[PATCH v3 1/2] char: xillybus: Move class-related functions to new xillybus_class.c

From: eli . billauer
Date: Tue Mar 09 2021 - 06:35:52 EST

From: Eli Billauer <eli.billauer@xxxxxxxxx>

This patch is a preparation for adding another related driver, XillyUSB.
In order to share some code between the existing Xillybus driver and the
one to be added, some functions are moved to xillybus_class.c

The header file, xillybus_class.h, is temporarily placed in include/linux/,
because the new XillyUSB driver is intended as a staging driver for the
time being.

Signed-off-by: Eli Billauer <eli.billauer@xxxxxxxxx>
---

Notes:
Changelog:

This patch did not exist prior to v3.

drivers/char/xillybus/Kconfig | 4 +
drivers/char/xillybus/Makefile | 1 +
drivers/char/xillybus/xillybus.h | 10 +-
drivers/char/xillybus/xillybus_class.c | 263 +++++++++++++++++++++++++
drivers/char/xillybus/xillybus_core.c | 181 +++--------------
include/linux/xillybus_class.h | 30 +++
6 files changed, 322 insertions(+), 167 deletions(-)
create mode 100644 drivers/char/xillybus/xillybus_class.c
create mode 100644 include/linux/xillybus_class.h

diff --git a/drivers/char/xillybus/Kconfig b/drivers/char/xillybus/Kconfig
index 130dbdce858f..e7800f025249 100644
--- a/drivers/char/xillybus/Kconfig
+++ b/drivers/char/xillybus/Kconfig
@@ -3,10 +3,14 @@
# Xillybus devices
#

+config XILLYBUS_CLASS
+ tristate
+
config XILLYBUS
tristate "Xillybus generic FPGA interface"
depends on PCI || OF
select CRC32
+ select XILLYBUS_CLASS
help
Xillybus is a generic interface for peripherals designed on
programmable logic (FPGA). The driver probes the hardware for
diff --git a/drivers/char/xillybus/Makefile b/drivers/char/xillybus/Makefile
index 099e9a3585fc..591615264591 100644
--- a/drivers/char/xillybus/Makefile
+++ b/drivers/char/xillybus/Makefile
@@ -3,6 +3,7 @@
# Makefile for Xillybus driver
#

+obj-$(CONFIG_XILLYBUS_CLASS) += xillybus_class.o
obj-$(CONFIG_XILLYBUS) += xillybus_core.o
obj-$(CONFIG_XILLYBUS_PCIE) += xillybus_pcie.o
obj-$(CONFIG_XILLYBUS_OF) += xillybus_of.o
diff --git a/drivers/char/xillybus/xillybus.h b/drivers/char/xillybus/xillybus.h
index 8e3ed4d1bb7f..c63ffc56637c 100644
--- a/drivers/char/xillybus/xillybus.h
+++ b/drivers/char/xillybus/xillybus.h
@@ -30,7 +30,8 @@ struct xilly_buffer {

struct xilly_idt_handle {
unsigned char *chandesc;
- unsigned char *idt;
+ unsigned char *names;
+ int names_len;
int entries;
};

@@ -94,7 +95,6 @@ struct xilly_endpoint {
struct device *dev;
struct xilly_endpoint_hardware *ephw;

- struct list_head ep_list;
int dma_using_dac; /* =1 if 64-bit DMA is used, =0 otherwise. */
__iomem void *registers;
int fatal_error;
@@ -102,12 +102,6 @@ struct xilly_endpoint {
struct mutex register_mutex;
wait_queue_head_t ep_wait;

