UVC Gadget Driver Issue

[sunil_embex]

Dear Team,

I am using IMX8M-Mini evk board and trying to configure usb uvc gadget  driver.

I followed this link: https://developer.ridgerun.com/wiki/index.php/How_to_use_the_UVC_gadget_driver_in_Linux

But I am not able to see any node in /sys/class/udc. 

Can you please help and do the needful.

Regards,

Sunilk

[AldoG]

Hello,

Could you share the BSP version that you're working with?
Also, to which USB port are you using for your test?

Best regards,
Aldo.

[sunil_embex]

Hi Aldo,

Thanks for reply. I moved on the usb printer gadget driver and i am able to transfer data on default end points.

Further I have added two more endpoints and able to see in libusb output but not able to send/receive data so if you can help me to resolve this issue that would be really great help otherwise you can close the ticket.

Below is the driver

// SPDX-License-Identifier: GPL-2.0+
/*
* f_printer.c - USB printer function driver
*
* Copied from drivers/usb/gadget/legacy/printer.c,
* which was:
*
* printer.c -- Printer gadget driver
*
* Copyright (C) 2003-2005 David Brownell
* Copyright (C) 2006 Craig W. Nadler
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/moduleparam.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/types.h>
#include <linux/ctype.h>
#include <linux/cdev.h>
#include <linux/kref.h>
#include <asm/byteorder.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/uaccess.h>
#include <asm/unaligned.h>
#include <linux/usb/ch9.h>
#include <linux/usb/composite.h>
#include <linux/usb/gadget.h>
#include <linux/usb/g_printer.h>
#include "u_printer.h"

#define PRINTER_MINORS 4
#define GET_DEVICE_ID 0
#define GET_PORT_STATUS 1
#define SOFT_RESET 2

#define DEFAULT_Q_LEN 10 /* same as legacy g_printer gadget */

static int major, minors;
static struct class *usb_gadget_class;
static DEFINE_IDA(printer_ida);
static DEFINE_MUTEX(printer_ida_lock); /* protects access do printer_ida */

/*-------------------------------------------------------------------------*/

struct printer_dev {
spinlock_t lock; /* lock this structure */
/* lock buffer lists during read/write calls */
struct mutex lock_printer_io;
struct usb_gadget *gadget;
s8 interface;
struct usb_ep *in_ep, *out_ep;
struct kref kref;
struct list_head rx_reqs; /* List of free RX structs */
struct list_head rx_reqs_active; /* List of Active RX xfers */
struct list_head rx_buffers; /* List of completed xfers */
/* wait until there is data to be read. */
wait_queue_head_t rx_wait;
struct list_head tx_reqs; /* List of free TX structs */
struct list_head tx_reqs_active; /* List of Active TX xfers */
/* Wait until there are write buffers available to use. */
wait_queue_head_t tx_wait;
/* Wait until all write buffers have been sent. */
wait_queue_head_t tx_flush_wait;
struct usb_request *current_rx_req;
size_t current_rx_bytes;
u8 *current_rx_buf;
u8 printer_status;
u8 reset_printer;
int minor;
struct cdev printer_cdev;
u8 printer_cdev_open;
wait_queue_head_t wait;
unsigned q_len;
char *pnp_string; /* We don't own memory! */
struct usb_function function;
};

static inline struct printer_dev *func_to_printer(struct usb_function *f)
{
return container_of(f, struct printer_dev, function);
}
/*-------------------------------------------------------------------------*/

/*
* DESCRIPTORS ... most are static, but strings and (full) configuration
* descriptors are built on demand.
*/

/* holds our biggest descriptor */
#define USB_DESC_BUFSIZE 256
#define USB_BUFSIZE 8192

static struct usb_interface_descriptor intf_desc = {
.bLength = sizeof(intf_desc),
.bDescriptorType = USB_DT_INTERFACE,
.bNumEndpoints = 4,
.bInterfaceClass = USB_CLASS_PER_INTERFACE,
.bInterfaceSubClass = USB_CLASS_PER_INTERFACE, /* Printer Sub-Class */
.bInterfaceProtocol = USB_CLASS_PER_INTERFACE, /* Bi-Directional */
.iInterface = 0
};

static struct usb_endpoint_descriptor fs_ep_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_BULK
};

static struct usb_endpoint_descriptor fs_ep_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK
};

static struct usb_endpoint_descriptor fs_ep1_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_IN | 0x02
};

static struct usb_endpoint_descriptor fs_ep1_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_OUT | 0x02
};

static struct usb_descriptor_header *fs_printer_function[] = {
(struct usb_descriptor_header *) &intf_desc,
(struct usb_descriptor_header *) &fs_ep_in_desc,
(struct usb_descriptor_header *) &fs_ep_out_desc,
(struct usb_descriptor_header *) &fs_ep1_in_desc,
(struct usb_descriptor_header *) &fs_ep1_out_desc,
NULL
};

/*
* usb 2.0 devices need to expose both high speed and full speed
* descriptors, unless they only run at full speed.
*/

static struct usb_endpoint_descriptor hs_ep_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_IN,
.wMaxPacketSize = cpu_to_le16(512)
};
//Commeted this to just get he ep1_out
static struct usb_endpoint_descriptor hs_ep_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_OUT,
.wMaxPacketSize = cpu_to_le16(512)
};
static struct usb_endpoint_descriptor hs_ep1_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_IN | 0x02,
.wMaxPacketSize = cpu_to_le16(512)
};

static struct usb_endpoint_descriptor hs_ep1_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_OUT | 0x02,
.wMaxPacketSize = cpu_to_le16(512)
};

static struct usb_descriptor_header *hs_printer_function[] = {
(struct usb_descriptor_header *) &intf_desc,
(struct usb_descriptor_header *) &hs_ep_in_desc,
(struct usb_descriptor_header *) &hs_ep_out_desc,
(struct usb_descriptor_header *) &hs_ep1_in_desc,
(struct usb_descriptor_header *) &hs_ep1_out_desc,
NULL
};

