drm/i915: Expose latest 200 CRC value for pipe through debugfs

There are several points in the display pipeline where CRCs can be
computed on the bits flowing there. For instance, it's usually possible
to compute the CRCs of the primary plane, the sprite plane or the CRCs
of the bits after the panel fitter (collectively called pipe CRCs).

v2: Quite a bit of rework here and there (Damien)

Signed-off-by: Shuang He <shuang.he@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Fix intermediate compile file reported by Wu Fengguang's
kernel builder.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 72d04588ecc..e1d45aaf688 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1732,6 +1732,36 @@ static int i915_pc8_status(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static int i915_pipe_crc(struct seq_file *m, void *data)
+{
+	struct drm_info_node *node = (struct drm_info_node *) m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum pipe pipe = (enum pipe)node->info_ent->data;
+	const struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[pipe];
+	int i;
+	int start;
+
+	if (!IS_IVYBRIDGE(dev)) {
+		seq_puts(m, "unsupported\n");
+		return 0;
+	}
+
+	start = atomic_read(&pipe_crc->slot) + 1;
+	seq_puts(m, " timestamp     CRC1     CRC2     CRC3     CRC4     CRC5\n");
+	for (i = 0; i < INTEL_PIPE_CRC_ENTRIES_NR; i++) {
+		const struct intel_pipe_crc_entry *entry =
+			&pipe_crc->entries[(start + i) %
+					   INTEL_PIPE_CRC_ENTRIES_NR];
+
+		seq_printf(m, "%12u %8x %8x %8x %8x %8x\n", entry->timestamp,
+			   entry->crc[0], entry->crc[1], entry->crc[2],
+			   entry->crc[3], entry->crc[4]);
+	}
+
+	return 0;
+}
+
 static int
 i915_wedged_get(void *data, u64 *val)
 {
@@ -2247,6 +2277,9 @@ static struct drm_info_list i915_debugfs_list[] = {
 	{"i915_edp_psr_status", i915_edp_psr_status, 0},
 	{"i915_energy_uJ", i915_energy_uJ, 0},
 	{"i915_pc8_status", i915_pc8_status, 0},
+	{"i915_pipe_A_crc", i915_pipe_crc, 0, (void *)PIPE_A},
+	{"i915_pipe_B_crc", i915_pipe_crc, 0, (void *)PIPE_B},
+	{"i915_pipe_C_crc", i915_pipe_crc, 0, (void *)PIPE_C},
 };
 #define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)