[PATCH v2 4/4] drm/dsc: Add helpers for DSC picture parameter set infoframes

[Manasi Navare <manasi.d.navare@intel.com>]

According to Display Stream compression spec 1.2, the picture
parameter set metadata is sent from source to sink device
using the DP Secondary data packet. An infoframe is formed
for the PPS SDP header and PPS SDP payload bytes.
This patch adds helpers to fill the PPS SDP header
and PPS SDP payload according to the DSC 1.2 specification.

v2:
* Add EXPORT_SYMBOL for the drm functions (Manasi)

Cc: dri-devel@lists.freedesktop.org
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
---
 drivers/gpu/drm/Makefile  |   2 +-
 drivers/gpu/drm/drm_dsc.c | 224 ++++++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_dsc.h     |  16 ++++
 3 files changed, 241 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/drm_dsc.c

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index ef9f3da..02f1b2c 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -31,7 +31,7 @@ drm-$(CONFIG_AGP) += drm_agpsupport.o
 drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
 drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
 
-drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
+drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
 		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
 		drm_simple_kms_helper.o drm_modeset_helper.o \
diff --git a/drivers/gpu/drm/drm_dsc.c b/drivers/gpu/drm/drm_dsc.c
new file mode 100644
index 0000000..c7b80c8
--- /dev/null
+++ b/drivers/gpu/drm/drm_dsc.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright © 2018 Intel Corp
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ *
+ * Author:
+ * Manasi Navare <manasi.d.navare@intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <drm/drm_dp_helper.h>
+#include <drm/drm_dsc.h>
+
+/**
+ * DOC: DSC Helpers
+ *
+ * These functions contain some common logic and helpers to deal with VESA
+ * Display Stream Compression standard required for DSC on Display Port/eDP or
+ * MIPI display interfaces.
+ */
+
+/**
+ * drm_dsc_dp_pps_header_init() - Initializes the PPS Header
+ * for DisplayPort as per the DP 1.4 spec.
+ * @pps_sdp: Secondary data packet for DSC Picture Parameter Set
+ */
+void drm_dsc_dp_pps_header_init(struct drm_dsc_pps_infoframe *pps_sdp)
+{
+	memset(&pps_sdp->pps_header, 0, sizeof(pps_sdp->pps_header));
+
+	pps_sdp->pps_header.HB1 = DP_SDP_PPS;
+	pps_sdp->pps_header.HB2 = DP_SDP_PPS_HEADER_PAYLOAD_BYTES_MINUS_1;
+}
+EXPORT_SYMBOL(drm_dsc_dp_pps_header_init);
+
+/**
+ * drm_dsc_pps_infoframe_pack() - Populates the DSC PPS infoframe
+ * using the DSC configuration parameters in the order expected
+ * by the DSC Display Sink device. For the DSC, the sink device
+ * expects the PPS payload in the big endian format for the fields
+ * that span more than 1 byte.
+ *
+ * @pps_sdp: Secondary data packet for DSC Picture Parameter Set
+ * @dsc_cfg: DSC Configuration data filled by driver
+ * @big_endian: Flag to indicate if HW is Big Endian
+ */
+void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
+				struct drm_dsc_config *dsc_cfg,
+				bool is_big_endian)
+{
+	u8 i = 0;
+
+	memset(&pps_sdp->pps_payload, 0, sizeof(pps_sdp->pps_payload));
+
+	/* PPS 0 */
+	pps_sdp->pps_payload.dsc_version_minor = dsc_cfg->dsc_version_minor;
+	pps_sdp->pps_payload.dsc_version_major = dsc_cfg->dsc_version_major;
+
+	/* PPS 1, 2 is 0 */
+
+	/* PPS 3 */
+	pps_sdp->pps_payload.linebuf_depth = dsc_cfg->line_buf_depth;
+	pps_sdp->pps_payload.bits_per_component = dsc_cfg->bits_per_component;
+
+	/* PPS 4, 5 */
+	pps_sdp->pps_payload.block_pred_enable = (u8)dsc_cfg->block_pred_enable;
+	pps_sdp->pps_payload.convert_rgb = (u8)dsc_cfg->convert_rgb;
+	pps_sdp->pps_payload.simple_422 = (u8)dsc_cfg->enable422;
+	pps_sdp->pps_payload.vbr_enable = (u8)dsc_cfg->vbr_enable;
+	pps_sdp->pps_payload.bpp_high = (u8)((dsc_cfg->bits_per_pixel & DSC_PPS_BPP_HIGH_MASK) >>
+					     DSC_PPS_MSB_SHIFT);
+	pps_sdp->pps_payload.bpp_low = (u8)(dsc_cfg->bits_per_pixel & DSC_PPS_LSB_MASK);
+
+	/*
+	 * The DSC panel expects the PPS packet to have big endian format
+	 * for data spanning 2 bytes. So if the HW does not store the data
+	 * in big endian format, it sets big_endian flag to false in which case
+	 * we need to convert from little endian to big endian.
+	 */
+
+	/* PPS 6, 7 */
+	pps_sdp->pps_payload.pic_height = DSC_PPS_SWAP_BYTES(dsc_cfg->pic_height,
+							     is_big_endian);
+
+	/* PPS 8, 9 */
