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Commit 7c1c5413 authored by Scott Wood's avatar Scott Wood Committed by Stephen Boyd
Browse files

clk: qoriq: Don't allow CPU clocks higher than starting value 



The boot-time frequency of a CPU is considered its rated maximum, as we
have no other source of such information.  However, this was previously
only used for chips with 80% restrictions on secondary PLLs.  This
usually wasn't a problem because most chips/configs boot with a divider
of /1, with other dividers being used only for dynamic frequency
reduction.  However, at least one config (LS1021A at less than 1 GHz)
uses a different divider for top speed.  This was causing cpufreq to set
a frequency beyond the chip's rated speed.

This is fixed by applying a 100%-of-initial-speed limit to all CPU PLLs,
similar to the existing 80% limit that only applied to some.

Signed-off-by: default avatarScott Wood <oss@buserror.net>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent c7129375

drivers/clk/clk-qoriq.c

+8 −5
Original line number Diff line number Diff line
@@ -700,6 +700,7 @@ static struct clk * __init create_mux_common(struct clockgen *cg, 
					     struct mux_hwclock *hwc,

					     const struct clk_ops *ops,

					     unsigned long min_rate,

					     unsigned long max_rate,

					     unsigned long pct80_rate,

					     const char *fmt, int idx)

{
@@ -728,6 +729,8 @@ static struct clk * __init create_mux_common(struct clockgen *cg, 
			continue;

		if (rate < min_rate)

			continue;

		if (rate > max_rate)

			continue;



		parent_names[j] = div->name;

		hwc->parent_to_clksel[j] = i;
@@ -759,7 +762,7 @@ static struct clk * __init create_one_cmux(struct clockgen *cg, int idx) 
	struct mux_hwclock *hwc;

	const struct clockgen_pll_div *div;

	unsigned long plat_rate, min_rate;

	u64 pct80_rate;

	u64 max_rate, pct80_rate;

	u32 clksel;



	hwc = kzalloc(sizeof(*hwc), GFP_KERNEL);
@@ -787,8 +790,8 @@ static struct clk * __init create_one_cmux(struct clockgen *cg, int idx) 
		return NULL;

	}



	pct80_rate = clk_get_rate(div->clk);

	pct80_rate *= 8;

	max_rate = clk_get_rate(div->clk);

	pct80_rate = max_rate * 8;

	do_div(pct80_rate, 10);



	plat_rate = clk_get_rate(cg->pll[PLATFORM_PLL].div[PLL_DIV1].clk);
@@ -798,7 +801,7 @@ static struct clk * __init create_one_cmux(struct clockgen *cg, int idx) 
	else

		min_rate = plat_rate / 2;



	return create_mux_common(cg, hwc, &cmux_ops, min_rate,

	return create_mux_common(cg, hwc, &cmux_ops, min_rate, max_rate,

				 pct80_rate, "cg-cmux%d", idx);

}
@@ -813,7 +816,7 @@ static struct clk * __init create_one_hwaccel(struct clockgen *cg, int idx) 
	hwc->reg = cg->regs + 0x20 * idx + 0x10;

	hwc->info = cg->info.hwaccel[idx];



	return create_mux_common(cg, hwc, &hwaccel_ops, 0, 0,

	return create_mux_common(cg, hwc, &hwaccel_ops, 0, ULONG_MAX, 0,

				 "cg-hwaccel%d", idx);

}