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clk: rockchip: fix deadlock possibility in cpuclk 

Lockdep reported a possible deadlock between the cpuclk lock and for example
the i2c driver.

       CPU0                    CPU1
       ----                    ----
  lock(clk_lock);
                               local_irq_disable();
                               lock(&(&i2c->lock)->rlock);
                               lock(clk_lock);
  <Interrupt>
    lock(&(&i2c->lock)->rlock);

 *** DEADLOCK ***

The generic clock-types of the core ccf already use spin_lock_irqsave when
touching clock registers, so do the same for the cpuclk.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
[mturquette@linaro.org: removed initialization of "flags"]
This commit is contained in:
Heiko Stübner 2015-01-16 17:52:44 +01:00 committed by Michael Turquette
parent b71e8ecd57
commit a5e1baf7dc
1 changed files with 6 additions and 4 deletions
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10
drivers/clk/rockchip/clk-cpu.c
View File

@ -124,10 +124,11 @@ static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk,
{
const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data;
unsigned long alt_prate, alt_div;
unsigned long flags;
alt_prate = clk_get_rate(cpuclk->alt_parent);
spin_lock(cpuclk->lock);
spin_lock_irqsave(cpuclk->lock, flags);
/*
* If the old parent clock speed is less than the clock speed
@ -164,7 +165,7 @@ static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk,
cpuclk->reg_base + reg_data->core_reg);
}
spin_unlock(cpuclk->lock);
spin_unlock_irqrestore(cpuclk->lock, flags);
return 0;
}
@ -173,6 +174,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk,
{
const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data;
const struct rockchip_cpuclk_rate_table *rate;
unsigned long flags;
rate = rockchip_get_cpuclk_settings(cpuclk, ndata->new_rate);
if (!rate) {
@ -181,7 +183,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk,
return -EINVAL;
}
spin_lock(cpuclk->lock);
spin_lock_irqsave(cpuclk->lock, flags);
if (ndata->old_rate < ndata->new_rate)
rockchip_cpuclk_set_dividers(cpuclk, rate);
@ -201,7 +203,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk,
if (ndata->old_rate > ndata->new_rate)
rockchip_cpuclk_set_dividers(cpuclk, rate);
spin_unlock(cpuclk->lock);
spin_unlock_irqrestore(cpuclk->lock, flags);
return 0;
}