[PATCH 2/7] fpga: dfl: pci: add irq info for feature devices enumeration

[Xu Yilun <yilun.xu@xxxxxxxxx>]

Some DFL FPGA PCIe cards (e.g. Intel FPGA Programmable Acceleration
Card) support MSI-X based interrupts. This patch allows PCIe driver
to prepare and pass interrupt resources to DFL via enumeration API.
These interrupt resources could then be assigned to actual features
which use them.

Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
---
 drivers/fpga/dfl-pci.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 61 insertions(+), 5 deletions(-)

diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
index 5387550..a3370e5 100644
--- a/drivers/fpga/dfl-pci.c
+++ b/drivers/fpga/dfl-pci.c
@@ -80,8 +80,23 @@ static void cci_remove_feature_devs(struct pci_dev *pcidev)
 	dfl_fpga_feature_devs_remove(drvdata->cdev);
 }
 
+static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec)
+{
+	int *table, i;
+
+	table = kcalloc(nvec, sizeof(int), GFP_KERNEL);
+	if (!table)
+		return NULL;
+
+	for (i = 0; i < nvec; i++)
+		table[i] = pci_irq_vector(pcidev, i);
+
+	return table;
+}
+
 /* enumerate feature devices under pci device */
-static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
+static int cci_enumerate_feature_devs(struct pci_dev *pcidev,
+				      unsigned int nvec)
 {
 	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
 	struct dfl_fpga_enum_info *info;
@@ -89,6 +104,7 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
 	resource_size_t start, len;
 	int port_num, bar, i, ret = 0;
 	void __iomem *base;
+	int *irq_table;
 	u32 offset;
 	u64 v;
 
@@ -97,6 +113,18 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
 	if (!info)
 		return -ENOMEM;
 
+	/* add irq info for enumeration if really needed */
+	if (nvec) {
+		irq_table = cci_pci_create_irq_table(pcidev, nvec);
+		if (irq_table) {
+			dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
+			kfree(irq_table);
+		} else {
+			ret = -ENOMEM;
+			goto enum_info_free_exit;
+		}
+	}
+
 	/* start to find Device Feature List from Bar 0 */
 	base = cci_pci_ioremap_bar(pcidev, 0);
 	if (!base) {
@@ -173,6 +201,28 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
 	return ret;
 }
 
+static int cci_pci_alloc_irq(struct pci_dev *pcidev)
+{
+	int nvec = pci_msix_vec_count(pcidev);
+	int ret;
+
+	if (nvec <= 0) {
+		dev_dbg(&pcidev->dev, "fpga interrupt not supported\n");
+		return 0;
+	}
+
+	ret = pci_alloc_irq_vectors(pcidev, nvec, nvec, PCI_IRQ_MSIX);
+	if (ret < 0)
+		return ret;
+
+	return nvec;
+}
+
+static void cci_pci_free_irq(struct pci_dev *pcidev)
+{
+	pci_free_irq_vectors(pcidev);
+}
+
 static
 int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
 {
@@ -210,14 +260,19 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
 		goto disable_error_report_exit;
 	}
 
-	ret = cci_enumerate_feature_devs(pcidev);
-	if (ret) {
-		dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
+	ret = cci_pci_alloc_irq(pcidev);
+	if (ret < 0) {
+		dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", ret);
 		goto disable_error_report_exit;
 	}
 
-	return ret;
+	ret = cci_enumerate_feature_devs(pcidev, (unsigned int)ret);
+	if (!ret)
+		return ret;
+
+	dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
 
+	cci_pci_free_irq(pcidev);
 disable_error_report_exit:
 	pci_disable_pcie_error_reporting(pcidev);
 	return ret;
@@ -263,6 +318,7 @@ static void cci_pci_remove(struct pci_dev *pcidev)
 		cci_pci_sriov_configure(pcidev, 0);
 
 	cci_remove_feature_devs(pcidev);
+	cci_pci_free_irq(pcidev);
 	pci_disable_pcie_error_reporting(pcidev);
 }
 
-- 
2.7.4