/*
* Added endpoint descriptors for 3.0 devices
*/

static struct usb_endpoint_descriptor ss_ep_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor ss_ep_in_comp_desc = {
.bLength = sizeof(ss_ep_in_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
};

static struct usb_endpoint_descriptor ss_ep_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor ss_ep_out_comp_desc = {
.bLength = sizeof(ss_ep_out_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
};

static struct usb_endpoint_descriptor ss_ep1_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_IN | 0x02,
.wMaxPacketSize = cpu_to_le16(1024)
};

static struct usb_ss_ep_comp_descriptor ss_ep1_in_comp_desc = {
.bLength = sizeof(ss_ep1_in_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
};

static struct usb_endpoint_descriptor ss_ep1_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.bEndpointAddress = USB_DIR_OUT | 0x02,
.wMaxPacketSize = cpu_to_le16(1024)
};

static struct usb_ss_ep_comp_descriptor ss_ep1_out_comp_desc = {
.bLength = sizeof(ss_ep1_out_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
};

static struct usb_descriptor_header *ss_printer_function[] = {
(struct usb_descriptor_header *) &intf_desc,
(struct usb_descriptor_header *) &ss_ep_in_desc,
(struct usb_descriptor_header *) &ss_ep_in_comp_desc,
(struct usb_descriptor_header *) &ss_ep_out_desc,
(struct usb_descriptor_header *) &ss_ep_out_comp_desc,
(struct usb_descriptor_header *) &ss_ep1_in_desc,
(struct usb_descriptor_header *) &ss_ep1_in_comp_desc,
(struct usb_descriptor_header *) &ss_ep1_out_desc,
(struct usb_descriptor_header *) &ss_ep1_out_comp_desc,
NULL
};

/* maxpacket and other transfer characteristics vary by speed. */
static inline struct usb_endpoint_descriptor *ep_desc(struct usb_gadget *gadget,
struct usb_endpoint_descriptor *fs,
struct usb_endpoint_descriptor *hs,
struct usb_endpoint_descriptor *ss)
{
switch (gadget->speed) {
case USB_SPEED_SUPER:
return ss;
case USB_SPEED_HIGH:
return hs;
default:
return fs;
}
}

/*-------------------------------------------------------------------------*/

static void printer_dev_free(struct kref *kref)
{
struct printer_dev *dev = container_of(kref, struct printer_dev, kref);

kfree(dev);
}

static struct usb_request *
printer_req_alloc(struct usb_ep *ep, unsigned len, gfp_t gfp_flags)
{
struct usb_request *req;

req = usb_ep_alloc_request(ep, gfp_flags);

if (req != NULL) {
req->length = len;
req->buf = kmalloc(len, gfp_flags);
if (req->buf == NULL) {
usb_ep_free_request(ep, req);
return NULL;
}
}

return req;
}

static void
printer_req_free(struct usb_ep *ep, struct usb_request *req)
{
if (ep != NULL && req != NULL) {
kfree(req->buf);
usb_ep_free_request(ep, req);
}
}

/*-------------------------------------------------------------------------*/

static void rx_complete(struct usb_ep *ep, struct usb_request *req)
{
struct printer_dev *dev = ep->driver_data;
int status = req->status;
unsigned long flags;

spin_lock_irqsave(&dev->lock, flags);

list_del_init(&req->list); /* Remode from Active List */

switch (status) {

/* normal completion */
case 0:
if (req->actual > 0) {
list_add_tail(&req->list, &dev->rx_buffers);
DBG(dev, "G_Printer : rx length %d\n", req->actual);
} else {
list_add(&req->list, &dev->rx_reqs);
}
break;

/* software-driven interface shutdown */
case -ECONNRESET: /* unlink */
case -ESHUTDOWN: /* disconnect etc */
VDBG(dev, "rx shutdown, code %d\n", status);
list_add(&req->list, &dev->rx_reqs);
break;

/* for hardware automagic (such as pxa) */
case -ECONNABORTED: /* endpoint reset */
DBG(dev, "rx %s reset\n", ep->name);
list_add(&req->list, &dev->rx_reqs);
break;

