PERST# assert happens in the above mentioned EPC drivers.

The EPF drivers, on receiving the event through the epc_deinit() callback should reset the EPF state machine and also cleanup any configuration that got affected by the fundamental reset like BAR, DMA etc...

This change also warrants skipping the cleanups in unbind() if already done in epc_deinit().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
 drivers/pci/controller/dwc/pcie-designware-ep.c |  1 -
 drivers/pci/controller/dwc/pcie-qcom-ep.c       |  1 +
 drivers/pci/controller/dwc/pcie-tegra194.c      |  1 +
 drivers/pci/endpoint/functions/pci-epf-mhi.c    | 19 +++++++++++++++++++
 drivers/pci/endpoint/functions/pci-epf-test.c   | 17 +++++++++++++++--
 drivers/pci/endpoint/pci-epc-core.c             | 25 +++++++++++++++++++++++++
 include/linux/pci-epc.h                         | 13 +++++++++++++
 include/linux/pci-epf.h                         |  2 ++
 8 files changed, 76 insertions(+), 3 deletions(-)

drivers/pci/controller/dwc/pcie-designware-ep.c +0 -1

index 2e69f81baf99..78d5fc72c9cb 100644
@@ -620,7 +620,6 @@ void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep)
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
 	dw_pcie_edma_remove(pci);
-	ep->epc->init_complete = false;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_cleanup);
 

drivers/pci/controller/dwc/pcie-qcom-ep.c +1 -0

index 4d2d7457dcb3..2324e56c9bfc 100644
@@ -507,6 +507,7 @@ static void qcom_pcie_perst_assert(struct dw_pcie *pci)
 		return;
 	}
 
+	pci_epc_deinit_notify(pci->ep.epc);
 	dw_pcie_ep_cleanup(&pci->ep);
 	qcom_pcie_disable_resources(pcie_ep);
 	pcie_ep->link_status = QCOM_PCIE_EP_LINK_DISABLED;

drivers/pci/controller/dwc/pcie-tegra194.c +1 -0

index 432ed9d9a463..4ca7404246a3 100644
@@ -1715,6 +1715,7 @@ static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie)
 	if (ret)
 		dev_err(pcie->dev, "Failed to go Detect state: %d\n", ret);
 
+	pci_epc_deinit_notify(pcie->pci.ep.epc);
 	dw_pcie_ep_cleanup(&pcie->pci.ep);
 
 	reset_control_assert(pcie->core_rst);

drivers/pci/endpoint/functions/pci-epf-mhi.c +19 -0

index 205c02953f25..5832989e55e8 100644
@@ -764,6 +764,24 @@ static int pci_epf_mhi_epc_init(struct pci_epf *epf)
 	return 0;
 }
 
+static void pci_epf_mhi_epc_deinit(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;
+	struct pci_epf_bar *epf_bar = &epf->bar[info->bar_num];
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+	struct pci_epc *epc = epf->epc;
+
+	if (mhi_cntrl->mhi_dev) {
+		mhi_ep_power_down(mhi_cntrl);
+		if (info->flags & MHI_EPF_USE_DMA)
+			pci_epf_mhi_dma_deinit(epf_mhi);
+		mhi_ep_unregister_controller(mhi_cntrl);
+	}
+
+	pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no, epf_bar);
+}
+
 static int pci_epf_mhi_link_up(struct pci_epf *epf)
 {
 	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);

@@ -898,6 +916,7 @@ static void pci_epf_mhi_unbind(struct pci_epf *epf)
 
 static const struct pci_epc_event_ops pci_epf_mhi_event_ops = {
 	.epc_init = pci_epf_mhi_epc_init,
+	.epc_deinit = pci_epf_mhi_epc_deinit,
 	.link_up = pci_epf_mhi_link_up,
 	.link_down = pci_epf_mhi_link_down,
 	.bus_master_enable = pci_epf_mhi_bus_master_enable,

drivers/pci/endpoint/functions/pci-epf-test.c +15 -2

index e771be7512a1..7c2ed6eae53a 100644
@@ -782,6 +782,15 @@ static int pci_epf_test_epc_init(struct pci_epf *epf)
 	return 0;
 }
 
