[PATCH 1/1] PCI: layerscape: Add the endpoint linkup notifier support

[PATCH 1/1] PCI: layerscape: Add the endpoint linkup notifier support

[Frank Li]

Layerscape has PME interrupt, which can be use as linkup notifer.
Set CFG_READY bit when linkup detected.

Signed-off-by: Xiaowei Bao <xiaowei.bao@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 .../pci/controller/dwc/pci-layerscape-ep.c    | 104 +++++++++++++++++-
 1 file changed, 103 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c
index c640db60edc6..66d4a78a30a4 100644
--- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
+++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
@@ -18,6 +18,20 @@
 
 #include "pcie-designware.h"
 
+#define PEX_PF0_CONFIG			0xC0014
+#define PEX_PF0_CFG_READY		BIT(0)
+
+/* PEX PFa PCIE pme and message interrupt registers*/
+#define PEX_PF0_PME_MES_DR		0xC0020
+#define PEX_PF0_PME_MES_DR_LUD		BIT(7)
+#define PEX_PF0_PME_MES_DR_LDD		BIT(9)
+#define PEX_PF0_PME_MES_DR_HRD		BIT(10)
+
+#define PEX_PF0_PME_MES_IER		0xC0028
+#define PEX_PF0_PME_MES_IER_LUDIE	BIT(7)
+#define PEX_PF0_PME_MES_IER_LDDIE	BIT(9)
+#define PEX_PF0_PME_MES_IER_HRDIE	BIT(10)
+
 #define to_ls_pcie_ep(x)	dev_get_drvdata((x)->dev)
 
 struct ls_pcie_ep_drvdata {
@@ -30,8 +44,88 @@ struct ls_pcie_ep {
 	struct dw_pcie			*pci;
 	struct pci_epc_features		*ls_epc;
 	const struct ls_pcie_ep_drvdata *drvdata;
+	bool				big_endian;
+	int				irq;
 };
 
+static u32 ls_lut_readl(struct ls_pcie_ep *pcie, u32 offset)
+{
+	struct dw_pcie *pci = pcie->pci;
+
+	if (pcie->big_endian)
+		return ioread32be(pci->dbi_base + offset);
+	else
+		return ioread32(pci->dbi_base + offset);
+}
+
+static void ls_lut_writel(struct ls_pcie_ep *pcie, u32 offset,
+			  u32 value)
+{
+	struct dw_pcie *pci = pcie->pci;
+
+	if (pcie->big_endian)
+		iowrite32be(value, pci->dbi_base + offset);
+	else
+		iowrite32(value, pci->dbi_base + offset);
+}
+
+static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id)
+{
+	struct ls_pcie_ep *pcie = (struct ls_pcie_ep *)dev_id;
+	struct dw_pcie *pci = pcie->pci;
+	u32 val, cfg;
+
+	val = ls_lut_readl(pcie, PEX_PF0_PME_MES_DR);
+	if (!val)
+		return IRQ_NONE;
+
+	if (val & PEX_PF0_PME_MES_DR_LUD) {
+		cfg = ls_lut_readl(pcie, PEX_PF0_CONFIG);
+		cfg |= PEX_PF0_CFG_READY;
+		ls_lut_writel(pcie, PEX_PF0_CONFIG, cfg);
+		dw_pcie_ep_linkup(&pci->ep);
+
+		dev_info(pci->dev, "Detect the link up state !\n");
+	} else if (val & PEX_PF0_PME_MES_DR_LDD) {
+		dev_info(pci->dev, "Detect the link down state !\n");
+	} else if (val & PEX_PF0_PME_MES_DR_HRD) {
+		dev_info(pci->dev, "Detect the hot reset state !\n");
+	}
+
+	ls_lut_writel(pcie, PEX_PF0_PME_MES_DR, val);
+
+	return IRQ_HANDLED;
+}
+
+static int ls_pcie_ep_interrupt_init(struct ls_pcie_ep *pcie,
+				     struct platform_device *pdev)
+{
+	u32 val;
+	int ret;
+
+	pcie->irq = platform_get_irq_byname(pdev, "pme");
+	if (pcie->irq < 0) {
+		dev_err(&pdev->dev, "Can't get 'pme' irq.\n");
+		return pcie->irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, pcie->irq,
+			       ls_pcie_ep_event_handler, IRQF_SHARED,
+			       pdev->name, pcie);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't register PCIe IRQ.\n");
+		return ret;
+	}
+
+	/* Enable interrupts */
+	val = ls_lut_readl(pcie, PEX_PF0_PME_MES_IER);
+	val |=  PEX_PF0_PME_MES_IER_LDDIE | PEX_PF0_PME_MES_IER_HRDIE |
+		PEX_PF0_PME_MES_IER_LUDIE;
+	ls_lut_writel(pcie, PEX_PF0_PME_MES_IER, val);
+
+	return 0;
+}
+
 static const struct pci_epc_features*
 ls_pcie_ep_get_features(struct dw_pcie_ep *ep)
 {
@@ -125,6 +219,7 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
 	struct ls_pcie_ep *pcie;
 	struct pci_epc_features *ls_epc;
 	struct resource *dbi_base;
+	int ret;
 
 	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
 	if (!pcie)
@@ -144,6 +239,7 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
 	pci->ops = pcie->drvdata->dw_pcie_ops;
 
 	ls_epc->bar_fixed_64bit = (1 << BAR_2) | (1 << BAR_4);
+	ls_epc->linkup_notifier = true;
 
 	pcie->pci = pci;
 	pcie->ls_epc = ls_epc;
@@ -155,9 +251,15 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
 
 	pci->ep.ops = &ls_pcie_ep_ops;
 
+	pcie->big_endian = of_property_read_bool(dev->of_node, "big-endian");
+
 	platform_set_drvdata(pdev, pcie);
 
-	return dw_pcie_ep_init(&pci->ep);
+	ret = dw_pcie_ep_init(&pci->ep);
+	if (ret)
+		return  ret;
+
+	return  ls_pcie_ep_interrupt_init(pcie, pdev);
 }
 
 static struct platform_driver ls_pcie_ep_driver = {
-- 
2.34.1

Re: [PATCH 1/1] PCI: layerscape: Add the endpoint linkup notifier support

[Bjorn Helgaas]

On Thu, Apr 20, 2023 at 06:11:17PM -0400, Frank Li wrote:
> Layerscape has PME interrupt, which can be use as linkup notifer.
> Set CFG_READY bit when linkup detected.

s/use/used/
s/notifer/notifier/

> +/* PEX PFa PCIE pme and message interrupt registers*/

s/pme/PME/ to match other usage and spec.

> +		dev_info(pci->dev, "Detect the link up state !\n");
> +	} else if (val & PEX_PF0_PME_MES_DR_LDD) {
> +		dev_info(pci->dev, "Detect the link down state !\n");
> +	} else if (val & PEX_PF0_PME_MES_DR_HRD) {
> +		dev_info(pci->dev, "Detect the hot reset state !\n");

No spaces before "!".  Omit the "!" completely unless these are
unexpected situations.  They seem ordinary to me.

Would probably be better as just "Link up", "Link down", "Hot reset".
Or "Link up state detected" if you want.

> +		dev_err(&pdev->dev, "Can't get 'pme' irq.\n");
> +		dev_err(&pdev->dev, "Can't register PCIe IRQ.\n");

Capitalize "IRQ" in both the above message and this one.  No "."
needed at the end.

Bjorn