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linux-next/drivers/usb/gadget/serial.c
Fengwei Yin 949bf64311 [PATCH] USB: One potential problem in gadget/serial.c 
It looks like that the gs_serial module maybe sleep with spinlock in gs_close.
Sometimes, system hang when I remove the gs_serial module.

From: Fengwei Yin <xaityyy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 13:48:34 -08:00

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/*
* g_serial.c -- USB gadget serial driver
*
* Copyright 2003 (C) Al Borchers (alborchers@steinerpoint.com)
*
* This code is based in part on the Gadget Zero driver, which
* is Copyright (C) 2003 by David Brownell, all rights reserved.
*
* This code also borrows from usbserial.c, which is
* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2000 Peter Berger (pberger@brimson.com)
* Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
*
* This software is distributed under the terms of the GNU General
* Public License ("GPL") as published by the Free Software Foundation,
* either version 2 of that License or (at your option) any later version.
*
*/
#include <linux/config.h>
#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/smp_lock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/utsname.h>
#include <linux/wait.h>
#include <linux/proc_fs.h>
#include <linux/device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/unaligned.h>
#include <asm/uaccess.h>
#include <linux/usb_ch9.h>
#include <linux/usb_cdc.h>
#include <linux/usb_gadget.h>
#include "gadget_chips.h"
/* Wait Cond */
#define __wait_cond_interruptible(wq, condition, lock, flags, ret) \
do { \
wait_queue_t __wait; \
init_waitqueue_entry(&__wait, current); \
\
add_wait_queue(&wq, &__wait); \
for (;;) { \
set_current_state(TASK_INTERRUPTIBLE); \
if (condition) \
break; \
if (!signal_pending(current)) { \
spin_unlock_irqrestore(lock, flags); \
schedule(); \
spin_lock_irqsave(lock, flags); \
continue; \
} \
ret = -ERESTARTSYS; \
break; \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&wq, &__wait); \
} while (0)
#define wait_cond_interruptible(wq, condition, lock, flags) \
({ \
int __ret = 0; \
if (!(condition)) \
__wait_cond_interruptible(wq, condition, lock, flags, \
__ret); \
__ret; \
})
#define __wait_cond_interruptible_timeout(wq, condition, lock, flags, \
timeout, ret) \
do { \
signed long __timeout = timeout; \
wait_queue_t __wait; \
init_waitqueue_entry(&__wait, current); \
\
add_wait_queue(&wq, &__wait); \
for (;;) { \
set_current_state(TASK_INTERRUPTIBLE); \
if (__timeout == 0) \
break; \
if (condition) \
break; \
if (!signal_pending(current)) { \
spin_unlock_irqrestore(lock, flags); \
__timeout = schedule_timeout(__timeout); \
spin_lock_irqsave(lock, flags); \
continue; \
} \
ret = -ERESTARTSYS; \
break; \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&wq, &__wait); \
} while (0)
#define wait_cond_interruptible_timeout(wq, condition, lock, flags, \
timeout) \
({ \
int __ret = 0; \
if (!(condition)) \
__wait_cond_interruptible_timeout(wq, condition, lock, \
flags, timeout, __ret); \
__ret; \
})
/* Defines */
#define GS_VERSION_STR "v2.0"
#define GS_VERSION_NUM 0x0200
#define GS_LONG_NAME "Gadget Serial"
#define GS_SHORT_NAME "g_serial"
#define GS_MAJOR 127
#define GS_MINOR_START 0
#define GS_NUM_PORTS 16
#define GS_NUM_CONFIGS 1
#define GS_NO_CONFIG_ID 0
#define GS_BULK_CONFIG_ID 1
#define GS_ACM_CONFIG_ID 2
#define GS_MAX_NUM_INTERFACES 2
#define GS_BULK_INTERFACE_ID 0
#define GS_CONTROL_INTERFACE_ID 0
#define GS_DATA_INTERFACE_ID 1
#define GS_MAX_DESC_LEN 256
#define GS_DEFAULT_READ_Q_SIZE 32
#define GS_DEFAULT_WRITE_Q_SIZE 32
#define GS_DEFAULT_WRITE_BUF_SIZE 8192
#define GS_TMP_BUF_SIZE 8192
#define GS_CLOSE_TIMEOUT 15
#define GS_DEFAULT_USE_ACM 0
#define GS_DEFAULT_DTE_RATE 9600
#define GS_DEFAULT_DATA_BITS 8
#define GS_DEFAULT_PARITY USB_CDC_NO_PARITY
#define GS_DEFAULT_CHAR_FORMAT USB_CDC_1_STOP_BITS
/* select highspeed/fullspeed, hiding highspeed if not configured */
#ifdef CONFIG_USB_GADGET_DUALSPEED
#define GS_SPEED_SELECT(is_hs,hs,fs) ((is_hs) ? (hs) : (fs))
#else
#define GS_SPEED_SELECT(is_hs,hs,fs) (fs)
#endif /* CONFIG_USB_GADGET_DUALSPEED */
/* debug settings */
#ifdef GS_DEBUG
static int debug = 1;
#define gs_debug(format, arg...) \
do { if (debug) printk(KERN_DEBUG format, ## arg); } while(0)
#define gs_debug_level(level, format, arg...) \
do { if (debug>=level) printk(KERN_DEBUG format, ## arg); } while(0)
#else
#define gs_debug(format, arg...) \
do { } while(0)
#define gs_debug_level(level, format, arg...) \
do { } while(0)
#endif /* GS_DEBUG */
/* Thanks to NetChip Technologies for donating this product ID.
*
* DO NOT REUSE THESE IDs with a protocol-incompatible driver!! Ever!!
* Instead: allocate your own, using normal USB-IF procedures.
*/
#define GS_VENDOR_ID 0x0525 /* NetChip */
#define GS_PRODUCT_ID 0xa4a6 /* Linux-USB Serial Gadget */
#define GS_CDC_PRODUCT_ID 0xa4a7 /* ... as CDC-ACM */
#define GS_LOG2_NOTIFY_INTERVAL 5 /* 1 << 5 == 32 msec */
#define GS_NOTIFY_MAXPACKET 8
/* Structures */
struct gs_dev;
/* circular buffer */
struct gs_buf {
unsigned int buf_size;
char *buf_buf;
char *buf_get;
char *buf_put;
};
/* list of requests */
struct gs_req_entry {
struct list_head re_entry;
struct usb_request *re_req;
};
/* the port structure holds info for each port, one for each minor number */
struct gs_port {
struct gs_dev *port_dev; /* pointer to device struct */
struct tty_struct *port_tty; /* pointer to tty struct */
spinlock_t port_lock;
int port_num;
int port_open_count;
int port_in_use; /* open/close in progress */
wait_queue_head_t port_write_wait;/* waiting to write */
struct gs_buf *port_write_buf;
struct usb_cdc_line_coding port_line_coding;
};
/* the device structure holds info for the USB device */
struct gs_dev {
struct usb_gadget *dev_gadget; /* gadget device pointer */
spinlock_t dev_lock; /* lock for set/reset config */
int dev_config; /* configuration number */
struct usb_ep *dev_notify_ep; /* address of notify endpoint */
struct usb_ep *dev_in_ep; /* address of in endpoint */
struct usb_ep *dev_out_ep; /* address of out endpoint */
struct usb_endpoint_descriptor /* descriptor of notify ep */
*dev_notify_ep_desc;
struct usb_endpoint_descriptor /* descriptor of in endpoint */
*dev_in_ep_desc;
struct usb_endpoint_descriptor /* descriptor of out endpoint */
*dev_out_ep_desc;
struct usb_request *dev_ctrl_req; /* control request */
struct list_head dev_req_list; /* list of write requests */
int dev_sched_port; /* round robin port scheduled */
struct gs_port *dev_port[GS_NUM_PORTS]; /* the ports */
};
/* Functions */
/* module */
static int __init gs_module_init(void);
static void __exit gs_module_exit(void);
/* tty driver */
static int gs_open(struct tty_struct *tty, struct file *file);
static void gs_close(struct tty_struct *tty, struct file *file);
static int gs_write(struct tty_struct *tty,
const unsigned char *buf, int count);
static void gs_put_char(struct tty_struct *tty, unsigned char ch);
static void gs_flush_chars(struct tty_struct *tty);
static int gs_write_room(struct tty_struct *tty);
static int gs_chars_in_buffer(struct tty_struct *tty);
static void gs_throttle(struct tty_struct * tty);
static void gs_unthrottle(struct tty_struct * tty);
static void gs_break(struct tty_struct *tty, int break_state);