+static void pci_epf_test_epc_deinit(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	cancel_delayed_work(&epf_test->cmd_handler);
+	pci_epf_test_clean_dma_chan(epf_test);
+	pci_epf_test_clear_bar(epf);
+}
+
 static int pci_epf_test_link_up(struct pci_epf *epf)
 {
 	struct pci_epf_test *epf_test = epf_get_drvdata(epf);

@@ -803,6 +812,7 @@ static int pci_epf_test_link_down(struct pci_epf *epf)
 
 static const struct pci_epc_event_ops pci_epf_test_event_ops = {
 	.epc_init = pci_epf_test_epc_init,
+	.epc_deinit = pci_epf_test_epc_deinit,
 	.link_up = pci_epf_test_link_up,
 	.link_down = pci_epf_test_link_down,
 };

@@ -905,10 +915,13 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 static void pci_epf_test_unbind(struct pci_epf *epf)
 {
 	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct pci_epc *epc = epf->epc;
 
 	cancel_delayed_work(&epf_test->cmd_handler);
-	pci_epf_test_clean_dma_chan(epf_test);
-	pci_epf_test_clear_bar(epf);
+	if (epc->init_complete) {
+		pci_epf_test_clean_dma_chan(epf_test);
+		pci_epf_test_clear_bar(epf);
+	}
 	pci_epf_test_free_space(epf);
 }
 

drivers/pci/endpoint/pci-epc-core.c +25 -0

index 56b60330355d..47a91dcb07d7 100644
@@ -774,6 +774,31 @@ void pci_epc_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf)
 }
 EXPORT_SYMBOL_GPL(pci_epc_notify_pending_init);
 
+/**
+ * pci_epc_deinit_notify() - Notify the EPF device about EPC deinitialization
+ * @epc: the EPC device whose deinitialization is completed
+ *
+ * Invoke to notify the EPF device that the EPC deinitialization is completed.
+ */
+void pci_epc_deinit_notify(struct pci_epc *epc)
+{
+	struct pci_epf *epf;
+
+	if (IS_ERR_OR_NULL(epc))
+		return;
+
+	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->epc_deinit)
+			epf->event_ops->epc_deinit(epf);
+		mutex_unlock(&epf->lock);
+	}
+	epc->init_complete = false;
+	mutex_unlock(&epc->list_lock);
+}
+EXPORT_SYMBOL_GPL(pci_epc_deinit_notify);
+
 /**
  * pci_epc_bus_master_enable_notify() - Notify the EPF device that the EPC
  *					device has received the Bus Master

include/linux/pci-epc.h +13 -0

index 11115cd0fe5b..85bdf2adb760 100644
@@ -197,6 +197,8 @@ struct pci_epc_features {
 
 #define to_pci_epc(device) container_of((device), struct pci_epc, dev)
 
+#ifdef CONFIG_PCI_ENDPOINT
+
 #define pci_epc_create(dev, ops)    \
 		__pci_epc_create((dev), (ops), THIS_MODULE)
 #define devm_pci_epc_create(dev, ops)    \

@@ -226,6 +228,7 @@ 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_deinit_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);

@@ -272,4 +275,14 @@ 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);
+
+#else
+static inline void pci_epc_init_notify(struct pci_epc *epc)
+{
+}
+
+static inline void pci_epc_deinit_notify(struct pci_epc *epc)
+{
+}
+#endif /* CONFIG_PCI_ENDPOINT */
 #endif /* __LINUX_PCI_EPC_H */

include/linux/pci-epf.h +2 -0

index dc759eb7157c..0639d4dc8986 100644
@@ -71,12 +71,14 @@ struct pci_epf_ops {
 /**
  * struct pci_epc_event_ops - Callbacks for capturing the EPC events
  * @epc_init: Callback for the EPC initialization complete event
+ * @epc_deinit: Callback for the EPC deinitialization event
  * @link_up: Callback for the EPC link up event
  * @link_down: Callback for the EPC link down event
  * @bus_master_enable: Callback for the EPC Bus Master Enable event
  */
 struct pci_epc_event_ops {
 	int (*epc_init)(struct pci_epf *epf);
+	void (*epc_deinit)(struct pci_epf *epf);
 	int (*link_up)(struct pci_epf *epf);
 	int (*link_down)(struct pci_epf *epf);
 	int (*bus_master_enable)(struct pci_epf *epf);

Signature · 2 lines

-- 
2.25.1

As like the 'epc_init' event, that is used to signal the EPF drivers about the EPC initialization, let's introduce 'epc_deinit' event that is used to signal EPC deinitialization.

