473 lines
14 KiB
C
473 lines
14 KiB
C
/*
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* Safe Encapsulated USB Serial Driver
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*
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* Copyright (C) 2001 Lineo
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* Copyright (C) 2001 Hewlett-Packard
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* By:
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* Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
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*/
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/*
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* The encapsultaion is designed to overcome difficulties with some USB
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* hardware.
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*
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* While the USB protocol has a CRC over the data while in transit, i.e. while
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* being carried over the bus, there is no end to end protection. If the
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* hardware has any problems getting the data into or out of the USB transmit
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* and receive FIFO's then data can be lost.
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*
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* This protocol adds a two byte trailer to each USB packet to specify the
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* number of bytes of valid data and a 10 bit CRC that will allow the receiver
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* to verify that the entire USB packet was received without error.
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*
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* Because in this case the sender and receiver are the class and function
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* drivers there is now end to end protection.
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*
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* There is an additional option that can be used to force all transmitted
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* packets to be padded to the maximum packet size. This provides a work
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* around for some devices which have problems with small USB packets.
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*
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* Assuming a packetsize of N:
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*
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* 0..N-2 data and optional padding
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*
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* N-2 bits 7-2 - number of bytes of valid data
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* bits 1-0 top two bits of 10 bit CRC
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* N-1 bottom 8 bits of 10 bit CRC
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*
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*
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* | Data Length | 10 bit CRC |
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* + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 | 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
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*
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* The 10 bit CRC is computed across the sent data, followed by the trailer
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* with the length set and the CRC set to zero. The CRC is then OR'd into
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* the trailer.
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*
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* When received a 10 bit CRC is computed over the entire frame including
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* the trailer and should be equal to zero.
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*
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* Two module parameters are used to control the encapsulation, if both are
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* turned of the module works as a simple serial device with NO
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* encapsulation.
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*
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* See linux/drivers/usbd/serial_fd for a device function driver
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* implementation of this.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/usb.h>
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#include <linux/usb/serial.h>
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#ifndef CONFIG_USB_SERIAL_SAFE_PADDED
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#define CONFIG_USB_SERIAL_SAFE_PADDED 0
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#endif
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static int debug;
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static int safe = 1;
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static int padded = CONFIG_USB_SERIAL_SAFE_PADDED;
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#define DRIVER_VERSION "v0.0b"
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#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
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#define DRIVER_DESC "USB Safe Encapsulated Serial"
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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static __u16 vendor; /* no default */
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static __u16 product; /* no default */
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module_param(vendor, ushort, 0);
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MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)");
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module_param(product, ushort, 0);
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MODULE_PARM_DESC(product, "User specified USB idProduct (required)");
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module_param(debug, bool, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(debug, "Debug enabled or not");
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module_param(safe, bool, 0);
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MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off");
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module_param(padded, bool, 0);
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MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off");
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#define CDC_DEVICE_CLASS 0x02
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#define CDC_INTERFACE_CLASS 0x02
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#define CDC_INTERFACE_SUBCLASS 0x06
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#define LINEO_INTERFACE_CLASS 0xff
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#define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01
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#define LINEO_SAFENET_CRC 0x01
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#define LINEO_SAFENET_CRC_PADDED 0x02
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#define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02
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#define LINEO_SAFESERIAL_CRC 0x01
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#define LINEO_SAFESERIAL_CRC_PADDED 0x02
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#define MY_USB_DEVICE(vend, prod, dc, ic, isc) \
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.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
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USB_DEVICE_ID_MATCH_DEV_CLASS | \
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USB_DEVICE_ID_MATCH_INT_CLASS | \
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USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
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.idVendor = (vend), \
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.idProduct = (prod),\
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.bDeviceClass = (dc),\
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.bInterfaceClass = (ic), \
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.bInterfaceSubClass = (isc),
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static struct usb_device_id id_table[] = {
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{MY_USB_DEVICE(0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Itsy */
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{MY_USB_DEVICE(0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Calypso */
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{MY_USB_DEVICE(0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Iris */
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{MY_USB_DEVICE(0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
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{MY_USB_DEVICE(0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
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{MY_USB_DEVICE(0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
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{MY_USB_DEVICE(0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Sharp tmp */
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/* extra null entry for module vendor/produc parameters */
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{MY_USB_DEVICE(0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
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{} /* terminating entry */
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};
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MODULE_DEVICE_TABLE(usb, id_table);
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static struct usb_driver safe_driver = {
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.name = "safe_serial",
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.probe = usb_serial_probe,
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.disconnect = usb_serial_disconnect,
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.id_table = id_table,
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.no_dynamic_id = 1,
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};
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static const __u16 crc10_table[256] = {
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0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff,
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0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
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0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce,
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0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
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0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d,
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0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
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0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac,
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0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
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0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b,
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0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
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0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a,
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0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
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0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259,
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0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
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0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268,
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0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
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0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377,
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0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
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0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346,
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0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
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0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315,
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0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
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0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324,
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0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
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0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3,
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0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
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0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382,
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0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
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0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1,
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0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
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0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0,
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0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
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};
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#define CRC10_INITFCS 0x000 /* Initial FCS value */
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#define CRC10_GOODFCS 0x000 /* Good final FCS value */
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#define CRC10_FCS(fcs, c) ((((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))
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/**
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* fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
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* @sp: pointer to buffer
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* @len: number of bytes
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* @fcs: starting FCS
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*
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* Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
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* new 10 bit FCS.
