drm/i915: add DP test request handling

DPCD 1.1+ adds some automated test infrastructure support.  Add support
for reading the IRQ source and jumping to a test handling routine if
needed.  Subsequent patches will handle particular tests; this patch
just ACKs any requested tests by default.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>

2 files changed, 62 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e0ff9085fd86..58c827b52a29 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1776,6 +1776,27 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
         return false;
 }
 
+static bool
+intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
+{
+        int ret;
+
+        ret = intel_dp_aux_native_read_retry(intel_dp,
+                                             DP_DEVICE_SERVICE_IRQ_VECTOR,
+                                             sink_irq_vector, 1);
+        if (!ret)
+                return false;
+
+        return true;
+}
+
+static void
+intel_dp_handle_test_request(struct intel_dp *intel_dp)
+{
+        /* NAK by default */
+        intel_dp_aux_native_write_1(intel_dp, DP_TEST_RESPONSE, DP_TEST_ACK);
+}
+
 /*
  * According to DP spec
  * 5.1.2:
@@ -1788,6 +1809,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 static void
 intel_dp_check_link_status(struct intel_dp *intel_dp)
 {
+        u8 sink_irq_vector;
+
         if (intel_dp->dpms_mode != DRM_MODE_DPMS_ON)
                 return;
 
@@ -1806,6 +1829,20 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
                 return;
         }
 
+        /* Try to read the source of the interrupt */
+        if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
+            intel_dp_get_sink_irq(intel_dp, &sink_irq_vector)) {
+                /* Clear interrupt source */
+                intel_dp_aux_native_write_1(intel_dp,
+                                            DP_DEVICE_SERVICE_IRQ_VECTOR,
+                                            sink_irq_vector);
+
+                if (sink_irq_vector & DP_AUTOMATED_TEST_REQUEST)
+                        intel_dp_handle_test_request(intel_dp);
+                if (sink_irq_vector & (DP_CP_IRQ | DP_SINK_SPECIFIC_IRQ))
+                        DRM_DEBUG_DRIVER("CP or sink specific irq unhandled\n");
+        }
+
         if (!intel_channel_eq_ok(intel_dp)) {
                 DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
                               drm_get_encoder_name(&intel_dp->base.base));
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 2b1a3585f8d8..0d2f727e96be 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -153,6 +153,12 @@
 # define DP_PSR_CRC_VERIFICATION            (1 << 2)
 # define DP_PSR_FRAME_CAPTURE               (1 << 3)
 
+#define DP_DEVICE_SERVICE_IRQ_VECTOR        0x201
+# define DP_REMOTE_CONTROL_COMMAND_PENDING  (1 << 0)
+# define DP_AUTOMATED_TEST_REQUEST          (1 << 1)
+# define DP_CP_IRQ                          (1 << 2)
+# define DP_SINK_SPECIFIC_IRQ               (1 << 6)
+
 #define DP_LANE0_1_STATUS                   0x202
 #define DP_LANE2_3_STATUS                   0x203
 # define DP_LANE_CR_DONE                    (1 << 0)
@@ -185,6 +191,25 @@
 # define DP_ADJUST_PRE_EMPHASIS_LANE1_MASK   0xc0
 # define DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT  6
 
+#define DP_TEST_REQUEST                     0x218
+# define DP_TEST_LINK_TRAINING              (1 << 0)
+# define DP_TEST_LINK_PATTERN               (1 << 1)
+# define DP_TEST_LINK_EDID_READ             (1 << 2)
+# define DP_TEST_LINK_PHY_TEST_PATTERN      (1 << 3) /* DPCD >= 1.1 */
+
+#define DP_TEST_LINK_RATE                   0x219
+# define DP_LINK_RATE_162                   (0x6)
+# define DP_LINK_RATE_27                    (0xa)
+
+#define DP_TEST_LANE_COUNT                  0x220
+
+#define DP_TEST_PATTERN                     0x221
+
+#define DP_TEST_RESPONSE                    0x260
+# define DP_TEST_ACK                        (1 << 0)
+# define DP_TEST_NAK                        (1 << 1)
+# define DP_TEST_EDID_CHECKSUM_WRITE        (1 << 2)
+
 #define DP_SET_POWER                        0x600
 # define DP_SET_POWER_D0                    0x1
 # define DP_SET_POWER_D3                    0x2