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linux-2.6/drivers/net/hamradio/baycom_par.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

577 lines
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/*****************************************************************************/
/*
* baycom_par.c -- baycom par96 and picpar radio modem driver.
*
* Copyright (C) 1996-2000 Thomas Sailer (sailer@ife.ee.ethz.ch)
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Please note that the GPL allows you to use the driver, NOT the radio.
* In order to use the radio, you need a license from the communications
* authority of your country.
*
*
* Supported modems
*
* par96: This is a modem for 9600 baud FSK compatible to the G3RUH standard.
* The modem does all the filtering and regenerates the receiver clock.
* Data is transferred from and to the PC via a shift register.
* The shift register is filled with 16 bits and an interrupt is
* signalled. The PC then empties the shift register in a burst. This
* modem connects to the parallel port, hence the name. The modem
* leaves the implementation of the HDLC protocol and the scrambler
* polynomial to the PC. This modem is no longer available (at least
* from Baycom) and has been replaced by the PICPAR modem (see below).
* You may however still build one from the schematics published in
* cq-DL :-).
*
* picpar: This is a redesign of the par96 modem by Henning Rech, DF9IC. The
* modem is protocol compatible to par96, but uses only three low
* power ICs and can therefore be fed from the parallel port and
* does not require an additional power supply. It features
* built in DCD circuitry. The driver should therefore be configured
* for hardware DCD.
*
*
* Command line options (insmod command line)
*
* mode driver mode string. Valid choices are par96 and picpar.
* iobase base address of the port; common values are 0x378, 0x278, 0x3bc
*
*
* History:
* 0.1 26.06.1996 Adapted from baycom.c and made network driver interface
* 18.10.1996 Changed to new user space access routines (copy_{to,from}_user)
* 0.3 26.04.1997 init code/data tagged
* 0.4 08.07.1997 alternative ser12 decoding algorithm (uses delta CTS ints)
* 0.5 11.11.1997 split into separate files for ser12/par96
* 0.6 03.08.1999 adapt to Linus' new __setup/__initcall
* removed some pre-2.2 kernel compatibility cruft
* 0.7 10.08.1999 Check if parport can do SPP and is safe to access during interrupt contexts
* 0.8 12.02.2000 adapted to softnet driver interface
* removed direct parport access, uses parport driver methods
* 0.9 03.07.2000 fix interface name handling
*/
/*****************************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/hdlcdrv.h>
#include <linux/baycom.h>
#include <linux/parport.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>
#include <asm/system.h>
#include <asm/uaccess.h>
/* --------------------------------------------------------------------- */
#define BAYCOM_DEBUG
/*
* modem options; bit mask
*/
#define BAYCOM_OPTIONS_SOFTDCD 1
/* --------------------------------------------------------------------- */
static const char bc_drvname[] = "baycom_par";
static const char bc_drvinfo[] = KERN_INFO "baycom_par: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA\n"
KERN_INFO "baycom_par: version 0.9 compiled " __TIME__ " " __DATE__ "\n";
/* --------------------------------------------------------------------- */
#define NR_PORTS 4
static struct net_device *baycom_device[NR_PORTS];
/* --------------------------------------------------------------------- */
#define PAR96_BURSTBITS 16
#define PAR96_BURST 4
#define PAR96_PTT 2
#define PAR96_TXBIT 1
#define PAR96_ACK 0x40
#define PAR96_RXBIT 0x20
#define PAR96_DCD 0x10
#define PAR97_POWER 0xf8
/* ---------------------------------------------------------------------- */
/*
* Information that need to be kept for each board.
