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kernel-ark/drivers/usb/serial/safe_serial.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

458 lines
14 KiB
C
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/*
* Safe Encapsulated USB Serial Driver
*
* 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/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#ifndef CONFIG_USB_SAFE_PADDED
#define CONFIG_USB_SAFE_PADDED 0
#endif
static int debug;
static int safe = 1;
static int padded = CONFIG_USB_SAFE_PADDED;
#define DRIVER_VERSION "v0.0b"
#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
#define DRIVER_DESC "USB Safe Encapsulated Serial"
MODULE_AUTHOR (DRIVER_AUTHOR);
MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_LICENSE("GPL");
#if defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) && !defined(CONFIG_USBD_SAFE_SERIAL_PRODUCT)
#error "SAFE_SERIAL_VENDOR defined without SAFE_SERIAL_PRODUCT"
#endif
#if ! defined(CONFIG_USBD_SAFE_SERIAL_VENDOR)
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)");
#endif
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
#if defined(CONFIG_USB_SAFE_SERIAL_VENDOR)
{MY_USB_DEVICE
(CONFIG_USB_SAFE_SERIAL_VENDOR, CONFIG_USB_SAFE_SERIAL_PRODUCT, CDC_DEVICE_CLASS,
LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
#endif
// 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 struct usb_driver safe_driver = {
.name = "safe_serial",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = id_table,
.no_dynamic_id = 1,
};
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_read_bulk_callback (struct urb *urb)
{
struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
unsigned char *data = urb->transfer_buffer;
unsigned char length = urb->actual_length;
int i;
int result;
dbg ("%s", __FUNCTION__);
if (urb->status) {
dbg ("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
return;
}
dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length);
#ifdef ECHO_RCV
{
int i;
unsigned char *cp = port->read_urb->transfer_buffer;
for (i = 0; i < port->read_urb->actual_length; i++) {
if ((i % 32) == 0) {
printk ("\nru[%02x] ", i);
}
printk ("%02x ", *cp++);
}
printk ("\n");
}
#endif
if (safe) {
__u16 fcs;
if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {
int actual_length = data[length - 2] >> 2;
if (actual_length <= (length - 2)) {
info ("%s - actual: %d", __FUNCTION__, actual_length);
for (i = 0; i < actual_length; i++) {
tty_insert_flip_char (port->tty, data[i], 0);
}
tty_flip_buffer_push (port->tty);
} else {
err ("%s - inconsistent lengths %d:%d", __FUNCTION__,
actual_length, length);
}
} else {
err ("%s - bad CRC %x", __FUNCTION__, fcs);
}
} else {
for (i = 0; i < length; i++) {
tty_insert_flip_char (port->tty, data[i], 0);
}
tty_flip_buffer_push (port->tty);
}
/* Continue trying to always read */
usb_fill_bulk_urb (urb, port->serial->dev,
usb_rcvbulkpipe (port->serial->dev, port->bulk_in_endpointAddress),
urb->transfer_buffer, urb->transfer_buffer_length,
safe_read_bulk_callback, port);
if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
}
}
static int safe_write (struct usb_serial_port *port, const unsigned char *buf, int count)
{
unsigned char *data;
int result;
int i;
int packet_length;
dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb,
count);
if (!port->write_urb) {
dbg ("%s - write urb NULL", __FUNCTION__);
return (0);
}
dbg ("safe_write write_urb: %d transfer_buffer_length",
port->write_urb->transfer_buffer_length);
if (!port->write_urb->transfer_buffer_length) {
dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__);
return (0);
}
if (count == 0) {
dbg ("%s - write request of 0 bytes", __FUNCTION__);
return (0);
}
spin_lock_bh(&port->lock);
if (port->write_urb_busy) {
spin_unlock_bh(&port->lock);
dbg("%s - already writing", __FUNCTION__);
return 0;
}
port->write_urb_busy = 1;
spin_unlock_bh(&port->lock);
packet_length = port->bulk_out_size; // get max packetsize
i = packet_length - (safe ? 2 : 0); // get bytes to send
count = (count > i) ? i : count;
// get the data into the transfer buffer
data = port->write_urb->transfer_buffer;
memset (data, '0', packet_length);
memcpy (data, buf, count);
if (safe) {
__u16 fcs;
// pad if necessary
if (!padded) {
packet_length = count + 2;
}
// set count
data[packet_length - 2] = count << 2;
data[packet_length - 1] = 0;
// compute fcs and insert into trailer
fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS);
data[packet_length - 2] |= fcs >> 8;
data[packet_length - 1] |= fcs & 0xff;
// set length to send
port->write_urb->transfer_buffer_length = packet_length;
} else {
port->write_urb->transfer_buffer_length = count;
}
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, port->write_urb->transfer_buffer);
#ifdef ECHO_TX
{
int i;
unsigned char *cp = port->write_urb->transfer_buffer;
for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
if ((i % 32) == 0) {
printk ("\nsu[%02x] ", i);
}
printk ("%02x ", *cp++);
}
printk ("\n");
}
#endif
port->write_urb->dev = port->serial->dev;
if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
port->write_urb_busy = 0;
err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
return 0;
}
dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb);
return (count);
}
static int safe_write_room (struct usb_serial_port *port)
{
int room = 0; // Default: no room
dbg ("%s", __FUNCTION__);
if (port->write_urb_busy)
room = port->bulk_out_size - (safe ? 2 : 0);
if (room) {
dbg ("safe_write_room returns %d", room);
}
return (room);
}
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_interrupt_in = NUM_DONT_CARE,
.num_bulk_in = NUM_DONT_CARE,
.num_bulk_out = NUM_DONT_CARE,
.num_ports = 1,
.write = safe_write,
.write_room = safe_write_room,
.read_bulk_callback = safe_read_bulk_callback,
.attach = safe_startup,
};
static int __init safe_init (void)
{
int i, retval;
info (DRIVER_VERSION " " DRIVER_AUTHOR);
info (DRIVER_DESC);
info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded);
// if we have vendor / product parameters patch them into id list
if (vendor || product) {
info ("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);
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