7d12e780e0
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)
221 lines
5.8 KiB
C
221 lines
5.8 KiB
C
/*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Time operations for IP22 machines. Original code may come from
|
|
* Ralf Baechle or David S. Miller (sorry guys, i'm really not sure)
|
|
*
|
|
* Copyright (C) 2001 by Ladislav Michl
|
|
* Copyright (C) 2003, 06 Ralf Baechle (ralf@linux-mips.org)
|
|
*/
|
|
#include <linux/bcd.h>
|
|
#include <linux/ds1286.h>
|
|
#include <linux/init.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/time.h>
|
|
|
|
#include <asm/cpu.h>
|
|
#include <asm/mipsregs.h>
|
|
#include <asm/io.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/time.h>
|
|
#include <asm/sgialib.h>
|
|
#include <asm/sgi/ioc.h>
|
|
#include <asm/sgi/hpc3.h>
|
|
#include <asm/sgi/ip22.h>
|
|
|
|
/*
|
|
* note that mktime uses month from 1 to 12 while to_tm
|
|
* uses 0 to 11.
|
|
*/
|
|
static unsigned long indy_rtc_get_time(void)
|
|
{
|
|
unsigned int yrs, mon, day, hrs, min, sec;
|
|
unsigned int save_control;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&rtc_lock, flags);
|
|
save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
|
|
hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
|
|
|
|
sec = BCD2BIN(hpc3c0->rtcregs[RTC_SECONDS] & 0xff);
|
|
min = BCD2BIN(hpc3c0->rtcregs[RTC_MINUTES] & 0xff);
|
|
hrs = BCD2BIN(hpc3c0->rtcregs[RTC_HOURS] & 0x3f);
|
|
day = BCD2BIN(hpc3c0->rtcregs[RTC_DATE] & 0xff);
|
|
mon = BCD2BIN(hpc3c0->rtcregs[RTC_MONTH] & 0x1f);
|
|
yrs = BCD2BIN(hpc3c0->rtcregs[RTC_YEAR] & 0xff);
|
|
|
|
hpc3c0->rtcregs[RTC_CMD] = save_control;
|
|
spin_unlock_irqrestore(&rtc_lock, flags);
|
|
|
|
if (yrs < 45)
|
|
yrs += 30;
|
|
if ((yrs += 40) < 70)
|
|
yrs += 100;
|
|
|
|
return mktime(yrs + 1900, mon, day, hrs, min, sec);
|
|
}
|
|
|
|
static int indy_rtc_set_time(unsigned long tim)
|
|
{
|
|
struct rtc_time tm;
|
|
unsigned int save_control;
|
|
unsigned long flags;
|
|
|
|
to_tm(tim, &tm);
|
|
|
|
tm.tm_mon += 1; /* tm_mon starts at zero */
|
|
tm.tm_year -= 1940;
|
|
if (tm.tm_year >= 100)
|
|
tm.tm_year -= 100;
|
|
|
|
spin_lock_irqsave(&rtc_lock, flags);
|
|
save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
|
|
hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
|
|
|
|
hpc3c0->rtcregs[RTC_YEAR] = BIN2BCD(tm.tm_year);
|
|
hpc3c0->rtcregs[RTC_MONTH] = BIN2BCD(tm.tm_mon);
|
|
hpc3c0->rtcregs[RTC_DATE] = BIN2BCD(tm.tm_mday);
|
|
hpc3c0->rtcregs[RTC_HOURS] = BIN2BCD(tm.tm_hour);
|
|
hpc3c0->rtcregs[RTC_MINUTES] = BIN2BCD(tm.tm_min);
|
|
hpc3c0->rtcregs[RTC_SECONDS] = BIN2BCD(tm.tm_sec);
|
|
hpc3c0->rtcregs[RTC_HUNDREDTH_SECOND] = 0;
|
|
|
|
hpc3c0->rtcregs[RTC_CMD] = save_control;
|
|
spin_unlock_irqrestore(&rtc_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long dosample(void)
|
|
{
|
|
u32 ct0, ct1;
|
|
volatile u8 msb, lsb;
|
|
|
|
/* Start the counter. */
|
|
sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
|
|
SGINT_TCWORD_MRGEN);
|
|
sgint->tcnt2 = SGINT_TCSAMP_COUNTER & 0xff;
|
|
sgint->tcnt2 = SGINT_TCSAMP_COUNTER >> 8;
|
|
|
|
/* Get initial counter invariant */
|
|
ct0 = read_c0_count();
|
|
|
|
/* Latch and spin until top byte of counter2 is zero */
|
|
do {
|
|
sgint->tcword = SGINT_TCWORD_CNT2 | SGINT_TCWORD_CLAT;
|
|
lsb = sgint->tcnt2;
|
|
msb = sgint->tcnt2;
|
|
ct1 = read_c0_count();
|
|
} while (msb);
|
|
|
|
/* Stop the counter. */
|
|
sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
|
|
SGINT_TCWORD_MSWST);
|
|
/*
|
|
* Return the difference, this is how far the r4k counter increments
|
|
* for every 1/HZ seconds. We round off the nearest 1 MHz of master
|
|
* clock (= 1000000 / HZ / 2).
