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clocksource: sh_tmu: compute mult and shift before registration

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Since commit 98962465ed ("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>
This commit is contained in:
Aurelien Jarno 2010-05-31 21:45:48 +00:00 committed by Paul Mundt
parent 019e2574f9
commit 66f49121ff
1 changed files with 11 additions and 9 deletions
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20
drivers/clocksource/sh_tmu.c
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@ -199,16 +199,8 @@ static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
static int sh_tmu_clocksource_enable(struct clocksource *cs) static int sh_tmu_clocksource_enable(struct clocksource *cs)
{ {
struct sh_tmu_priv *p = cs_to_sh_tmu(cs); struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
int ret;
ret = sh_tmu_enable(p); return 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;
} }
static void sh_tmu_clocksource_disable(struct clocksource *cs) 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->disable = sh_tmu_clocksource_disable;
cs->mask = CLOCKSOURCE_MASK(32); cs->mask = CLOCKSOURCE_MASK(32);
cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; 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"); dev_info(&p->pdev->dev, "used as clock source\n");
clocksource_register(cs); clocksource_register(cs);
return 0; return 0;