static int gs_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
static void gs_set_termios(struct tty_struct *tty, struct termios *old);
static int gs_send(struct gs_dev *dev);
static int gs_send_packet(struct gs_dev *dev, char *packet,
unsigned int size);
static int gs_recv_packet(struct gs_dev *dev, char *packet,
unsigned int size);
static void gs_read_complete(struct usb_ep *ep, struct usb_request *req);
static void gs_write_complete(struct usb_ep *ep, struct usb_request *req);
/* gadget driver */
static int gs_bind(struct usb_gadget *gadget);
static void gs_unbind(struct usb_gadget *gadget);
static int gs_setup(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl);
static int gs_setup_standard(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl);
static int gs_setup_class(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl);
static void gs_setup_complete(struct usb_ep *ep, struct usb_request *req);
static void gs_disconnect(struct usb_gadget *gadget);
static int gs_set_config(struct gs_dev *dev, unsigned config);
static void gs_reset_config(struct gs_dev *dev);
static int gs_build_config_buf(u8 *buf, enum usb_device_speed speed,
u8 type, unsigned int index, int is_otg);
static struct usb_request *gs_alloc_req(struct usb_ep *ep, unsigned int len,
gfp_t kmalloc_flags);
static void gs_free_req(struct usb_ep *ep, struct usb_request *req);
static struct gs_req_entry *gs_alloc_req_entry(struct usb_ep *ep, unsigned len,
gfp_t kmalloc_flags);
static void gs_free_req_entry(struct usb_ep *ep, struct gs_req_entry *req);
static int gs_alloc_ports(struct gs_dev *dev, gfp_t kmalloc_flags);
static void gs_free_ports(struct gs_dev *dev);
/* circular buffer */
static struct gs_buf *gs_buf_alloc(unsigned int size, gfp_t kmalloc_flags);
static void gs_buf_free(struct gs_buf *gb);
static void gs_buf_clear(struct gs_buf *gb);
static unsigned int gs_buf_data_avail(struct gs_buf *gb);
static unsigned int gs_buf_space_avail(struct gs_buf *gb);
static unsigned int gs_buf_put(struct gs_buf *gb, const char *buf,
unsigned int count);
static unsigned int gs_buf_get(struct gs_buf *gb, char *buf,
unsigned int count);
/* external functions */
extern int net2280_set_fifo_mode(struct usb_gadget *gadget, int mode);
/* Globals */
static struct gs_dev *gs_device;
static const char *EP_IN_NAME;
static const char *EP_OUT_NAME;
static const char *EP_NOTIFY_NAME;
static struct semaphore gs_open_close_sem[GS_NUM_PORTS];
static unsigned int read_q_size = GS_DEFAULT_READ_Q_SIZE;
static unsigned int write_q_size = GS_DEFAULT_WRITE_Q_SIZE;
static unsigned int write_buf_size = GS_DEFAULT_WRITE_BUF_SIZE;
static unsigned int use_acm = GS_DEFAULT_USE_ACM;
/* tty driver struct */
static struct tty_operations gs_tty_ops = {
.open = gs_open,
.close = gs_close,
.write = gs_write,
.put_char = gs_put_char,
.flush_chars = gs_flush_chars,
.write_room = gs_write_room,
.ioctl = gs_ioctl,
.set_termios = gs_set_termios,
.throttle = gs_throttle,
.unthrottle = gs_unthrottle,
.break_ctl = gs_break,
.chars_in_buffer = gs_chars_in_buffer,
};
static struct tty_driver *gs_tty_driver;
/* gadget driver struct */
static struct usb_gadget_driver gs_gadget_driver = {
#ifdef CONFIG_USB_GADGET_DUALSPEED
.speed = USB_SPEED_HIGH,
#else
.speed = USB_SPEED_FULL,
#endif /* CONFIG_USB_GADGET_DUALSPEED */
.function = GS_LONG_NAME,
.bind = gs_bind,
.unbind = gs_unbind,
.setup = gs_setup,
.disconnect = gs_disconnect,
.driver = {
.name = GS_SHORT_NAME,
/* .shutdown = ... */
/* .suspend = ... */
/* .resume = ... */
},
};
/* USB descriptors */
#define GS_MANUFACTURER_STR_ID 1
#define GS_PRODUCT_STR_ID 2
#define GS_SERIAL_STR_ID 3
#define GS_BULK_CONFIG_STR_ID 4
#define GS_ACM_CONFIG_STR_ID 5
#define GS_CONTROL_STR_ID 6
#define GS_DATA_STR_ID 7
/* static strings, in UTF-8 */
static char manufacturer[50];
static struct usb_string gs_strings[] = {
{ GS_MANUFACTURER_STR_ID, manufacturer },
{ GS_PRODUCT_STR_ID, GS_LONG_NAME },
{ GS_SERIAL_STR_ID, "0" },
{ GS_BULK_CONFIG_STR_ID, "Gadget Serial Bulk" },
{ GS_ACM_CONFIG_STR_ID, "Gadget Serial CDC ACM" },
{ GS_CONTROL_STR_ID, "Gadget Serial Control" },
{ GS_DATA_STR_ID, "Gadget Serial Data" },
{ } /* end of list */
};
static struct usb_gadget_strings gs_string_table = {
.language = 0x0409, /* en-us */
.strings = gs_strings,
};
static struct usb_device_descriptor gs_device_desc = {
.bLength = USB_DT_DEVICE_SIZE,
.bDescriptorType = USB_DT_DEVICE,
.bcdUSB = __constant_cpu_to_le16(0x0200),
.bDeviceSubClass = 0,
.bDeviceProtocol = 0,
.idVendor = __constant_cpu_to_le16(GS_VENDOR_ID),
.idProduct = __constant_cpu_to_le16(GS_PRODUCT_ID),
.iManufacturer = GS_MANUFACTURER_STR_ID,
.iProduct = GS_PRODUCT_STR_ID,
.iSerialNumber = GS_SERIAL_STR_ID,
.bNumConfigurations = GS_NUM_CONFIGS,
};
static struct usb_otg_descriptor gs_otg_descriptor = {
.bLength = sizeof(gs_otg_descriptor),
.bDescriptorType = USB_DT_OTG,
.bmAttributes = USB_OTG_SRP,
};
static struct usb_config_descriptor gs_bulk_config_desc = {
.bLength = USB_DT_CONFIG_SIZE,
.bDescriptorType = USB_DT_CONFIG,
/* .wTotalLength computed dynamically */
.bNumInterfaces = 1,
.bConfigurationValue = GS_BULK_CONFIG_ID,
.iConfiguration = GS_BULK_CONFIG_STR_ID,
.bmAttributes = USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
.bMaxPower = 1,
};
static struct usb_config_descriptor gs_acm_config_desc = {
.bLength = USB_DT_CONFIG_SIZE,
.bDescriptorType = USB_DT_CONFIG,
/* .wTotalLength computed dynamically */
.bNumInterfaces = 2,
.bConfigurationValue = GS_ACM_CONFIG_ID,
.iConfiguration = GS_ACM_CONFIG_STR_ID,
.bmAttributes = USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
.bMaxPower = 1,
};
static const struct usb_interface_descriptor gs_bulk_interface_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = GS_BULK_INTERFACE_ID,
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_CDC_DATA,
.bInterfaceSubClass = 0,
.bInterfaceProtocol = 0,
.iInterface = GS_DATA_STR_ID,
};
static const struct usb_interface_descriptor gs_control_interface_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = GS_CONTROL_INTERFACE_ID,
.bNumEndpoints = 1,
.bInterfaceClass = USB_CLASS_COMM,
.bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
.bInterfaceProtocol = USB_CDC_ACM_PROTO_AT_V25TER,
.iInterface = GS_CONTROL_STR_ID,
};
static const struct usb_interface_descriptor gs_data_interface_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = GS_DATA_INTERFACE_ID,
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_CDC_DATA,
.bInterfaceSubClass = 0,
.bInterfaceProtocol = 0,
.iInterface = GS_DATA_STR_ID,
};
static const struct usb_cdc_header_desc gs_header_desc = {
.bLength = sizeof(gs_header_desc),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_HEADER_TYPE,
.bcdCDC = __constant_cpu_to_le16(0x0110),
};
static const struct usb_cdc_call_mgmt_descriptor gs_call_mgmt_descriptor = {
.bLength = sizeof(gs_call_mgmt_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_CALL_MANAGEMENT_TYPE,
.bmCapabilities = 0,
.bDataInterface = 1, /* index of data interface */
};
static struct usb_cdc_acm_descriptor gs_acm_descriptor = {
.bLength = sizeof(gs_acm_descriptor),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_ACM_TYPE,
.bmCapabilities = 0,
};
static const struct usb_cdc_union_desc gs_union_desc = {
.bLength = sizeof(gs_union_desc),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_UNION_TYPE,