The EPC deinitialization applies only when any sort of fundamental reset is supported by the endpoint controller as per the PCIe spec.

Reference: PCIe Base spec v5.0, sections 4.2.4.9.1 and 6.6.1.

Currently, some EPC drivers like pcie-qcom-ep and pcie-tegra194 support PERST# as the fundamental reset. So the 'deinit' event will be notified to the EPF drivers when PERST# assert happens in the above mentioned EPC drivers.

The EPF drivers, on receiving the event through the epc_deinit() callback should reset the EPF state machine and also cleanup any configuration that got affected by the fundamental reset like BAR, DMA etc...

This change also warrants skipping the cleanups in unbind() if already done in epc_deinit().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

Quoted 4 lines · Manivannan Sadhasivam

As like the 'epc_init' event, that is used to signal the EPF drivers about the EPC initialization, let's introduce 'epc_deinit' event that is used to signal EPC deinitialization.

Quoted 4 lines

The EPC deinitialization applies only when any sort of fundamental reset is supported by the endpoint controller as per the PCIe spec.

Reference: PCIe Base spec v5.0, sections 4.2.4.9.1 and 6.6.1.

PCIe r6.0, sec 4.2.5.9.1 and 6.6.1.

(Not 4.2.4.9.1, which no longer exists in r6.x)

Quoted 14 lines

Currently, some EPC drivers like pcie-qcom-ep and pcie-tegra194 support PERST# as the fundamental reset. So the 'deinit' event will be notified to the EPF drivers when PERST# assert happens in the above mentioned EPC drivers.

The EPF drivers, on receiving the event through the epc_deinit() callback should reset the EPF state machine and also cleanup any configuration that got affected by the fundamental reset like BAR, DMA etc...

This change also warrants skipping the cleanups in unbind() if already done in epc_deinit().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

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

drivers/pci/endpoint/pci-epc-core.c +2 -0

+void pci_epc_deinit_notify(struct pci_epc *epc)
+{

As per the PCIe base spec r5.0, section 5.2, Link Down event can happen under any of the following circumstances:

1. Fundamental/Hot reset
2. Link disable transmission by upstream component
3. Moving from L2/L3 to L0

In those cases, Link Down causes some non-sticky DWC registers to loose the state (like REBAR, etc...). So the drivers need to reinitialize them to function properly once the link comes back again.

This is not a problem for drivers supporting PERST# IRQ, since they can reinitialize the registers in the PERST# IRQ callback. But for the drivers not supporting PERST#, there is no way they can reinitialize the registers other than relying on Link Down IRQ received when the link goes down. So let's add a DWC generic API dw_pcie_ep_linkdown() that reinitializes the non-sticky registers and also notifies the EPF drivers about link going down.

This API can also be used by the drivers supporting PERST# to handle the scenario (2) mentioned above.

NOTE: For the sake of code organization, move the dw_pcie_ep_linkup() definition just above dw_pcie_ep_linkdown().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

As per the PCIe base spec r5.0, section 5.2, Link Down event can happen under any of the following circumstances:

1. Fundamental/Hot reset
2. Link disable transmission by upstream component
3. Moving from L2/L3 to L0

In those cases, Link Down causes some non-sticky DWC registers to loose the state (like REBAR, etc...). So the drivers need to reinitialize them to function properly once the link comes back again.

This is not a problem for drivers supporting PERST# IRQ, since they can reinitialize the registers in the PERST# IRQ callback. But for the drivers not supporting PERST#, there is no way they can reinitialize the registers other than relying on Link Down IRQ received when the link goes down. So let's add a DWC generic API dw_pcie_ep_linkdown() that reinitializes the non-sticky registers and also notifies the EPF drivers about link going down.