/* data overrun */
case -EOVERFLOW:
fallthrough;

default:
DBG(dev, "rx status %d\n", status);
list_add(&req->list, &dev->rx_reqs);
break;
}

wake_up_interruptible(&dev->rx_wait);
spin_unlock_irqrestore(&dev->lock, flags);
}

static void tx_complete(struct usb_ep *ep, struct usb_request *req)
{
struct printer_dev *dev = ep->driver_data;

switch (req->status) {
default:
VDBG(dev, "tx err %d\n", req->status);
fallthrough;
case -ECONNRESET: /* unlink */
case -ESHUTDOWN: /* disconnect etc */
break;
case 0:
break;
}

spin_lock(&dev->lock);
/* Take the request struct off the active list and put it on the
* free list.
*/
list_del_init(&req->list);
list_add(&req->list, &dev->tx_reqs);
wake_up_interruptible(&dev->tx_wait);
if (likely(list_empty(&dev->tx_reqs_active)))
wake_up_interruptible(&dev->tx_flush_wait);

spin_unlock(&dev->lock);
}

/*-------------------------------------------------------------------------*/

static int
printer_open(struct inode *inode, struct file *fd)
{
struct printer_dev *dev;
unsigned long flags;
int ret = -EBUSY;

dev = container_of(inode->i_cdev, struct printer_dev, printer_cdev);

spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
return -ENODEV;
}
printk(KERN_INFO "Opening Sonosa Driver=================\n");
if (!dev->printer_cdev_open) {
dev->printer_cdev_open = 1;
fd->private_data = dev;
ret = 0;
/* Change the printer status to show that it's on-line. */
dev->printer_status |= PRINTER_SELECTED;
}

spin_unlock_irqrestore(&dev->lock, flags);

kref_get(&dev->kref);
DBG(dev, "Sonosa_open returned %x\n", ret);
return ret;
}

static int
printer_close(struct inode *inode, struct file *fd)
{
struct printer_dev *dev = fd->private_data;
unsigned long flags;

spin_lock_irqsave(&dev->lock, flags);
dev->printer_cdev_open = 0;
fd->private_data = NULL;
/* Change printer status to show that the printer is off-line. */
dev->printer_status &= ~PRINTER_SELECTED;
spin_unlock_irqrestore(&dev->lock, flags);

kref_put(&dev->kref, printer_dev_free);
DBG(dev, "Sonosa_close\n");

return 0;
}

/* This function must be called with interrupts turned off. */
static void
setup_rx_reqs(struct printer_dev *dev)
{
struct usb_request *req;

while (likely(!list_empty(&dev->rx_reqs))) {
int error;

req = container_of(dev->rx_reqs.next,
struct usb_request, list);
list_del_init(&req->list);

/* The USB Host sends us whatever amount of data it wants to
* so we always set the length field to the full USB_BUFSIZE.
* If the amount of data is more than the read() caller asked
* for it will be stored in the request buffer until it is
* asked for by read().
*/
req->length = USB_BUFSIZE;
req->complete = rx_complete;

/* here, we unlock, and only unlock, to avoid deadlock. */
spin_unlock(&dev->lock);
error = usb_ep_queue(dev->out_ep, req, GFP_ATOMIC);
spin_lock(&dev->lock);
if (error) {
DBG(dev, "rx submit --> %d\n", error);
list_add(&req->list, &dev->rx_reqs);
break;
}
/* if the req is empty, then add it into dev->rx_reqs_active. */
else if (list_empty(&req->list))
list_add(&req->list, &dev->rx_reqs_active);
}
}

static ssize_t
printer_read(struct file *fd, char __user *buf, size_t len, loff_t *ptr)
{
struct printer_dev *dev = fd->private_data;
unsigned long flags;
size_t size;
size_t bytes_copied;
struct usb_request *req;
/* This is a pointer to the current USB rx request. */
struct usb_request *current_rx_req;
/* This is the number of bytes in the current rx buffer. */
size_t current_rx_bytes;
/* This is a pointer to the current rx buffer. */
u8 *current_rx_buf;

if (len == 0)
return -EINVAL;

DBG(dev, "sonosa_read trying to read %d bytes\n", (int)len);
printk(KERN_INFO "Sonosa Read=================:\n");
mutex_lock(&dev->lock_printer_io);
spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -ENODEV;
}

/* We will use this flag later to check if a printer reset happened
* after we turn interrupts back on.
*/
dev->reset_printer = 0;

setup_rx_reqs(dev);

bytes_copied = 0;
current_rx_req = dev->current_rx_req;
current_rx_bytes = dev->current_rx_bytes;
current_rx_buf = dev->current_rx_buf;
dev->current_rx_req = NULL;
dev->current_rx_bytes = 0;
dev->current_rx_buf = NULL;

/* Check if there is any data in the read buffers. Please note that
* current_rx_bytes is the number of bytes in the current rx buffer.
* If it is zero then check if there are any other rx_buffers that
* are on the completed list. We are only out of data if all rx
* buffers are empty.
*/
if ((current_rx_bytes == 0) &&
(likely(list_empty(&dev->rx_buffers)))) {
/* Turn interrupts back on before sleeping. */
spin_unlock_irqrestore(&dev->lock, flags);

/*
* If no data is available check if this is a NON-Blocking
* call or not.
*/
if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}

/* Sleep until data is available */
wait_event_interruptible(dev->rx_wait,
(likely(!list_empty(&dev->rx_buffers))));
spin_lock_irqsave(&dev->lock, flags);
}

/* We have data to return then copy it to the caller's buffer.*/
while ((current_rx_bytes || likely(!list_empty(&dev->rx_buffers)))
&& len) {
if (current_rx_bytes == 0) {
req = container_of(dev->rx_buffers.next,
struct usb_request, list);
list_del_init(&req->list);

if (req->actual && req->buf) {
current_rx_req = req;
current_rx_bytes = req->actual;
current_rx_buf = req->buf;
} else {
list_add(&req->list, &dev->rx_reqs);
continue;
}
}

/* Don't leave irqs off while doing memory copies */
spin_unlock_irqrestore(&dev->lock, flags);

if (len > current_rx_bytes)
size = current_rx_bytes;
else
size = len;

size -= copy_to_user(buf, current_rx_buf, size);
bytes_copied += size;
len -= size;
buf += size;

spin_lock_irqsave(&dev->lock, flags);