*/
struct baycom_state {
struct hdlcdrv_state hdrv;
struct pardevice *pdev;
unsigned int options;
struct modem_state {
short arb_divider;
unsigned char flags;
unsigned int shreg;
struct modem_state_par96 {
int dcd_count;
unsigned int dcd_shreg;
unsigned long descram;
unsigned long scram;
} par96;
} modem;
#ifdef BAYCOM_DEBUG
struct debug_vals {
unsigned long last_jiffies;
unsigned cur_intcnt;
unsigned last_intcnt;
int cur_pllcorr;
int last_pllcorr;
} debug_vals;
#endif /* BAYCOM_DEBUG */
};
/* --------------------------------------------------------------------- */
static void __inline__ baycom_int_freq(struct baycom_state *bc)
{
#ifdef BAYCOM_DEBUG
unsigned long cur_jiffies = jiffies;
/*
* measure the interrupt frequency
*/
bc->debug_vals.cur_intcnt++;
if (time_after_eq(cur_jiffies, bc->debug_vals.last_jiffies + HZ)) {
bc->debug_vals.last_jiffies = cur_jiffies;
bc->debug_vals.last_intcnt = bc->debug_vals.cur_intcnt;
bc->debug_vals.cur_intcnt = 0;
bc->debug_vals.last_pllcorr = bc->debug_vals.cur_pllcorr;
bc->debug_vals.cur_pllcorr = 0;
}
#endif /* BAYCOM_DEBUG */
}
/* --------------------------------------------------------------------- */
/*
* ===================== PAR96 specific routines =========================
*/
#define PAR96_DESCRAM_TAP1 0x20000
#define PAR96_DESCRAM_TAP2 0x01000
#define PAR96_DESCRAM_TAP3 0x00001
#define PAR96_DESCRAM_TAPSH1 17
#define PAR96_DESCRAM_TAPSH2 12
#define PAR96_DESCRAM_TAPSH3 0
#define PAR96_SCRAM_TAP1 0x20000 /* X^17 */
#define PAR96_SCRAM_TAPN 0x00021 /* X^0+X^5 */
/* --------------------------------------------------------------------- */
static __inline__ void par96_tx(struct net_device *dev, struct baycom_state *bc)
{
int i;
unsigned int data = hdlcdrv_getbits(&bc->hdrv);
struct parport *pp = bc->pdev->port;
for(i = 0; i < PAR96_BURSTBITS; i++, data >>= 1) {
unsigned char val = PAR97_POWER;
bc->modem.par96.scram = ((bc->modem.par96.scram << 1) |
(bc->modem.par96.scram & 1));
if (!(data & 1))
bc->modem.par96.scram ^= 1;
if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 1))
bc->modem.par96.scram ^=
(PAR96_SCRAM_TAPN << 1);
if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 2))
val |= PAR96_TXBIT;
pp->ops->write_data(pp, val);
pp->ops->write_data(pp, val | PAR96_BURST);
}
}
/* --------------------------------------------------------------------- */
static __inline__ void par96_rx(struct net_device *dev, struct baycom_state *bc)
{
int i;
unsigned int data, mask, mask2, descx;
struct parport *pp = bc->pdev->port;
/*
* do receiver; differential decode and descramble on the fly
*/
for(data = i = 0; i < PAR96_BURSTBITS; i++) {
bc->modem.par96.descram = (bc->modem.par96.descram << 1);
if (pp->ops->read_status(pp) & PAR96_RXBIT)
bc->modem.par96.descram |= 1;
descx = bc->modem.par96.descram ^
(bc->modem.par96.descram >> 1);
/* now the diff decoded data is inverted in descram */
pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT);
descx ^= ((descx >> PAR96_DESCRAM_TAPSH1) ^
(descx >> PAR96_DESCRAM_TAPSH2));
data >>= 1;
if (!(descx & 1))
data |= 0x8000;
pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT | PAR96_BURST);
}
hdlcdrv_putbits(&bc->hdrv, data);
/*
* do DCD algorithm
*/
if (bc->options & BAYCOM_OPTIONS_SOFTDCD) {
bc->modem.par96.dcd_shreg = (bc->modem.par96.dcd_shreg >> 16)
| (data << 16);
/* search for flags and set the dcd counter appropriately */
for(mask = 0x1fe00, mask2 = 0xfc00, i = 0;
i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
if ((bc->modem.par96.dcd_shreg & mask) == mask2)
bc->modem.par96.dcd_count = HDLCDRV_MAXFLEN+4;
/* check for abort/noise sequences */
for(mask = 0x1fe00, mask2 = 0x1fe00, i = 0;
i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
if (((bc->modem.par96.dcd_shreg & mask) == mask2) &&
(bc->modem.par96.dcd_count >= 0))