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*/
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static __u16 __inline__ fcs_compute10(unsigned char *sp, int len, __u16 fcs)
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{
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for (; len-- > 0; fcs = CRC10_FCS(fcs, *sp++));
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return fcs;
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}
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static void safe_read_bulk_callback(struct urb *urb)
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{
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struct usb_serial_port *port = urb->context;
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unsigned char *data = urb->transfer_buffer;
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unsigned char length = urb->actual_length;
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struct tty_struct *tty;
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int result;
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int status = urb->status;
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dbg("%s", __func__);
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if (status) {
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dbg("%s - nonzero read bulk status received: %d",
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__func__, status);
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return;
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}
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dbg("safe_read_bulk_callback length: %d",
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port->read_urb->actual_length);
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#ifdef ECHO_RCV
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{
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int i;
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unsigned char *cp = port->read_urb->transfer_buffer;
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for (i = 0; i < port->read_urb->actual_length; i++) {
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if ((i % 32) == 0)
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printk("\nru[%02x] ", i);
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printk("%02x ", *cp++);
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}
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printk("\n");
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}
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#endif
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tty = tty_port_tty_get(&port->port);
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if (safe) {
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__u16 fcs;
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fcs = fcs_compute10(data, length, CRC10_INITFCS);
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if (!fcs) {
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int actual_length = data[length - 2] >> 2;
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if (actual_length <= (length - 2)) {
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dev_info(&urb->dev->dev, "%s - actual: %d\n",
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__func__, actual_length);
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tty_insert_flip_string(tty,
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data, actual_length);
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tty_flip_buffer_push(tty);
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} else {
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dev_err(&port->dev,
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"%s - inconsistent lengths %d:%d\n",
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__func__, actual_length, length);
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}
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} else {
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dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);
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}
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} else {
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tty_insert_flip_string(tty, data, length);
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tty_flip_buffer_push(tty);
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}
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tty_kref_put(tty);
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/* Continue trying to always read */
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usb_fill_bulk_urb(urb, port->serial->dev,
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usb_rcvbulkpipe(port->serial->dev,
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port->bulk_in_endpointAddress),
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urb->transfer_buffer, urb->transfer_buffer_length,
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safe_read_bulk_callback, port);
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result = usb_submit_urb(urb, GFP_ATOMIC);
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if (result)
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dev_err(&port->dev,
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"%s - failed resubmitting read urb, error %d\n",
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__func__, result);
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/* FIXME: Need a mechanism to retry later if this happens */
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}
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static int safe_write(struct tty_struct *tty, struct usb_serial_port *port,
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const unsigned char *buf, int count)
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{
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unsigned char *data;
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int result;
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int i;
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int packet_length;
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dbg("safe_write port: %p %d urb: %p count: %d",
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port, port->number, port->write_urb, count);
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if (!port->write_urb) {
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dbg("%s - write urb NULL", __func__);
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return 0;
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}
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dbg("safe_write write_urb: %d transfer_buffer_length",
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port->write_urb->transfer_buffer_length);
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if (!port->write_urb->transfer_buffer_length) {
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dbg("%s - write urb transfer_buffer_length zero", __func__);
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return 0;
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}
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if (count == 0) {
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dbg("%s - write request of 0 bytes", __func__);
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return 0;
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}
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spin_lock_bh(&port->lock);
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if (port->write_urb_busy) {
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spin_unlock_bh(&port->lock);