/* We've disconnected or reset so return. */
if (dev->reset_printer) {
list_add(&current_rx_req->list, &dev->rx_reqs);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}

/* If we not returning all the data left in this RX request
* buffer then adjust the amount of data left in the buffer.
* Othewise if we are done with this RX request buffer then
* requeue it to get any incoming data from the USB host.
*/
if (size < current_rx_bytes) {
current_rx_bytes -= size;
current_rx_buf += size;
} else {
list_add(&current_rx_req->list, &dev->rx_reqs);
current_rx_bytes = 0;
current_rx_buf = NULL;
current_rx_req = NULL;
}
}

dev->current_rx_req = current_rx_req;
dev->current_rx_bytes = current_rx_bytes;
dev->current_rx_buf = current_rx_buf;

spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);

DBG(dev, "printer_read returned %d bytes\n", (int)bytes_copied);

if (bytes_copied)
return bytes_copied;
else
return -EAGAIN;
}

static ssize_t
printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
{
struct printer_dev *dev = fd->private_data;
unsigned long flags;
size_t size; /* Amount of data in a TX request. */
size_t bytes_copied = 0;
struct usb_request *req;
int value;

DBG(dev, "printer_write trying to send %d bytes\n", (int)len);

if (len == 0)
return -EINVAL;

mutex_lock(&dev->lock_printer_io);
spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -ENODEV;
}

/* Check if a printer reset happens while we have interrupts on */
dev->reset_printer = 0;

/* Check if there is any available write buffers */
if (likely(list_empty(&dev->tx_reqs))) {
/* Turn interrupts back on before sleeping. */
spin_unlock_irqrestore(&dev->lock, flags);

/*
* If write buffers are available check if this is
* a NON-Blocking call or not.
*/
if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}

/* Sleep until a write buffer is available */
wait_event_interruptible(dev->tx_wait,
(likely(!list_empty(&dev->tx_reqs))));
spin_lock_irqsave(&dev->lock, flags);
}

while (likely(!list_empty(&dev->tx_reqs)) && len) {

if (len > USB_BUFSIZE)
size = USB_BUFSIZE;
else
size = len;

req = container_of(dev->tx_reqs.next, struct usb_request,
list);
list_del_init(&req->list);

req->complete = tx_complete;
req->length = size;

/* Check if we need to send a zero length packet. */
if (len > size)
/* They will be more TX requests so no yet. */
req->zero = 0;
else
/* If the data amount is not a multiple of the
* maxpacket size then send a zero length packet.
*/
req->zero = ((len % dev->in_ep->maxpacket) == 0);

/* Don't leave irqs off while doing memory copies */
spin_unlock_irqrestore(&dev->lock, flags);

if (copy_from_user(req->buf, buf, size)) {
list_add(&req->list, &dev->tx_reqs);
mutex_unlock(&dev->lock_printer_io);
return bytes_copied;
}

bytes_copied += size;
len -= size;
buf += size;

spin_lock_irqsave(&dev->lock, flags);

/* We've disconnected or reset so free the req and buffer */
if (dev->reset_printer) {
list_add(&req->list, &dev->tx_reqs);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}

list_add(&req->list, &dev->tx_reqs_active);

/* here, we unlock, and only unlock, to avoid deadlock. */
spin_unlock(&dev->lock);
value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC);
spin_lock(&dev->lock);
if (value) {
list_move(&req->list, &dev->tx_reqs);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}
}

spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);

DBG(dev, "printer_write sent %d bytes\n", (int)bytes_copied);

if (bytes_copied)
return bytes_copied;
else
return -EAGAIN;
}

static int
printer_fsync(struct file *fd, loff_t start, loff_t end, int datasync)
{
struct printer_dev *dev = fd->private_data;
struct inode *inode = file_inode(fd);
unsigned long flags;
int tx_list_empty;

inode_lock(inode);
spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
inode_unlock(inode);
return -ENODEV;
}

tx_list_empty = (likely(list_empty(&dev->tx_reqs)));
spin_unlock_irqrestore(&dev->lock, flags);

if (!tx_list_empty) {
/* Sleep until all data has been sent */
wait_event_interruptible(dev->tx_flush_wait,
(likely(list_empty(&dev->tx_reqs_active))));
}
inode_unlock(inode);

return 0;
}

static __poll_t
printer_poll(struct file *fd, poll_table *wait)
{
struct printer_dev *dev = fd->private_data;
unsigned long flags;
__poll_t status = 0;

mutex_lock(&dev->lock_printer_io);
spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return EPOLLERR | EPOLLHUP;
}

setup_rx_reqs(dev);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);

poll_wait(fd, &dev->rx_wait, wait);
poll_wait(fd, &dev->tx_wait, wait);

spin_lock_irqsave(&dev->lock, flags);
if (likely(!list_empty(&dev->tx_reqs)))
status |= EPOLLOUT | EPOLLWRNORM;

if (likely(dev->current_rx_bytes) ||
likely(!list_empty(&dev->rx_buffers)))
status |= EPOLLIN | EPOLLRDNORM;

spin_unlock_irqrestore(&dev->lock, flags);

return status;
}

static long
printer_ioctl(struct file *fd, unsigned int code, unsigned long arg)
{
struct printer_dev *dev = fd->private_data;
unsigned long flags;
int status = 0;

