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linux/drivers/usb/serial/safe_serial.c
Greg Kroah-Hartman 68e2411345 USB: serial: rework usb_serial_register/deregister_drivers() 
This reworks the usb_serial_register_drivers() and
usb_serial_deregister_drivers() to not need a pointer to a struct
usb_driver anymore.  The usb_driver structure is now created dynamically
and registered and unregistered as needed.

This saves lines of code in each usb-serial driver.  All in-kernel users
of these functions were also fixed up at this time.  The pl2303 driver
was tested that everything worked properly.

Thanks for the idea to do this from Alan Stern.

Cc: Adhir Ramjiawan <adhirramjiawan0@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Al Borchers <alborchers@steinerpoint.com>
Cc: Aleksey Babahin <tamerlan311@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Worsley <amworsley@gmail.com>
Cc: Bart Hartgers <bart.hartgers@gmail.com>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Donald Lee <donald@asix.com.tw>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Gary Brubaker <xavyer@ix.netcom.com>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: Kautuk Consul <consul.kautuk@gmail.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Lonnie Mendez <dignome@gmail.com>
Cc: Matthias Bruestle and Harald Welte <support@reiner-sct.com>
Cc: Matthias Urlichs <smurf@smurf.noris.de>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Michal Sroczynski <msroczyn@gmail.com>
Cc: "Michał Wróbel" <michal.wrobel@flytronic.pl>
Cc: Oliver Neukum <oliver@neukum.name>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Berger <pberger@brimson.com>
Cc: Preston Fick <preston.fick@silabs.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rigbert Hamisch <rigbert@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Support Department <support@connecttech.com>
Cc: Thomas Tuttle <ttuttle@chromium.org>
Cc: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Cc: Wang YanQing <Udknight@gmail.com>
Cc: William Greathouse <wgreathouse@smva.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-08 15:46:14 -07:00

