kernel-ark/arch/tile/kernel/pmc.c
Zhigang Lu 8e3441ebab tile: Add support for handling PMC hardware
The PMC module is used by perf_events, oprofile and watchdogs.

Signed-off-by: Zhigang Lu <zlu@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2014-03-07 11:19:47 -05:00

122 lines
3.1 KiB
C

/*
* Copyright 2014 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/atomic.h>
#include <linux/interrupt.h>
#include <asm/processor.h>
#include <asm/pmc.h>
perf_irq_t perf_irq = NULL;
int handle_perf_interrupt(struct pt_regs *regs, int fault)
{
int retval;
if (!perf_irq)
panic("Unexpected PERF_COUNT interrupt %d\n", fault);
nmi_enter();
retval = perf_irq(regs, fault);
nmi_exit();
return retval;
}
/* Reserve PMC hardware if it is available. */
perf_irq_t reserve_pmc_hardware(perf_irq_t new_perf_irq)
{
return cmpxchg(&perf_irq, NULL, new_perf_irq);
}
EXPORT_SYMBOL(reserve_pmc_hardware);
/* Release PMC hardware. */
void release_pmc_hardware(void)
{
perf_irq = NULL;
}
EXPORT_SYMBOL(release_pmc_hardware);
/*
* Get current overflow status of each performance counter,
* and auxiliary performance counter.
*/
unsigned long
pmc_get_overflow(void)
{
unsigned long status;
/*
* merge base+aux into a single vector
*/
status = __insn_mfspr(SPR_PERF_COUNT_STS);
status |= __insn_mfspr(SPR_AUX_PERF_COUNT_STS) << TILE_BASE_COUNTERS;
return status;
}
/*
* Clear the status bit for the corresponding counter, if written
* with a one.
*/
void
pmc_ack_overflow(unsigned long status)
{
/*
* clear overflow status by writing ones
*/
__insn_mtspr(SPR_PERF_COUNT_STS, status);
__insn_mtspr(SPR_AUX_PERF_COUNT_STS, status >> TILE_BASE_COUNTERS);
}
/*
* The perf count interrupts are masked and unmasked explicitly,
* and only here. The normal irq_enable() does not enable them,
* and irq_disable() does not disable them. That lets these
* routines drive the perf count interrupts orthogonally.
*
* We also mask the perf count interrupts on entry to the perf count
* interrupt handler in assembly code, and by default unmask them
* again (with interrupt critical section protection) just before
* returning from the interrupt. If the perf count handler returns
* a non-zero error code, then we don't re-enable them before returning.
*
* For Pro, we rely on both interrupts being in the same word to update
* them atomically so we never have one enabled and one disabled.
*/
#if CHIP_HAS_SPLIT_INTR_MASK()
# if INT_PERF_COUNT < 32 || INT_AUX_PERF_COUNT < 32
# error Fix assumptions about which word PERF_COUNT interrupts are in
# endif
#endif
static inline unsigned long long pmc_mask(void)
{
unsigned long long mask = 1ULL << INT_PERF_COUNT;
mask |= 1ULL << INT_AUX_PERF_COUNT;
return mask;
}
void unmask_pmc_interrupts(void)
{
interrupt_mask_reset_mask(pmc_mask());
}
void mask_pmc_interrupts(void)
{
interrupt_mask_set_mask(pmc_mask());
}