drm/dp_helper: Add support for Configuring DSC for HDMI2.1 Pcon

This patch adds registers for getting DSC encoder capability for
a HDMI2.1 PCon. It also addes helper functions to configure
DSC between the PCON and HDMI2.1 sink.

v2: Corrected offset for DSC encoder bpc and minor changes.
Also added helper functions for getting pcon dsc encoder capabilities
as suggested by Uma Shankar.

v3: Only setting the DSC bits for the Protocol Converter control
registers, avoiding overwritining color conversion bits.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com> (v2)
[Jani: Fixed checkpatch BLOCK_COMMENT_STYLE.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-7-ankit.k.nautiyal@intel.com

drivers/gpu/drm/drm_dp_helper.c

@@ -2898,3 +2898,206 @@ void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux,
 	}
 }
 EXPORT_SYMBOL(drm_dp_pcon_hdmi_frl_link_error_count);
+
+/*
+ * drm_dp_pcon_enc_is_dsc_1_2 - Does PCON Encoder supports DSC 1.2
+ * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder
+ *
+ * Returns true is PCON encoder is DSC 1.2 else returns false.
+ */
+bool drm_dp_pcon_enc_is_dsc_1_2(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE])
+{
+	u8 buf;
+	u8 major_v, minor_v;
+
+	buf = pcon_dsc_dpcd[DP_PCON_DSC_VERSION - DP_PCON_DSC_ENCODER];
+	major_v = (buf & DP_PCON_DSC_MAJOR_MASK) >> DP_PCON_DSC_MAJOR_SHIFT;
+	minor_v = (buf & DP_PCON_DSC_MINOR_MASK) >> DP_PCON_DSC_MINOR_SHIFT;
+
+	if (major_v == 1 && minor_v == 2)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(drm_dp_pcon_enc_is_dsc_1_2);
+
+/*
+ * drm_dp_pcon_dsc_max_slices - Get max slices supported by PCON DSC Encoder
+ * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder
+ *
+ * Returns maximum no. of slices supported by the PCON DSC Encoder.
+ */
+int drm_dp_pcon_dsc_max_slices(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE])
+{
+	u8 slice_cap1, slice_cap2;
+
+	slice_cap1 = pcon_dsc_dpcd[DP_PCON_DSC_SLICE_CAP_1 - DP_PCON_DSC_ENCODER];
+	slice_cap2 = pcon_dsc_dpcd[DP_PCON_DSC_SLICE_CAP_2 - DP_PCON_DSC_ENCODER];
+
+	if (slice_cap2 & DP_PCON_DSC_24_PER_DSC_ENC)
+		return 24;
+	if (slice_cap2 & DP_PCON_DSC_20_PER_DSC_ENC)
+		return 20;
+	if (slice_cap2 & DP_PCON_DSC_16_PER_DSC_ENC)
+		return 16;
+	if (slice_cap1 & DP_PCON_DSC_12_PER_DSC_ENC)
+		return 12;
+	if (slice_cap1 & DP_PCON_DSC_10_PER_DSC_ENC)
+		return 10;
+	if (slice_cap1 & DP_PCON_DSC_8_PER_DSC_ENC)
+		return 8;
+	if (slice_cap1 & DP_PCON_DSC_6_PER_DSC_ENC)
+		return 6;
+	if (slice_cap1 & DP_PCON_DSC_4_PER_DSC_ENC)
+		return 4;
+	if (slice_cap1 & DP_PCON_DSC_2_PER_DSC_ENC)
+		return 2;
+	if (slice_cap1 & DP_PCON_DSC_1_PER_DSC_ENC)
+		return 1;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_dsc_max_slices);
+
+/*
+ * drm_dp_pcon_dsc_max_slice_width() - Get max slice width for Pcon DSC encoder
+ * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder
+ *
+ * Returns maximum width of the slices in pixel width i.e. no. of pixels x 320.
+ */
+int drm_dp_pcon_dsc_max_slice_width(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE])
+{
+	u8 buf;
+
+	buf = pcon_dsc_dpcd[DP_PCON_DSC_MAX_SLICE_WIDTH - DP_PCON_DSC_ENCODER];
