linux-kernel - Re: [PATCH] clk: tegra: Add missing spinlock for hclk and pclk

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Date:	Fri, 8 Feb 2013 10:53:27 +0530
From:	Prashant Gaikwad <pgaikwad@...dia.com>
To:	Peter De Schrijver <pdeschrijver@...dia.com>
CC:	Stephen Warren <swarren@...dia.com>,
	Mike Turquette <mturquette@...aro.org>,
	Joseph Lo <josephl@...dia.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] clk: tegra: Add missing spinlock for hclk and pclk

On Thursday 07 February 2013 10:07 PM, Peter De Schrijver wrote:
> The hclk and pclk clocks are controlled by the same register. Hence a lock is
> required to avoid corruption.
>
> Signed-off-by: Peter De Schrijver <pdeschrijver@...dia.com>

Reviewed-by: Prashant Gaikwad <pgaikwad@...dia.com>

> ---
>   drivers/clk/tegra/clk-tegra20.c |   11 +++++++----
>   drivers/clk/tegra/clk-tegra30.c |   11 +++++++----
>   2 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/clk/tegra/clk-tegra20.c b/drivers/clk/tegra/clk-tegra20.c
> index 5d41569..4612b2e 100644
> --- a/drivers/clk/tegra/clk-tegra20.c
> +++ b/drivers/clk/tegra/clk-tegra20.c
> @@ -194,6 +194,7 @@ static void __iomem *clk_base;
>   static void __iomem *pmc_base;
>   
>   static DEFINE_SPINLOCK(pll_div_lock);
> +static DEFINE_SPINLOCK(sysrate_lock);
>   
>   #define TEGRA_INIT_DATA_MUX(_name, _con_id, _dev_id, _parents, _offset,	\
>   			    _clk_num, _regs, _gate_flags, _clk_id)	\
> @@ -768,19 +769,21 @@ static void tegra20_super_clk_init(void)
>   
>   	/* HCLK */
>   	clk = clk_register_divider(NULL, "hclk_div", "sclk", 0,
> -				   clk_base + CLK_SYSTEM_RATE, 4, 2, 0, NULL);
> +				   clk_base + CLK_SYSTEM_RATE, 4, 2, 0,
> +				   &sysrate_lock);
>   	clk = clk_register_gate(NULL, "hclk", "hclk_div", CLK_SET_RATE_PARENT,
>   				clk_base + CLK_SYSTEM_RATE, 7,
> -				CLK_GATE_SET_TO_DISABLE, NULL);
> +				CLK_GATE_SET_TO_DISABLE, &sysrate_lock);
>   	clk_register_clkdev(clk, "hclk", NULL);
>   	clks[hclk] = clk;
>   
>   	/* PCLK */
>   	clk = clk_register_divider(NULL, "pclk_div", "hclk", 0,
> -				   clk_base + CLK_SYSTEM_RATE, 0, 2, 0, NULL);
> +				   clk_base + CLK_SYSTEM_RATE, 0, 2, 0,
> +				   &sysrate_lock);
>   	clk = clk_register_gate(NULL, "pclk", "pclk_div", CLK_SET_RATE_PARENT,
>   				clk_base + CLK_SYSTEM_RATE, 3,
> -				CLK_GATE_SET_TO_DISABLE, NULL);
> +				CLK_GATE_SET_TO_DISABLE, &sysrate_lock);
>   	clk_register_clkdev(clk, "pclk", NULL);
>   	clks[pclk] = clk;
>   
> diff --git a/drivers/clk/tegra/clk-tegra30.c b/drivers/clk/tegra/clk-tegra30.c
> index d169ef0..c5415ce 100644
> --- a/drivers/clk/tegra/clk-tegra30.c
> +++ b/drivers/clk/tegra/clk-tegra30.c
> @@ -275,6 +275,7 @@ static DEFINE_SPINLOCK(clk_out_lock);
>   static DEFINE_SPINLOCK(pll_div_lock);
>   static DEFINE_SPINLOCK(cml_lock);
>   static DEFINE_SPINLOCK(pll_d_lock);
> +static DEFINE_SPINLOCK(sysrate_lock);
>   
>   #define TEGRA_INIT_DATA_MUX(_name, _con_id, _dev_id, _parents, _offset,	\
>   			    _clk_num, _regs, _gate_flags, _clk_id)	\
> @@ -1348,19 +1349,21 @@ static void __init tegra30_super_clk_init(void)
>   
>   	/* HCLK */
>   	clk = clk_register_divider(NULL, "hclk_div", "sclk", 0,
> -				   clk_base + SYSTEM_CLK_RATE, 4, 2, 0, NULL);
> +				   clk_base + SYSTEM_CLK_RATE, 4, 2, 0,
> +				   &sysrate_lock);
>   	clk = clk_register_gate(NULL, "hclk", "hclk_div", CLK_SET_RATE_PARENT,
>   				clk_base + SYSTEM_CLK_RATE, 7,
> -				CLK_GATE_SET_TO_DISABLE, NULL);
> +				CLK_GATE_SET_TO_DISABLE, &sysrate_lock);
>   	clk_register_clkdev(clk, "hclk", NULL);
>   	clks[hclk] = clk;
>   
>   	/* PCLK */
>   	clk = clk_register_divider(NULL, "pclk_div", "hclk", 0,
> -				   clk_base + SYSTEM_CLK_RATE, 0, 2, 0, NULL);
> +				   clk_base + SYSTEM_CLK_RATE, 0, 2, 0,
> +				   &sysrate_lock);
>   	clk = clk_register_gate(NULL, "pclk", "pclk_div", CLK_SET_RATE_PARENT,
>   				clk_base + SYSTEM_CLK_RATE, 3,
> -				CLK_GATE_SET_TO_DISABLE, NULL);
> +				CLK_GATE_SET_TO_DISABLE, &sysrate_lock);
>   	clk_register_clkdev(clk, "pclk", NULL);
>   	clks[pclk] = clk;
>   

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