clocksource: sh_tmu: compute mult and shift before registration (66f49121) · Commits · 戴 / test

Since commit ("nohz: Prevent clocksource wrapping during idle"), the CPU of an R2D board never goes to idle. This commit assumes that mult and shift are assigned before the clocksource is registered. As a consequence the safe maximum sleep time is negative and the CPU never goes into idle. This patch fixes the problem by moving mult and shift initialization from sh_tmu_clocksource_enable() to sh_tmu_register_clocksource(). Signed-off-by:

Aurelien Jarno <aurelien@aurel32.net> Cc: stable@kernel.org Signed-off-by:

Paul Mundt <lethal@linux-sh.org>

drivers/clocksource/sh_tmu.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -199,16 +199,8 @@ static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
		static int sh_tmu_clocksource_enable(struct clocksource *cs)
		{
		struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
		int ret;

		ret = sh_tmu_enable(p);
		if (ret)
		return ret;

		/* TODO: calculate good shift from rate and counter bit width */
		cs->shift = 10;
		cs->mult = clocksource_hz2mult(p->rate, cs->shift);
		return 0;
		return sh_tmu_enable(p);
		}

		static void sh_tmu_clocksource_disable(struct clocksource *cs)
		@@ -228,6 +220,16 @@ static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
		cs->disable = sh_tmu_clocksource_disable;
		cs->mask = CLOCKSOURCE_MASK(32);
		cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;

		/* clk_get_rate() needs an enabled clock */
		clk_enable(p->clk);
		/* channel will be configured at parent clock / 4 */
		p->rate = clk_get_rate(p->clk) / 4;
		clk_disable(p->clk);
		/* TODO: calculate good shift from rate and counter bit width */
		cs->shift = 10;
		cs->mult = clocksource_hz2mult(p->rate, cs->shift);

		dev_info(&p->pdev->dev, "used as clock source\n");
		clocksource_register(cs);
		return 0;

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