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dbg("%s - already writing", __func__);
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return 0;
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}
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port->write_urb_busy = 1;
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spin_unlock_bh(&port->lock);
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packet_length = port->bulk_out_size; /* get max packetsize */
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i = packet_length - (safe ? 2 : 0); /* get bytes to send */
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count = (count > i) ? i : count;
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/* get the data into the transfer buffer */
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data = port->write_urb->transfer_buffer;
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memset(data, '0', packet_length);
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memcpy(data, buf, count);
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if (safe) {
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__u16 fcs;
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/* pad if necessary */
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if (!padded)
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packet_length = count + 2;
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/* set count */
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data[packet_length - 2] = count << 2;
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data[packet_length - 1] = 0;
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/* compute fcs and insert into trailer */
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fcs = fcs_compute10(data, packet_length, CRC10_INITFCS);
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data[packet_length - 2] |= fcs >> 8;
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data[packet_length - 1] |= fcs & 0xff;
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/* set length to send */
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port->write_urb->transfer_buffer_length = packet_length;
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} else {
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port->write_urb->transfer_buffer_length = count;
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}
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usb_serial_debug_data(debug, &port->dev, __func__, count,
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port->write_urb->transfer_buffer);
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#ifdef ECHO_TX
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{
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int i;
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unsigned char *cp = port->write_urb->transfer_buffer;
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for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
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if ((i % 32) == 0)
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printk("\nsu[%02x] ", i);
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printk("%02x ", *cp++);
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}
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printk("\n");
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}
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#endif
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port->write_urb->dev = port->serial->dev;
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result = usb_submit_urb(port->write_urb, GFP_KERNEL);
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if (result) {
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port->write_urb_busy = 0;
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dev_err(&port->dev,
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"%s - failed submitting write urb, error %d\n",
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__func__, result);
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return 0;
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}
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dbg("%s urb: %p submitted", __func__, port->write_urb);
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return count;
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}
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static int safe_write_room(struct tty_struct *tty)
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{
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struct usb_serial_port *port = tty->driver_data;
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int room = 0; /* Default: no room */
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unsigned long flags;
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dbg("%s", __func__);
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spin_lock_irqsave(&port->lock, flags);
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if (port->write_urb_busy)
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room = port->bulk_out_size - (safe ? 2 : 0);
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spin_unlock_irqrestore(&port->lock, flags);
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if (room)
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dbg("safe_write_room returns %d", room);
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return room;
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}
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static int safe_startup(struct usb_serial *serial)
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{
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switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
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case LINEO_SAFESERIAL_CRC:
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break;
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case LINEO_SAFESERIAL_CRC_PADDED:
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padded = 1;
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static struct usb_serial_driver safe_device = {
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.driver = {
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.owner = THIS_MODULE,
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.name = "safe_serial",
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},
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.id_table = id_table,
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.usb_driver = &safe_driver,
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.num_ports = 1,
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.write = safe_write,
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.write_room = safe_write_room,
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.read_bulk_callback = safe_read_bulk_callback,
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.attach = safe_startup,
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};
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static int __init safe_init(void)
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{
|
|
int i, retval;
|
|
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
retval = usb_serial_register(&safe_device);
|
|
if (retval)
|
|
goto failed_usb_serial_register;
|
|
retval = usb_register(&safe_driver);
|
|
if (retval)
|
|
goto failed_usb_register;
|
|
|
|
return 0;
|
|
failed_usb_register:
|
|
usb_serial_deregister(&safe_device);
|
|
failed_usb_serial_register:
|
|
return retval;
|
|
}
|
|
|
|
static void __exit safe_exit(void)
|
|
{
|
|
usb_deregister(&safe_driver);
|
|
usb_serial_deregister(&safe_device);
|
|
}
|
|
|
|
module_init(safe_init);
|
|
module_exit(safe_exit);
|