- /* Channels and message handling */
- struct cdev cdev;
-
- int major;
- int lowest_minor; /* Highest minor = lowest_minor + num_channels - 1 */
-
int num_channels; /* EXCLUDING message buffer */
struct xilly_channel **channels;
int msg_counter;
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
new file mode 100644
index 000000000000..f3cfb76623c8
--- /dev/null
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021 Xillybus Ltd, http://xillybus.com
+ *
+ * Driver for the Xillybus class
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+
+#include <linux/xillybus_class.h>
+
+MODULE_DESCRIPTION("Driver for Xillybus class");
+MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
+MODULE_VERSION("1.0");
+MODULE_ALIAS("xillybus_class");
+MODULE_LICENSE("GPL v2");
+
+static DEFINE_MUTEX(unit_mutex);
+static LIST_HEAD(unit_list);
+static struct class *xillybus_class;
+
+#define UNITNAMELEN 16
+
+struct xilly_unit {
+ struct list_head list_entry;
+ void *private_data;
+
+ struct cdev *cdev;
+ char name[UNITNAMELEN];
+ int major;
+ int lowest_minor;
+ int num_nodes;
+};
+
+int xillybus_init_chrdev(struct device *dev,
+ const struct file_operations *fops,
+ struct module *owner,
+ void *private_data,
+ unsigned char *idt, unsigned int len,
+ int num_nodes,
+ const char *prefix, bool enumerate)
+{
+ int rc;
+ dev_t mdev;
+ int i;
+ char devname[48];
+
+ struct device *device;
+ size_t namelen;
+ struct xilly_unit *unit, *u;
+
+ unit = kzalloc(sizeof(*unit), GFP_KERNEL);
+
+ if (!unit)
+ return -ENOMEM;
+
+ mutex_lock(&unit_mutex);
+
+ if (!enumerate)
+ snprintf(unit->name, UNITNAMELEN, "%s", prefix);
+
+ for (i = 0; enumerate; i++) {
+ snprintf(unit->name, UNITNAMELEN, "%s_%02d",
+ prefix, i);
+
+ enumerate = false;
+ list_for_each_entry(u, &unit_list, list_entry)
+ if (!strcmp(unit->name, u->name)) {
+ enumerate = true;
+ break;
+ }
+ }
+
+ rc = alloc_chrdev_region(&mdev, 0, num_nodes, unit->name);
+
+ if (rc) {
+ dev_warn(dev, "Failed to obtain major/minors");
+ goto fail_obtain;
+ return rc;
+ }
+
+ unit->major = MAJOR(mdev);
+ unit->lowest_minor = MINOR(mdev);
+ unit->num_nodes = num_nodes;
+ unit->private_data = private_data;
+
+ unit->cdev = cdev_alloc();
+ if (!unit->cdev)
+ goto unregister_chrdev;
+
+ unit->cdev->ops = fops;
+ unit->cdev->owner = owner;
+
+ rc = cdev_add(unit->cdev, MKDEV(unit->major, unit->lowest_minor),
+ unit->num_nodes);
+ if (rc) {
+ dev_err(dev, "Failed to add cdev.\n");
+ /* kobject_put() is normally done by cdev_del() */
+ kobject_put(&unit->cdev->kobj);
+ goto unregister_chrdev;
+ }
+
+ for (i = 0; i < num_nodes; i++) {
+ namelen = strnlen(idt, len);
+
+ if (namelen == len) {
+ dev_err(dev, "IDT's list of names is too short. This is exceptionally weird, because its CRC is OK\n");
+ rc = -ENODEV;
+ goto unroll_device_create;
+ }
+
+ snprintf(devname, sizeof(devname), "%s_%s",
+ unit->name, idt);
+
+ len -= namelen + 1;
+ idt += namelen + 1;
+
+ device = device_create(xillybus_class,
+ NULL,
+ MKDEV(unit->major,
+ i + unit->lowest_minor),
+ NULL,
+ "%s", devname);
+
+ if (IS_ERR(device)) {
+ dev_err(dev, "Failed to create %s device. Aborting.\n",
+ devname);
