mpc7450-pmu.c

/*
 * Performance counter support for MPC7450-family processors.
 *
 * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
 *
 * 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.
 */
#include <linux/string.h>
#include <linux/perf_event.h>
#include <asm/reg.h>
#include <asm/cputable.h>

#define N_COUNTER	6	/* Number of hardware counters */
#define MAX_ALT		3	/* Maximum number of event alternative codes */

/*
 * Bits in event code for MPC7450 family
 */
#define PM_THRMULT_MSKS	0x40000
#define PM_THRESH_SH	12
#define PM_THRESH_MSK	0x3f
#define PM_PMC_SH	8
#define PM_PMC_MSK	7
#define PM_PMCSEL_MSK	0x7f

/*
 * Classify events according to how specific their PMC requirements are.
 * Result is:
 *	0: can go on any PMC
 *	1: can go on PMCs 1-4
 *	2: can go on PMCs 1,2,4
 *	3: can go on PMCs 1 or 2
 *	4: can only go on one PMC
 *	-1: event code is invalid
 */
#define N_CLASSES	5

static int mpc7450_classify_event(u32 event)
{
	int pmc;

	pmc = (event >> PM_PMC_SH) & PM_PMC_MSK;
	if (pmc) {
		if (pmc > N_COUNTER)
			return -1;
		return 4;
	}
	event &= PM_PMCSEL_MSK;
	if (event <= 1)
		return 0;
	if (event <= 7)
		return 1;
	if (event <= 13)
		return 2;
	if (event <= 22)
		return 3;
	return -1;
}

/*
 * Events using threshold and possible threshold scale:
 *	code	scale?	name
 *	11e	N	PM_INSTQ_EXCEED_CYC
 *	11f	N	PM_ALTV_IQ_EXCEED_CYC
 *	128	Y	PM_DTLB_SEARCH_EXCEED_CYC
 *	12b	Y	PM_LD_MISS_EXCEED_L1_CYC
 *	220	N	PM_CQ_EXCEED_CYC
 *	30c	N	PM_GPR_RB_EXCEED_CYC
 *	30d	?	PM_FPR_IQ_EXCEED_CYC ?
 *	311	Y	PM_ITLB_SEARCH_EXCEED
 *	410	N	PM_GPR_IQ_EXCEED_CYC
 */

/*
 * Return use of threshold and threshold scale bits:
 * 0 = uses neither, 1 = uses threshold, 2 = uses both
 */
static int mpc7450_threshold_use(u32 event)
{
	int pmc, sel;

	pmc = (event >> PM_PMC_SH) & PM_PMC_MSK;
	sel = event & PM_PMCSEL_MSK;
	switch (pmc) {
	case 1:
		if (sel == 0x1e || sel == 0x1f)
			return 1;
		if (sel == 0x28 || sel == 0x2b)
			return 2;
		break;
	case 2:
		if (sel == 0x20)
			return 1;
		break;
	case 3:
		if (sel == 0xc || sel == 0xd)
			return 1;
		if (sel == 0x11)
			return 2;
		break;
	case 4:
		if (sel == 0x10)
			return 1;
		break;
	}
	return 0;
}

/*
 * Layout of constraint bits:
 * 33222222222211111111110000000000
 * 10987654321098765432109876543210
 *  |<    ><  > < > < ><><><><><><>
 *  TS TV   G4   G3  G2P6P5P4P3P2P1
 *
 * P1 - P6
 *	0 - 11: Count of events needing PMC1 .. PMC6
 *
 * G2
 *	12 - 14: Count of events needing PMC1 or PMC2
 *
 * G3
 *	16 - 18: Count of events needing PMC1, PMC2 or PMC4
 *
 * G4
 *	20 - 23: Count of events needing PMC1, PMC2, PMC3 or PMC4
 *
 * TV
 *	24 - 29: Threshold value requested
 *
 * TS
 *	30: Threshold scale value requested
 */

static u32 pmcbits[N_COUNTER][2] = {
	{ 0x00844002, 0x00111001 },	/* PMC1 mask, value: P1,G2,G3,G4 */
	{ 0x00844008, 0x00111004 },	/* PMC2: P2,G2,G3,G4 */
	{ 0x00800020, 0x00100010 },	/* PMC3: P3,G4 */
	{ 0x00840080, 0x00110040 },	/* PMC4: P4,G3,G4 */
	{ 0x00000200, 0x00000100 },	/* PMC5: P5 */
	{ 0x00000800, 0x00000400 }	/* PMC6: P6 */
};

static u32 classbits[N_CLASSES - 1][2] = {
	{ 0x00000000, 0x00000000 },	/* class 0: no constraint */
	{ 0x00800000, 0x00100000 },	/* class 1: G4 */
	{ 0x00040000, 0x00010000 },	/* class 2: G3 */
	{ 0x00004000, 0x00001000 },	/* class 3: G2 */
};

static int mpc7450_get_constraint(u64 event, unsigned long *maskp,
				  unsigned long *valp)
{
	int pmc, class;
	u32 mask, value;
	int thresh, tuse;