bc->modem.par96.dcd_count -= HDLCDRV_MAXFLEN-10;
/* decrement and set the dcd variable */
if (bc->modem.par96.dcd_count >= 0)
bc->modem.par96.dcd_count -= 2;
hdlcdrv_setdcd(&bc->hdrv, bc->modem.par96.dcd_count > 0);
} else {
hdlcdrv_setdcd(&bc->hdrv, !!(pp->ops->read_status(pp) & PAR96_DCD));
}
}
/* --------------------------------------------------------------------- */
static void par96_interrupt(int irq, void *dev_id)
{
struct net_device *dev = (struct net_device *)dev_id;
struct baycom_state *bc = netdev_priv(dev);
baycom_int_freq(bc);
/*
* check if transmitter active
*/
if (hdlcdrv_ptt(&bc->hdrv))
par96_tx(dev, bc);
else {
par96_rx(dev, bc);
if (--bc->modem.arb_divider <= 0) {
bc->modem.arb_divider = 6;
local_irq_enable();
hdlcdrv_arbitrate(dev, &bc->hdrv);
}
}
local_irq_enable();
hdlcdrv_transmitter(dev, &bc->hdrv);
hdlcdrv_receiver(dev, &bc->hdrv);
local_irq_disable();
}
/* --------------------------------------------------------------------- */
static void par96_wakeup(void *handle)
{
struct net_device *dev = (struct net_device *)handle;
struct baycom_state *bc = netdev_priv(dev);
printk(KERN_DEBUG "baycom_par: %s: why am I being woken up?\n", dev->name);
if (!parport_claim(bc->pdev))
printk(KERN_DEBUG "baycom_par: %s: I'm broken.\n", dev->name);
}
/* --------------------------------------------------------------------- */
static int par96_open(struct net_device *dev)
{
struct baycom_state *bc = netdev_priv(dev);
struct parport *pp;
if (!dev || !bc)
return -ENXIO;
pp = parport_find_base(dev->base_addr);
if (!pp) {
printk(KERN_ERR "baycom_par: parport at 0x%lx unknown\n", dev->base_addr);
return -ENXIO;
}
if (pp->irq < 0) {
printk(KERN_ERR "baycom_par: parport at 0x%lx has no irq\n", pp->base);
parport_put_port(pp);
return -ENXIO;
}
if ((~pp->modes) & (PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT)) {
printk(KERN_ERR "baycom_par: parport at 0x%lx cannot be used\n", pp->base);
parport_put_port(pp);
return -ENXIO;
}
memset(&bc->modem, 0, sizeof(bc->modem));
bc->hdrv.par.bitrate = 9600;
bc->pdev = parport_register_device(pp, dev->name, NULL, par96_wakeup,
par96_interrupt, PARPORT_DEV_EXCL, dev);
parport_put_port(pp);
if (!bc->pdev) {
printk(KERN_ERR "baycom_par: cannot register parport at 0x%lx\n", dev->base_addr);
return -ENXIO;
}
if (parport_claim(bc->pdev)) {
printk(KERN_ERR "baycom_par: parport at 0x%lx busy\n", pp->base);
parport_unregister_device(bc->pdev);
return -EBUSY;
}
pp = bc->pdev->port;
dev->irq = pp->irq;
pp->ops->data_forward(pp);
bc->hdrv.par.bitrate = 9600;
pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER); /* switch off PTT */
pp->ops->enable_irq(pp);
printk(KERN_INFO "%s: par96 at iobase 0x%lx irq %u options 0x%x\n",
bc_drvname, dev->base_addr, dev->irq, bc->options);
return 0;
}
/* --------------------------------------------------------------------- */
static int par96_close(struct net_device *dev)
{
struct baycom_state *bc = netdev_priv(dev);
struct parport *pp;
if (!dev || !bc)
return -EINVAL;
pp = bc->pdev->port;
/* disable interrupt */
pp->ops->disable_irq(pp);
/* switch off PTT */
pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER);
parport_release(bc->pdev);
parport_unregister_device(bc->pdev);
printk(KERN_INFO "%s: close par96 at iobase 0x%lx irq %u\n",
bc_drvname, dev->base_addr, dev->irq);
return 0;
}
/* --------------------------------------------------------------------- */
/*
* ===================== hdlcdrv driver interface =========================
*/
static int baycom_ioctl(struct net_device *dev, struct ifreq *ifr,
struct hdlcdrv_ioctl *hi, int cmd);
/* --------------------------------------------------------------------- */
static struct hdlcdrv_ops par96_ops = {
.drvname = bc_drvname,
.drvinfo = bc_drvinfo,
.open = par96_open,
.close = par96_close,
.ioctl = baycom_ioctl