.bMasterInterface0 = 0, /* index of control interface */
.bSlaveInterface0 = 1, /* index of data interface */
};
static struct usb_endpoint_descriptor gs_fullspeed_notify_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_INT,
.wMaxPacketSize = __constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
.bInterval = 1 << GS_LOG2_NOTIFY_INTERVAL,
};
static struct usb_endpoint_descriptor gs_fullspeed_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 gs_fullspeed_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
};
static const struct usb_descriptor_header *gs_bulk_fullspeed_function[] = {
(struct usb_descriptor_header *) &gs_otg_descriptor,
(struct usb_descriptor_header *) &gs_bulk_interface_desc,
(struct usb_descriptor_header *) &gs_fullspeed_in_desc,
(struct usb_descriptor_header *) &gs_fullspeed_out_desc,
NULL,
};
static const struct usb_descriptor_header *gs_acm_fullspeed_function[] = {
(struct usb_descriptor_header *) &gs_otg_descriptor,
(struct usb_descriptor_header *) &gs_control_interface_desc,
(struct usb_descriptor_header *) &gs_header_desc,
(struct usb_descriptor_header *) &gs_call_mgmt_descriptor,
(struct usb_descriptor_header *) &gs_acm_descriptor,
(struct usb_descriptor_header *) &gs_union_desc,
(struct usb_descriptor_header *) &gs_fullspeed_notify_desc,
(struct usb_descriptor_header *) &gs_data_interface_desc,
(struct usb_descriptor_header *) &gs_fullspeed_in_desc,
(struct usb_descriptor_header *) &gs_fullspeed_out_desc,
NULL,
};
#ifdef CONFIG_USB_GADGET_DUALSPEED
static struct usb_endpoint_descriptor gs_highspeed_notify_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_INT,
.wMaxPacketSize = __constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
.bInterval = GS_LOG2_NOTIFY_INTERVAL+4,
};
static struct usb_endpoint_descriptor gs_highspeed_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = __constant_cpu_to_le16(512),
};
static struct usb_endpoint_descriptor gs_highspeed_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = __constant_cpu_to_le16(512),
};
static struct usb_qualifier_descriptor gs_qualifier_desc = {
.bLength = sizeof(struct usb_qualifier_descriptor),
.bDescriptorType = USB_DT_DEVICE_QUALIFIER,
.bcdUSB = __constant_cpu_to_le16 (0x0200),
/* assumes ep0 uses the same value for both speeds ... */
.bNumConfigurations = GS_NUM_CONFIGS,
};
static const struct usb_descriptor_header *gs_bulk_highspeed_function[] = {
(struct usb_descriptor_header *) &gs_otg_descriptor,
(struct usb_descriptor_header *) &gs_bulk_interface_desc,
(struct usb_descriptor_header *) &gs_highspeed_in_desc,
(struct usb_descriptor_header *) &gs_highspeed_out_desc,
NULL,
};
static const struct usb_descriptor_header *gs_acm_highspeed_function[] = {
(struct usb_descriptor_header *) &gs_otg_descriptor,
(struct usb_descriptor_header *) &gs_control_interface_desc,
(struct usb_descriptor_header *) &gs_header_desc,
(struct usb_descriptor_header *) &gs_call_mgmt_descriptor,
(struct usb_descriptor_header *) &gs_acm_descriptor,
(struct usb_descriptor_header *) &gs_union_desc,
(struct usb_descriptor_header *) &gs_highspeed_notify_desc,
(struct usb_descriptor_header *) &gs_data_interface_desc,
(struct usb_descriptor_header *) &gs_highspeed_in_desc,
(struct usb_descriptor_header *) &gs_highspeed_out_desc,
NULL,
};
#endif /* CONFIG_USB_GADGET_DUALSPEED */
/* Module */
MODULE_DESCRIPTION(GS_LONG_NAME);
MODULE_AUTHOR("Al Borchers");
MODULE_LICENSE("GPL");
#ifdef GS_DEBUG
module_param(debug, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug, "Enable debugging, 0=off, 1=on");
#endif
module_param(read_q_size, uint, S_IRUGO);
MODULE_PARM_DESC(read_q_size, "Read request queue size, default=32");
module_param(write_q_size, uint, S_IRUGO);
MODULE_PARM_DESC(write_q_size, "Write request queue size, default=32");
module_param(write_buf_size, uint, S_IRUGO);
MODULE_PARM_DESC(write_buf_size, "Write buffer size, default=8192");
module_param(use_acm, uint, S_IRUGO);
MODULE_PARM_DESC(use_acm, "Use CDC ACM, 0=no, 1=yes, default=no");
module_init(gs_module_init);
module_exit(gs_module_exit);
/*
* gs_module_init
*
* Register as a USB gadget driver and a tty driver.
*/
static int __init gs_module_init(void)
{
int i;
int retval;
retval = usb_gadget_register_driver(&gs_gadget_driver);
if (retval) {
printk(KERN_ERR "gs_module_init: cannot register gadget driver, ret=%d\n", retval);
return retval;
}
gs_tty_driver = alloc_tty_driver(GS_NUM_PORTS);
if (!gs_tty_driver)
return -ENOMEM;
gs_tty_driver->owner = THIS_MODULE;
gs_tty_driver->driver_name = GS_SHORT_NAME;
gs_tty_driver->name = "ttygs";
gs_tty_driver->devfs_name = "usb/ttygs/";
gs_tty_driver->major = GS_MAJOR;
gs_tty_driver->minor_start = GS_MINOR_START;
gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
gs_tty_driver->init_termios = tty_std_termios;
gs_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
tty_set_operations(gs_tty_driver, &gs_tty_ops);
for (i=0; i < GS_NUM_PORTS; i++)
sema_init(&gs_open_close_sem[i], 1);
retval = tty_register_driver(gs_tty_driver);
if (retval) {
usb_gadget_unregister_driver(&gs_gadget_driver);
put_tty_driver(gs_tty_driver);
printk(KERN_ERR "gs_module_init: cannot register tty driver, ret=%d\n", retval);
return retval;
}
printk(KERN_INFO "gs_module_init: %s %s loaded\n", GS_LONG_NAME, GS_VERSION_STR);
return 0;
}
/*
* gs_module_exit
*
* Unregister as a tty driver and a USB gadget driver.
*/
static void __exit gs_module_exit(void)
{
tty_unregister_driver(gs_tty_driver);
put_tty_driver(gs_tty_driver);
usb_gadget_unregister_driver(&gs_gadget_driver);
printk(KERN_INFO "gs_module_exit: %s %s unloaded\n", GS_LONG_NAME, GS_VERSION_STR);
}
/* TTY Driver */
/*
* gs_open
*/
static int gs_open(struct tty_struct *tty, struct file *file)
{
int port_num;
unsigned long flags;
struct gs_port *port;
struct gs_dev *dev;
struct gs_buf *buf;
struct semaphore *sem;
int ret;
port_num = tty->index;
gs_debug("gs_open: (%d,%p,%p)\n", port_num, tty, file);
if (port_num < 0 || port_num >= GS_NUM_PORTS) {
printk(KERN_ERR "gs_open: (%d,%p,%p) invalid port number\n",
port_num, tty, file);
return -ENODEV;
}
dev = gs_device;
if (dev == NULL) {
printk(KERN_ERR "gs_open: (%d,%p,%p) NULL device pointer\n",
port_num, tty, file);
return -ENODEV;
}
sem = &gs_open_close_sem[port_num];
if (down_interruptible(sem)) {
printk(KERN_ERR
"gs_open: (%d,%p,%p) interrupted waiting for semaphore\n",
port_num, tty, file);
return -ERESTARTSYS;
}
spin_lock_irqsave(&dev->dev_lock, flags);
if (dev->dev_config == GS_NO_CONFIG_ID) {
printk(KERN_ERR
"gs_open: (%d,%p,%p) device is not connected\n",
port_num, tty, file);
ret = -ENODEV;
goto exit_unlock_dev;
}
port = dev->dev_port[port_num];
if (port == NULL) {
printk(KERN_ERR "gs_open: (%d,%p,%p) NULL port pointer\n",
port_num, tty, file);
ret = -ENODEV;
goto exit_unlock_dev;
}
spin_lock(&port->port_lock);
spin_unlock(&dev->dev_lock);
if (port->port_dev == NULL) {
printk(KERN_ERR "gs_open: (%d,%p,%p) port disconnected (1)\n",
port_num, tty, file);
ret = -EIO;
goto exit_unlock_port;
}
if (port->port_open_count > 0) {
++port->port_open_count;
gs_debug("gs_open: (%d,%p,%p) already open\n",
port_num, tty, file);
ret = 0;
goto exit_unlock_port;
}
tty->driver_data = NULL;
/* mark port as in use, we can drop port lock and sleep if necessary */
port->port_in_use = 1;
/* allocate write buffer on first open */
if (port->port_write_buf == NULL) {