This API can also be used by the drivers supporting PERST# to handle the scenario (2) mentioned above.

NOTE: For the sake of code organization, move the dw_pcie_ep_linkup() definition just above dw_pcie_ep_linkdown().

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

---

Now that the API is available, let's make use of it. It also handles the reinitialization of DWC non-sticky registers in addition to sending the notification to EPF drivers.

Reviewed-by Niklas Cassel <[email protected]>

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
 drivers/pci/controller/dwc/pcie-qcom-ep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/pci/controller/dwc/pcie-qcom-ep.c +1 -1

index 2324e56c9bfc..02a2a871a91f 100644
@@ -641,7 +641,7 @@ static irqreturn_t qcom_pcie_ep_global_irq_thread(int irq, void *data)
 	if (FIELD_GET(PARF_INT_ALL_LINK_DOWN, status)) {
 		dev_dbg(dev, "Received Linkdown event\n");
 		pcie_ep->link_status = QCOM_PCIE_EP_LINK_DOWN;
-		pci_epc_linkdown(pci->ep.epc);
+		dw_pcie_ep_linkdown(&pci->ep);
 	} else if (FIELD_GET(PARF_INT_ALL_BME, status)) {
 		dev_dbg(dev, "Received Bus Master Enable event\n");
 		pcie_ep->link_status = QCOM_PCIE_EP_LINK_ENABLED;

Signature · 2 lines

-- 
2.25.1

Now that the API is available, let's make use of it. It also handles the reinitialization of DWC non-sticky registers in addition to sending the notification to EPF drivers.

Reported-by Bjorn Helgaas <[email protected]>

Closes https://lore.kernel.org/linux-pci/20240528195539.GA458945@bhelgaas/ open here

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
 drivers/pci/controller/dwc/pci-layerscape-ep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/pci/controller/dwc/pci-layerscape-ep.c +1 -1

index 35bb481564c7..a4a800699f89 100644
@@ -104,7 +104,7 @@ static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id)
 		dev_dbg(pci->dev, "Link up\n");
 	} else if (val & PEX_PF0_PME_MES_DR_LDD) {
 		dev_dbg(pci->dev, "Link down\n");
-		pci_epc_linkdown(pci->ep.epc);
+		dw_pcie_ep_linkdown(&pci->ep);
 	} else if (val & PEX_PF0_PME_MES_DR_HRD) {
 		dev_dbg(pci->dev, "Hot reset\n");
 	}

Signature · 2 lines

-- 
2.25.1

Now that the API is available, let's make use of it. It also handles the reinitialization of DWC non-sticky registers in addition to sending the notification to EPF drivers.

Reported-by Bjorn Helgaas <[email protected]>

Closes https://lore.kernel.org/linux-pci/20240528195539.GA458945@bhelgaas/ open here

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
 drivers/pci/controller/dwc/pci-layerscape-ep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/pci/controller/dwc/pci-layerscape-ep.c +1 -1

index 35bb481564c7..a4a800699f89 100644
@@ -104,7 +104,7 @@ static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id)
 		dev_dbg(pci->dev, "Link up\n");
 	} else if (val & PEX_PF0_PME_MES_DR_LDD) {
 		dev_dbg(pci->dev, "Link down\n");
-		pci_epc_linkdown(pci->ep.epc);
+		dw_pcie_ep_linkdown(&pci->ep);
 	} else if (val & PEX_PF0_PME_MES_DR_HRD) {
 		dev_dbg(pci->dev, "Hot reset\n");
 	}

Signature · 2 lines

-- 
2.25.1

Hi,

This series includes patches that were left over from previous series [1] for making the host reboot handling robust in endpoint framework.

When the above mentioned series got merged to pci/endpoint, we got a bug report from LKP bot [2] and due to that the offending patches were dropped.

This series addressed the issue reported by the bot by adding the stub APIs in include/pci/pci-epc.h and also removed the unused dwc wrapper as concluded in [3].

Testing
=======

This series is tested on Qcom SM8450 based development board with 2 SM8450 SoCs connected over PCIe.

