From a5e1baf7dca10f8cf945394034013260297bc416 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Heiko=20St=C3=BCbner?= Date: Fri, 16 Jan 2015 17:52:44 +0100 Subject: [PATCH] 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); 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 Reviewed-by: Doug Anderson Signed-off-by: Michael Turquette [mturquette@linaro.org: removed initialization of "flags"] --- drivers/clk/rockchip/clk-cpu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/clk/rockchip/clk-cpu.c b/drivers/clk/rockchip/clk-cpu.c index 75c8c45ef728..8539c4fd34cc 100644 --- a/drivers/clk/rockchip/clk-cpu.c +++ b/drivers/clk/rockchip/clk-cpu.c @@ -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; } -- 2.20.1