+
+	return buf * DP_DSC_SLICE_WIDTH_MULTIPLIER;
+}
+EXPORT_SYMBOL(drm_dp_pcon_dsc_max_slice_width);
+
+/*
+ * drm_dp_pcon_dsc_bpp_incr() - Get bits per pixel increment for PCON DSC encoder
+ * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder
+ *
+ * Returns the bpp precision supported by the PCON encoder.
+ */
+int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE])
+{
+	u8 buf;
+
+	buf = pcon_dsc_dpcd[DP_PCON_DSC_BPP_INCR - DP_PCON_DSC_ENCODER];
+
+	switch (buf & DP_PCON_DSC_BPP_INCR_MASK) {
+	case DP_PCON_DSC_ONE_16TH_BPP:
+		return 16;
+	case DP_PCON_DSC_ONE_8TH_BPP:
+		return 8;
+	case DP_PCON_DSC_ONE_4TH_BPP:
+		return 4;
+	case DP_PCON_DSC_ONE_HALF_BPP:
+		return 2;
+	case DP_PCON_DSC_ONE_BPP:
+		return 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_dsc_bpp_incr);
+
+static
+int drm_dp_pcon_configure_dsc_enc(struct drm_dp_aux *aux, u8 pps_buf_config)
+{
+	u8 buf;
+	int ret;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, &buf);
+	if (ret < 0)
+		return ret;
+
+	buf |= DP_PCON_ENABLE_DSC_ENCODER;
+
+	if (pps_buf_config <= DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER) {
+		buf &= ~DP_PCON_ENCODER_PPS_OVERRIDE_MASK;
+		buf |= pps_buf_config << 2;
+	}
+
+	ret = drm_dp_dpcd_writeb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * drm_dp_pcon_pps_default() - Let PCON fill the default pps parameters
+ * for DSC1.2 between PCON & HDMI2.1 sink
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 on success, else returns negative error code.
+ */
+int drm_dp_pcon_pps_default(struct drm_dp_aux *aux)
+{
+	int ret;
+
+	ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_DISABLED);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_pps_default);
+
+/**
+ * drm_dp_pcon_pps_override_buf() - Configure PPS encoder override buffer for
+ * HDMI sink
+ * @aux: DisplayPort AUX channel
+ * @pps_buf: 128 bytes to be written into PPS buffer for HDMI sink by PCON.
+ *
+ * Returns 0 on success, else returns negative error code.
+ */
+int drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128])
+{
+	int ret;
+
+	ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVERRIDE_BASE, &pps_buf, 128);
+	if (ret < 0)
+		return ret;
+
+	ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_pps_override_buf);
+
+/*
+ * drm_dp_pcon_pps_override_param() - Write PPS parameters to DSC encoder
+ * override registers
+ * @aux: DisplayPort AUX channel
+ * @pps_param: 3 Parameters (2 Bytes each) : Slice Width, Slice Height,
+ * bits_per_pixel.
+ *
+ * Returns 0 on success, else returns negative error code.
+ */
+int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6])
+{
+	int ret;
+
+	ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_SLICE_HEIGHT, &pps_param[0], 2);
+	if (ret < 0)
+		return ret;
+	ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_SLICE_WIDTH, &pps_param[2], 2);
+	if (ret < 0)
+		return ret;
+	ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_BPP, &pps_param[4], 2);
+	if (ret < 0)
+		return ret;
+
+	ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_pps_override_param);