+ rc = -ENODEV;
+ goto unroll_device_create;
+ }
+ }
+
+ if (len) {
+ dev_err(dev, "IDT's list of names is too long. This is exceptionally weird, because its CRC is OK\n");
+ rc = -ENODEV;
+ goto unroll_device_create;
+ }
+
+ list_add_tail(&unit->list_entry, &unit_list);
+
+ dev_info(dev, "Created %d device files.\n", num_nodes);
+
+ mutex_unlock(&unit_mutex);
+
+ return 0;
+
+unroll_device_create:
+ for (i--; i >= 0; i--)
+ device_destroy(xillybus_class, MKDEV(unit->major,
+ i + unit->lowest_minor));
+
+ cdev_del(unit->cdev);
+
+unregister_chrdev:
+ unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
+ unit->num_nodes);
+
+fail_obtain:
+ mutex_unlock(&unit_mutex);
+
+ kfree(unit);
+
+ return rc;
+}
+EXPORT_SYMBOL(xillybus_init_chrdev);
+
+void xillybus_cleanup_chrdev(void *private_data,
+ struct device *dev)
+{
+ int minor;
+ struct xilly_unit *unit;
+ bool found = false;
+
+ mutex_lock(&unit_mutex);
+
+ list_for_each_entry(unit, &unit_list, list_entry)
+ if (unit->private_data == private_data) {
+ found = true;
+ break;
+ }
+
+ if (!found) {
+ dev_err(dev, "Weird bug: Failed to find unit\n");
+ mutex_unlock(&unit_mutex);
+ return;
+ }
+
+ for (minor = unit->lowest_minor;
+ minor < (unit->lowest_minor + unit->num_nodes);
+ minor++)
+ device_destroy(xillybus_class, MKDEV(unit->major, minor));
+
+ cdev_del(unit->cdev);
+
+ unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
+ unit->num_nodes);
+
+ dev_info(dev, "Removed %d device files.\n",
+ unit->num_nodes);
+
+ list_del(&unit->list_entry);
+ kfree(unit);
+
+ mutex_unlock(&unit_mutex);
+}
+EXPORT_SYMBOL(xillybus_cleanup_chrdev);
+
+int xillybus_find_inode(struct inode *inode,
+ void **private_data, int *index)
+{
+ int minor = iminor(inode);
+ int major = imajor(inode);
+ struct xilly_unit *unit;
+ bool found = false;
+
+ mutex_lock(&unit_mutex);
+
+ list_for_each_entry(unit, &unit_list, list_entry)
+ if (unit->major == major &&
+ minor >= unit->lowest_minor &&
+ minor < (unit->lowest_minor + unit->num_nodes)) {
+ found = true;
+ break;
+ }
+
+ mutex_unlock(&unit_mutex);
+
+ if (!found)
+ return -ENODEV;
+
+ *private_data = unit->private_data;
+ *index = minor - unit->lowest_minor;
+
+ return 0;
+}
+EXPORT_SYMBOL(xillybus_find_inode);
+
+static int __init xillybus_class_init(void)
+{
+ xillybus_class = class_create(THIS_MODULE, "xillybus");
+
+ if (IS_ERR(xillybus_class)) {
+ pr_warn("Failed to register xillybus class\n");
+
+ return PTR_ERR(xillybus_class);
+ }
+ return 0;
+}
+
+static void __exit xillybus_class_exit(void)
+{
+ class_destroy(xillybus_class);
+}
+
+module_init(xillybus_class_init);
+module_exit(xillybus_class_exit);
diff --git a/drivers/char/xillybus/xillybus_core.c b/drivers/char/xillybus/xillybus_core.c
index 57fa68834981..57884fdd07d8 100644
--- a/drivers/char/xillybus/xillybus_core.c
+++ b/drivers/char/xillybus/xillybus_core.c
@@ -21,7 +21,6 @@
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/fs.h>
-#include <linux/cdev.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/crc32.h>
@@ -30,10 +29,11 @@
#include <linux/slab.h>
#include <linux/workqueue.h>
#include "xillybus.h"
+#include <linux/xillybus_class.h>