spin_unlock_irqrestore(&port->port_lock, flags);
buf = gs_buf_alloc(write_buf_size, GFP_KERNEL);
spin_lock_irqsave(&port->port_lock, flags);
/* might have been disconnected while asleep, check */
if (port->port_dev == NULL) {
printk(KERN_ERR
"gs_open: (%d,%p,%p) port disconnected (2)\n",
port_num, tty, file);
port->port_in_use = 0;
ret = -EIO;
goto exit_unlock_port;
}
if ((port->port_write_buf=buf) == NULL) {
printk(KERN_ERR "gs_open: (%d,%p,%p) cannot allocate port write buffer\n",
port_num, tty, file);
port->port_in_use = 0;
ret = -ENOMEM;
goto exit_unlock_port;
}
}
/* wait for carrier detect (not implemented) */
/* might have been disconnected while asleep, check */
if (port->port_dev == NULL) {
printk(KERN_ERR "gs_open: (%d,%p,%p) port disconnected (3)\n",
port_num, tty, file);
port->port_in_use = 0;
ret = -EIO;
goto exit_unlock_port;
}
tty->driver_data = port;
port->port_tty = tty;
port->port_open_count = 1;
port->port_in_use = 0;
gs_debug("gs_open: (%d,%p,%p) completed\n", port_num, tty, file);
ret = 0;
exit_unlock_port:
spin_unlock_irqrestore(&port->port_lock, flags);
up(sem);
return ret;
exit_unlock_dev:
spin_unlock_irqrestore(&dev->dev_lock, flags);
up(sem);
return ret;
}
/*
* gs_close
*/
static void gs_close(struct tty_struct *tty, struct file *file)
{
unsigned long flags;
struct gs_port *port = tty->driver_data;
struct semaphore *sem;
if (port == NULL) {
printk(KERN_ERR "gs_close: NULL port pointer\n");
return;
}
gs_debug("gs_close: (%d,%p,%p)\n", port->port_num, tty, file);
sem = &gs_open_close_sem[port->port_num];
down(sem);
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_open_count == 0) {
printk(KERN_ERR
"gs_close: (%d,%p,%p) port is already closed\n",
port->port_num, tty, file);
goto exit;
}
if (port->port_open_count > 1) {
--port->port_open_count;
goto exit;
}
/* free disconnected port on final close */
if (port->port_dev == NULL) {
kfree(port);
goto exit;
}
/* mark port as closed but in use, we can drop port lock */
/* and sleep if necessary */
port->port_in_use = 1;
port->port_open_count = 0;
/* wait for write buffer to drain, or */
/* at most GS_CLOSE_TIMEOUT seconds */
if (gs_buf_data_avail(port->port_write_buf) > 0) {
spin_unlock_irqrestore(&port->port_lock, flags);
wait_cond_interruptible_timeout(port->port_write_wait,
port->port_dev == NULL
|| gs_buf_data_avail(port->port_write_buf) == 0,
&port->port_lock, flags, GS_CLOSE_TIMEOUT * HZ);
spin_lock_irqsave(&port->port_lock, flags);
}
/* free disconnected port on final close */
/* (might have happened during the above sleep) */
if (port->port_dev == NULL) {
kfree(port);
goto exit;
}
gs_buf_clear(port->port_write_buf);
tty->driver_data = NULL;
port->port_tty = NULL;
port->port_in_use = 0;
gs_debug("gs_close: (%d,%p,%p) completed\n",
port->port_num, tty, file);
exit:
spin_unlock_irqrestore(&port->port_lock, flags);
up(sem);
}
/*
* gs_write
*/
static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
unsigned long flags;
struct gs_port *port = tty->driver_data;
int ret;
if (port == NULL) {
printk(KERN_ERR "gs_write: NULL port pointer\n");
return -EIO;
}
gs_debug("gs_write: (%d,%p) writing %d bytes\n", port->port_num, tty,
count);
if (count == 0)
return 0;
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_dev == NULL) {
printk(KERN_ERR "gs_write: (%d,%p) port is not connected\n",
port->port_num, tty);
ret = -EIO;
goto exit;
}
if (port->port_open_count == 0) {
printk(KERN_ERR "gs_write: (%d,%p) port is closed\n",
port->port_num, tty);
ret = -EBADF;
goto exit;
}
count = gs_buf_put(port->port_write_buf, buf, count);
spin_unlock_irqrestore(&port->port_lock, flags);
gs_send(gs_device);
gs_debug("gs_write: (%d,%p) wrote %d bytes\n", port->port_num, tty,
count);
return count;
exit:
spin_unlock_irqrestore(&port->port_lock, flags);
return ret;
}
/*
* gs_put_char
*/
static void gs_put_char(struct tty_struct *tty, unsigned char ch)
{
unsigned long flags;
struct gs_port *port = tty->driver_data;
if (port == NULL) {
printk(KERN_ERR "gs_put_char: NULL port pointer\n");
return;
}
gs_debug("gs_put_char: (%d,%p) char=0x%x, called from %p, %p, %p\n", port->port_num, tty, ch, __builtin_return_address(0), __builtin_return_address(1), __builtin_return_address(2));
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_dev == NULL) {
printk(KERN_ERR "gs_put_char: (%d,%p) port is not connected\n",
port->port_num, tty);
goto exit;
}
if (port->port_open_count == 0) {
printk(KERN_ERR "gs_put_char: (%d,%p) port is closed\n",
port->port_num, tty);
goto exit;
}
gs_buf_put(port->port_write_buf, &ch, 1);
exit:
spin_unlock_irqrestore(&port->port_lock, flags);
}
/*
* gs_flush_chars
*/
static void gs_flush_chars(struct tty_struct *tty)
{
unsigned long flags;
struct gs_port *port = tty->driver_data;
if (port == NULL) {
printk(KERN_ERR "gs_flush_chars: NULL port pointer\n");
return;
}
gs_debug("gs_flush_chars: (%d,%p)\n", port->port_num, tty);
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_dev == NULL) {
printk(KERN_ERR
"gs_flush_chars: (%d,%p) port is not connected\n",
port->port_num, tty);
goto exit;
}
if (port->port_open_count == 0) {
printk(KERN_ERR "gs_flush_chars: (%d,%p) port is closed\n",
port->port_num, tty);
goto exit;
}
spin_unlock_irqrestore(&port->port_lock, flags);
gs_send(gs_device);
return;
exit:
spin_unlock_irqrestore(&port->port_lock, flags);
}
/*
* gs_write_room
*/
static int gs_write_room(struct tty_struct *tty)
{
int room = 0;
unsigned long flags;
struct gs_port *port = tty->driver_data;
if (port == NULL)
return 0;
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_dev != NULL && port->port_open_count > 0
&& port->port_write_buf != NULL)
room = gs_buf_space_avail(port->port_write_buf);
spin_unlock_irqrestore(&port->port_lock, flags);
gs_debug("gs_write_room: (%d,%p) room=%d\n",
port->port_num, tty, room);
return room;
}
/*
* gs_chars_in_buffer
*/
static int gs_chars_in_buffer(struct tty_struct *tty)
{
int chars = 0;
unsigned long flags;
struct gs_port *port = tty->driver_data;
if (port == NULL)
return 0;
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_dev != NULL && port->port_open_count > 0
&& port->port_write_buf != NULL)
chars = gs_buf_data_avail(port->port_write_buf);
spin_unlock_irqrestore(&port->port_lock, flags);
gs_debug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
port->port_num, tty, chars);
return chars;
}
/*
* gs_throttle
*/
static void gs_throttle(struct tty_struct *tty)
{
}
/*
* gs_unthrottle
*/
static void gs_unthrottle(struct tty_struct *tty)
{
}
/*
* gs_break
*/
static void gs_break(struct tty_struct *tty, int break_state)
{
}
/*
* gs_ioctl
*/
static int gs_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
{
struct gs_port *port = tty->driver_data;
if (port == NULL) {
printk(KERN_ERR "gs_ioctl: NULL port pointer\n");
return -EIO;
}
gs_debug("gs_ioctl: (%d,%p,%p) cmd=0x%4.4x, arg=%lu\n",
port->port_num, tty, file, cmd, arg);
/* handle ioctls */
/* could not handle ioctl */
return -ENOIOCTLCMD;
}
/*
* gs_set_termios
*/
static void gs_set_termios(struct tty_struct *tty, struct termios *old)
{
}
/*
* gs_send
*
* This function finds available write requests, calls
* gs_send_packet to fill these packets with data, and
* continues until either there are no more write requests
* available or no more data to send. This function is
* run whenever data arrives or write requests are available.
