From: Dibin Moolakadan Subrahmanian Date: Wed, 28 May 2025 06:45:56 +0000 (+0530) Subject: drm/i915/display: Fix u32 overflow in SNPS PHY HDMI PLL setup X-Git-Tag: v6.16-rc1~33^2~4^2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=791d76005de0ab556b590473eb4cbfede727fce0;p=linux-block.git drm/i915/display: Fix u32 overflow in SNPS PHY HDMI PLL setup When configuring the HDMI PLL, calculations use DIV_ROUND_UP_ULL and DIV_ROUND_DOWN_ULL macros, which internally rely on do_div. However, do_div expects a 32-bit (u32) divisor, and at higher data rates, the divisor can exceed this limit. This leads to incorrect division results and ultimately misconfigured PLL values. This fix replaces do_div calls with div64_base64 calls where diviser can exceed u32 limit. Fixes: 5947642004bf ("drm/i915/display: Add support for SNPS PHY HDMI PLL algorithm for DG2") Cc: Ankit Nautiyal Cc: Suraj Kandpal Cc: Jani Nikula Signed-off-by: Dibin Moolakadan Subrahmanian Reviewed-by: Ankit Nautiyal Signed-off-by: Ankit Nautiyal Link: https://lore.kernel.org/r/20250528064557.4172149-1-dibin.moolakadan.subrahmanian@intel.com (cherry picked from commit ce924116e43ffbfa544d82976c4b9d11bcde9334) Signed-off-by: Joonas Lahtinen --- diff --git a/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c b/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c index c6321dafef4f..74bb3bedf30f 100644 --- a/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c +++ b/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c @@ -41,12 +41,12 @@ static s64 interp(s64 x, s64 x1, s64 x2, s64 y1, s64 y2) { s64 dydx; - dydx = DIV_ROUND_UP_ULL((y2 - y1) * 100000, (x2 - x1)); + dydx = DIV64_U64_ROUND_UP((y2 - y1) * 100000, (x2 - x1)); - return (y1 + DIV_ROUND_UP_ULL(dydx * (x - x1), 100000)); + return (y1 + DIV64_U64_ROUND_UP(dydx * (x - x1), 100000)); } -static void get_ana_cp_int_prop(u32 vco_clk, +static void get_ana_cp_int_prop(u64 vco_clk, u32 refclk_postscalar, int mpll_ana_v2i, int c, int a, @@ -115,16 +115,16 @@ static void get_ana_cp_int_prop(u32 vco_clk, CURVE0_MULTIPLIER)); scaled_interpolated_sqrt = - int_sqrt(DIV_ROUND_UP_ULL(interpolated_product, vco_div_refclk_float) * + int_sqrt(DIV64_U64_ROUND_UP(interpolated_product, vco_div_refclk_float) * DIV_ROUND_DOWN_ULL(1000000000000ULL, 55)); /* Scale vco_div_refclk for ana_cp_int */ scaled_vco_div_refclk2 = DIV_ROUND_UP_ULL(vco_div_refclk_float, 1000000); - adjusted_vco_clk2 = 1460281 * DIV_ROUND_UP_ULL(scaled_interpolated_sqrt * + adjusted_vco_clk2 = 1460281 * DIV64_U64_ROUND_UP(scaled_interpolated_sqrt * scaled_vco_div_refclk2, curve_1_interpolated); - *ana_cp_prop = DIV_ROUND_UP_ULL(adjusted_vco_clk2, curve_2_scaled2); + *ana_cp_prop = DIV64_U64_ROUND_UP(adjusted_vco_clk2, curve_2_scaled2); *ana_cp_prop = max(1, min(*ana_cp_prop, 127)); } @@ -165,10 +165,10 @@ static void compute_hdmi_tmds_pll(u64 pixel_clock, u32 refclk, /* Select appropriate v2i point */ if (datarate <= INTEL_SNPS_PHY_HDMI_9999MHZ) { mpll_ana_v2i = 2; - tx_clk_div = ilog2(DIV_ROUND_DOWN_ULL(INTEL_SNPS_PHY_HDMI_9999MHZ, datarate)); + tx_clk_div = ilog2(div64_u64(INTEL_SNPS_PHY_HDMI_9999MHZ, datarate)); } else { mpll_ana_v2i = 3; - tx_clk_div = ilog2(DIV_ROUND_DOWN_ULL(INTEL_SNPS_PHY_HDMI_16GHZ, datarate)); + tx_clk_div = ilog2(div64_u64(INTEL_SNPS_PHY_HDMI_16GHZ, datarate)); } vco_clk = (datarate << tx_clk_div) >> 1;