MODULE_DESCRIPTION("Xillybus core functions");
MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
-MODULE_VERSION("1.07");
+MODULE_VERSION("1.10");
MODULE_ALIAS("xillybus_core");
MODULE_LICENSE("GPL v2");

@@ -58,16 +58,6 @@ MODULE_LICENSE("GPL v2");

static const char xillyname[] = "xillybus";

-static struct class *xillybus_class;
-
-/*
- * ep_list_lock is the last lock to be taken; No other lock requests are
- * allowed while holding it. It merely protects list_of_endpoints, and not
- * the endpoints listed in it.
- */
-
-static LIST_HEAD(list_of_endpoints);
-static struct mutex ep_list_lock;
static struct workqueue_struct *xillybus_wq;

/*
@@ -570,10 +560,8 @@ static int xilly_scan_idt(struct xilly_endpoint *endpoint,
unsigned char *scan;
int len;

- scan = idt;
- idt_handle->idt = idt;
-
- scan++; /* Skip version number */
+ scan = idt + 1;
+ idt_handle->names = scan;

while ((scan <= end_of_idt) && *scan) {
while ((scan <= end_of_idt) && *scan++)
@@ -581,6 +569,8 @@ static int xilly_scan_idt(struct xilly_endpoint *endpoint,
count++;
}

+ idt_handle->names_len = scan - idt_handle->names;
+
scan++;

if (scan > end_of_idt) {
@@ -1407,36 +1397,20 @@ static ssize_t xillybus_write(struct file *filp, const char __user *userbuf,

static int xillybus_open(struct inode *inode, struct file *filp)
{
- int rc = 0;
+ int rc;
unsigned long flags;
- int minor = iminor(inode);
- int major = imajor(inode);
- struct xilly_endpoint *ep_iter, *endpoint = NULL;
+ struct xilly_endpoint *endpoint;
struct xilly_channel *channel;
+ int index;

- mutex_lock(&ep_list_lock);
-
- list_for_each_entry(ep_iter, &list_of_endpoints, ep_list) {
- if ((ep_iter->major == major) &&
- (minor >= ep_iter->lowest_minor) &&
- (minor < (ep_iter->lowest_minor +
- ep_iter->num_channels))) {
- endpoint = ep_iter;
- break;
- }
- }
- mutex_unlock(&ep_list_lock);
-
- if (!endpoint) {
- pr_err("xillybus: open() failed to find a device for major=%d and minor=%d\n",
- major, minor);
- return -ENODEV;
- }
+ rc = xillybus_find_inode(inode, (void **)&endpoint, &index);
+ if (rc)
+ return rc;

if (endpoint->fatal_error)
return -EIO;

- channel = endpoint->channels[1 + minor - endpoint->lowest_minor];
+ channel = endpoint->channels[1 + index];
filp->private_data = channel;

/*
@@ -1799,95 +1773,6 @@ static const struct file_operations xillybus_fops = {
.poll = xillybus_poll,
};

-static int xillybus_init_chrdev(struct xilly_endpoint *endpoint,
- const unsigned char *idt)
-{
- int rc;
- dev_t dev;
- int devnum, i, minor, major;
- char devname[48];
- struct device *device;
-
- rc = alloc_chrdev_region(&dev, 0, /* minor start */
- endpoint->num_channels,
- xillyname);
- if (rc) {
- dev_warn(endpoint->dev, "Failed to obtain major/minors");
- return rc;
- }
-
- endpoint->major = major = MAJOR(dev);
- endpoint->lowest_minor = minor = MINOR(dev);
-
- cdev_init(&endpoint->cdev, &xillybus_fops);
- endpoint->cdev.owner = endpoint->ephw->owner;
- rc = cdev_add(&endpoint->cdev, MKDEV(major, minor),
- endpoint->num_channels);
- if (rc) {
- dev_warn(endpoint->dev, "Failed to add cdev. Aborting.\n");
- goto unregister_chrdev;
- }
-
- idt++;
-
- for (i = minor, devnum = 0;
- devnum < endpoint->num_channels;
- devnum++, i++) {
- snprintf(devname, sizeof(devname)-1, "xillybus_%s", idt);
-
- devname[sizeof(devname)-1] = 0; /* Should never matter */
-
- while (*idt++)
- /* Skip to next */;
-
- device = device_create(xillybus_class,
- NULL,
- MKDEV(major, i),
- NULL,
- "%s", devname);
-
- if (IS_ERR(device)) {
- dev_warn(endpoint->dev,
- "Failed to create %s device. Aborting.\n",
- devname);
- rc = -ENODEV;
- goto unroll_device_create;
- }
- }
-
- dev_info(endpoint->dev, "Created %d device files.\n",
- endpoint->num_channels);
- return 0; /* succeed */
-
-unroll_device_create:
- devnum--; i--;
- for (; devnum >= 0; devnum--, i--)
- device_destroy(xillybus_class, MKDEV(major, i));
-
- cdev_del(&endpoint->cdev);
-unregister_chrdev:
- unregister_chrdev_region(MKDEV(major, minor), endpoint->num_channels);
-
- return rc;
-}
-
-static void xillybus_cleanup_chrdev(struct xilly_endpoint *endpoint)
-{
- int minor;
-
- for (minor = endpoint->lowest_minor;
- minor < (endpoint->lowest_minor + endpoint->num_channels);
- minor++)
- device_destroy(xillybus_class, MKDEV(endpoint->major, minor));
- cdev_del(&endpoint->cdev);
- unregister_chrdev_region(MKDEV(endpoint->major,
- endpoint->lowest_minor),
- endpoint->num_channels);
-
- dev_info(endpoint->dev, "Removed %d device files.\n",
- endpoint->num_channels);
-}
-
struct xilly_endpoint *xillybus_init_endpoint(struct pci_dev *pdev,
struct device *dev,
struct xilly_endpoint_hardware
@@ -2027,28 +1912,20 @@ int xillybus_endpoint_discovery(struct xilly_endpoint *endpoint)
if (rc)
goto failed_idt;

