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linux-stable/drivers/isdn/hisax/nj_u.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

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6.5 KiB
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/* $Id: nj_u.c,v 2.14.2.3 2004/01/13 14:31:26 keil Exp $
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
*/
#include <linux/init.h>
#include "hisax.h"
#include "icc.h"
#include "isdnl1.h"
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/ppp_defs.h>
#include "netjet.h"
static const char *NETjet_U_revision = "$Revision: 2.14.2.3 $";
static u_char dummyrr(struct IsdnCardState *cs, int chan, u_char off)
{
return(5);
}
static void dummywr(struct IsdnCardState *cs, int chan, u_char off, u_char value)
{
}
static irqreturn_t
netjet_u_interrupt(int intno, void *dev_id)
{
struct IsdnCardState *cs = dev_id;
u_char val, sval;
u_long flags;
spin_lock_irqsave(&cs->lock, flags);
if (!((sval = bytein(cs->hw.njet.base + NETJET_IRQSTAT1)) &
NETJET_ISACIRQ)) {
val = NETjet_ReadIC(cs, ICC_ISTA);
if (cs->debug & L1_DEB_ISAC)
debugl1(cs, "tiger: i1 %x %x", sval, val);
if (val) {
icc_interrupt(cs, val);
NETjet_WriteIC(cs, ICC_MASK, 0xFF);
NETjet_WriteIC(cs, ICC_MASK, 0x0);
}
}
/* start new code 13/07/00 GE */
/* set bits in sval to indicate which page is free */
if (inl(cs->hw.njet.base + NETJET_DMA_WRITE_ADR) <
inl(cs->hw.njet.base + NETJET_DMA_WRITE_IRQ))
/* the 2nd write page is free */
sval = 0x08;
else /* the 1st write page is free */
sval = 0x04;
if (inl(cs->hw.njet.base + NETJET_DMA_READ_ADR) <
inl(cs->hw.njet.base + NETJET_DMA_READ_IRQ))
/* the 2nd read page is free */
sval = sval | 0x02;
else /* the 1st read page is free */
sval = sval | 0x01;
if (sval != cs->hw.njet.last_is0) /* we have a DMA interrupt */
{
if (test_and_set_bit(FLG_LOCK_ATOMIC, &cs->HW_Flags)) {
spin_unlock_irqrestore(&cs->lock, flags);
return IRQ_HANDLED;
}
cs->hw.njet.irqstat0 = sval;
if ((cs->hw.njet.irqstat0 & NETJET_IRQM0_READ) !=
(cs->hw.njet.last_is0 & NETJET_IRQM0_READ))
/* we have a read dma int */
read_tiger(cs);
if ((cs->hw.njet.irqstat0 & NETJET_IRQM0_WRITE) !=
(cs->hw.njet.last_is0 & NETJET_IRQM0_WRITE))
/* we have a write dma int */
write_tiger(cs);
/* end new code 13/07/00 GE */
test_and_clear_bit(FLG_LOCK_ATOMIC, &cs->HW_Flags);
}
spin_unlock_irqrestore(&cs->lock, flags);
return IRQ_HANDLED;
}
static void
reset_netjet_u(struct IsdnCardState *cs)
{
cs->hw.njet.ctrl_reg = 0xff; /* Reset On */
byteout(cs->hw.njet.base + NETJET_CTRL, cs->hw.njet.ctrl_reg);
mdelay(10);
cs->hw.njet.ctrl_reg = 0x40; /* Reset Off and status read clear */
/* now edge triggered for TJ320 GE 13/07/00 */
byteout(cs->hw.njet.base + NETJET_CTRL, cs->hw.njet.ctrl_reg);
mdelay(10);
cs->hw.njet.auxd = 0xC0;
cs->hw.njet.dmactrl = 0;
byteout(cs->hw.njet.auxa, 0);
byteout(cs->hw.njet.base + NETJET_AUXCTRL, ~NETJET_ISACIRQ);
byteout(cs->hw.njet.base + NETJET_IRQMASK1, NETJET_ISACIRQ);
byteout(cs->hw.njet.auxa, cs->hw.njet.auxd);
}
static int
NETjet_U_card_msg(struct IsdnCardState *cs, int mt, void *arg)
{
u_long flags;
switch (mt) {
case CARD_RESET:
spin_lock_irqsave(&cs->lock, flags);
reset_netjet_u(cs);
spin_unlock_irqrestore(&cs->lock, flags);
return(0);
