[PATCH 02/23] drm/amd/display: Add dc cap for dp tunneling

Alex Hung alex.hung at amd.com
Wed Jun 4 18:43:13 UTC 2025


From: Peichen Huang <PeiChen.Huang at amd.com>

[WHAT]
1. add dc cap for dp tunneling
2. add function to get index of host router

Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
Reviewed-by: Cruise Hung <cruise.hung at amd.com>
Signed-off-by: Peichen Huang <PeiChen.Huang at amd.com>
Signed-off-by: Alex Hung <alex.hung at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c      | 33 +++++++++++++++++++
 drivers/gpu/drm/amd/display/dc/dc.h           |  8 ++++-
 .../dc/resource/dcn31/dcn31_resource.c        |  3 ++
 .../dc/resource/dcn314/dcn314_resource.c      |  3 ++
 .../dc/resource/dcn35/dcn35_resource.c        |  3 ++
 .../dc/resource/dcn351/dcn351_resource.c      |  3 ++
 .../dc/resource/dcn36/dcn36_resource.c        |  3 ++
 7 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 284261cd372f..eaf44e6046b5 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -241,6 +241,7 @@ static bool create_links(
 	DC_LOG_DC("BIOS object table - end");
 
 	/* Create a link for each usb4 dpia port */
+	dc->lowest_dpia_link_index = MAX_LINKS;
 	for (i = 0; i < dc->res_pool->usb4_dpia_count; i++) {
 		struct link_init_data link_init_params = {0};
 		struct dc_link *link;
@@ -253,6 +254,9 @@ static bool create_links(
 
 		link = dc->link_srv->create_link(&link_init_params);
 		if (link) {
+			if (dc->lowest_dpia_link_index > dc->link_count)
+				dc->lowest_dpia_link_index = dc->link_count;
+
 			dc->links[dc->link_count] = link;
 			link->dc = dc;
 			++dc->link_count;
@@ -6378,6 +6382,35 @@ unsigned int dc_get_det_buffer_size_from_state(const struct dc_state *context)
 	else
 		return 0;
 }
+/**
+ ***********************************************************************************************
+ * dc_get_host_router_index: Get index of host router from a dpia link
+ *
+ * This function return a host router index of the target link. If the target link is dpia link.
+ *
+ * @param [in] link: target link
+ * @param [out] host_router_index: host router index of the target link
+ *
+ * @return: true if the host router index is found and valid.
+ *
+ ***********************************************************************************************
+ */
+bool dc_get_host_router_index(const struct dc_link *link, unsigned int *host_router_index)
+{
+	struct dc *dc = link->ctx->dc;
+
+	if (link->ep_type != DISPLAY_ENDPOINT_USB4_DPIA)
+		return false;
+
+	if (link->link_index < dc->lowest_dpia_link_index)
+		return false;
+
+	*host_router_index = (link->link_index - dc->lowest_dpia_link_index) / dc->caps.num_of_dpias_per_host_router;
+	if (*host_router_index < dc->caps.num_of_host_routers)
+		return true;
+	else
+		return false;
+}
 
 bool dc_is_cursor_limit_pending(struct dc *dc)
 {
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index d0839a679901..5c01a535b4fa 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -68,7 +68,8 @@ struct dmub_notification;
 #define MAX_STREAMS 6
 #define MIN_VIEWPORT_SIZE 12
 #define MAX_NUM_EDP 2
-#define MAX_HOST_ROUTERS_NUM 2
+#define MAX_HOST_ROUTERS_NUM 3
+#define MAX_DPIA_PER_HOST_ROUTER 2
 #define MAX_SUPPORTED_FORMATS 7
 
 /* Display Core Interfaces */
@@ -338,6 +339,8 @@ struct dc_caps {
 	/* Conservative limit for DCC cases which require ODM4:1 to support*/
 	uint32_t dcc_plane_width_limit;
 	struct dc_scl_caps scl_caps;
+	uint8_t num_of_host_routers;
+	uint8_t num_of_dpias_per_host_router;
 };
 
 struct dc_bug_wa {
@@ -1637,6 +1640,7 @@ struct dc {
 
 	uint8_t link_count;
 	struct dc_link *links[MAX_LINKS];
+	uint8_t lowest_dpia_link_index;
 	struct link_service *link_srv;
 
 	struct dc_state *current_state;
@@ -2625,6 +2629,8 @@ struct dc_power_profile dc_get_power_profile_for_dc_state(const struct dc_state
 
 unsigned int dc_get_det_buffer_size_from_state(const struct dc_state *context);
 
+bool dc_get_host_router_index(const struct dc_link *link, unsigned int *host_router_index);
+
 /* DSC Interfaces */
 #include "dc_dsc.h"
 
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
index 6b6efc2e75c0..2a33c82cfedb 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
@@ -1954,6 +1954,9 @@ static bool dcn31_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	dc->caps.num_of_host_routers = 2;
+	dc->caps.num_of_dpias_per_host_router = 2;
+
 	/* Use pipe context based otg sync logic */
 	dc->config.use_pipe_ctx_sync_logic = true;
 	dc->config.disable_hbr_audio_dp2 = true;
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn314/dcn314_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn314/dcn314_resource.c
index e84526c51590..cec03e81c6bd 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn314/dcn314_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn314/dcn314_resource.c
@@ -1885,6 +1885,9 @@ static bool dcn314_resource_construct(
 
 	dc->caps.max_disp_clock_khz_at_vmin = 650000;
 
+	dc->caps.num_of_host_routers = 2;
+	dc->caps.num_of_dpias_per_host_router = 2;
+
 	/* Use pipe context based otg sync logic */
 	dc->config.use_pipe_ctx_sync_logic = true;
 
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
index 62f6c7abb9c6..1f20069018ca 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
@@ -1894,6 +1894,9 @@ static bool dcn35_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	dc->caps.num_of_host_routers = 2;
+	dc->caps.num_of_dpias_per_host_router = 2;
+
 	/* max_disp_clock_khz_at_vmin is slightly lower than the STA value in order
 	 * to provide some margin.
 	 * It's expected for furture ASIC to have equal or higher value, in order to
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c
index 85a96258bce8..6266fc77c7eb 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c
@@ -1866,6 +1866,9 @@ static bool dcn351_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	dc->caps.num_of_host_routers = 2;
+	dc->caps.num_of_dpias_per_host_router = 2;
+
 	/* max_disp_clock_khz_at_vmin is slightly lower than the STA value in order
 	 * to provide some margin.
 	 * It's expected for furture ASIC to have equal or higher value, in order to
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c
index e977866802bf..10d3182b3058 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c
@@ -1867,6 +1867,9 @@ static bool dcn36_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	dc->caps.num_of_host_routers = 2;
+	dc->caps.num_of_dpias_per_host_router = 2;
+
 	/* max_disp_clock_khz_at_vmin is slightly lower than the STA value in order
 	 * to provide some margin.
 	 * It's expected for furture ASIC to have equal or higher value, in order to
-- 
2.43.0



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