+	pps_sdp->pps_payload.pic_width = DSC_PPS_SWAP_BYTES(dsc_cfg->pic_height,
+							    is_big_endian);
+
+	/* PPS 10, 11 */
+	pps_sdp->pps_payload.slice_height = DSC_PPS_SWAP_BYTES(dsc_cfg->slice_height,
+							       is_big_endian);
+
+	/* PPS 12, 13 */
+	pps_sdp->pps_payload.slice_width = DSC_PPS_SWAP_BYTES(dsc_cfg->slice_width,
+							      is_big_endian);
+
+	/* PPS 14, 15 */
+	pps_sdp->pps_payload.chunk_size = DSC_PPS_SWAP_BYTES(dsc_cfg->slice_chunk_size,
+							     is_big_endian);
+
+	/* PPS 16, 17 */
+	pps_sdp->pps_payload.initial_xmit_delay_high = (u8)((dsc_cfg->initial_xmit_delay &
+							     DSC_PPS_INIT_XMIT_DELAY_HIGH_MASK) >>
+							    DSC_PPS_MSB_SHIFT);
+	pps_sdp->pps_payload.initial_xmit_delay_low = (u8)(dsc_cfg->initial_xmit_delay &
+							   DSC_PPS_LSB_MASK);
+
+	/* PPS 18, 19 */
+	pps_sdp->pps_payload.initial_dec_delay = DSC_PPS_SWAP_BYTES(dsc_cfg->initial_dec_delay,
+								    is_big_endian);
+
+	/* PPS 20 is 0 */
+
+	/* PPS 21 */
+	pps_sdp->pps_payload.initial_scale_value = (u8)dsc_cfg->initial_scale_value;
+
+	/* PPS 22, 23 */
+	pps_sdp->pps_payload.scale_increment_interval = DSC_PPS_SWAP_BYTES(dsc_cfg->scale_increment_interval,
+									   is_big_endian);
+
+	/* PPS 24, 25 */
+	pps_sdp->pps_payload.scale_decrement_interval_high = (u8)((dsc_cfg->scale_decrement_interval &
+								   DSC_PPS_SCALE_DEC_INT_HIGH_MASK) >>
+								  DSC_PPS_MSB_SHIFT);
+	pps_sdp->pps_payload.scale_decrement_interval_low = (u8)(dsc_cfg->scale_decrement_interval &
+								 DSC_PPS_LSB_MASK);
+
+	/* PPS 27 */
+	pps_sdp->pps_payload.first_line_bpg_offset = (u8)dsc_cfg->first_line_bpg_offset;
+
+	/* PPS 28, 29 */
+	pps_sdp->pps_payload.nfl_bpg_offset = DSC_PPS_SWAP_BYTES(dsc_cfg->nfl_bpg_offset,
+								 is_big_endian);
+
+	/* PPS 30, 31 */
+	pps_sdp->pps_payload.slice_bpg_offset = DSC_PPS_SWAP_BYTES(dsc_cfg->slice_bpg_offset,
+								   is_big_endian);
+
+	/* PPS 32, 33 */
+	pps_sdp->pps_payload.initial_offset = DSC_PPS_SWAP_BYTES(dsc_cfg->initial_offset,
+								 is_big_endian);
+
+	/* PPS 34, 35 */
+	pps_sdp->pps_payload.final_offset = DSC_PPS_SWAP_BYTES(dsc_cfg->final_offset,
+							       is_big_endian);
+
+	/* PPS 36 */
+	pps_sdp->pps_payload.flatness_min_qp = (u8)dsc_cfg->flatness_min_qp;
+
+	/* PPS 37 */
+	pps_sdp->pps_payload.flatness_max_qp = (u8)dsc_cfg->flatness_max_qp;
+
+	/* PPS 38, 39 */
+	pps_sdp->pps_payload.rc_model_size = DSC_PPS_SWAP_BYTES(dsc_cfg->rc_model_size,
+								is_big_endian);
+
+	/* PPS 40 */
+	pps_sdp->pps_payload.rc_edge_factor = (u8)dsc_cfg->rc_edge_factor;
+
+	/* PPS 41 */
+	pps_sdp->pps_payload.rc_quant_incr_limit0 = (u8)dsc_cfg->rc_quant_incr_limit0;
+
+	/* PPS 42 */
+	pps_sdp->pps_payload.rc_quant_incr_limit1 = (u8)dsc_cfg->rc_quant_incr_limit1;
+
+	/* PPS 43 */
+	pps_sdp->pps_payload.rc_tgt_offset_lo = (u8)dsc_cfg->rc_tgt_offset_low;
+	pps_sdp->pps_payload.rc_tgt_offset_hi = (u8)dsc_cfg->rc_tgt_offset_high;
+
+	/* PPS 44 - 57 */
+	for (i = 0; i < DSC_NUM_BUF_RANGES - 1; i++)
+		pps_sdp->pps_payload.rc_buf_thresh[i] = dsc_cfg->rc_buf_thresh[i];
+
+	/* PPS 58 - 87 */
+	/*
+	 * For DSC sink programming the RC Range parameter fields
+	 * are as follows: Min_qp[15:11], max_qp[10:6], offset[5:0]
+	 */
+	for (i = 0; i < DSC_NUM_BUF_RANGES; i++) {
+		pps_sdp->pps_payload.rc_range_parameters[i] =
+			(u16)((dsc_cfg->rc_range_params[i].range_min_qp << DSC_PPS_RC_RANGE_MINQP_SHIFT) |
+			      (dsc_cfg->rc_range_params[i].range_max_qp << DSC_PPS_RC_RANGE_MAXQP_SHIFT) |
+			      (dsc_cfg->rc_range_params[i].range_bpg_offset));
+		pps_sdp->pps_payload.rc_range_parameters[i] = DSC_PPS_SWAP_BYTES(pps_sdp->pps_payload.rc_range_parameters[i],
+										 is_big_endian);
+	}
+
+	/* PPS 88 */
+	pps_sdp->pps_payload.native_422 = (u8)dsc_cfg->native_422;
+	pps_sdp->pps_payload.native_420 = (u8)dsc_cfg->native_420;
+
+	/* PPS 89 */
+	pps_sdp->pps_payload.second_line_bpg_offset = (u8)dsc_cfg->second_line_bpg_offset;
+
+	/* PPS 90, 91 */
+	pps_sdp->pps_payload.nsl_bpg_offset = DSC_PPS_SWAP_BYTES(dsc_cfg->nsl_bpg_offset,
+								 is_big_endian);
+
+	/* PPS 92, 93 */
+	pps_sdp->pps_payload.second_line_offset_adj = DSC_PPS_SWAP_BYTES(dsc_cfg->second_line_offset_adj,
+									 is_big_endian);
+
+	/* PPS 94 - 127 are O */
+}
+EXPORT_SYMBOL(drm_dsc_pps_infoframe_pack);
diff --git a/include/drm/drm_dsc.h b/include/drm/drm_dsc.h
index e0b4577..0fd5da0 100644
--- a/include/drm/drm_dsc.h
+++ b/include/drm/drm_dsc.h
@@ -26,6 +26,7 @@
 #ifndef DRM_DSC_H_
 #define DRM_DSC_H_
 