	class = mpc7450_classify_event(event);
	if (class < 0)
		return -1;
	if (class == 4) {
		pmc = ((unsigned int)event >> PM_PMC_SH) & PM_PMC_MSK;
		mask  = pmcbits[pmc - 1][0];
		value = pmcbits[pmc - 1][1];
	} else {
		mask  = classbits[class][0];
		value = classbits[class][1];
	}

	tuse = mpc7450_threshold_use(event);
	if (tuse) {
		thresh = ((unsigned int)event >> PM_THRESH_SH) & PM_THRESH_MSK;
		mask  |= 0x3f << 24;
		value |= thresh << 24;
		if (tuse == 2) {
			mask |= 0x40000000;
			if ((unsigned int)event & PM_THRMULT_MSKS)
				value |= 0x40000000;
		}
	}

	*maskp = mask;
	*valp = value;
	return 0;
}

static const unsigned int event_alternatives[][MAX_ALT] = {
	{ 0x217, 0x317 },		/* PM_L1_DCACHE_MISS */
	{ 0x418, 0x50f, 0x60f },	/* PM_SNOOP_RETRY */
	{ 0x502, 0x602 },		/* PM_L2_HIT */
	{ 0x503, 0x603 },		/* PM_L3_HIT */
	{ 0x504, 0x604 },		/* PM_L2_ICACHE_MISS */
	{ 0x505, 0x605 },		/* PM_L3_ICACHE_MISS */
	{ 0x506, 0x606 },		/* PM_L2_DCACHE_MISS */
	{ 0x507, 0x607 },		/* PM_L3_DCACHE_MISS */
	{ 0x50a, 0x623 },		/* PM_LD_HIT_L3 */
	{ 0x50b, 0x624 },		/* PM_ST_HIT_L3 */
	{ 0x50d, 0x60d },		/* PM_L2_TOUCH_HIT */
	{ 0x50e, 0x60e },		/* PM_L3_TOUCH_HIT */
	{ 0x512, 0x612 },		/* PM_INT_LOCAL */
	{ 0x513, 0x61d },		/* PM_L2_MISS */
	{ 0x514, 0x61e },		/* PM_L3_MISS */
};

/*
 * Scan the alternatives table for a match and return the
 * index into the alternatives table if found, else -1.
 */
static int find_alternative(u32 event)
{
	int i, j;

	for (i = 0; i < ARRAY_SIZE(event_alternatives); ++i) {
		if (event < event_alternatives[i][0])
			break;
		for (j = 0; j < MAX_ALT && event_alternatives[i][j]; ++j)
			if (event == event_alternatives[i][j])
				return i;
	}
	return -1;
}

static int mpc7450_get_alternatives(u64 event, unsigned int flags, u64 alt[])
{
	int i, j, nalt = 1;
	u32 ae;

	alt[0] = event;
	nalt = 1;
	i = find_alternative((u32)event);
	if (i >= 0) {
		for (j = 0; j < MAX_ALT; ++j) {
			ae = event_alternatives[i][j];
			if (ae && ae != (u32)event)
				alt[nalt++] = ae;
		}
	}
	return nalt;
}

/*
 * Bitmaps of which PMCs each class can use for classes 0 - 3.
 * Bit i is set if PMC i+1 is usable.
 */
static const u8 classmap[N_CLASSES] = {
	0x3f, 0x0f, 0x0b, 0x03, 0
};

/* Bit position and width of each PMCSEL field */
static const int pmcsel_shift[N_COUNTER] = {
	6,	0,	27,	22,	17,	11
};
static const u32 pmcsel_mask[N_COUNTER] = {
	0x7f,	0x3f,	0x1f,	0x1f,	0x1f,	0x3f
};

/*
 * Compute MMCR0/1/2 values for a set of events.
 */
static int mpc7450_compute_mmcr(u64 event[], int n_ev,
				unsigned int hwc[], unsigned long mmcr[])
{
	u8 event_index[N_CLASSES][N_COUNTER];
	int n_classevent[N_CLASSES];
	int i, j, class, tuse;
	u32 pmc_inuse = 0, pmc_avail;
	u32 mmcr0 = 0, mmcr1 = 0, mmcr2 = 0;
	u32 ev, pmc, thresh;

	if (n_ev > N_COUNTER)
		return -1;

	/* First pass: count usage in each class */
	for (i = 0; i < N_CLASSES; ++i)
		n_classevent[i] = 0;
	for (i = 0; i < n_ev; ++i) {
		class = mpc7450_classify_event(event[i]);
		if (class < 0)
			return -1;
		j = n_classevent[class]++;
		event_index[class][j] = i;
	}