- Mani

[1] https://lore.kernel.org/linux-pci/[email protected]/
[2] https://lore.kernel.org/linux-pci/[email protected]/
[3] https://lore.kernel.org/linux-pci/20240529141614.GA3293@thinkpad/

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
Manivannan Sadhasivam (5):
PCI: dwc: ep: Remove dw_pcie_ep_init_notify() wrapper
PCI: endpoint: Introduce 'epc_deinit' event and notify the EPF drivers
PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: qcom-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: layerscape-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event

 drivers/pci/controller/dwc/pci-dra7xx.c           |   2 +-
 drivers/pci/controller/dwc/pci-imx6.c             |   2 +-
 drivers/pci/controller/dwc/pci-keystone.c         |   2 +-
 drivers/pci/controller/dwc/pci-layerscape-ep.c    |   4 +-
 drivers/pci/controller/dwc/pcie-artpec6.c         |   2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c   | 116 +++++++++++++---------
 drivers/pci/controller/dwc/pcie-designware-plat.c |   2 +-
 drivers/pci/controller/dwc/pcie-designware.h      |  10 +-
 drivers/pci/controller/dwc/pcie-keembay.c         |   2 +-
 drivers/pci/controller/dwc/pcie-qcom-ep.c         |   5 +-
 drivers/pci/controller/dwc/pcie-rcar-gen4.c       |   2 +-
 drivers/pci/controller/dwc/pcie-tegra194.c        |   3 +-
 drivers/pci/controller/dwc/pcie-uniphier-ep.c     |   2 +-
 drivers/pci/endpoint/functions/pci-epf-mhi.c      |  19 ++++
 drivers/pci/endpoint/functions/pci-epf-test.c     |  17 +++-
 drivers/pci/endpoint/pci-epc-core.c               |  25 +++++
 include/linux/pci-epc.h                           |  13 +++
 include/linux/pci-epf.h                           |   2 +
 18 files changed, 162 insertions(+), 68 deletions(-)

---
base-commit: 7d96527bc16e46545739c6fe0ab6e4c915e9910e
change-id: 20240606-pci-deinit-2e6cdf1bd69f

Best regards,

Signature · 1 line

Manivannan Sadhasivam <[email protected]>

Quoted 52 lines · Manivannan Sadhasivam

Hi,

This series includes patches that were left over from previous series [1] for making the host reboot handling robust in endpoint framework.

When the above mentioned series got merged to pci/endpoint, we got a bug report from LKP bot [2] and due to that the offending patches were dropped.

This series addressed the issue reported by the bot by adding the stub APIs in include/pci/pci-epc.h and also removed the unused dwc wrapper as concluded in [3].

Testing
=======

This series is tested on Qcom SM8450 based development board with 2 SM8450 SoCs connected over PCIe.

- Mani

[1] https://lore.kernel.org/linux-pci/[email protected]/
[2] https://lore.kernel.org/linux-pci/[email protected]/
[3] https://lore.kernel.org/linux-pci/20240529141614.GA3293@thinkpad/

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
Manivannan Sadhasivam (5):
PCI: dwc: ep: Remove dw_pcie_ep_init_notify() wrapper
PCI: endpoint: Introduce 'epc_deinit' event and notify the EPF drivers
PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: qcom-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: layerscape-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event

 drivers/pci/controller/dwc/pci-dra7xx.c           |   2 +-
 drivers/pci/controller/dwc/pci-imx6.c             |   2 +-
 drivers/pci/controller/dwc/pci-keystone.c         |   2 +-
 drivers/pci/controller/dwc/pci-layerscape-ep.c    |   4 +-
 drivers/pci/controller/dwc/pcie-artpec6.c         |   2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c   | 116 +++++++++++++---------
 drivers/pci/controller/dwc/pcie-designware-plat.c |   2 +-
 drivers/pci/controller/dwc/pcie-designware.h      |  10 +-
 drivers/pci/controller/dwc/pcie-keembay.c         |   2 +-
 drivers/pci/controller/dwc/pcie-qcom-ep.c         |   5 +-
 drivers/pci/controller/dwc/pcie-rcar-gen4.c       |   2 +-
 drivers/pci/controller/dwc/pcie-tegra194.c        |   3 +-
 drivers/pci/controller/dwc/pcie-uniphier-ep.c     |   2 +-
 drivers/pci/endpoint/functions/pci-epf-mhi.c      |  19 ++++
 drivers/pci/endpoint/functions/pci-epf-test.c     |  17 +++-
 drivers/pci/endpoint/pci-epc-core.c               |  25 +++++
 include/linux/pci-epc.h                           |  13 +++
 include/linux/pci-epf.h                           |   2 +
 18 files changed, 162 insertions(+), 68 deletions(-)