*/
static int gs_send(struct gs_dev *dev)
{
int ret,len;
unsigned long flags;
struct usb_ep *ep;
struct usb_request *req;
struct gs_req_entry *req_entry;
if (dev == NULL) {
printk(KERN_ERR "gs_send: NULL device pointer\n");
return -ENODEV;
}
spin_lock_irqsave(&dev->dev_lock, flags);
ep = dev->dev_in_ep;
while(!list_empty(&dev->dev_req_list)) {
req_entry = list_entry(dev->dev_req_list.next,
struct gs_req_entry, re_entry);
req = req_entry->re_req;
len = gs_send_packet(dev, req->buf, ep->maxpacket);
if (len > 0) {
gs_debug_level(3, "gs_send: len=%d, 0x%2.2x 0x%2.2x 0x%2.2x ...\n", len, *((unsigned char *)req->buf), *((unsigned char *)req->buf+1), *((unsigned char *)req->buf+2));
list_del(&req_entry->re_entry);
req->length = len;
if ((ret=usb_ep_queue(ep, req, GFP_ATOMIC))) {
printk(KERN_ERR
"gs_send: cannot queue read request, ret=%d\n",
ret);
break;
}
} else {
break;
}
}
spin_unlock_irqrestore(&dev->dev_lock, flags);
return 0;
}
/*
* gs_send_packet
*
* If there is data to send, a packet is built in the given
* buffer and the size is returned. If there is no data to
* send, 0 is returned. If there is any error a negative
* error number is returned.
*
* Called during USB completion routine, on interrupt time.
*
* We assume that disconnect will not happen until all completion
* routines have completed, so we can assume that the dev_port
* array does not change during the lifetime of this function.
*/
static int gs_send_packet(struct gs_dev *dev, char *packet, unsigned int size)
{
unsigned int len;
struct gs_port *port;
/* TEMPORARY -- only port 0 is supported right now */
port = dev->dev_port[0];
if (port == NULL) {
printk(KERN_ERR
"gs_send_packet: port=%d, NULL port pointer\n",
0);
return -EIO;
}
spin_lock(&port->port_lock);
len = gs_buf_data_avail(port->port_write_buf);
if (len < size)
size = len;
if (size == 0)
goto exit;
size = gs_buf_get(port->port_write_buf, packet, size);
if (port->port_tty)
wake_up_interruptible(&port->port_tty->write_wait);
exit:
spin_unlock(&port->port_lock);
return size;
}
/*
* gs_recv_packet
*
* Called for each USB packet received. Reads the packet
* header and stuffs the data in the appropriate tty buffer.
* Returns 0 if successful, or a negative error number.
*
* Called during USB completion routine, on interrupt time.
*
* We assume that disconnect will not happen until all completion
* routines have completed, so we can assume that the dev_port
* array does not change during the lifetime of this function.
*/
static int gs_recv_packet(struct gs_dev *dev, char *packet, unsigned int size)
{
unsigned int len;
struct gs_port *port;
int ret;
/* TEMPORARY -- only port 0 is supported right now */
port = dev->dev_port[0];
if (port == NULL) {
printk(KERN_ERR "gs_recv_packet: port=%d, NULL port pointer\n",
port->port_num);
return -EIO;
}
spin_lock(&port->port_lock);
if (port->port_open_count == 0) {
printk(KERN_ERR "gs_recv_packet: port=%d, port is closed\n",
port->port_num);
ret = -EIO;
goto exit;
}
if (port->port_tty == NULL) {
printk(KERN_ERR "gs_recv_packet: port=%d, NULL tty pointer\n",
port->port_num);
ret = -EIO;
goto exit;
}
if (port->port_tty->magic != TTY_MAGIC) {
printk(KERN_ERR "gs_recv_packet: port=%d, bad tty magic\n",
port->port_num);
ret = -EIO;
goto exit;
}
len = (unsigned int)(TTY_FLIPBUF_SIZE - port->port_tty->flip.count);
if (len < size)
size = len;
if (size > 0) {
memcpy(port->port_tty->flip.char_buf_ptr, packet, size);
port->port_tty->flip.char_buf_ptr += size;
port->port_tty->flip.count += size;
tty_flip_buffer_push(port->port_tty);
wake_up_interruptible(&port->port_tty->read_wait);
}
ret = 0;
exit:
spin_unlock(&port->port_lock);
return ret;
}
/*
* gs_read_complete
*/
static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
{
int ret;
struct gs_dev *dev = ep->driver_data;
if (dev == NULL) {
printk(KERN_ERR "gs_read_complete: NULL device pointer\n");
return;
}
switch(req->status) {
case 0:
/* normal completion */
gs_recv_packet(dev, req->buf, req->actual);
requeue:
req->length = ep->maxpacket;
if ((ret=usb_ep_queue(ep, req, GFP_ATOMIC))) {
printk(KERN_ERR
"gs_read_complete: cannot queue read request, ret=%d\n",
ret);
}
break;
case -ESHUTDOWN:
/* disconnect */
gs_debug("gs_read_complete: shutdown\n");
gs_free_req(ep, req);
break;
default:
/* unexpected */
printk(KERN_ERR
"gs_read_complete: unexpected status error, status=%d\n",
req->status);
goto requeue;
break;
}
}
/*
* gs_write_complete
*/
static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
{
struct gs_dev *dev = ep->driver_data;
struct gs_req_entry *gs_req = req->context;
if (dev == NULL) {
printk(KERN_ERR "gs_write_complete: NULL device pointer\n");
return;
}
switch(req->status) {
case 0:
/* normal completion */
requeue:
if (gs_req == NULL) {
printk(KERN_ERR
"gs_write_complete: NULL request pointer\n");
return;
}
spin_lock(&dev->dev_lock);
list_add(&gs_req->re_entry, &dev->dev_req_list);
spin_unlock(&dev->dev_lock);
gs_send(dev);
break;
case -ESHUTDOWN:
/* disconnect */
gs_debug("gs_write_complete: shutdown\n");
gs_free_req(ep, req);
break;
default:
printk(KERN_ERR
"gs_write_complete: unexpected status error, status=%d\n",
req->status);
goto requeue;
break;
}
}
/* Gadget Driver */
/*
* gs_bind
*
* Called on module load. Allocates and initializes the device
* structure and a control request.
*/
static int gs_bind(struct usb_gadget *gadget)
{
int ret;
struct usb_ep *ep;
struct gs_dev *dev;
int gcnum;
/* Some controllers can't support CDC ACM:
* - sh doesn't support multiple interfaces or configs;
* - sa1100 doesn't have a third interrupt endpoint
*/
if (gadget_is_sh(gadget) || gadget_is_sa1100(gadget))
use_acm = 0;
gcnum = usb_gadget_controller_number(gadget);
if (gcnum >= 0)
gs_device_desc.bcdDevice =
cpu_to_le16(GS_VERSION_NUM | gcnum);
else {
printk(KERN_WARNING "gs_bind: controller '%s' not recognized\n",
gadget->name);
/* unrecognized, but safe unless bulk is REALLY quirky */
gs_device_desc.bcdDevice =
__constant_cpu_to_le16(GS_VERSION_NUM|0x0099);
}
usb_ep_autoconfig_reset(gadget);
ep = usb_ep_autoconfig(gadget, &gs_fullspeed_in_desc);
if (!ep)
goto autoconf_fail;
EP_IN_NAME = ep->name;
ep->driver_data = ep; /* claim the endpoint */
ep = usb_ep_autoconfig(gadget, &gs_fullspeed_out_desc);
if (!ep)
goto autoconf_fail;
EP_OUT_NAME = ep->name;
ep->driver_data = ep; /* claim the endpoint */
if (use_acm) {
ep = usb_ep_autoconfig(gadget, &gs_fullspeed_notify_desc);
if (!ep) {
printk(KERN_ERR "gs_bind: cannot run ACM on %s\n", gadget->name);
goto autoconf_fail;
}
gs_device_desc.idProduct = __constant_cpu_to_le16(
GS_CDC_PRODUCT_ID),
EP_NOTIFY_NAME = ep->name;
ep->driver_data = ep; /* claim the endpoint */
}
gs_device_desc.bDeviceClass = use_acm
? USB_CLASS_COMM : USB_CLASS_VENDOR_SPEC;
gs_device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
#ifdef CONFIG_USB_GADGET_DUALSPEED
gs_qualifier_desc.bDeviceClass = use_acm
? USB_CLASS_COMM : USB_CLASS_VENDOR_SPEC;
/* assume ep0 uses the same packet size for both speeds */
gs_qualifier_desc.bMaxPacketSize0 = gs_device_desc.bMaxPacketSize0;
/* assume endpoints are dual-speed */
gs_highspeed_notify_desc.bEndpointAddress =
gs_fullspeed_notify_desc.bEndpointAddress;
gs_highspeed_in_desc.bEndpointAddress =
gs_fullspeed_in_desc.bEndpointAddress;
gs_highspeed_out_desc.bEndpointAddress =
gs_fullspeed_out_desc.bEndpointAddress;
#endif /* CONFIG_USB_GADGET_DUALSPEED */
usb_gadget_set_selfpowered(gadget);
if (gadget->is_otg) {
gs_otg_descriptor.bmAttributes |= USB_OTG_HNP,
gs_bulk_config_desc.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
gs_acm_config_desc.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
}
gs_device = dev = kmalloc(sizeof(struct gs_dev), GFP_KERNEL);
if (dev == NULL)
return -ENOMEM;
snprintf(manufacturer, sizeof(manufacturer), "%s %s with %s",
system_utsname.sysname, system_utsname.release,
gadget->name);
memset(dev, 0, sizeof(struct gs_dev));
dev->dev_gadget = gadget;
spin_lock_init(&dev->dev_lock);
INIT_LIST_HEAD(&dev->dev_req_list);
set_gadget_data(gadget, dev);
if ((ret=gs_alloc_ports(dev, GFP_KERNEL)) != 0) {
printk(KERN_ERR "gs_bind: cannot allocate ports\n");
gs_unbind(gadget);
return ret;
}
/* preallocate control response and buffer */
dev->dev_ctrl_req = gs_alloc_req(gadget->ep0, GS_MAX_DESC_LEN,
GFP_KERNEL);
if (dev->dev_ctrl_req == NULL) {
gs_unbind(gadget);
return -ENOMEM;
}
dev->dev_ctrl_req->complete = gs_setup_complete;
gadget->ep0->driver_data = dev;
printk(KERN_INFO "gs_bind: %s %s bound\n",
GS_LONG_NAME, GS_VERSION_STR);
return 0;
autoconf_fail:
printk(KERN_ERR "gs_bind: cannot autoconfigure on %s\n", gadget->name);
return -ENODEV;
}
/*
* gs_unbind
*
* Called on module unload. Frees the control request and device
* structure.