+#include <linux/byteorder/generic.h>
 #include <drm/drm_dp_helper.h>
 
 #define DSC_NUM_BUF_RANGES	15
@@ -33,6 +34,16 @@
 /* VESA Display Stream Compression DSC 1.2 constants */
 #define DSC_NUM_BUF_RANGES		15
 
+/* DSC PPS constants and macros */
+#define DSC_PPS_MSB_SHIFT			8
+#define DSC_PPS_LSB_MASK			(0xFF << 0)
+#define DSC_PPS_BPP_HIGH_MASK			(0x3 << 8)
+#define DSC_PPS_INIT_XMIT_DELAY_HIGH_MASK	(0x3 << 8)
+#define DSC_PPS_SCALE_DEC_INT_HIGH_MASK		(0xF << 8)
+#define DSC_PPS_RC_RANGE_MINQP_SHIFT		11
+#define DSC_PPS_RC_RANGE_MAXQP_SHIFT		6
+#define DSC_PPS_SWAP_BYTES(val, swap)		((swap) ? val : cpu_to_be16(val))
+
 /* Configuration for a single Rate Control model range */
 struct dsc_rc_range_parameters {
 	/* Min Quantization Parameters allowed for this range */
@@ -520,4 +531,9 @@ struct drm_dsc_pps_infoframe {
 	struct picture_parameter_set pps_payload;
 } __packed;
 
+void drm_dsc_dp_pps_header_init(struct drm_dsc_pps_infoframe *pps_sdp);
+void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
+				struct drm_dsc_config *dsc_cfg,
+				bool big_endian);
+
 #endif /* _DRM_DSC_H_ */
-- 
2.7.4

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