|
|
*/
|
|
/*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/
|
|
return (ct1 - ct0) / (500000/HZ) * (500000/HZ);
|
|
}
|
|
|
|
/*
|
|
* Here we need to calibrate the cycle counter to at least be close.
|
|
*/
|
|
static __init void indy_time_init(void)
|
|
{
|
|
unsigned long r4k_ticks[3];
|
|
unsigned long r4k_tick;
|
|
|
|
/*
|
|
* Figure out the r4k offset, the algorithm is very simple and works in
|
|
* _all_ cases as long as the 8254 counter register itself works ok (as
|
|
* an interrupt driving timer it does not because of bug, this is why
|
|
* we are using the onchip r4k counter/compare register to serve this
|
|
* purpose, but for r4k_offset calculation it will work ok for us).
|
|
* There are other very complicated ways of performing this calculation
|
|
* but this one works just fine so I am not going to futz around. ;-)
|
|
*/
|
|
printk(KERN_INFO "Calibrating system timer... ");
|
|
dosample(); /* Prime cache. */
|
|
dosample(); /* Prime cache. */
|
|
/* Zero is NOT an option. */
|
|
do {
|
|
r4k_ticks[0] = dosample();
|
|
} while (!r4k_ticks[0]);
|
|
do {
|
|
r4k_ticks[1] = dosample();
|
|
} while (!r4k_ticks[1]);
|
|
|
|
if (r4k_ticks[0] != r4k_ticks[1]) {
|
|
printk("warning: timer counts differ, retrying... ");
|
|
r4k_ticks[2] = dosample();
|
|
if (r4k_ticks[2] == r4k_ticks[0]
|
|
|| r4k_ticks[2] == r4k_ticks[1])
|
|
r4k_tick = r4k_ticks[2];
|
|
else {
|
|
printk("disagreement, using average... ");
|
|
r4k_tick = (r4k_ticks[0] + r4k_ticks[1]
|
|
+ r4k_ticks[2]) / 3;
|
|
}
|
|
} else
|
|
r4k_tick = r4k_ticks[0];
|
|
|
|
printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick,
|
|
(int) (r4k_tick / (500000 / HZ)),
|
|
(int) (r4k_tick % (500000 / HZ)));
|
|
|
|
mips_hpt_frequency = r4k_tick * HZ;
|
|
}
|
|
|
|
/* Generic SGI handler for (spurious) 8254 interrupts */
|
|
void indy_8254timer_irq(struct pt_regs *regs)
|
|
{
|
|
int irq = SGI_8254_0_IRQ;
|
|
ULONG cnt;
|
|
char c;
|
|
|
|
irq_enter();
|
|
kstat_this_cpu.irqs[irq]++;
|
|
printk(KERN_ALERT "Oops, got 8254 interrupt.\n");
|
|
ArcRead(0, &c, 1, &cnt);
|
|
ArcEnterInteractiveMode();
|
|
irq_exit();
|
|
}
|
|
|
|
void indy_r4k_timer_interrupt(struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *old_regs = set_irq_regs(regs);
|
|
int irq = SGI_TIMER_IRQ;
|
|
|
|
irq_enter();
|
|
kstat_this_cpu.irqs[irq]++;
|
|
timer_interrupt(irq, NULL);
|
|
irq_exit();
|
|
set_irq_regs(old_regs);
|
|
}
|
|
|
|
void __init plat_timer_setup(struct irqaction *irq)
|
|
{
|
|
/* over-write the handler, we use our own way */
|
|
irq->handler = no_action;
|
|
|
|
/* setup irqaction */
|
|
setup_irq(SGI_TIMER_IRQ, irq);
|
|
}
|
|
|
|
void __init ip22_time_init(void)
|
|
{
|
|
/* setup hookup functions */
|
|
rtc_mips_get_time = indy_rtc_get_time;
|
|
rtc_mips_set_time = indy_rtc_set_time;
|
|
|
|
board_time_init = indy_time_init;
|
|
}
|