*/
static void gs_unbind(struct usb_gadget *gadget)
{
struct gs_dev *dev = get_gadget_data(gadget);
gs_device = NULL;
/* read/write requests already freed, only control request remains */
if (dev != NULL) {
if (dev->dev_ctrl_req != NULL) {
gs_free_req(gadget->ep0, dev->dev_ctrl_req);
dev->dev_ctrl_req = NULL;
}
gs_free_ports(dev);
kfree(dev);
set_gadget_data(gadget, NULL);
}
printk(KERN_INFO "gs_unbind: %s %s unbound\n", GS_LONG_NAME,
GS_VERSION_STR);
}
/*
* gs_setup
*
* Implements all the control endpoint functionality that's not
* handled in hardware or the hardware driver.
*
* Returns the size of the data sent to the host, or a negative
* error number.
*/
static int gs_setup(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl)
{
int ret = -EOPNOTSUPP;
struct gs_dev *dev = get_gadget_data(gadget);
struct usb_request *req = dev->dev_ctrl_req;
u16 wIndex = le16_to_cpu(ctrl->wIndex);
u16 wValue = le16_to_cpu(ctrl->wValue);
u16 wLength = le16_to_cpu(ctrl->wLength);
switch (ctrl->bRequestType & USB_TYPE_MASK) {
case USB_TYPE_STANDARD:
ret = gs_setup_standard(gadget,ctrl);
break;
case USB_TYPE_CLASS:
ret = gs_setup_class(gadget,ctrl);
break;
default:
printk(KERN_ERR "gs_setup: unknown request, type=%02x, request=%02x, value=%04x, index=%04x, length=%d\n",
ctrl->bRequestType, ctrl->bRequest,
wValue, wIndex, wLength);
break;
}
/* respond with data transfer before status phase? */
if (ret >= 0) {
req->length = ret;
req->zero = ret < wLength
&& (ret % gadget->ep0->maxpacket) == 0;
ret = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
if (ret < 0) {
printk(KERN_ERR "gs_setup: cannot queue response, ret=%d\n",
ret);
req->status = 0;
gs_setup_complete(gadget->ep0, req);
}
}
/* device either stalls (ret < 0) or reports success */
return ret;
}
static int gs_setup_standard(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl)
{
int ret = -EOPNOTSUPP;
struct gs_dev *dev = get_gadget_data(gadget);
struct usb_request *req = dev->dev_ctrl_req;
u16 wIndex = le16_to_cpu(ctrl->wIndex);
u16 wValue = le16_to_cpu(ctrl->wValue);
u16 wLength = le16_to_cpu(ctrl->wLength);
switch (ctrl->bRequest) {
case USB_REQ_GET_DESCRIPTOR:
if (ctrl->bRequestType != USB_DIR_IN)
break;
switch (wValue >> 8) {
case USB_DT_DEVICE:
ret = min(wLength,
(u16)sizeof(struct usb_device_descriptor));
memcpy(req->buf, &gs_device_desc, ret);
break;
#ifdef CONFIG_USB_GADGET_DUALSPEED
case USB_DT_DEVICE_QUALIFIER:
if (!gadget->is_dualspeed)
break;
ret = min(wLength,
(u16)sizeof(struct usb_qualifier_descriptor));
memcpy(req->buf, &gs_qualifier_desc, ret);
break;
case USB_DT_OTHER_SPEED_CONFIG:
if (!gadget->is_dualspeed)
break;
/* fall through */
#endif /* CONFIG_USB_GADGET_DUALSPEED */
case USB_DT_CONFIG:
ret = gs_build_config_buf(req->buf, gadget->speed,
wValue >> 8, wValue & 0xff,
gadget->is_otg);
if (ret >= 0)
ret = min(wLength, (u16)ret);
break;
case USB_DT_STRING:
/* wIndex == language code. */
ret = usb_gadget_get_string(&gs_string_table,
wValue & 0xff, req->buf);
if (ret >= 0)
ret = min(wLength, (u16)ret);
break;
}
break;
case USB_REQ_SET_CONFIGURATION:
if (ctrl->bRequestType != 0)
break;
spin_lock(&dev->dev_lock);
ret = gs_set_config(dev, wValue);
spin_unlock(&dev->dev_lock);
break;
case USB_REQ_GET_CONFIGURATION:
if (ctrl->bRequestType != USB_DIR_IN)
break;
*(u8 *)req->buf = dev->dev_config;
ret = min(wLength, (u16)1);
break;
case USB_REQ_SET_INTERFACE:
if (ctrl->bRequestType != USB_RECIP_INTERFACE
|| !dev->dev_config
|| wIndex >= GS_MAX_NUM_INTERFACES)
break;
if (dev->dev_config == GS_BULK_CONFIG_ID
&& wIndex != GS_BULK_INTERFACE_ID)
break;
/* no alternate interface settings */
if (wValue != 0)
break;
spin_lock(&dev->dev_lock);
/* PXA hardware partially handles SET_INTERFACE;
* we need to kluge around that interference. */
if (gadget_is_pxa(gadget)) {
ret = gs_set_config(dev, use_acm ?
GS_ACM_CONFIG_ID : GS_BULK_CONFIG_ID);
goto set_interface_done;
}
if (dev->dev_config != GS_BULK_CONFIG_ID
&& wIndex == GS_CONTROL_INTERFACE_ID) {
if (dev->dev_notify_ep) {
usb_ep_disable(dev->dev_notify_ep);
usb_ep_enable(dev->dev_notify_ep, dev->dev_notify_ep_desc);
}
} else {
usb_ep_disable(dev->dev_in_ep);
usb_ep_disable(dev->dev_out_ep);
usb_ep_enable(dev->dev_in_ep, dev->dev_in_ep_desc);
usb_ep_enable(dev->dev_out_ep, dev->dev_out_ep_desc);
}
ret = 0;
set_interface_done:
spin_unlock(&dev->dev_lock);
break;
case USB_REQ_GET_INTERFACE:
if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE)
|| dev->dev_config == GS_NO_CONFIG_ID)
break;
if (wIndex >= GS_MAX_NUM_INTERFACES
|| (dev->dev_config == GS_BULK_CONFIG_ID
&& wIndex != GS_BULK_INTERFACE_ID)) {
ret = -EDOM;
break;
}
/* no alternate interface settings */
*(u8 *)req->buf = 0;
ret = min(wLength, (u16)1);
break;
default:
printk(KERN_ERR "gs_setup: unknown standard request, type=%02x, request=%02x, value=%04x, index=%04x, length=%d\n",
ctrl->bRequestType, ctrl->bRequest,
wValue, wIndex, wLength);
break;
}
return ret;
}
static int gs_setup_class(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl)
{
int ret = -EOPNOTSUPP;
struct gs_dev *dev = get_gadget_data(gadget);
struct gs_port *port = dev->dev_port[0]; /* ACM only has one port */
struct usb_request *req = dev->dev_ctrl_req;
u16 wIndex = le16_to_cpu(ctrl->wIndex);
u16 wValue = le16_to_cpu(ctrl->wValue);
u16 wLength = le16_to_cpu(ctrl->wLength);
switch (ctrl->bRequest) {
case USB_CDC_REQ_SET_LINE_CODING:
ret = min(wLength,
(u16)sizeof(struct usb_cdc_line_coding));
if (port) {
spin_lock(&port->port_lock);
memcpy(&port->port_line_coding, req->buf, ret);
spin_unlock(&port->port_lock);
}
break;
case USB_CDC_REQ_GET_LINE_CODING:
port = dev->dev_port[0]; /* ACM only has one port */
ret = min(wLength,
(u16)sizeof(struct usb_cdc_line_coding));
if (port) {
spin_lock(&port->port_lock);
memcpy(req->buf, &port->port_line_coding, ret);
spin_unlock(&port->port_lock);
}
break;
case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
ret = 0;
break;
default:
printk(KERN_ERR "gs_setup: unknown class request, type=%02x, request=%02x, value=%04x, index=%04x, length=%d\n",
ctrl->bRequestType, ctrl->bRequest,
wValue, wIndex, wLength);
break;
}
return ret;
}
/*
* gs_setup_complete
*/
static void gs_setup_complete(struct usb_ep *ep, struct usb_request *req)
{
if (req->status || req->actual != req->length) {
printk(KERN_ERR "gs_setup_complete: status error, status=%d, actual=%d, length=%d\n",
req->status, req->actual, req->length);
}
}
/*
* gs_disconnect
*
* Called when the device is disconnected. Frees the closed
* ports and disconnects open ports. Open ports will be freed
* on close. Then reallocates the ports for the next connection.
