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39
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44
45
46/**
47 * @file
48 *
49 * Module to support operations on bitmap of cores. Coremask can be used to
50 * select a specific core, a group of cores, or all available cores, for
51 * initialization and differentiation of roles within a single shared binary
52 * executable image.
53 *
54 * <hr>$Revision: 70030 $<hr>
55 *
56 */
57
58#include "cvmx-config.h"
59#include "cvmx.h"
60#include "cvmx-spinlock.h"
61#include "cvmx-coremask.h"
62
63
64#define  CVMX_COREMASK_MAX_SYNCS  20  /* maximum number of coremasks for barrier sync */
65
66/**
67 * This structure defines the private state maintained by coremask module.
68 *
69 */
70CVMX_SHARED static struct {
71
72    cvmx_spinlock_t            lock;       /**< mutex spinlock */
73
74    struct {
75
76        unsigned int           coremask;   /**< coremask specified for barrier */
77        unsigned int           checkin;    /**< bitmask of cores checking in */
78        volatile unsigned int  exit;       /**< variable to poll for exit condition */
79
80    } s[CVMX_COREMASK_MAX_SYNCS];
81
82} state = {
83
84    { CVMX_SPINLOCK_UNLOCKED_VAL },
85
86    { { 0, 0, 0 } },
87};
88
89
90/**
91 * Wait (stall) until all cores in the given coremask has reached this point
92 * in the program execution before proceeding.
93 *
94 * @param  coremask  the group of cores performing the barrier sync
95 *
96 */
97void cvmx_coremask_barrier_sync(unsigned int coremask)
98{
99    int i;
100    unsigned int target;
101
102    assert(coremask != 0);
103
104    cvmx_spinlock_lock(&state.lock);
105
106    for (i = 0; i < CVMX_COREMASK_MAX_SYNCS; i++) {
107
108        if (state.s[i].coremask == 0) {
109            /* end of existing coremask list, create new entry, fall-thru */
110            state.s[i].coremask = coremask;
111        }
112
113        if (state.s[i].coremask == coremask) {
114
115            target = state.s[i].exit + 1;  /* wrap-around at 32b */
116
117            state.s[i].checkin |= cvmx_coremask_core(cvmx_get_core_num());
118            if (state.s[i].checkin == coremask) {
119                state.s[i].checkin = 0;
120                state.s[i].exit = target;  /* signal exit condition */
121            }
122            cvmx_spinlock_unlock(&state.lock);
123
124            while (state.s[i].exit != target)
125                ;
126
127            return;
128        }
129    }
130
131    /* error condition - coremask array overflowed */
132    cvmx_spinlock_unlock(&state.lock);
133    assert(0);
134}
135