DBG(dev, "printer_ioctl: cmd=0x%4.4x, arg=%lu\n", code, arg);

/* handle ioctls */

spin_lock_irqsave(&dev->lock, flags);

if (dev->interface < 0) {
spin_unlock_irqrestore(&dev->lock, flags);
return -ENODEV;
}

switch (code) {
case GADGET_GET_PRINTER_STATUS:
status = (int)dev->printer_status;
break;
case GADGET_SET_PRINTER_STATUS:
dev->printer_status = (u8)arg;
break;
default:
/* could not handle ioctl */
DBG(dev, "printer_ioctl: ERROR cmd=0x%4.4xis not supported\n",
code);
status = -ENOTTY;
}

spin_unlock_irqrestore(&dev->lock, flags);

return status;
}

/* used after endpoint configuration */
static const struct file_operations printer_io_operations = {
.owner = THIS_MODULE,
.open = printer_open,
.read = printer_read,
.write = printer_write,
.fsync = printer_fsync,
.poll = printer_poll,
.unlocked_ioctl = printer_ioctl,
.release = printer_close,
.llseek = noop_llseek,
};

/*-------------------------------------------------------------------------*/

static int
set_printer_interface(struct printer_dev *dev)
{
int result = 0;

dev->in_ep->desc = ep_desc(dev->gadget, &fs_ep_in_desc, &hs_ep_in_desc,
&ss_ep_in_desc);
dev->in_ep->driver_data = dev;

dev->out_ep->desc = ep_desc(dev->gadget, &fs_ep_out_desc,
&hs_ep1_out_desc,&ss_ep_out_desc);
dev->out_ep->driver_data = dev;

result = usb_ep_enable(dev->in_ep);
if (result != 0) {
DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
printk(KERN_INFO, "Enabling Endpoints+++++++++++++++++++");
goto done;
}

result = usb_ep_enable(dev->out_ep);
if (result != 0) {
DBG(dev, "enable %s --> %d\n", dev->out_ep->name, result);
goto done;
}

done:
/* on error, disable any endpoints */
if (result != 0) {
(void) usb_ep_disable(dev->in_ep);
(void) usb_ep_disable(dev->out_ep);
dev->in_ep->desc = NULL;
dev->out_ep->desc = NULL;
}

/* caller is responsible for cleanup on error */
return result;
}

static void printer_reset_interface(struct printer_dev *dev)
{
unsigned long flags;

if (dev->interface < 0)
return;

DBG(dev, "%s\n", __func__);

if (dev->in_ep->desc)
usb_ep_disable(dev->in_ep);

if (dev->out_ep->desc)
usb_ep_disable(dev->out_ep);

spin_lock_irqsave(&dev->lock, flags);
dev->in_ep->desc = NULL;
dev->out_ep->desc = NULL;
dev->interface = -1;
spin_unlock_irqrestore(&dev->lock, flags);
}

/* Change our operational Interface. */
static int set_interface(struct printer_dev *dev, unsigned number)
{
int result = 0;

/* Free the current interface */
printer_reset_interface(dev);

result = set_printer_interface(dev);
if (result)
printer_reset_interface(dev);
else
dev->interface = number;

if (!result)
INFO(dev, "Using interface %x\n", number);

return result;
}

static void printer_soft_reset(struct printer_dev *dev)
{
struct usb_request *req;

INFO(dev, "Received Printer Reset Request\n");

if (usb_ep_disable(dev->in_ep))
DBG(dev, "Failed to disable USB in_ep\n");
if (usb_ep_disable(dev->out_ep))
DBG(dev, "Failed to disable USB out_ep\n");

if (dev->current_rx_req != NULL) {
list_add(&dev->current_rx_req->list, &dev->rx_reqs);
dev->current_rx_req = NULL;
}
dev->current_rx_bytes = 0;
dev->current_rx_buf = NULL;
dev->reset_printer = 1;

while (likely(!(list_empty(&dev->rx_buffers)))) {
req = container_of(dev->rx_buffers.next, struct usb_request,
list);
list_del_init(&req->list);
list_add(&req->list, &dev->rx_reqs);
}

while (likely(!(list_empty(&dev->rx_reqs_active)))) {
req = container_of(dev->rx_buffers.next, struct usb_request,
list);
list_del_init(&req->list);
list_add(&req->list, &dev->rx_reqs);
}

while (likely(!(list_empty(&dev->tx_reqs_active)))) {
req = container_of(dev->tx_reqs_active.next,
struct usb_request, list);
list_del_init(&req->list);
list_add(&req->list, &dev->tx_reqs);
}

if (usb_ep_enable(dev->in_ep))
DBG(dev, "Failed to enable USB in_ep\n");
if (usb_ep_enable(dev->out_ep))
DBG(dev, "Failed to enable USB out_ep\n");

wake_up_interruptible(&dev->rx_wait);
wake_up_interruptible(&dev->tx_wait);
wake_up_interruptible(&dev->tx_flush_wait);
}