Quoted 8 lines

---
base-commit: 7d96527bc16e46545739c6fe0ab6e4c915e9910e
change-id: 20240606-pci-deinit-2e6cdf1bd69f

Best regards,

Signature · 1 line

Manivannan Sadhasivam <[email protected]>

Considering certain dependency patches have been merged to pci/endpoint and other dependency patches have been merged to pci/controller/dwc, perhaps it is best if you split this series:

Series 1 based on pci/endpoint: with patch 1/5 and 2/5. Series 2 based on pci/controller/dwc: with patch 5/5.

Hi,

This series includes patches that were left over from previous series [1] for making the host reboot handling robust in endpoint framework.

When the above mentioned series got merged to pci/endpoint, we got a bug report from LKP bot [2] and due to that the offending patches were dropped.

This series addressed the issue reported by the bot by adding the stub APIs in include/pci/pci-epc.h and also removed the unused dwc wrapper as concluded in [3].

Testing
=======

This series is tested on Qcom SM8450 based development board with 2 SM8450 SoCs connected over PCIe.

- Mani

[1] https://lore.kernel.org/linux-pci/[email protected]/
[2] https://lore.kernel.org/linux-pci/[email protected]/
[3] https://lore.kernel.org/linux-pci/20240529141614.GA3293@thinkpad/

Signed-off-by Manivannan Sadhasivam <[email protected]>

---
Manivannan Sadhasivam (5):
PCI: dwc: ep: Remove dw_pcie_ep_init_notify() wrapper
PCI: endpoint: Introduce 'epc_deinit' event and notify the EPF drivers
PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: qcom-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event
PCI: layerscape-ep: Use the generic dw_pcie_ep_linkdown() API to handle Link Down event

 drivers/pci/controller/dwc/pci-dra7xx.c           |   2 +-
 drivers/pci/controller/dwc/pci-imx6.c             |   2 +-
 drivers/pci/controller/dwc/pci-keystone.c         |   2 +-
 drivers/pci/controller/dwc/pci-layerscape-ep.c    |   4 +-
 drivers/pci/controller/dwc/pcie-artpec6.c         |   2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c   | 116 +++++++++++++---------
 drivers/pci/controller/dwc/pcie-designware-plat.c |   2 +-
 drivers/pci/controller/dwc/pcie-designware.h      |  10 +-
 drivers/pci/controller/dwc/pcie-keembay.c         |   2 +-
 drivers/pci/controller/dwc/pcie-qcom-ep.c         |   5 +-
 drivers/pci/controller/dwc/pcie-rcar-gen4.c       |   2 +-
 drivers/pci/controller/dwc/pcie-tegra194.c        |   3 +-
 drivers/pci/controller/dwc/pcie-uniphier-ep.c     |   2 +-
 drivers/pci/endpoint/functions/pci-epf-mhi.c      |  19 ++++
 drivers/pci/endpoint/functions/pci-epf-test.c     |  17 +++-
 drivers/pci/endpoint/pci-epc-core.c               |  25 +++++
 include/linux/pci-epc.h                           |  13 +++
 include/linux/pci-epf.h                           |   2 +
 18 files changed, 162 insertions(+), 68 deletions(-)

---
base-commit: 7d96527bc16e46545739c6fe0ab6e4c915e9910e
change-id: 20240606-pci-deinit-2e6cdf1bd69f

Best regards,

Signature · 1 line

Manivannan Sadhasivam <[email protected]>

Applied patch 2/5 to pci/endpoint! Krzysztof, please apply patches 1/5 and 5/5 to controller/dwc (patches 3/5 and 4/5 are already applied by you).