1/**
2 * @file arch/alpha/oprofile/op_model_ev4.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author Richard Henderson <rth@twiddle.net>
8 */
9
10#include <linux/oprofile.h>
11#include <linux/init.h>
12#include <linux/smp.h>
13#include <asm/ptrace.h>
14
15#include "op_impl.h"
16
17
18/* Compute all of the registers in preparation for enabling profiling.  */
19
20static void
21ev4_reg_setup(struct op_register_config *reg,
22	      struct op_counter_config *ctr,
23	      struct op_system_config *sys)
24{
25	unsigned long ctl = 0, count, hilo;
26
27	/* Select desired events.  We've mapped the event numbers
28	   such that they fit directly into the event selection fields.
29
30	   Note that there is no "off" setting.  In both cases we select
31	   the EXTERNAL event source, hoping that it'll be the lowest
32	   frequency, and set the frequency counter to LOW.  The interrupts
33	   for these "disabled" counter overflows are ignored by the
34	   interrupt handler.
35
36	   This is most irritating, because the hardware *can* enable and
37	   disable the interrupts for these counters independently, but the
38	   wrperfmon interface doesn't allow it.  */
39
40	ctl |= (ctr[0].enabled ? ctr[0].event << 8 : 14 << 8);
41	ctl |= (ctr[1].enabled ? (ctr[1].event - 16) << 32 : 7ul << 32);
42
43	/* EV4 can not read or write its counter registers.  The only
44	   thing one can do at all is see if you overflow and get an
45	   interrupt.  We can set the width of the counters, to some
46	   extent.  Take the interrupt count selected by the user,
47	   map it onto one of the possible values, and write it back.  */
48
49	count = ctr[0].count;
50	if (count <= 4096)
51		count = 4096, hilo = 1;
52	else
53		count = 65536, hilo = 0;
54	ctr[0].count = count;
55	ctl |= (ctr[0].enabled && hilo) << 3;
56
57	count = ctr[1].count;
58	if (count <= 256)
59		count = 256, hilo = 1;
60	else
61		count = 4096, hilo = 0;
62	ctr[1].count = count;
63	ctl |= (ctr[1].enabled && hilo);
64
65	reg->mux_select = ctl;
66
67	/* Select performance monitoring options.  */
68	/* ??? Need to come up with some mechanism to trace only
69	   selected processes.  EV4 does not have a mechanism to
70	   select kernel or user mode only.  For now, enable always.  */
71	reg->proc_mode = 0;
72
73	/* Frequency is folded into mux_select for EV4.  */
74	reg->freq = 0;
75
76	/* See above regarding no writes.  */
77	reg->reset_values = 0;
78	reg->need_reset = 0;
79
80}
81
82/* Program all of the registers in preparation for enabling profiling.  */
83
84static void
85ev4_cpu_setup(void *x)
86{
87	struct op_register_config *reg = x;
88
89	wrperfmon(2, reg->mux_select);
90	wrperfmon(3, reg->proc_mode);
91}
92
93static void
94ev4_handle_interrupt(unsigned long which, struct pt_regs *regs,
95		     struct op_counter_config *ctr)
96{
97	/* EV4 can't properly disable counters individually.
98	   Discard "disabled" events now.  */
99	if (!ctr[which].enabled)
100		return;
101
102	/* Record the sample.  */
103	oprofile_add_sample(regs, which);
104}
105
106
107struct op_axp_model op_model_ev4 = {
108	.reg_setup		= ev4_reg_setup,
109	.cpu_setup		= ev4_cpu_setup,
110	.reset_ctr		= NULL,
111	.handle_interrupt	= ev4_handle_interrupt,
112	.cpu_type		= "alpha/ev4",
113	.num_counters		= 2,
114	.can_set_proc_mode	= 0,
115};
116