[PATCH 2/8] drm/dp: get/set phy compliance pattern

[Manasi Navare]

From: Animesh Manna <animesh.manna at intel.com>

During phy compliance auto test mode source need to read
requested test pattern from sink through DPCD. After processing
the request source need to set the pattern. So set/get method
added in drm layer as it is DP protocol.

v2: As per review feedback from Manasi on RFC version,
- added dp revision as function argument in set_phy_pattern api.
- used int for link_rate and u8 for lane_count to align with existing code.

v3: As per review feedback from Harry,
- used sizeof() instead of magic number.
- corrected kernel-doc for drm_dp_phy_test_params structure.

Reviewed-by: Harry Wentland <harry.wentland at amd.com>
Signed-off-by: Animesh Manna <animesh.manna at intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 94 +++++++++++++++++++++++++++++++++
 include/drm/drm_dp_helper.h     | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index a4b98f8055f4..1b79924a555d 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1454,3 +1454,97 @@ int drm_dp_dsc_sink_supported_input_bpcs(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_S
 	return num_bpc;
 }
 EXPORT_SYMBOL(drm_dp_dsc_sink_supported_input_bpcs);
+
+/**
+ * drm_dp_get_phy_test_pattern() - get the requested pattern from the sink.
+ * @aux: DisplayPort AUX channel
+ * @data: DP phy compliance test parameters.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
+				struct drm_dp_phy_test_params *data)
+{
+	int err;
+	u8 rate, lanes;
+
+	err = drm_dp_dpcd_readb(aux, DP_TEST_LINK_RATE, &rate);
+	if (err < 0)
+		return err;
+	data->link_rate = drm_dp_bw_code_to_link_rate(rate);
+
+	err = drm_dp_dpcd_readb(aux, DP_TEST_LANE_COUNT, &lanes);
+	if (err < 0)
+		return err;
+	data->num_lanes = lanes & DP_MAX_LANE_COUNT_MASK;
+
+	if (lanes & DP_ENHANCED_FRAME_CAP)
+		data->enhanced_frame_cap = true;
+
+	err = drm_dp_dpcd_readb(aux, DP_PHY_TEST_PATTERN, &data->phy_pattern);
+	if (err < 0)
+		return err;
+
+	switch (data->phy_pattern) {
+	case DP_PHY_TEST_PATTERN_80BIT_CUSTOM:
+		err = drm_dp_dpcd_read(aux, DP_TEST_80BIT_CUSTOM_PATTERN_7_0,
+				       &data->custom80, sizeof(data->custom80));
+		if (err < 0)
+			return err;
+
+		break;
+	case DP_PHY_TEST_PATTERN_CP2520:
+		err = drm_dp_dpcd_read(aux, DP_TEST_HBR2_SCRAMBLER_RESET,
+				       &data->hbr2_reset,
+				       sizeof(data->hbr2_reset));
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_get_phy_test_pattern);
+
+/**
+ * drm_dp_set_phy_test_pattern() - set the pattern to the sink.
+ * @aux: DisplayPort AUX channel
+ * @data: DP phy compliance test parameters.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
+				struct drm_dp_phy_test_params *data, u8 dp_rev)
+{
+	int err, i;
+	u8 link_config[2];
+	u8 test_pattern;
+
+	link_config[0] = drm_dp_link_rate_to_bw_code(data->link_rate);
+	link_config[1] = data->num_lanes;
+	if (data->enhanced_frame_cap)
+		link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
+	err = drm_dp_dpcd_write(aux, DP_LINK_BW_SET, link_config, 2);
+	if (err < 0)
+		return err;
+
+	test_pattern = data->phy_pattern;
+	if (dp_rev < 0x12) {
+		test_pattern = (test_pattern << 2) &
+			       DP_LINK_QUAL_PATTERN_11_MASK;
+		err = drm_dp_dpcd_writeb(aux, DP_TRAINING_PATTERN_SET,
+					 test_pattern);
+		if (err < 0)
+			return err;
+	} else {
+		for (i = 0; i < data->num_lanes; i++) {
+			err = drm_dp_dpcd_writeb(aux,
+						 DP_LINK_QUAL_LANE0_SET + i,
+						 test_pattern);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_set_phy_test_pattern);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 01e4869ff72e..8cb6941807ae 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -702,6 +702,15 @@
 # define DP_TEST_COUNT_MASK		    0xf
 
 #define DP_PHY_TEST_PATTERN                 0x248
+# define DP_PHY_TEST_PATTERN_SEL_MASK       0x7
+# define DP_PHY_TEST_PATTERN_NONE           0x0
+# define DP_PHY_TEST_PATTERN_D10_2          0x1
+# define DP_PHY_TEST_PATTERN_ERROR_COUNT    0x2
+# define DP_PHY_TEST_PATTERN_PRBS7          0x3
+# define DP_PHY_TEST_PATTERN_80BIT_CUSTOM   0x4
+# define DP_PHY_TEST_PATTERN_CP2520         0x5
+
+#define DP_TEST_HBR2_SCRAMBLER_RESET        0x24A
 #define DP_TEST_80BIT_CUSTOM_PATTERN_7_0    0x250
 #define	DP_TEST_80BIT_CUSTOM_PATTERN_15_8   0x251
 #define	DP_TEST_80BIT_CUSTOM_PATTERN_23_16  0x252
@@ -1583,4 +1592,26 @@ static inline void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
 
 #endif
 
+/**
+ * struct drm_dp_phy_test_params - DP Phy Compliance parameters
+ * @link_rate: Requested Link rate from DPCD 0x219
+ * @num_lanes: Number of lanes requested by sing through DPCD 0x220
+ * @phy_pattern: DP Phy test pattern from DPCD 0x248
+ * @hb2_reset: DP HBR2_COMPLIANCE_SCRAMBLER_RESET from DCPD 0x24A and 0x24B
+ * @custom80: DP Test_80BIT_CUSTOM_PATTERN from DPCDs 0x250 through 0x259
+ * @enhanced_frame_cap: flag for enhanced frame capability.
+ */
+struct drm_dp_phy_test_params {
+	int link_rate;
+	u8 num_lanes;
+	u8 phy_pattern;
+	u8 hbr2_reset[2];
+	u8 custom80[10];
+	bool enhanced_frame_cap;
+};
+
+int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
+				struct drm_dp_phy_test_params *data);
+int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
+				struct drm_dp_phy_test_params *data, u8 dp_rev);
 #endif /* _DRM_DP_HELPER_H_ */
-- 
2.19.1