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| author | Tero Kristo <t-kristo@ti.com> | 2012-09-25 19:05:32 +0300 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2012-10-17 09:00:31 -0700 |
| commit | 64e29fd5ed42f5d0ff5b0ea9395b3abd5d43f89b (patch) | |
| tree | 2d1a162662e2279f03d17de9b2e33c5d6cb8ca54 /arch/arm | |
| parent | 49c58e82023649924b1b0f38d715d94093f4044b (diff) | |
| download | linux-64e29fd5ed42f5d0ff5b0ea9395b3abd5d43f89b.tar.gz linux-64e29fd5ed42f5d0ff5b0ea9395b3abd5d43f89b.tar.xz | |
ARM: OMAP: clockdomain: Fix locking on _clkdm_clk_hwmod_enable / disable
Previously the code only acquired spinlock after increasing / decreasing
the usecount value, which is wrong. This leaves a small window where
a task switch may occur between the check of the usecount and the actual
wakeup / sleep of the domain. Fixed by moving the spinlock locking before
the usecount access. Left the usecount as atomic_t if someone wants an
easy access to the parameter through atomic_read.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mach-omap2/clockdomain.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c index cbb879139c51..512e79a842cb 100644 --- a/arch/arm/mach-omap2/clockdomain.c +++ b/arch/arm/mach-omap2/clockdomain.c @@ -925,15 +925,18 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm) if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable) return -EINVAL; + spin_lock_irqsave(&clkdm->lock, flags); + /* * For arch's with no autodeps, clkcm_clk_enable * should be called for every clock instance or hwmod that is * enabled, so the clkdm can be force woken up. */ - if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps) + if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps) { + spin_unlock_irqrestore(&clkdm->lock, flags); return 0; + } - spin_lock_irqsave(&clkdm->lock, flags); arch_clkdm->clkdm_clk_enable(clkdm); pwrdm_state_switch(clkdm->pwrdm.ptr); spin_unlock_irqrestore(&clkdm->lock, flags); @@ -950,15 +953,19 @@ static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm) if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable) return -EINVAL; + spin_lock_irqsave(&clkdm->lock, flags); + if (atomic_read(&clkdm->usecount) == 0) { + spin_unlock_irqrestore(&clkdm->lock, flags); WARN_ON(1); /* underflow */ return -ERANGE; } - if (atomic_dec_return(&clkdm->usecount) > 0) + if (atomic_dec_return(&clkdm->usecount) > 0) { + spin_unlock_irqrestore(&clkdm->lock, flags); return 0; + } - spin_lock_irqsave(&clkdm->lock, flags); arch_clkdm->clkdm_clk_disable(clkdm); pwrdm_state_switch(clkdm->pwrdm.ptr); spin_unlock_irqrestore(&clkdm->lock, flags); |