/*-------------------------------------------------------------------------*/

static bool gprinter_req_match(struct usb_function *f,
const struct usb_ctrlrequest *ctrl,
bool config0)
{
struct printer_dev *dev = func_to_printer(f);
u16 w_index = le16_to_cpu(ctrl->wIndex);
u16 w_value = le16_to_cpu(ctrl->wValue);
u16 w_length = le16_to_cpu(ctrl->wLength);

if (config0)
return false;

if ((ctrl->bRequestType & USB_RECIP_MASK) != USB_RECIP_INTERFACE ||
(ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
return false;

switch (ctrl->bRequest) {
case GET_DEVICE_ID:
w_index >>= 8;
if (USB_DIR_IN & ctrl->bRequestType)
break;
return false;
case GET_PORT_STATUS:
if (!w_value && w_length == 1 &&
(USB_DIR_IN & ctrl->bRequestType))
break;
return false;
case SOFT_RESET:
if (!w_value && !w_length &&
!(USB_DIR_IN & ctrl->bRequestType))
break;
fallthrough;
default:
return false;
}
return w_index == dev->interface;
}

/*
* The setup() callback implements all the ep0 functionality that's not
* handled lower down.
*/
static int printer_func_setup(struct usb_function *f,
const struct usb_ctrlrequest *ctrl)
{
struct printer_dev *dev = func_to_printer(f);
struct usb_composite_dev *cdev = f->config->cdev;
struct usb_request *req = cdev->req;
u8 *buf = req->buf;
int value = -EOPNOTSUPP;
u16 wIndex = le16_to_cpu(ctrl->wIndex);
u16 wValue = le16_to_cpu(ctrl->wValue);
u16 wLength = le16_to_cpu(ctrl->wLength);

DBG(dev, "ctrl req%02x.%02x v%04x i%04x l%d\n",
ctrl->bRequestType, ctrl->bRequest, wValue, wIndex, wLength);

switch (ctrl->bRequestType&USB_TYPE_MASK) {
case USB_TYPE_CLASS:
switch (ctrl->bRequest) {
case GET_DEVICE_ID: /* Get the IEEE-1284 PNP String */
/* Only one printer interface is supported. */
if ((wIndex>>8) != dev->interface)
break;

if (!dev->pnp_string) {
value = 0;
break;
}
value = strlen(dev->pnp_string);
buf[0] = (value >> & 0xFF;
buf[1] = value & 0xFF;
memcpy(buf + 2, dev->pnp_string, value);
DBG(dev, "1284 PNP String: %x %s\n", value,
dev->pnp_string);
break;

case GET_PORT_STATUS: /* Get Port Status */
/* Only one printer interface is supported. */
if (wIndex != dev->interface)
break;

buf[0] = dev->printer_status;
value = min_t(u16, wLength, 1);
break;

case SOFT_RESET: /* Soft Reset */
/* Only one printer interface is supported. */
if (wIndex != dev->interface)
break;

printer_soft_reset(dev);

value = 0;
break;

default:
goto unknown;
}
break;

default:
unknown:
VDBG(dev,
"unknown ctrl req%02x.%02x v%04x i%04x l%d\n",
ctrl->bRequestType, ctrl->bRequest,
wValue, wIndex, wLength);
break;
}
/* host either stalls (value < 0) or reports success */
if (value >= 0) {
req->length = value;
req->zero = value < wLength;
value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
if (value < 0) {
ERROR(dev, "%s:%d Error!\n", __func__, __LINE__);
req->status = 0;
}
}
return value;
}

static int printer_func_bind(struct usb_configuration *c,
struct usb_function *f)
{
struct usb_gadget *gadget = c->cdev->gadget;
struct printer_dev *dev = func_to_printer(f);
struct device *pdev;
struct usb_composite_dev *cdev = c->cdev;
struct usb_ep *in_ep;
struct usb_ep *out_ep = NULL;
struct usb_request *req;
int id;
int ret;
u32 i;
dev_t devt;
id = usb_interface_id(c, f);
if (id < 0)
return id;
intf_desc.bInterfaceNumber = id;

/* finish hookup to lower layer ... */
dev->gadget = gadget;

/* all we really need is bulk IN/OUT */
in_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_in_desc);
if (!in_ep) {
autoconf_fail:
dev_err(&cdev->gadget->dev, "can't autoconfigure on %s\n",
cdev->gadget->name);
return -ENODEV;
}

out_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_out_desc);
if (!out_ep)
goto autoconf_fail;

/* assumes that all endpoints are dual-speed */
hs_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
// hs_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
hs_ep1_out_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
// hs_ep1_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
ss_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
ss_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;

ret = usb_assign_descriptors(f, fs_printer_function,
hs_printer_function, ss_printer_function,
ss_printer_function);
if (ret)
return ret;

dev->in_ep = in_ep;
dev->out_ep = out_ep;

ret = -ENOMEM;
for (i = 0; i < dev->q_len; i++) {
req = printer_req_alloc(dev->in_ep, USB_BUFSIZE, GFP_KERNEL);
if (!req)
goto fail_tx_reqs;
list_add(&req->list, &dev->tx_reqs);
}

for (i = 0; i < dev->q_len; i++) {
req = printer_req_alloc(dev->out_ep, USB_BUFSIZE, GFP_KERNEL);
if (!req)
goto fail_rx_reqs;
list_add(&req->list, &dev->rx_reqs);
}

/* Setup the sysfs files for the printer gadget. */
devt = MKDEV(major, dev->minor);
pdev = device_create(usb_gadget_class, NULL, devt,
NULL, "sonosa_acu%d", dev->minor);
if (IS_ERR(pdev)) {
ERROR(dev, "Failed to create device: sonosa_acu\n");
ret = PTR_ERR(pdev);
goto fail_rx_reqs;
}

