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drm/v3d: Add a little debugfs entry for measuring the core clock.

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This adds just enough performance counter support to measure the
clock.  We don't have linux kernel drivers for the clock driving the
HW, and this was useful for determining that the V3D HW is running on
a slow clock, not that the driver was slow.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20180928232126.4332-2-eric@anholt.net
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
This commit is contained in:
Eric Anholt
2018-09-28 16:21:24 -07:00
parent 34c2c4f632
commit 6915c9a525
2 changed files with 65 additions and 0 deletions
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35
drivers/gpu/drm/v3d/v3d_debugfs.c
View File

@@ -176,9 +176,44 @@ static int v3d_debugfs_bo_stats(struct seq_file *m, void *unused)
return 0;
}
static int v3d_measure_clock(struct seq_file *m, void *unused)
{
struct drm_info_node *node = (struct drm_info_node *)m->private;
struct drm_device *dev = node->minor->dev;
struct v3d_dev *v3d = to_v3d_dev(dev);
uint32_t cycles;
int core = 0;
int measure_ms = 1000;
if (v3d->ver >= 40) {
V3D_CORE_WRITE(core, V3D_V4_PCTR_0_SRC_0_3,
V3D_SET_FIELD(V3D_PCTR_CYCLE_COUNT,
V3D_PCTR_S0));
V3D_CORE_WRITE(core, V3D_V4_PCTR_0_CLR, 1);
V3D_CORE_WRITE(core, V3D_V4_PCTR_0_EN, 1);
} else {
V3D_CORE_WRITE(core, V3D_V3_PCTR_0_PCTRS0,
V3D_PCTR_CYCLE_COUNT);
V3D_CORE_WRITE(core, V3D_V3_PCTR_0_CLR, 1);
V3D_CORE_WRITE(core, V3D_V3_PCTR_0_EN,
V3D_V3_PCTR_0_EN_ENABLE |
1);
}
msleep(measure_ms);
cycles = V3D_CORE_READ(core, V3D_PCTR_0_PCTR0);
seq_printf(m, "cycles: %d (%d.%d Mhz)\n",
cycles,
cycles / (measure_ms * 1000),
(cycles / (measure_ms * 100)) % 10);
return 0;
}
static const struct drm_info_list v3d_debugfs_list[] = {
{"v3d_ident", v3d_v3d_debugfs_ident, 0},
{"v3d_regs", v3d_v3d_debugfs_regs, 0},
{"measure_clock", v3d_measure_clock, 0},
{"bo_stats", v3d_debugfs_bo_stats, 0},
};