cndm: Register misc device

Signed-off-by: Alex Forencich <alex@alexforencich.com>

src/cndm/modules/cndm/Makefile

@@ -6,6 +6,7 @@ ifneq ($(KERNELRELEASE),)
 obj-m += cndm.o
 cndm-y += cndm_main.o
 cndm-y += cndm_devlink.o
+cndm-y += cndm_dev.o
 cndm-y += cndm_netdev.o
 cndm-y += cndm_tx.o
 cndm-y += cndm_rx.o

src/cndm/modules/cndm/cndm.h

@@ -13,6 +13,7 @@ Authors:
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/miscdevice.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/ptp_clock_kernel.h>
@@ -28,6 +29,8 @@ struct cndm_dev {
 	unsigned int id;
 	char name[16];
 
+	struct miscdevice misc_dev;
+
 	struct net_device *ndev[32];
 
 	void __iomem *bar;
@@ -135,6 +138,9 @@ irqreturn_t cndm_irq(int irqn, void *data);
 struct net_device *cndm_create_netdev(struct cndm_dev *cdev, int port, void __iomem *hw_addr);
 void cndm_destroy_netdev(struct net_device *ndev);
 
+// cndm_dev.c
+extern const struct file_operations cndm_fops;
+
 // cndm_tx.c
 int cndm_free_tx_buf(struct cndm_priv *priv);
 int cndm_poll_tx_cq(struct napi_struct *napi, int budget);

src/cndm/modules/cndm/cndm_dev.c

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL
+/*
+
+Copyright (c) 2025 FPGA Ninja, LLC
+
+Authors:
+- Alex Forencich
+
+*/
+
+#include "cndm.h"
+
+#include <linux/uaccess.h>
+
+static int cndm_open(struct inode *inode, struct file *file)
+{
+	// struct miscdevice *miscdev = file->private_data;
+	// struct cndm_dev *cdev = container_of(miscdev, struct cndm_dev, misc_dev);
+
+	return 0;
+}
+
+static int cndm_release(struct inode *inode, struct file *file)
+{
+	// struct miscdevice *miscdev = file->private_data;
+	// struct cndm_dev *cdev = container_of(miscdev, struct cndm_dev, misc_dev);
+
+	return 0;
+}
+
+const struct file_operations cndm_fops = {
+	.owner = THIS_MODULE,
+	.open = cndm_open,
+	.release = cndm_release,
+};

src/cndm/modules/cndm/cndm_main.c

@@ -135,8 +135,24 @@ static int cndm_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		cdev->ndev[k] = ndev;
 	}
 
+	cdev->misc_dev.minor = MISC_DYNAMIC_MINOR;
+	cdev->misc_dev.name = cdev->name;
+	cdev->misc_dev.fops = &cndm_fops;
+	cdev->misc_dev.parent = dev;
+
+	ret = misc_register(&cdev->misc_dev);
+	if (ret) {
+		cdev->misc_dev.this_device = NULL;
+		dev_err(dev, "misc_register failed: %d", ret);
+		goto fail_miscdev;
+
+	}
+
+	dev_info(dev, "Registered device %s", cdev->name);
+
 	return 0;
 
+fail_miscdev:
 fail_netdev:
 	for (k = 0; k < 32; k++) {
 		if (cdev->ndev[k]) {
@@ -170,6 +186,9 @@ static void cndm_pci_remove(struct pci_dev *pdev)
 
 	dev_info(dev, DRIVER_NAME " PCI remove");
 
+	if (cdev->misc_dev.this_device)
+		misc_deregister(&cdev->misc_dev);
+
 	for (k = 0; k < 32; k++) {
 		if (cdev->ndev[k]) {
 			pci_free_irq(pdev, k, cdev->ndev[k]);