*/
static void gs_disconnect(struct usb_gadget *gadget)
{
unsigned long flags;
struct gs_dev *dev = get_gadget_data(gadget);
spin_lock_irqsave(&dev->dev_lock, flags);
gs_reset_config(dev);
/* free closed ports and disconnect open ports */
/* (open ports will be freed when closed) */
gs_free_ports(dev);
/* re-allocate ports for the next connection */
if (gs_alloc_ports(dev, GFP_ATOMIC) != 0)
printk(KERN_ERR "gs_disconnect: cannot re-allocate ports\n");
spin_unlock_irqrestore(&dev->dev_lock, flags);
printk(KERN_INFO "gs_disconnect: %s disconnected\n", GS_LONG_NAME);
}
/*
* gs_set_config
*
* Configures the device by enabling device specific
* optimizations, setting up the endpoints, allocating
* read and write requests and queuing read requests.
*
* The device lock must be held when calling this function.
*/
static int gs_set_config(struct gs_dev *dev, unsigned config)
{
int i;
int ret = 0;
struct usb_gadget *gadget = dev->dev_gadget;
struct usb_ep *ep;
struct usb_endpoint_descriptor *ep_desc;
struct usb_request *req;
struct gs_req_entry *req_entry;
if (dev == NULL) {
printk(KERN_ERR "gs_set_config: NULL device pointer\n");
return 0;
}
if (config == dev->dev_config)
return 0;
gs_reset_config(dev);
switch (config) {
case GS_NO_CONFIG_ID:
return 0;
case GS_BULK_CONFIG_ID:
if (use_acm)
return -EINVAL;
/* device specific optimizations */
if (gadget_is_net2280(gadget))
net2280_set_fifo_mode(gadget, 1);
break;
case GS_ACM_CONFIG_ID:
if (!use_acm)
return -EINVAL;
/* device specific optimizations */
if (gadget_is_net2280(gadget))
net2280_set_fifo_mode(gadget, 1);
break;
default:
return -EINVAL;
}
dev->dev_config = config;
gadget_for_each_ep(ep, gadget) {
if (EP_NOTIFY_NAME
&& strcmp(ep->name, EP_NOTIFY_NAME) == 0) {
ep_desc = GS_SPEED_SELECT(
gadget->speed == USB_SPEED_HIGH,
&gs_highspeed_notify_desc,
&gs_fullspeed_notify_desc);
ret = usb_ep_enable(ep,ep_desc);
if (ret == 0) {
ep->driver_data = dev;
dev->dev_notify_ep = ep;
dev->dev_notify_ep_desc = ep_desc;
} else {
printk(KERN_ERR "gs_set_config: cannot enable notify endpoint %s, ret=%d\n",
ep->name, ret);
goto exit_reset_config;
}
}
else if (strcmp(ep->name, EP_IN_NAME) == 0) {
ep_desc = GS_SPEED_SELECT(
gadget->speed == USB_SPEED_HIGH,
&gs_highspeed_in_desc,
&gs_fullspeed_in_desc);
ret = usb_ep_enable(ep,ep_desc);
if (ret == 0) {
ep->driver_data = dev;
dev->dev_in_ep = ep;
dev->dev_in_ep_desc = ep_desc;
} else {
printk(KERN_ERR "gs_set_config: cannot enable in endpoint %s, ret=%d\n",
ep->name, ret);
goto exit_reset_config;
}
}
else if (strcmp(ep->name, EP_OUT_NAME) == 0) {
ep_desc = GS_SPEED_SELECT(
gadget->speed == USB_SPEED_HIGH,
&gs_highspeed_out_desc,
&gs_fullspeed_out_desc);
ret = usb_ep_enable(ep,ep_desc);
if (ret == 0) {
ep->driver_data = dev;
dev->dev_out_ep = ep;
dev->dev_out_ep_desc = ep_desc;
} else {
printk(KERN_ERR "gs_set_config: cannot enable out endpoint %s, ret=%d\n",
ep->name, ret);
goto exit_reset_config;
}
}
}
if (dev->dev_in_ep == NULL || dev->dev_out_ep == NULL
|| (config != GS_BULK_CONFIG_ID && dev->dev_notify_ep == NULL)) {
printk(KERN_ERR "gs_set_config: cannot find endpoints\n");
ret = -ENODEV;
goto exit_reset_config;
}
/* allocate and queue read requests */
ep = dev->dev_out_ep;
for (i=0; i<read_q_size && ret == 0; i++) {
if ((req=gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC))) {
req->complete = gs_read_complete;
if ((ret=usb_ep_queue(ep, req, GFP_ATOMIC))) {
printk(KERN_ERR "gs_set_config: cannot queue read request, ret=%d\n",
ret);
}
} else {
printk(KERN_ERR "gs_set_config: cannot allocate read requests\n");
ret = -ENOMEM;
goto exit_reset_config;
}
}
/* allocate write requests, and put on free list */
ep = dev->dev_in_ep;
for (i=0; i<write_q_size; i++) {
if ((req_entry=gs_alloc_req_entry(ep, ep->maxpacket, GFP_ATOMIC))) {
req_entry->re_req->complete = gs_write_complete;
list_add(&req_entry->re_entry, &dev->dev_req_list);
} else {
printk(KERN_ERR "gs_set_config: cannot allocate write requests\n");
ret = -ENOMEM;
goto exit_reset_config;
}
}
printk(KERN_INFO "gs_set_config: %s configured, %s speed %s config\n",
GS_LONG_NAME,
gadget->speed == USB_SPEED_HIGH ? "high" : "full",
config == GS_BULK_CONFIG_ID ? "BULK" : "CDC-ACM");
return 0;
exit_reset_config:
gs_reset_config(dev);
return ret;
}
/*
* gs_reset_config
*
* Mark the device as not configured, disable all endpoints,
* which forces completion of pending I/O and frees queued
* requests, and free the remaining write requests on the
* free list.
*
* The device lock must be held when calling this function.
*/
static void gs_reset_config(struct gs_dev *dev)
{
struct gs_req_entry *req_entry;
if (dev == NULL) {
printk(KERN_ERR "gs_reset_config: NULL device pointer\n");
return;
}
if (dev->dev_config == GS_NO_CONFIG_ID)
return;
dev->dev_config = GS_NO_CONFIG_ID;
/* free write requests on the free list */
while(!list_empty(&dev->dev_req_list)) {
req_entry = list_entry(dev->dev_req_list.next,
struct gs_req_entry, re_entry);
list_del(&req_entry->re_entry);
gs_free_req_entry(dev->dev_in_ep, req_entry);
}
/* disable endpoints, forcing completion of pending i/o; */
/* completion handlers free their requests in this case */
if (dev->dev_notify_ep) {
usb_ep_disable(dev->dev_notify_ep);
dev->dev_notify_ep = NULL;
}
if (dev->dev_in_ep) {
usb_ep_disable(dev->dev_in_ep);
dev->dev_in_ep = NULL;
}
if (dev->dev_out_ep) {
usb_ep_disable(dev->dev_out_ep);
dev->dev_out_ep = NULL;
}
}
/*
* gs_build_config_buf
*
* Builds the config descriptors in the given buffer and returns the
* length, or a negative error number.