include/drm/drm_dp_helper.h

@@ -441,6 +441,84 @@ struct drm_device;
 # define DP_FEC_CORR_BLK_ERROR_COUNT_CAP    (1 << 2)
 # define DP_FEC_BIT_ERROR_COUNT_CAP	    (1 << 3)
 
+/* DP-HDMI2.1 PCON DSC ENCODER SUPPORT */
+#define DP_PCON_DSC_ENCODER_CAP_SIZE        0xC	/* 0x9E - 0x92 */
+#define DP_PCON_DSC_ENCODER                 0x092
+# define DP_PCON_DSC_ENCODER_SUPPORTED      (1 << 0)
+# define DP_PCON_DSC_PPS_ENC_OVERRIDE       (1 << 1)
+
+/* DP-HDMI2.1 PCON DSC Version */
+#define DP_PCON_DSC_VERSION                 0x093
+# define DP_PCON_DSC_MAJOR_MASK		    (0xF << 0)
+# define DP_PCON_DSC_MINOR_MASK		    (0xF << 4)
+# define DP_PCON_DSC_MAJOR_SHIFT	    0
+# define DP_PCON_DSC_MINOR_SHIFT	    4
+
+/* DP-HDMI2.1 PCON DSC RC Buffer block size */
+#define DP_PCON_DSC_RC_BUF_BLK_INFO	    0x094
+# define DP_PCON_DSC_RC_BUF_BLK_SIZE	    (0x3 << 0)
+# define DP_PCON_DSC_RC_BUF_BLK_1KB	    0
+# define DP_PCON_DSC_RC_BUF_BLK_4KB	    1
+# define DP_PCON_DSC_RC_BUF_BLK_16KB	    2
+# define DP_PCON_DSC_RC_BUF_BLK_64KB	    3
+
+/* DP-HDMI2.1 PCON DSC RC Buffer size */
+#define DP_PCON_DSC_RC_BUF_SIZE		    0x095
+
+/* DP-HDMI2.1 PCON DSC Slice capabilities-1 */
+#define DP_PCON_DSC_SLICE_CAP_1		    0x096
+# define DP_PCON_DSC_1_PER_DSC_ENC     (0x1 << 0)
+# define DP_PCON_DSC_2_PER_DSC_ENC     (0x1 << 1)
+# define DP_PCON_DSC_4_PER_DSC_ENC     (0x1 << 3)
+# define DP_PCON_DSC_6_PER_DSC_ENC     (0x1 << 4)
+# define DP_PCON_DSC_8_PER_DSC_ENC     (0x1 << 5)
+# define DP_PCON_DSC_10_PER_DSC_ENC    (0x1 << 6)
+# define DP_PCON_DSC_12_PER_DSC_ENC    (0x1 << 7)
+
+#define DP_PCON_DSC_BUF_BIT_DEPTH	    0x097
+# define DP_PCON_DSC_BIT_DEPTH_MASK	    (0xF << 0)
+# define DP_PCON_DSC_DEPTH_9_BITS	    0
+# define DP_PCON_DSC_DEPTH_10_BITS	    1
+# define DP_PCON_DSC_DEPTH_11_BITS	    2
+# define DP_PCON_DSC_DEPTH_12_BITS	    3
+# define DP_PCON_DSC_DEPTH_13_BITS	    4
+# define DP_PCON_DSC_DEPTH_14_BITS	    5
+# define DP_PCON_DSC_DEPTH_15_BITS	    6
+# define DP_PCON_DSC_DEPTH_16_BITS	    7
+# define DP_PCON_DSC_DEPTH_8_BITS	    8
+
+#define DP_PCON_DSC_BLOCK_PREDICTION	    0x098
+# define DP_PCON_DSC_BLOCK_PRED_SUPPORT	    (0x1 << 0)
+
+#define DP_PCON_DSC_ENC_COLOR_FMT_CAP	    0x099
+# define DP_PCON_DSC_ENC_RGB		    (0x1 << 0)
+# define DP_PCON_DSC_ENC_YUV444		    (0x1 << 1)
+# define DP_PCON_DSC_ENC_YUV422_S	    (0x1 << 2)
+# define DP_PCON_DSC_ENC_YUV422_N	    (0x1 << 3)
+# define DP_PCON_DSC_ENC_YUV420_N	    (0x1 << 4)
+
+#define DP_PCON_DSC_ENC_COLOR_DEPTH_CAP	    0x09A
+# define DP_PCON_DSC_ENC_8BPC		    (0x1 << 1)
+# define DP_PCON_DSC_ENC_10BPC		    (0x1 << 2)
+# define DP_PCON_DSC_ENC_12BPC		    (0x1 << 3)
+
+#define DP_PCON_DSC_MAX_SLICE_WIDTH	    0x09B
+
+/* DP-HDMI2.1 PCON DSC Slice capabilities-2 */
+#define DP_PCON_DSC_SLICE_CAP_2             0x09C
+# define DP_PCON_DSC_16_PER_DSC_ENC	    (0x1 << 0)
+# define DP_PCON_DSC_20_PER_DSC_ENC         (0x1 << 1)
+# define DP_PCON_DSC_24_PER_DSC_ENC         (0x1 << 2)
+
+/* DP-HDMI2.1 PCON HDMI TX Encoder Bits/pixel increment */
+#define DP_PCON_DSC_BPP_INCR		    0x09E
+# define DP_PCON_DSC_BPP_INCR_MASK	    (0x7 << 0)
+# define DP_PCON_DSC_ONE_16TH_BPP	    0
+# define DP_PCON_DSC_ONE_8TH_BPP	    1
+# define DP_PCON_DSC_ONE_4TH_BPP	    2
+# define DP_PCON_DSC_ONE_HALF_BPP	    3
+# define DP_PCON_DSC_ONE_BPP		    4
+
 /* DP Extended DSC Capabilities */
 #define DP_DSC_BRANCH_OVERALL_THROUGHPUT_0  0x0a0   /* DP 1.4a SCR */
 #define DP_DSC_BRANCH_OVERALL_THROUGHPUT_1  0x0a1
@@ -1124,6 +1202,12 @@ struct drm_device;
 # define DP_HDMI_FORCE_SCRAMBLING		(1 << 3) /* DP 1.4 */
 #define DP_PROTOCOL_CONVERTER_CONTROL_2		0x3052 /* DP 1.3 */
 # define DP_CONVERSION_TO_YCBCR422_ENABLE	(1 << 0) /* DP 1.3 */
+# define DP_PCON_ENABLE_DSC_ENCODER	        (1 << 1)
+# define DP_PCON_ENCODER_PPS_OVERRIDE_MASK	(0x3 << 2)
+# define DP_PCON_ENC_PPS_OVERRIDE_DISABLED      0
+# define DP_PCON_ENC_PPS_OVERRIDE_EN_PARAMS     1
+# define DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER     2
+
 
