Commit b906c056 authored Apr 12, 2019 by Dmitry Osipenko Committed by Thierry Reding Apr 18, 2019

memory: tegra: Fix integer overflow on tick value calculation



Multiplying the Memory Controller clock rate by the tick count results
in an integer overflow and in result the truncated tick value is being
programmed into hardware, such that the GR3D memory client performance is
reduced by two times.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

parent 76b959a4

drivers/memory/tegra/mc.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -285,7 +285,7 @@ static int tegra_mc_setup_latency_allowance(struct tegra_mc *mc)
		u32 value;

		/* compute the number of MC clock cycles per tick */
		tick = mc->tick * clk_get_rate(mc->clk);
		tick = (unsigned long long)mc->tick * clk_get_rate(mc->clk);
		do_div(tick, NSEC_PER_SEC);

		value = readl(mc->regs + MC_EMEM_ARB_CFG);

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