| Date | Thu, 01 Jul 2010 10:43:46 -0700 | From | Greg KH <> | Subject | [136/200] clocksource: sh_tmu: compute mult and shift before registration |
| |
2.6.34-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aurelien Jarno <aurelien@aurel32.net>
commit 66f49121ffa41a19c59965b31b046d8368fec3c7 upstream.
Since commit 98962465ed9e6ea99c38e0af63fe1dcb5a79dc25 ("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> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/clocksource/sh_tmu.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
--- a/drivers/clocksource/sh_tmu.c +++ b/drivers/clocksource/sh_tmu.c @@ -200,16 +200,8 @@ static cycle_t sh_tmu_clocksource_read(s 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) @@ -229,6 +221,16 @@ static int sh_tmu_register_clocksource(s 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); + pr_info("sh_tmu: %s used as clock source\n", cs->name); clocksource_register(cs); return 0;
|