 /* PCON Downstream HDMI ERROR Status per Lane */
 #define DP_PCON_HDMI_ERROR_STATUS_LN0          0x3037
@@ -1135,6 +1219,29 @@ struct drm_device;
 # define DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS     (1 << 1)
 # define DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS (1 << 2)
 
+/* PCON HDMI CONFIG PPS Override Buffer
+ * Valid Offsets to be added to Base : 0-127
+ */
+#define DP_PCON_HDMI_PPS_OVERRIDE_BASE        0x3100
+
+/* PCON HDMI CONFIG PPS Override Parameter: Slice height
+ * Offset-0 8LSBs of the Slice height.
+ * Offset-1 8MSBs of the Slice height.
+ */
+#define DP_PCON_HDMI_PPS_OVRD_SLICE_HEIGHT    0x3180
+
+/* PCON HDMI CONFIG PPS Override Parameter: Slice width
+ * Offset-0 8LSBs of the Slice width.
+ * Offset-1 8MSBs of the Slice width.
+ */
+#define DP_PCON_HDMI_PPS_OVRD_SLICE_WIDTH    0x3182
+
+/* PCON HDMI CONFIG PPS Override Parameter: bits_per_pixel
+ * Offset-0 8LSBs of the bits_per_pixel.
+ * Offset-1 2MSBs of the bits_per_pixel.
+ */
+#define DP_PCON_HDMI_PPS_OVRD_BPP	     0x3184
+
 /* HDCP 1.3 and HDCP 2.2 */
 #define DP_AUX_HDCP_BKSV		0x68000
 #define DP_AUX_HDCP_RI_PRIME		0x68005
@@ -2053,5 +2160,12 @@ bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux);
 int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask);
 void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux,
 					   struct drm_connector *connector);
+bool drm_dp_pcon_enc_is_dsc_1_2(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
+int drm_dp_pcon_dsc_max_slices(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
+int drm_dp_pcon_dsc_max_slice_width(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
+int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
+int drm_dp_pcon_pps_default(struct drm_dp_aux *aux);
+int drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128]);
+int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]);
 
 #endif /* _DRM_DP_HELPER_H_ */