drm/amd/display: avoid reset DTBCLK at clock init

[ Upstream commit 0ae47e971b9add8f7b8f8d55ac5f407f6f346758 ]

[why & how]
this is to init to HW real DTBCLK.
and use real HW DTBCLK status to update internal logic state

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Martin Leung <martin.leung@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Signed-off-by: Ausef Yousof <Ausef.Yousof@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: cfa0904a35fd ("drm/amd/display: Prevent Gating DTBCLK before It Is Properly Latched")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
index a4ac601a30c350348f3c985457f99a5b88ef5084..3114b3fae9eff4b5440e1171c1dacc8e6372ddf3 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
@@ -393,6 +393,7 @@ void dcn35_update_clocks(struct clk_mgr *clk_mgr_base,
                if (clk_mgr_base->clks.dtbclk_en && !new_clocks->dtbclk_en) {
                        if (clk_mgr->base.ctx->dc->config.allow_0_dtb_clk)
                                dcn35_smu_set_dtbclk(clk_mgr, false);
+
                        clk_mgr_base->clks.dtbclk_en = new_clocks->dtbclk_en;
                }
                /* check that we're not already in lower */
@@ -410,11 +411,17 @@ void dcn35_update_clocks(struct clk_mgr *clk_mgr_base,
                }
 
                if (!clk_mgr_base->clks.dtbclk_en && new_clocks->dtbclk_en) {
-                       dcn35_smu_set_dtbclk(clk_mgr, true);
-                       clk_mgr_base->clks.dtbclk_en = new_clocks->dtbclk_en;
+                       int actual_dtbclk = 0;
 
                        dcn35_update_clocks_update_dtb_dto(clk_mgr, context, new_clocks->ref_dtbclk_khz);
-                       clk_mgr_base->clks.ref_dtbclk_khz = new_clocks->ref_dtbclk_khz;
+                       dcn35_smu_set_dtbclk(clk_mgr, true);
+
+                       actual_dtbclk = REG_READ(CLK1_CLK4_CURRENT_CNT);
+
+                       if (actual_dtbclk) {
+                               clk_mgr_base->clks.ref_dtbclk_khz = new_clocks->ref_dtbclk_khz;
+                               clk_mgr_base->clks.dtbclk_en = new_clocks->dtbclk_en;
+                       }
                }
 
                /* check that we're not already in D0 */
@@ -581,12 +588,10 @@ static bool dcn35_is_spll_ssc_enabled(struct clk_mgr *clk_mgr_base)
 
 static void init_clk_states(struct clk_mgr *clk_mgr)
 {
-       struct clk_mgr_internal *clk_mgr_int = TO_CLK_MGR_INTERNAL(clk_mgr);
        uint32_t ref_dtbclk = clk_mgr->clks.ref_dtbclk_khz;
+
        memset(&(clk_mgr->clks), 0, sizeof(struct dc_clocks));
 
-       if (clk_mgr_int->smu_ver >= SMU_VER_THRESHOLD)
-               clk_mgr->clks.dtbclk_en = true; // request DTBCLK disable on first commit
        clk_mgr->clks.ref_dtbclk_khz = ref_dtbclk;      // restore ref_dtbclk
        clk_mgr->clks.p_state_change_support = true;
        clk_mgr->clks.prev_p_state_change_support = true;
@@ -597,6 +602,7 @@ static void init_clk_states(struct clk_mgr *clk_mgr)
 void dcn35_init_clocks(struct clk_mgr *clk_mgr)
 {
        struct clk_mgr_internal *clk_mgr_int = TO_CLK_MGR_INTERNAL(clk_mgr);
+
        init_clk_states(clk_mgr);
 
        // to adjust dp_dto reference clock if ssc is enable otherwise to apply dprefclk