	/* Second pass: allocate PMCs from most specific event to least */
	for (class = N_CLASSES - 1; class >= 0; --class) {
		for (i = 0; i < n_classevent[class]; ++i) {
			ev = event[event_index[class][i]];
			if (class == 4) {
				pmc = (ev >> PM_PMC_SH) & PM_PMC_MSK;
				if (pmc_inuse & (1 << (pmc - 1)))
					return -1;
			} else {
				/* Find a suitable PMC */
				pmc_avail = classmap[class] & ~pmc_inuse;
				if (!pmc_avail)
					return -1;
				pmc = ffs(pmc_avail);
			}
			pmc_inuse |= 1 << (pmc - 1);

			tuse = mpc7450_threshold_use(ev);
			if (tuse) {
				thresh = (ev >> PM_THRESH_SH) & PM_THRESH_MSK;
				mmcr0 |= thresh << 16;
				if (tuse == 2 && (ev & PM_THRMULT_MSKS))
					mmcr2 = 0x80000000;
			}
			ev &= pmcsel_mask[pmc - 1];
			ev <<= pmcsel_shift[pmc - 1];
			if (pmc <= 2)
				mmcr0 |= ev;
			else
				mmcr1 |= ev;
			hwc[event_index[class][i]] = pmc - 1;
		}
	}

	if (pmc_inuse & 1)
		mmcr0 |= MMCR0_PMC1CE;
	if (pmc_inuse & 0x3e)
		mmcr0 |= MMCR0_PMCnCE;

	/* Return MMCRx values */
	mmcr[0] = mmcr0;
	mmcr[1] = mmcr1;
	mmcr[2] = mmcr2;
	return 0;
}

/*
 * Disable counting by a PMC.
 * Note that the pmc argument is 0-based here, not 1-based.
 */
static void mpc7450_disable_pmc(unsigned int pmc, unsigned long mmcr[])
{
	if (pmc <= 1)
		mmcr[0] &= ~(pmcsel_mask[pmc] << pmcsel_shift[pmc]);
	else
		mmcr[1] &= ~(pmcsel_mask[pmc] << pmcsel_shift[pmc]);
}

static int mpc7450_generic_events[] = {
	[PERF_COUNT_HW_CPU_CYCLES]		= 1,
	[PERF_COUNT_HW_INSTRUCTIONS]		= 2,
	[PERF_COUNT_HW_CACHE_MISSES]		= 0x217, /* PM_L1_DCACHE_MISS */
	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= 0x122, /* PM_BR_CMPL */
	[PERF_COUNT_HW_BRANCH_MISSES] 		= 0x41c, /* PM_BR_MPRED */
};

#define C(x)	PERF_COUNT_HW_CACHE_##x

/*
 * Table of generalized cache-related events.
 * 0 means not supported, -1 means nonsensical, other values
 * are event codes.
 */
static int mpc7450_cache_events[C(MAX)][C(OP_MAX)][C(RESULT_MAX)] = {
	[C(L1D)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0,		0x225	},
		[C(OP_WRITE)] = {	0,		0x227	},
		[C(OP_PREFETCH)] = {	0,		0	},
	},
	[C(L1I)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0x129,		0x115	},
		[C(OP_WRITE)] = {	-1,		-1	},
		[C(OP_PREFETCH)] = {	0x634,		0	},
	},
	[C(LL)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0,		0	},
		[C(OP_WRITE)] = {	0,		0	},
		[C(OP_PREFETCH)] = {	0,		0	},
	},
	[C(DTLB)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0,		0x312	},
		[C(OP_WRITE)] = {	-1,		-1	},
		[C(OP_PREFETCH)] = {	-1,		-1	},
	},
	[C(ITLB)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0,		0x223	},
		[C(OP_WRITE)] = {	-1,		-1	},
		[C(OP_PREFETCH)] = {	-1,		-1	},
	},
	[C(BPU)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	0x122,		0x41c	},
		[C(OP_WRITE)] = {	-1,		-1	},
		[C(OP_PREFETCH)] = {	-1,		-1	},
	},
	[C(NODE)] = {		/* 	RESULT_ACCESS	RESULT_MISS */
		[C(OP_READ)] = {	-1,		-1	},
		[C(OP_WRITE)] = {	-1,		-1	},
		[C(OP_PREFETCH)] = {	-1,		-1	},
	},
};

struct power_pmu mpc7450_pmu = {
	.name			= "MPC7450 family",
	.n_counter		= N_COUNTER,
	.max_alternatives	= MAX_ALT,
	.add_fields		= 0x00111555ul,
	.test_adder		= 0x00301000ul,
	.compute_mmcr		= mpc7450_compute_mmcr,
	.get_constraint		= mpc7450_get_constraint,
	.get_alternatives	= mpc7450_get_alternatives,
	.disable_pmc		= mpc7450_disable_pmc,
	.n_generic		= ARRAY_SIZE(mpc7450_generic_events),
	.generic_events		= mpc7450_generic_events,
	.cache_events		= &mpc7450_cache_events,
};

static int init_mpc7450_pmu(void)
{
	if (!cur_cpu_spec->oprofile_cpu_type ||
	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc/7450"))
		return -ENODEV;

	return register_power_pmu(&mpc7450_pmu);
}

early_initcall(init_mpc7450_pmu);