case CARD_RELEASE:
release_io_netjet(cs);
return(0);
case CARD_INIT:
spin_lock_irqsave(&cs->lock, flags);
inittiger(cs);
reset_netjet_u(cs);
clear_pending_icc_ints(cs);
initicc(cs);
/* Reenable all IRQ */
cs->writeisac(cs, ICC_MASK, 0);
spin_unlock_irqrestore(&cs->lock, flags);
return(0);
case CARD_TEST:
return(0);
}
return(0);
}
static struct pci_dev *dev_netjet __devinitdata = NULL;
int __devinit
setup_netjet_u(struct IsdnCard *card)
{
int bytecnt;
struct IsdnCardState *cs = card->cs;
char tmp[64];
#ifdef CONFIG_PCI
#endif
#ifdef __BIG_ENDIAN
#error "not running on big endian machines now"
#endif
strcpy(tmp, NETjet_U_revision);
printk(KERN_INFO "HiSax: Traverse Tech. NETspider-U driver Rev. %s\n", HiSax_getrev(tmp));
if (cs->typ != ISDN_CTYPE_NETJET_U)
return(0);
test_and_clear_bit(FLG_LOCK_ATOMIC, &cs->HW_Flags);
#ifdef CONFIG_PCI
for ( ;; )
{
if ((dev_netjet = pci_find_device(PCI_VENDOR_ID_TIGERJET,
PCI_DEVICE_ID_TIGERJET_300, dev_netjet))) {
if (pci_enable_device(dev_netjet))
return(0);
pci_set_master(dev_netjet);
cs->irq = dev_netjet->irq;
if (!cs->irq) {
printk(KERN_WARNING "NETspider-U: No IRQ for PCI card found\n");
return(0);
}
cs->hw.njet.base = pci_resource_start(dev_netjet, 0);
if (!cs->hw.njet.base) {
printk(KERN_WARNING "NETspider-U: No IO-Adr for PCI card found\n");
return(0);
}
} else {
printk(KERN_WARNING "NETspider-U: No PCI card found\n");
return(0);
}
cs->hw.njet.auxa = cs->hw.njet.base + NETJET_AUXDATA;
cs->hw.njet.isac = cs->hw.njet.base | NETJET_ISAC_OFF;
mdelay(10);
cs->hw.njet.ctrl_reg = 0xff; /* Reset On */
byteout(cs->hw.njet.base + NETJET_CTRL, cs->hw.njet.ctrl_reg);
mdelay(10);
cs->hw.njet.ctrl_reg = 0x00; /* Reset Off and status read clear */
byteout(cs->hw.njet.base + NETJET_CTRL, cs->hw.njet.ctrl_reg);
mdelay(10);
cs->hw.njet.auxd = 0xC0;
cs->hw.njet.dmactrl = 0;
byteout(cs->hw.njet.auxa, 0);
byteout(cs->hw.njet.base + NETJET_AUXCTRL, ~NETJET_ISACIRQ);
byteout(cs->hw.njet.base + NETJET_IRQMASK1, NETJET_ISACIRQ);
byteout(cs->hw.njet.auxa, cs->hw.njet.auxd);
switch ( ( ( NETjet_ReadIC( cs, ICC_RBCH ) >> 5 ) & 3 ) )
{
case 3 :
break;
case 0 :
printk( KERN_WARNING "NETspider-U: NETjet-S PCI card found\n" );
continue;
default :
printk( KERN_WARNING "NETspider-U: No PCI card found\n" );
return 0;
}
break;
}
#else
printk(KERN_WARNING "NETspider-U: NO_PCI_BIOS\n");
printk(KERN_WARNING "NETspider-U: unable to config NETspider-U PCI\n");
return (0);
#endif /* CONFIG_PCI */
bytecnt = 256;
printk(KERN_INFO
"NETspider-U: PCI card configured at %#lx IRQ %d\n",
cs->hw.njet.base, cs->irq);
if (!request_region(cs->hw.njet.base, bytecnt, "netspider-u isdn")) {
printk(KERN_WARNING
"HiSax: %s config port %#lx-%#lx already in use\n",
CardType[card->typ],
cs->hw.njet.base,
cs->hw.njet.base + bytecnt);
return (0);
}
setup_icc(cs);
cs->readisac = &NETjet_ReadIC;
cs->writeisac = &NETjet_WriteIC;
cs->readisacfifo = &NETjet_ReadICfifo;
cs->writeisacfifo = &NETjet_WriteICfifo;
cs->BC_Read_Reg = &dummyrr;
cs->BC_Write_Reg = &dummywr;
cs->BC_Send_Data = &netjet_fill_dma;
cs->cardmsg = &NETjet_U_card_msg;
cs->irq_func = &netjet_u_interrupt;
cs->irq_flags |= IRQF_SHARED;
ICCVersion(cs, "NETspider-U:");
return (1);
}
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