clk: qcom: rcg2: Rectify clk_gfx3d rate rounding without mux division

In case the mux is not divided parent_req was mistakenly not assigned to
leading __clk_determine_rate to determine the best frequency setting for
a requested rate of 0, resulting in the msm8996 platform not booting.
Rectify this by refactoring the logic to unconditionally assign to
parent_req.rate with the clock rate the caller is expecting.

Fixes: 7cbb78a99db6 ("clk: qcom: rcg2: Stop hardcoding gfx3d pingpong parent numbers")
Reported-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Tested-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-By: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Link: https://lore.kernel.org/r/20210302234106.3418665-1-marijn.suijten@somainline.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 42f13a2..05ff3b0 100644 (file)
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -730,7 +730,8 @@ static int clk_gfx3d_determine_rate(struct clk_hw *hw,
        struct clk_rate_request parent_req = { };
        struct clk_rcg2_gfx3d *cgfx = to_clk_rcg2_gfx3d(hw);
        struct clk_hw *xo, *p0, *p1, *p2;
-       unsigned long request, p0_rate;
+       unsigned long p0_rate;
+       u8 mux_div = cgfx->div;
        int ret;
 
        p0 = cgfx->hws[0];
@@ -750,14 +751,15 @@ static int clk_gfx3d_determine_rate(struct clk_hw *hw,
                return 0;
        }
 
-       request = req->rate;
-       if (cgfx->div > 1)
-               parent_req.rate = request = request * cgfx->div;
+       if (mux_div == 0)
+               mux_div = 1;
+
+       parent_req.rate = req->rate * mux_div;
 
        /* This has to be a fixed rate PLL */
        p0_rate = clk_hw_get_rate(p0);
 
-       if (request == p0_rate) {
+       if (parent_req.rate == p0_rate) {
                req->rate = req->best_parent_rate = p0_rate;
                req->best_parent_hw = p0;
                return 0;
@@ -765,7 +767,7 @@ static int clk_gfx3d_determine_rate(struct clk_hw *hw,
 
        if (req->best_parent_hw == p0) {
                /* Are we going back to a previously used rate? */
-               if (clk_hw_get_rate(p2) == request)
+               if (clk_hw_get_rate(p2) == parent_req.rate)
                        req->best_parent_hw = p2;
                else
                        req->best_parent_hw = p1;
@@ -780,8 +782,7 @@ static int clk_gfx3d_determine_rate(struct clk_hw *hw,
                return ret;
 
        req->rate = req->best_parent_rate = parent_req.rate;
-       if (cgfx->div > 1)
-               req->rate /= cgfx->div;
+       req->rate /= mux_div;
 
        return 0;
 }