};
/* --------------------------------------------------------------------- */
static int baycom_setmode(struct baycom_state *bc, const char *modestr)
{
if (!strncmp(modestr, "picpar", 6))
bc->options = 0;
else if (!strncmp(modestr, "par96", 5))
bc->options = BAYCOM_OPTIONS_SOFTDCD;
else
bc->options = !!strchr(modestr, '*');
return 0;
}
/* --------------------------------------------------------------------- */
static int baycom_ioctl(struct net_device *dev, struct ifreq *ifr,
struct hdlcdrv_ioctl *hi, int cmd)
{
struct baycom_state *bc;
struct baycom_ioctl bi;
if (!dev)
return -EINVAL;
bc = netdev_priv(dev);
BUG_ON(bc->hdrv.magic != HDLCDRV_MAGIC);
if (cmd != SIOCDEVPRIVATE)
return -ENOIOCTLCMD;
switch (hi->cmd) {
default:
break;
case HDLCDRVCTL_GETMODE:
strcpy(hi->data.modename, bc->options ? "par96" : "picpar");
if (copy_to_user(ifr->ifr_data, hi, sizeof(struct hdlcdrv_ioctl)))
return -EFAULT;
return 0;
case HDLCDRVCTL_SETMODE:
if (netif_running(dev) || !capable(CAP_NET_ADMIN))
return -EACCES;
hi->data.modename[sizeof(hi->data.modename)-1] = '\0';
return baycom_setmode(bc, hi->data.modename);
case HDLCDRVCTL_MODELIST:
strcpy(hi->data.modename, "par96,picpar");
if (copy_to_user(ifr->ifr_data, hi, sizeof(struct hdlcdrv_ioctl)))
return -EFAULT;
return 0;
case HDLCDRVCTL_MODEMPARMASK:
return HDLCDRV_PARMASK_IOBASE;
}
if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
return -EFAULT;
switch (bi.cmd) {
default:
return -ENOIOCTLCMD;
#ifdef BAYCOM_DEBUG
case BAYCOMCTL_GETDEBUG:
bi.data.dbg.debug1 = bc->hdrv.ptt_keyed;
bi.data.dbg.debug2 = bc->debug_vals.last_intcnt;
bi.data.dbg.debug3 = bc->debug_vals.last_pllcorr;
break;
#endif /* BAYCOM_DEBUG */
}
if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
return -EFAULT;
return 0;
}
/* --------------------------------------------------------------------- */
/*
* command line settable parameters
*/
static const char *mode[NR_PORTS] = { "picpar", };
static int iobase[NR_PORTS] = { 0x378, };
module_param_array(mode, charp, NULL, 0);
MODULE_PARM_DESC(mode, "baycom operating mode; eg. par96 or picpar");
module_param_array(iobase, int, NULL, 0);
MODULE_PARM_DESC(iobase, "baycom io base address");
MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
MODULE_DESCRIPTION("Baycom par96 and picpar amateur radio modem driver");
MODULE_LICENSE("GPL");
/* --------------------------------------------------------------------- */
static int __init init_baycompar(void)
{
int i, found = 0;
char set_hw = 1;
printk(bc_drvinfo);
/*
* register net devices
*/
for (i = 0; i < NR_PORTS; i++) {
struct net_device *dev;
struct baycom_state *bc;
char ifname[IFNAMSIZ];
sprintf(ifname, "bcp%d", i);
if (!mode[i])
set_hw = 0;
if (!set_hw)
iobase[i] = 0;
dev = hdlcdrv_register(&par96_ops,
sizeof(struct baycom_state),
ifname, iobase[i], 0, 0);
if (IS_ERR(dev))
break;
bc = netdev_priv(dev);
if (set_hw && baycom_setmode(bc, mode[i]))
set_hw = 0;
found++;
baycom_device[i] = dev;
}
if (!found)
return -ENXIO;
return 0;
}
static void __exit cleanup_baycompar(void)
{
int i;
for(i = 0; i < NR_PORTS; i++) {
struct net_device *dev = baycom_device[i];
if (dev)
hdlcdrv_unregister(dev);
}
}
module_init(init_baycompar);
module_exit(cleanup_baycompar);
/* --------------------------------------------------------------------- */
#ifndef MODULE
/*
* format: baycom_par=io,mode
* mode: par96,picpar
*/
static int __init baycom_par_setup(char *str)
{
static unsigned nr_dev;
int ints[2];
if (nr_dev >= NR_PORTS)
return 0;
str = get_options(str, 2, ints);
if (ints[0] < 1)
return 0;
mode[nr_dev] = str;
iobase[nr_dev] = ints[1];
nr_dev++;
return 1;
}
__setup("baycom_par=", baycom_par_setup);
#endif /* MODULE */
/* --------------------------------------------------------------------- */
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