/*
* Register a character device as an interface to a user mode
* program that handles the printer specific functionality.
*/
cdev_init(&dev->printer_cdev, &printer_io_operations);
dev->printer_cdev.owner = THIS_MODULE;
ret = cdev_add(&dev->printer_cdev, devt, 1);
if (ret) {
ERROR(dev, "Failed to open char device\n");
goto fail_cdev_add;
}

return 0;

fail_cdev_add:
device_destroy(usb_gadget_class, devt);

fail_rx_reqs:
while (!list_empty(&dev->rx_reqs)) {
req = container_of(dev->rx_reqs.next, struct usb_request, list);
list_del(&req->list);
printer_req_free(dev->out_ep, req);
}

fail_tx_reqs:
while (!list_empty(&dev->tx_reqs)) {
req = container_of(dev->tx_reqs.next, struct usb_request, list);
list_del(&req->list);
printer_req_free(dev->in_ep, req);
}

usb_free_all_descriptors(f);
return ret;

}

static int printer_func_set_alt(struct usb_function *f,
unsigned intf, unsigned alt)
{
struct printer_dev *dev = func_to_printer(f);
int ret = -ENOTSUPP;

if (!alt)
ret = set_interface(dev, intf);

return ret;
}

static void printer_func_disable(struct usb_function *f)
{
struct printer_dev *dev = func_to_printer(f);

DBG(dev, "%s\n", __func__);

printer_reset_interface(dev);
}

static inline struct f_printer_opts
*to_f_printer_opts(struct config_item *item)
{
return container_of(to_config_group(item), struct f_printer_opts,
func_inst.group);
}

static void printer_attr_release(struct config_item *item)
{
struct f_printer_opts *opts = to_f_printer_opts(item);

usb_put_function_instance(&opts->func_inst);
}

static struct configfs_item_operations printer_item_ops = {
.release = printer_attr_release,
};

static ssize_t f_printer_opts_pnp_string_show(struct config_item *item,
char *page)
{
struct f_printer_opts *opts = to_f_printer_opts(item);
int result = 0;

mutex_lock(&opts->lock);
if (!opts->pnp_string)
goto unlock;

result = strlcpy(page, opts->pnp_string, PAGE_SIZE);
if (result >= PAGE_SIZE) {
result = PAGE_SIZE;
} else if (page[result - 1] != '\n' && result + 1 < PAGE_SIZE) {
page[result++] = '\n';
page[result] = '\0';
}

unlock:
mutex_unlock(&opts->lock);

return result;
}

static ssize_t f_printer_opts_pnp_string_store(struct config_item *item,
const char *page, size_t len)
{
struct f_printer_opts *opts = to_f_printer_opts(item);
char *new_pnp;
int result;

mutex_lock(&opts->lock);

new_pnp = kstrndup(page, len, GFP_KERNEL);
if (!new_pnp) {
result = -ENOMEM;
goto unlock;
}

if (opts->pnp_string_allocated)
kfree(opts->pnp_string);

opts->pnp_string_allocated = true;
opts->pnp_string = new_pnp;
result = len;
unlock:
mutex_unlock(&opts->lock);

return result;
}

CONFIGFS_ATTR(f_printer_opts_, pnp_string);

static ssize_t f_printer_opts_q_len_show(struct config_item *item,
char *page)
{
struct f_printer_opts *opts = to_f_printer_opts(item);
int result;

mutex_lock(&opts->lock);
result = sprintf(page, "%d\n", opts->q_len);
mutex_unlock(&opts->lock);

return result;
}

static ssize_t f_printer_opts_q_len_store(struct config_item *item,
const char *page, size_t len)
{
struct f_printer_opts *opts = to_f_printer_opts(item);
int ret;
u16 num;

mutex_lock(&opts->lock);
if (opts->refcnt) {
ret = -EBUSY;
goto end;
}

ret = kstrtou16(page, 0, &num);
if (ret)
goto end;

opts->q_len = (unsigned)num;
ret = len;
end:
mutex_unlock(&opts->lock);
return ret;
}

CONFIGFS_ATTR(f_printer_opts_, q_len);

static struct configfs_attribute *printer_attrs[] = {
&f_printer_opts_attr_pnp_string,
&f_printer_opts_attr_q_len,
NULL,
};

static const struct config_item_type printer_func_type = {
.ct_item_ops = &printer_item_ops,
.ct_attrs = printer_attrs,
.ct_owner = THIS_MODULE,
};

static inline int gprinter_get_minor(void)
{
int ret;

ret = ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL);
if (ret >= PRINTER_MINORS) {
ida_simple_remove(&printer_ida, ret);
ret = -ENODEV;
}

return ret;
}

static inline void gprinter_put_minor(int minor)
{
ida_simple_remove(&printer_ida, minor);
}

static int gprinter_setup(int);
static void gprinter_cleanup(void);

static void gprinter_free_inst(struct usb_function_instance *f)
{
struct f_printer_opts *opts;

opts = container_of(f, struct f_printer_opts, func_inst);

mutex_lock(&printer_ida_lock);

gprinter_put_minor(opts->minor);
if (ida_is_empty(&printer_ida))
gprinter_cleanup();

mutex_unlock(&printer_ida_lock);

if (opts->pnp_string_allocated)
kfree(opts->pnp_string);
kfree(opts);
}

static struct usb_function_instance *gprinter_alloc_inst(void)
{
struct f_printer_opts *opts;
struct usb_function_instance *ret;
int status = 0;

opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);

mutex_init(&opts->lock);
opts->func_inst.free_func_inst = gprinter_free_inst;
ret = &opts->func_inst;