*/
static int gs_build_config_buf(u8 *buf, enum usb_device_speed speed,
u8 type, unsigned int index, int is_otg)
{
int len;
int high_speed;
const struct usb_config_descriptor *config_desc;
const struct usb_descriptor_header **function;
if (index >= gs_device_desc.bNumConfigurations)
return -EINVAL;
/* other speed switches high and full speed */
high_speed = (speed == USB_SPEED_HIGH);
if (type == USB_DT_OTHER_SPEED_CONFIG)
high_speed = !high_speed;
if (use_acm) {
config_desc = &gs_acm_config_desc;
function = GS_SPEED_SELECT(high_speed,
gs_acm_highspeed_function,
gs_acm_fullspeed_function);
} else {
config_desc = &gs_bulk_config_desc;
function = GS_SPEED_SELECT(high_speed,
gs_bulk_highspeed_function,
gs_bulk_fullspeed_function);
}
/* for now, don't advertise srp-only devices */
if (!is_otg)
function++;
len = usb_gadget_config_buf(config_desc, buf, GS_MAX_DESC_LEN, function);
if (len < 0)
return len;
((struct usb_config_descriptor *)buf)->bDescriptorType = type;
return len;
}
/*
* gs_alloc_req
*
* Allocate a usb_request and its buffer. Returns a pointer to the
* usb_request or NULL if there is an error.
*/
static struct usb_request *
gs_alloc_req(struct usb_ep *ep, unsigned int len, gfp_t kmalloc_flags)
{
struct usb_request *req;
if (ep == NULL)
return NULL;
req = usb_ep_alloc_request(ep, kmalloc_flags);
if (req != NULL) {
req->length = len;
req->buf = kmalloc(len, kmalloc_flags);
if (req->buf == NULL) {
usb_ep_free_request(ep, req);
return NULL;
}
}
return req;
}
/*
* gs_free_req
*
* Free a usb_request and its buffer.
*/
static void gs_free_req(struct usb_ep *ep, struct usb_request *req)
{
if (ep != NULL && req != NULL) {
kfree(req->buf);
usb_ep_free_request(ep, req);
}
}
/*
* gs_alloc_req_entry
*
* Allocates a request and its buffer, using the given
* endpoint, buffer len, and kmalloc flags.
*/
static struct gs_req_entry *
gs_alloc_req_entry(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
{
struct gs_req_entry *req;
req = kmalloc(sizeof(struct gs_req_entry), kmalloc_flags);
if (req == NULL)
return NULL;
req->re_req = gs_alloc_req(ep, len, kmalloc_flags);
if (req->re_req == NULL) {
kfree(req);
return NULL;
}
req->re_req->context = req;
return req;
}
/*
* gs_free_req_entry
*
* Frees a request and its buffer.
*/
static void gs_free_req_entry(struct usb_ep *ep, struct gs_req_entry *req)
{
if (ep != NULL && req != NULL) {
if (req->re_req != NULL)
gs_free_req(ep, req->re_req);
kfree(req);
}
}
/*
* gs_alloc_ports
*
* Allocate all ports and set the gs_dev struct to point to them.
* Return 0 if successful, or a negative error number.
*
* The device lock is normally held when calling this function.
*/
static int gs_alloc_ports(struct gs_dev *dev, gfp_t kmalloc_flags)
{
int i;
struct gs_port *port;
if (dev == NULL)
return -EIO;
for (i=0; i<GS_NUM_PORTS; i++) {
if ((port=(struct gs_port *)kmalloc(sizeof(struct gs_port), kmalloc_flags)) == NULL)
return -ENOMEM;
memset(port, 0, sizeof(struct gs_port));
port->port_dev = dev;
port->port_num = i;
port->port_line_coding.dwDTERate = cpu_to_le32(GS_DEFAULT_DTE_RATE);
port->port_line_coding.bCharFormat = GS_DEFAULT_CHAR_FORMAT;
port->port_line_coding.bParityType = GS_DEFAULT_PARITY;
port->port_line_coding.bDataBits = GS_DEFAULT_DATA_BITS;
spin_lock_init(&port->port_lock);
init_waitqueue_head(&port->port_write_wait);
dev->dev_port[i] = port;
}
return 0;
}
/*
* gs_free_ports
*
* Free all closed ports. Open ports are disconnected by
* freeing their write buffers, setting their device pointers
* and the pointers to them in the device to NULL. These
* ports will be freed when closed.
*
* The device lock is normally held when calling this function.
*/
static void gs_free_ports(struct gs_dev *dev)
{
int i;
unsigned long flags;
struct gs_port *port;
if (dev == NULL)
return;
for (i=0; i<GS_NUM_PORTS; i++) {
if ((port=dev->dev_port[i]) != NULL) {
dev->dev_port[i] = NULL;
spin_lock_irqsave(&port->port_lock, flags);
if (port->port_write_buf != NULL) {
gs_buf_free(port->port_write_buf);
port->port_write_buf = NULL;
}
if (port->port_open_count > 0 || port->port_in_use) {
port->port_dev = NULL;
wake_up_interruptible(&port->port_write_wait);
if (port->port_tty) {
wake_up_interruptible(&port->port_tty->read_wait);
wake_up_interruptible(&port->port_tty->write_wait);
}
spin_unlock_irqrestore(&port->port_lock, flags);
} else {
spin_unlock_irqrestore(&port->port_lock, flags);
kfree(port);
}
}
}
}
/* Circular Buffer */
/*
* gs_buf_alloc
*
* Allocate a circular buffer and all associated memory.
*/
static struct gs_buf *gs_buf_alloc(unsigned int size, gfp_t kmalloc_flags)
{
struct gs_buf *gb;
if (size == 0)
return NULL;
gb = (struct gs_buf *)kmalloc(sizeof(struct gs_buf), kmalloc_flags);
if (gb == NULL)
return NULL;
gb->buf_buf = kmalloc(size, kmalloc_flags);
if (gb->buf_buf == NULL) {
kfree(gb);
return NULL;
}
gb->buf_size = size;
gb->buf_get = gb->buf_put = gb->buf_buf;
return gb;
}
/*
* gs_buf_free
*
* Free the buffer and all associated memory.
*/
void gs_buf_free(struct gs_buf *gb)
{
if (gb) {
kfree(gb->buf_buf);
kfree(gb);
}
}
/*
* gs_buf_clear
*
* Clear out all data in the circular buffer.
*/
void gs_buf_clear(struct gs_buf *gb)
{
if (gb != NULL)
gb->buf_get = gb->buf_put;
/* equivalent to a get of all data available */
}
/*
* gs_buf_data_avail
*
* Return the number of bytes of data available in the circular
* buffer.
*/
unsigned int gs_buf_data_avail(struct gs_buf *gb)
{
if (gb != NULL)
return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size;
else
return 0;
}
/*
* gs_buf_space_avail
*
* Return the number of bytes of space available in the circular
* buffer.
*/
unsigned int gs_buf_space_avail(struct gs_buf *gb)
{
if (gb != NULL)
return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size;
else
return 0;
}
/*
* gs_buf_put
*
* Copy data data from a user buffer and put it into the circular buffer.
* Restrict to the amount of space available.
*
* Return the number of bytes copied.
*/
unsigned int gs_buf_put(struct gs_buf *gb, const char *buf, unsigned int count)
{
unsigned int len;
if (gb == NULL)
return 0;
len = gs_buf_space_avail(gb);
if (count > len)
count = len;
if (count == 0)
return 0;
len = gb->buf_buf + gb->buf_size - gb->buf_put;
if (count > len) {
memcpy(gb->buf_put, buf, len);
memcpy(gb->buf_buf, buf+len, count - len);
gb->buf_put = gb->buf_buf + count - len;
} else {
memcpy(gb->buf_put, buf, count);
if (count < len)
gb->buf_put += count;
else /* count == len */
gb->buf_put = gb->buf_buf;
}
return count;
}
/*
* gs_buf_get
*
* Get data from the circular buffer and copy to the given buffer.
* Restrict to the amount of data available.
*
* Return the number of bytes copied.
*/
unsigned int gs_buf_get(struct gs_buf *gb, char *buf, unsigned int count)
{
unsigned int len;
if (gb == NULL)
return 0;
len = gs_buf_data_avail(gb);
if (count > len)
count = len;
if (count == 0)
return 0;
len = gb->buf_buf + gb->buf_size - gb->buf_get;
if (count > len) {
memcpy(buf, gb->buf_get, len);
memcpy(buf+len, gb->buf_buf, count - len);
gb->buf_get = gb->buf_buf + count - len;
} else {
memcpy(buf, gb->buf_get, count);
if (count < len)
gb->buf_get += count;
else /* count == len */
gb->buf_get = gb->buf_buf;
}
return count;
}
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