drm/nouveau/disp: add dp sst config method

This is presently unused on HW, we read a bunch of regs and calculate
the watermark during the second supervisor interrupt.

I don't want to change this yet as I need to re-remember how older HW
works exactly, but RM wants this info via RPC.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Danilo Krummrich <me@dakr.org>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919220442.202488-35-lyude@redhat.com

drivers/gpu/drm/nouveau/include/nvif/if0012.h

@@ -36,6 +36,7 @@ union nvif_outp_args {
 #define NVIF_OUTP_V0_DP_RATES      0x72
 #define NVIF_OUTP_V0_DP_TRAIN      0x73
 #define NVIF_OUTP_V0_DP_DRIVE      0x74
+#define NVIF_OUTP_V0_DP_SST        0x75
 #define NVIF_OUTP_V0_DP_MST_VCPI   0x78
 
 union nvif_outp_detect_args {
@@ -222,6 +223,17 @@ union nvif_outp_dp_drive_args {
 	} v0;
 };
 
+union nvif_outp_dp_sst_args {
+	struct nvif_outp_dp_sst_v0 {
+		__u8  version;
+		__u8  head;
+		__u8  pad02[2];
+		__u32 watermark;
+		__u32 hblanksym;
+		__u32 vblanksym;
+	} v0;
+};
+
 union nvif_outp_dp_mst_vcpi_args {
 	struct nvif_outp_dp_mst_vcpi_v0 {
 		__u8  version;

drivers/gpu/drm/nouveau/include/nvif/outp.h

@@ -68,6 +68,7 @@ int nvif_outp_dp_train(struct nvif_outp *, u8 dpcd[DP_RECEIVER_CAP_SIZE],
 		       u8 lttprs, u8 link_nr, u32 link_bw, bool mst, bool post_lt_adj,
 		       bool retrain);
 int nvif_outp_dp_drive(struct nvif_outp *, u8 link_nr, u8 pe[4], u8 vs[4]);
+int nvif_outp_dp_sst(struct nvif_outp *, int head, u32 watermark, u32 hblanksym, u32 vblanksym);
 int nvif_outp_dp_mst_vcpi(struct nvif_outp *, int head,
 			  u8 start_slot, u8 num_slots, u16 pbn, u16 aligned_pbn);
 #endif

drivers/gpu/drm/nouveau/nvif/outp.c

@@ -46,6 +46,24 @@ nvif_outp_dp_mst_vcpi(struct nvif_outp *outp, int head,
 	return ret;
 }
 
+int
+nvif_outp_dp_sst(struct nvif_outp *outp, int head, u32 watermark, u32 hblanksym, u32 vblanksym)
+{
+	struct nvif_outp_dp_sst_v0 args;
+	int ret;
+
+	args.version = 0;
+	args.head = head;
+	args.watermark = watermark;
+	args.hblanksym = hblanksym;
+	args.vblanksym = vblanksym;
+	ret = nvif_object_mthd(&outp->object, NVIF_OUTP_V0_DP_SST, &args, sizeof(args));
+	NVIF_ERRON(ret, &outp->object,
+		   "[DP_SST head:%d watermark:%d hblanksym:%d vblanksym:%d]",
+		   args.head, args.watermark, args.hblanksym, args.vblanksym);
+	return ret;
+}
+
 int
 nvif_outp_dp_drive(struct nvif_outp *outp, u8 link_nr, u8 pe[4], u8 vs[4])
 {

drivers/gpu/drm/nouveau/nvkm/engine/disp/ior.h

@@ -84,6 +84,8 @@ struct nvkm_ior_func {
 		void (*pattern)(struct nvkm_ior *, int pattern);
 		void (*drive)(struct nvkm_ior *, int ln, int pc,
 			      int dc, int pe, int tx_pu);
+		int (*sst)(struct nvkm_ior *, int head, bool ef,
+			   u32 watermark, u32 hblanksym, u32 vblanksym);
 		void (*vcpi)(struct nvkm_ior *, int head, u8 slot,
 			     u8 slot_nr, u16 pbn, u16 aligned);
 		void (*audio)(struct nvkm_ior *, int head, bool enable);

drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c

@@ -45,6 +45,26 @@ nvkm_uoutp_mthd_dp_mst_vcpi(struct nvkm_outp *outp, void *argv, u32 argc)
 	return 0;
 }
 
+static int
+nvkm_uoutp_mthd_dp_sst(struct nvkm_outp *outp, void *argv, u32 argc)
+{
+	union nvif_outp_dp_sst_args *args = argv;
+	struct nvkm_disp *disp = outp->disp;
+	struct nvkm_ior *ior = outp->ior;
+
+	if (argc != sizeof(args->v0) || args->v0.version != 0)
+		return -ENOSYS;
+
+	if (!ior->func->dp || !nvkm_head_find(disp, args->v0.head))
+		return -EINVAL;
+	if (!ior->func->dp->sst)
+		return 0;
+
+	return ior->func->dp->sst(ior, args->v0.head,
+				  outp->dp.dpcd[DPCD_RC02] & DPCD_RC02_ENHANCED_FRAME_CAP,
+				  args->v0.watermark, args->v0.hblanksym, args->v0.vblanksym);
+}
+
 static int
 nvkm_uoutp_mthd_dp_drive(struct nvkm_outp *outp, void *argv, u32 argc)
 {
@@ -461,6 +481,7 @@ nvkm_uoutp_mthd_acquired(struct nvkm_outp *outp, u32 mthd, void *argv, u32 argc)
 	case NVIF_OUTP_V0_HDA_ELD      : return nvkm_uoutp_mthd_hda_eld      (outp, argv, argc);
 	case NVIF_OUTP_V0_DP_TRAIN     : return nvkm_uoutp_mthd_dp_train     (outp, argv, argc);
 	case NVIF_OUTP_V0_DP_DRIVE     : return nvkm_uoutp_mthd_dp_drive     (outp, argv, argc);
+	case NVIF_OUTP_V0_DP_SST       : return nvkm_uoutp_mthd_dp_sst       (outp, argv, argc);
 	case NVIF_OUTP_V0_DP_MST_VCPI  : return nvkm_uoutp_mthd_dp_mst_vcpi  (outp, argv, argc);
 	default:
 		break;