From: jsg <jsg@openbsd.org>
Date: Thu, 24 Aug 2023 06:27:21 +0000 (+0000)
Subject: drm/amd/display: Implement workaround for writing to OTG_PIXEL_RATE_DIV register
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2e4e504830ac7f9435bf28c86be169354729f3de;p=openbsd

drm/amd/display: Implement workaround for writing to OTG_PIXEL_RATE_DIV register

From Saaem Rizvi
4bdfe20d85b32274234bbcd705d5547fd70a4ea1 in linux-6.1.y/6.1.47
74fa4c81aadf418341f0d073c864ea7dca730a2e in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/display/dc/dcn20/dcn20_dccg.h b/sys/dev/pci/drm/amd/display/dc/dcn20/dcn20_dccg.h
index 915a20461c7..893c0809cd4 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn20/dcn20_dccg.h
+++ b/sys/dev/pci/drm/amd/display/dc/dcn20/dcn20_dccg.h
@@ -230,7 +230,8 @@
 	type DTBCLK_P2_SRC_SEL;\
 	type DTBCLK_P2_EN;\
 	type DTBCLK_P3_SRC_SEL;\
-	type DTBCLK_P3_EN;
+	type DTBCLK_P3_EN;\
+	type DENTIST_DISPCLK_CHG_DONE;
 
 struct dccg_shift {
 	DCCG_REG_FIELD_LIST(uint8_t)
diff --git a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.c b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.c
index 3fb4bcc3435..ffbb739d85b 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.c
+++ b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.c
@@ -42,6 +42,20 @@
 #define DC_LOGGER \
 	dccg->ctx->logger
 
+/* This function is a workaround for writing to OTG_PIXEL_RATE_DIV
+ * without the probability of causing a DIG FIFO error.
+ */
+static void dccg32_wait_for_dentist_change_done(
+	struct dccg *dccg)
+{
+	struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
+
+	uint32_t dentist_dispclk_value = REG_READ(DENTIST_DISPCLK_CNTL);
+
+	REG_WRITE(DENTIST_DISPCLK_CNTL, dentist_dispclk_value);
+	REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, 1, 50, 2000);
+}
+
 static void dccg32_get_pixel_rate_div(
 		struct dccg *dccg,
 		uint32_t otg_inst,
@@ -110,21 +124,29 @@ static void dccg32_set_pixel_rate_div(
 		REG_UPDATE_2(OTG_PIXEL_RATE_DIV,
 				OTG0_PIXEL_RATE_DIVK1, k1,
 				OTG0_PIXEL_RATE_DIVK2, k2);
+
+		dccg32_wait_for_dentist_change_done(dccg);
 		break;
 	case 1:
 		REG_UPDATE_2(OTG_PIXEL_RATE_DIV,
 				OTG1_PIXEL_RATE_DIVK1, k1,
 				OTG1_PIXEL_RATE_DIVK2, k2);
+
+		dccg32_wait_for_dentist_change_done(dccg);
 		break;
 	case 2:
 		REG_UPDATE_2(OTG_PIXEL_RATE_DIV,
 				OTG2_PIXEL_RATE_DIVK1, k1,
 				OTG2_PIXEL_RATE_DIVK2, k2);
+
+		dccg32_wait_for_dentist_change_done(dccg);
 		break;
 	case 3:
 		REG_UPDATE_2(OTG_PIXEL_RATE_DIV,
 				OTG3_PIXEL_RATE_DIVK1, k1,
 				OTG3_PIXEL_RATE_DIVK2, k2);
+
+		dccg32_wait_for_dentist_change_done(dccg);
 		break;
 	default:
 		BREAK_TO_DEBUGGER();
diff --git a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.h b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.h
index 1c46fad0977..fc3c9c650d4 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.h
+++ b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_dccg.h
@@ -147,7 +147,8 @@
 	DCCG_SF(DTBCLK_P_CNTL, DTBCLK_P3_SRC_SEL, mask_sh),\
 	DCCG_SF(DTBCLK_P_CNTL, DTBCLK_P3_EN, mask_sh),\
 	DCCG_SF(DCCG_AUDIO_DTO_SOURCE, DCCG_AUDIO_DTO_SEL, mask_sh),\
-	DCCG_SF(DCCG_AUDIO_DTO_SOURCE, DCCG_AUDIO_DTO0_SOURCE_SEL, mask_sh)
+	DCCG_SF(DCCG_AUDIO_DTO_SOURCE, DCCG_AUDIO_DTO0_SOURCE_SEL, mask_sh),\
+	DCCG_SF(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, mask_sh)
 
 
 struct dccg *dccg32_create(
diff --git a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_hwseq.c b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_hwseq.c
index 601b65483ef..fa075789c9e 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_hwseq.c
+++ b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_hwseq.c
@@ -1177,7 +1177,7 @@ unsigned int dcn32_calculate_dccg_k1_k2_values(struct pipe_ctx *pipe_ctx, unsign
 			*k2_div = PIXEL_RATE_DIV_BY_2;
 		else
 			*k2_div = PIXEL_RATE_DIV_BY_4;
-	} else if (dc_is_dp_signal(stream->signal)) {
+	} else if (dc_is_dp_signal(stream->signal) || dc_is_virtual_signal(stream->signal)) {
 		if (two_pix_per_container) {
 			*k1_div = PIXEL_RATE_DIV_BY_1;
 			*k2_div = PIXEL_RATE_DIV_BY_2;
diff --git a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_resource.h b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_resource.h
index 026cf13d203..03cdfb55778 100644
--- a/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_resource.h
+++ b/sys/dev/pci/drm/amd/display/dc/dcn32/dcn32_resource.h
@@ -1272,7 +1272,8 @@ unsigned int dcn32_calc_num_avail_chans_for_mall(struct dc *dc, int num_chans);
       DCCG_SRII(PHASE, DTBCLK_DTO, 0), DCCG_SRII(PHASE, DTBCLK_DTO, 1),        \
       DCCG_SRII(PHASE, DTBCLK_DTO, 2), DCCG_SRII(PHASE, DTBCLK_DTO, 3),        \
       SR(DCCG_AUDIO_DTBCLK_DTO_MODULO), SR(DCCG_AUDIO_DTBCLK_DTO_PHASE),       \
-      SR(OTG_PIXEL_RATE_DIV), SR(DTBCLK_P_CNTL), SR(DCCG_AUDIO_DTO_SOURCE)     \
+      SR(OTG_PIXEL_RATE_DIV), SR(DTBCLK_P_CNTL),                               \
+      SR(DCCG_AUDIO_DTO_SOURCE), SR(DENTIST_DISPCLK_CNTL)                      \
   )
 
 /* VMID */