Adds support for older kernel Versions < 4.8

platform/vc709/module/Makefile

 # Makefile to build the ffLink module, which can be loaded with 'sudo insmod ffLink.ko' afterwards
 # make should not be run as root, otherwise generated files cannot be removed correctly
 
-# Name of Kernel module 
+# Name of Kernel module
 obj-m := ffLink.o
 
 # composition of files needed to compile
@@ -35,5 +35,5 @@ ccflags-y := $(COMPILEFLAGS) $(DEBUGFLAGS)
 all:
 	#@ KCFLAGS+="$(COMPILEFLAGS) $(DEBUGFLAGS)" make -C $(LINUX_HOME) M=$(PWD) modules
 	@ make -C $(LINUX_HOME) M=$(PWD) modules
-clean:	
+clean:
 	@ make -C $(LINUX_HOME) M=$(PWD) clean

platform/vc709/module/pcie_device.c

@@ -33,6 +33,15 @@
 
 static struct pci_data_struct pci_data;
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
+static struct msix_entry msix_entries[REQUIRED_INTERRUPTS];
+
+u32 pci_irq_vector(struct pci_dev *pdev, int c) {
+	return msix_entries[c].vector;
+}
+
+#endif
+
 /******************************************************************************/
 
 /**
@@ -125,7 +134,6 @@ static int register_intr_handler(struct pci_dev *pdev, int c)
 	/* Request interrupt line for unique function
 	 * alternatively function will be called from free_irq as well with flag IRQF_SHARED */
 	if (c == 0) {
-
 		err = request_irq(pci_irq_vector(pdev, c), intr_handler_dma, IRQF_EARLY_RESUME, FFLINK_PCI_NAME, pdev);
 	}
 
@@ -306,10 +314,17 @@ static int claim_msi(struct pci_dev *pdev)
 
 	for (i = 0; i < REQUIRED_INTERRUPTS; i++) {
 		pci_data.irq_mapping[i] = -1;
+		#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
+		msix_entries[i].entry = i;
+		#endif
 	}
 
+	#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
+	err = pci_enable_msix_range(pdev, msix_entries, REQUIRED_INTERRUPTS, REQUIRED_INTERRUPTS);
+	#else
 	/* set up MSI interrupt vector to max size */
 	err = pci_alloc_irq_vectors(pdev, REQUIRED_INTERRUPTS, REQUIRED_INTERRUPTS, PCI_IRQ_MSIX);
+	#endif
 
 	if (err <= 0) {
 		fflink_warn("Cannot set MSI vector (%d)\n", err);
@@ -332,7 +347,11 @@ static int claim_msi(struct pci_dev *pdev)
 
 error_pci_req_irq:
 	free_irqs(pdev);
+	#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
+	pci_disable_msix(pdev);
+	#else
 	pci_free_irq_vectors(pdev);
+	#endif
 error_no_msi:
 	return -ENOSPC;
 }
@@ -503,7 +522,11 @@ static void fflink_pci_remove(struct pci_dev *pdev)
 	fflink_info("Unload pci-device\n");
 
 	free_irqs(pdev);
+	#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
+	pci_disable_msix(pdev);
+	#else
 	pci_free_irq_vectors(pdev);
+	#endif
 
 	iounmap(pci_data.kvirt_addr_bar0);
 

platform/vc709/module/pcie_device.h

@@ -62,7 +62,6 @@
 #include "common/device_user.h"
 #include "common/dma_ctrl.h"
 #include "common/device_pcie.h"
-
 /******************************************************************************/
 
 #define FFLINK_PCI_NAME "FFLINK_PCI_DRIVER"