- /*
- * endpoint is now completely configured. We put it on the list
- * available to open() before registering the char device(s)
- */
-
- mutex_lock(&ep_list_lock);
- list_add_tail(&endpoint->ep_list, &list_of_endpoints);
- mutex_unlock(&ep_list_lock);
+ rc = xillybus_init_chrdev(dev, &xillybus_fops,
+ endpoint->ephw->owner, endpoint,
+ idt_handle.names,
+ idt_handle.names_len,
+ endpoint->num_channels,
+ xillyname, false);

- rc = xillybus_init_chrdev(endpoint, idt_handle.idt);
if (rc)
- goto failed_chrdevs;
+ goto failed_idt;

devres_release_group(dev, bootstrap_resources);

return 0;

-failed_chrdevs:
- mutex_lock(&ep_list_lock);
- list_del(&endpoint->ep_list);
- mutex_unlock(&ep_list_lock);
-
failed_idt:
xilly_quiesce(endpoint);
flush_workqueue(xillybus_wq);
@@ -2059,11 +1936,7 @@ EXPORT_SYMBOL(xillybus_endpoint_discovery);

void xillybus_endpoint_remove(struct xilly_endpoint *endpoint)
{
- xillybus_cleanup_chrdev(endpoint);
-
- mutex_lock(&ep_list_lock);
- list_del(&endpoint->ep_list);
- mutex_unlock(&ep_list_lock);
+ xillybus_cleanup_chrdev(endpoint, endpoint->dev);

xilly_quiesce(endpoint);

@@ -2077,17 +1950,9 @@ EXPORT_SYMBOL(xillybus_endpoint_remove);

static int __init xillybus_init(void)
{
- mutex_init(&ep_list_lock);
-
- xillybus_class = class_create(THIS_MODULE, xillyname);
- if (IS_ERR(xillybus_class))
- return PTR_ERR(xillybus_class);
-
xillybus_wq = alloc_workqueue(xillyname, 0, 0);
- if (!xillybus_wq) {
- class_destroy(xillybus_class);
+ if (!xillybus_wq)
return -ENOMEM;
- }

return 0;
}
@@ -2096,8 +1961,6 @@ static void __exit xillybus_exit(void)
{
/* flush_workqueue() was called for each endpoint released */
destroy_workqueue(xillybus_wq);
-
- class_destroy(xillybus_class);
}

module_init(xillybus_init);
diff --git a/include/linux/xillybus_class.h b/include/linux/xillybus_class.h
new file mode 100644
index 000000000000..5dbfdfc95c65
--- /dev/null
+++ b/include/linux/xillybus_class.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2021 Xillybus Ltd, http://www.xillybus.com
+ *
+ * Header file for the Xillybus class
+ */
+
+#ifndef __XILLYBUS_CLASS_H
+#define __XILLYBUS_CLASS_H
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+
+int xillybus_init_chrdev(struct device *dev,
+ const struct file_operations *fops,
+ struct module *owner,
+ void *private_data,
+ unsigned char *idt, unsigned int len,
+ int num_nodes,
+ const char *prefix, bool enumerate);
+
+void xillybus_cleanup_chrdev(void *private_data,
+ struct device *dev);
+
+int xillybus_find_inode(struct inode *inode,
+ void **private_data, int *index);
+
+#endif /* __XILLYBUS_CLASS_H */
--
2.17.1