/* Make sure q_len is initialized, otherwise the bound device can't support read/write! */
opts->q_len = DEFAULT_Q_LEN;

mutex_lock(&printer_ida_lock);

if (ida_is_empty(&printer_ida)) {
status = gprinter_setup(PRINTER_MINORS);
if (status) {
ret = ERR_PTR(status);
kfree(opts);
goto unlock;
}
}

opts->minor = gprinter_get_minor();
if (opts->minor < 0) {
ret = ERR_PTR(opts->minor);
kfree(opts);
if (ida_is_empty(&printer_ida))
gprinter_cleanup();
goto unlock;
}
config_group_init_type_name(&opts->func_inst.group, "",
&printer_func_type);

unlock:
mutex_unlock(&printer_ida_lock);
return ret;
}

static void gprinter_free(struct usb_function *f)
{
struct printer_dev *dev = func_to_printer(f);
struct f_printer_opts *opts;

opts = container_of(f->fi, struct f_printer_opts, func_inst);

kref_put(&dev->kref, printer_dev_free);
mutex_lock(&opts->lock);
--opts->refcnt;
mutex_unlock(&opts->lock);
}

static void printer_func_unbind(struct usb_configuration *c,
struct usb_function *f)
{
struct printer_dev *dev;
struct usb_request *req;

dev = func_to_printer(f);

device_destroy(usb_gadget_class, MKDEV(major, dev->minor));

/* Remove Character Device */
cdev_del(&dev->printer_cdev);

/* we must already have been disconnected ... no i/o may be active */
WARN_ON(!list_empty(&dev->tx_reqs_active));
WARN_ON(!list_empty(&dev->rx_reqs_active));

/* Free all memory for this driver. */
while (!list_empty(&dev->tx_reqs)) {
req = container_of(dev->tx_reqs.next, struct usb_request,
list);
list_del(&req->list);
printer_req_free(dev->in_ep, req);
}

if (dev->current_rx_req != NULL)
printer_req_free(dev->out_ep, dev->current_rx_req);

while (!list_empty(&dev->rx_reqs)) {
req = container_of(dev->rx_reqs.next,
struct usb_request, list);
list_del(&req->list);
printer_req_free(dev->out_ep, req);
}

while (!list_empty(&dev->rx_buffers)) {
req = container_of(dev->rx_buffers.next,
struct usb_request, list);
list_del(&req->list);
printer_req_free(dev->out_ep, req);
}
usb_free_all_descriptors(f);
}

static struct usb_function *gprinter_alloc(struct usb_function_instance *fi)
{
struct printer_dev *dev;
struct f_printer_opts *opts;

opts = container_of(fi, struct f_printer_opts, func_inst);

mutex_lock(&opts->lock);
if (opts->minor >= minors) {
mutex_unlock(&opts->lock);
return ERR_PTR(-ENOENT);
}

dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
mutex_unlock(&opts->lock);
return ERR_PTR(-ENOMEM);
}

kref_init(&dev->kref);
++opts->refcnt;
dev->minor = opts->minor;
dev->pnp_string = opts->pnp_string;
dev->q_len = opts->q_len;
mutex_unlock(&opts->lock);

dev->function.name = "printer";
dev->function.bind = printer_func_bind;
dev->function.setup = printer_func_setup;
dev->function.unbind = printer_func_unbind;
dev->function.set_alt = printer_func_set_alt;
dev->function.disable = printer_func_disable;
dev->function.req_match = gprinter_req_match;
dev->function.free_func = gprinter_free;

INIT_LIST_HEAD(&dev->tx_reqs);
INIT_LIST_HEAD(&dev->rx_reqs);
INIT_LIST_HEAD(&dev->rx_buffers);
INIT_LIST_HEAD(&dev->tx_reqs_active);
INIT_LIST_HEAD(&dev->rx_reqs_active);

spin_lock_init(&dev->lock);
mutex_init(&dev->lock_printer_io);
init_waitqueue_head(&dev->rx_wait);
init_waitqueue_head(&dev->tx_wait);
init_waitqueue_head(&dev->tx_flush_wait);

dev->interface = -1;
dev->printer_cdev_open = 0;
dev->printer_status = PRINTER_NOT_ERROR;
dev->current_rx_req = NULL;
dev->current_rx_bytes = 0;
dev->current_rx_buf = NULL;

return &dev->function;
}

DECLARE_USB_FUNCTION_INIT(printer, gprinter_alloc_inst, gprinter_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Craig Nadler");

static int gprinter_setup(int count)
{
int status;
dev_t devt;

usb_gadget_class = class_create(THIS_MODULE, "usb_printer_gadget");
//usb_gadget_class = class_create(THIS_MODULE, "sonosa_acu");
if (IS_ERR(usb_gadget_class)) {
status = PTR_ERR(usb_gadget_class);
usb_gadget_class = NULL;
pr_err("unable to create usb_gadget class %d\n", status);
return status;
}
status = alloc_chrdev_region(&devt, 0, count, "sonosa_acu");
if (status) {
pr_err("alloc_chrdev_region %d\n", status);
class_destroy(usb_gadget_class);
usb_gadget_class = NULL;
return status;
}

major = MAJOR(devt);
minors = count;

return status;
}

static void gprinter_cleanup(void)
{
if (major) {
unregister_chrdev_region(MKDEV(major, 0), minors);
major = minors = 0;
}
class_destroy(usb_gadget_class);
usb_gadget_class= NULL;
}