345 lines
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/*
* Safe Encapsulated USB Serial Driver
*
* Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
* Copyright (C) 2001 Lineo
* Copyright (C) 2001 Hewlett-Packard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* By:
* Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
*/
/*
* The encapsultaion is designed to overcome difficulties with some USB
* hardware.
*
* While the USB protocol has a CRC over the data while in transit, i.e. while
* being carried over the bus, there is no end to end protection. If the
* hardware has any problems getting the data into or out of the USB transmit
* and receive FIFO's then data can be lost.
*
* This protocol adds a two byte trailer to each USB packet to specify the
* number of bytes of valid data and a 10 bit CRC that will allow the receiver
* to verify that the entire USB packet was received without error.
*
* Because in this case the sender and receiver are the class and function
* drivers there is now end to end protection.
*
* There is an additional option that can be used to force all transmitted
* packets to be padded to the maximum packet size. This provides a work
* around for some devices which have problems with small USB packets.
*
* Assuming a packetsize of N:
*
* 0..N-2 data and optional padding
*
* N-2 bits 7-2 - number of bytes of valid data
* bits 1-0 top two bits of 10 bit CRC
* N-1 bottom 8 bits of 10 bit CRC
*
*
* | Data Length | 10 bit CRC |
* + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 | 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
*
* The 10 bit CRC is computed across the sent data, followed by the trailer
* with the length set and the CRC set to zero. The CRC is then OR'd into
* the trailer.
*
* When received a 10 bit CRC is computed over the entire frame including
* the trailer and should be equal to zero.
*
* Two module parameters are used to control the encapsulation, if both are
* turned of the module works as a simple serial device with NO
* encapsulation.
*
* See linux/drivers/usbd/serial_fd for a device function driver
* implementation of this.
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#ifndef CONFIG_USB_SERIAL_SAFE_PADDED
#define CONFIG_USB_SERIAL_SAFE_PADDED 0
#endif
static bool debug;
static bool safe = 1;
static bool padded = CONFIG_USB_SERIAL_SAFE_PADDED;
#define DRIVER_VERSION "v0.1"
#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com, Johan Hovold <jhovold@gmail.com>"
#define DRIVER_DESC "USB Safe Encapsulated Serial"
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
static __u16 vendor; /* no default */
static __u16 product; /* no default */
module_param(vendor, ushort, 0);
MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)");
module_param(product, ushort, 0);
MODULE_PARM_DESC(product, "User specified USB idProduct (required)");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
module_param(safe, bool, 0);
MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off");
module_param(padded, bool, 0);
MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off");
#define CDC_DEVICE_CLASS 0x02
#define CDC_INTERFACE_CLASS 0x02
#define CDC_INTERFACE_SUBCLASS 0x06
#define LINEO_INTERFACE_CLASS 0xff
#define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01
#define LINEO_SAFENET_CRC 0x01
#define LINEO_SAFENET_CRC_PADDED 0x02
#define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02
#define LINEO_SAFESERIAL_CRC 0x01
#define LINEO_SAFESERIAL_CRC_PADDED 0x02
#define MY_USB_DEVICE(vend, prod, dc, ic, isc) \
.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
USB_DEVICE_ID_MATCH_DEV_CLASS | \
USB_DEVICE_ID_MATCH_INT_CLASS | \
USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
.idVendor = (vend), \
.idProduct = (prod),\
.bDeviceClass = (dc),\
.bInterfaceClass = (ic), \
.bInterfaceSubClass = (isc),
static struct usb_device_id id_table[] = {
{MY_USB_DEVICE(0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Itsy */
{MY_USB_DEVICE(0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Calypso */
{MY_USB_DEVICE(0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Iris */
{MY_USB_DEVICE(0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
{MY_USB_DEVICE(0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
{MY_USB_DEVICE(0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
{MY_USB_DEVICE(0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Sharp tmp */
/* extra null entry for module vendor/produc parameters */
{MY_USB_DEVICE(0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
{} /* terminating entry */
};
MODULE_DEVICE_TABLE(usb, id_table);
static const __u16 crc10_table[256] = {
0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff,
0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce,
0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d,
0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac,
0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b,
0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a,
0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259,
0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268,
0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377,
0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346,
0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315,
0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324,
0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3,
0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382,
0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1,
0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0,
0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
};
#define CRC10_INITFCS 0x000 /* Initial FCS value */
#define CRC10_GOODFCS 0x000 /* Good final FCS value */
#define CRC10_FCS(fcs, c) ((((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))
/**
* fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
* @sp: pointer to buffer
* @len: number of bytes
* @fcs: starting FCS
*
* Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
* new 10 bit FCS.
*/
static __u16 __inline__ fcs_compute10(unsigned char *sp, int len, __u16 fcs)
{
for (; len-- > 0; fcs = CRC10_FCS(fcs, *sp++));
return fcs;
}
static void safe_process_read_urb(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
unsigned char length = urb->actual_length;
int actual_length;
struct tty_struct *tty;
__u16 fcs;
if (!length)
return;
tty = tty_port_tty_get(&port->port);
if (!tty)
return;
if (!safe)
goto out;
fcs = fcs_compute10(data, length, CRC10_INITFCS);
if (fcs) {
dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);
goto err;
}
actual_length = data[length - 2] >> 2;
if (actual_length > (length - 2)) {
dev_err(&port->dev, "%s - inconsistent lengths %d:%d\n",
__func__, actual_length, length);
goto err;
}
dev_info(&urb->dev->dev, "%s - actual: %d\n", __func__, actual_length);
length = actual_length;
out:
tty_insert_flip_string(tty, data, length);
tty_flip_buffer_push(tty);
err:
tty_kref_put(tty);
}
static int safe_prepare_write_buffer(struct usb_serial_port *port,
void *dest, size_t size)
{
unsigned char *buf = dest;
int count;
int trailer_len;
int pkt_len;
__u16 fcs;
trailer_len = safe ? 2 : 0;
count = kfifo_out_locked(&port->write_fifo, buf, size - trailer_len,
&port->lock);
if (!safe)
return count;
/* pad if necessary */
if (padded) {
pkt_len = size;
memset(buf + count, '0', pkt_len - count - trailer_len);
} else {
pkt_len = count + trailer_len;
}
/* set count */
buf[pkt_len - 2] = count << 2;
buf[pkt_len - 1] = 0;
/* compute fcs and insert into trailer */
fcs = fcs_compute10(buf, pkt_len, CRC10_INITFCS);
buf[pkt_len - 2] |= fcs >> 8;
buf[pkt_len - 1] |= fcs & 0xff;
return pkt_len;
}
static int safe_startup(struct usb_serial *serial)
{
switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
case LINEO_SAFESERIAL_CRC:
break;
case LINEO_SAFESERIAL_CRC_PADDED:
padded = 1;
break;
default:
return -EINVAL;
}
return 0;
}
static struct usb_serial_driver safe_device = {
.driver = {
.owner = THIS_MODULE,
.name = "safe_serial",
},
.id_table = id_table,
.num_ports = 1,
.process_read_urb = safe_process_read_urb,
.prepare_write_buffer = safe_prepare_write_buffer,
.attach = safe_startup,
};
static struct usb_serial_driver * const serial_drivers[] = {
&safe_device, NULL
};
static int __init safe_init(void)
{
int i;
printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
DRIVER_DESC "\n");
/* if we have vendor / product parameters patch them into id list */
if (vendor || product) {
printk(KERN_INFO KBUILD_MODNAME ": vendor: %x product: %x\n",
vendor, product);
for (i = 0; i < ARRAY_SIZE(id_table); i++) {
if (!id_table[i].idVendor && !id_table[i].idProduct) {
id_table[i].idVendor = vendor;
id_table[i].idProduct = product;
break;
}
}
}
return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, id_table);
}
static void __exit safe_exit(void)
{
usb_serial_deregister_drivers(serial_drivers);
}
module_init(safe_init);
module_exit(safe_exit);
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