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Date: Mon, 13 May 2024 08:39:34 +0200
From: Sascha Hauer <s.hauer@pengutronix.de>
To: "Peng Fan (OSS)" <peng.fan@oss.nxp.com>
Cc: Abel Vesa <abelvesa@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>, Jacky Bai <ping.bai@nxp.com>,
	Ye Li <ye.li@nxp.com>, Dong Aisheng <aisheng.dong@nxp.com>,
	linux-clk@vger.kernel.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
	Abel Vesa <abel.vesa@linaro.org>, Peng Fan <peng.fan@nxp.com>
Subject: Re: [PATCH v2 01/17] clk: imx: composite-8m: Enable gate clk with
 mcore_booted
Message-ID: <ZkG1put2k33K4c_b@pengutronix.de>
References: <20240510-imx-clk-v2-0-c998f315d29c@nxp.com>
 <20240510-imx-clk-v2-1-c998f315d29c@nxp.com>
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In-Reply-To: <20240510-imx-clk-v2-1-c998f315d29c@nxp.com>

On Fri, May 10, 2024 at 05:18:56PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> Bootloader might disable some CCM ROOT Slices. So if mcore_booted set with
> display CCM ROOT disabled by Bootloader, kernel display BLK CTRL driver
> imx8m_blk_ctrl_driver_init may hang the system because the BUS clk is
> disabled.
> 
> Add back gate ops, but with disable doing nothing, then the CCM ROOT
> will be enabled when used.
> 
> Fixes: 489bbee0c983 ("clk: imx: composite-8m: Enable gate clk with mcore_booted")

I can't find this commitish anywhere, also the subject looks like this
patch fixes itself.

> Reviewed-by: Ye Li <ye.li@nxp.com>
> Reviewed-by: Jacky Bai <ping.bai@nxp.com>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/clk/imx/clk-composite-8m.c | 53 ++++++++++++++++++++++++++++++--------
>  1 file changed, 42 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
> index 8cc07d056a83..f187582ba491 100644
> --- a/drivers/clk/imx/clk-composite-8m.c
> +++ b/drivers/clk/imx/clk-composite-8m.c
> @@ -204,6 +204,34 @@ static const struct clk_ops imx8m_clk_composite_mux_ops = {
>  	.determine_rate = imx8m_clk_composite_mux_determine_rate,
>  };
>  
> +static int imx8m_clk_composite_gate_enable(struct clk_hw *hw)
> +{
> +	struct clk_gate *gate = to_clk_gate(hw);
> +	unsigned long flags;
> +	u32 val;
> +
> +	spin_lock_irqsave(gate->lock, flags);
> +
> +	val = readl(gate->reg);
> +	val |= BIT(gate->bit_idx);
> +	writel(val, gate->reg);
> +
> +	spin_unlock_irqrestore(gate->lock, flags);
> +
> +	return 0;
> +}
> +
> +static void imx8m_clk_composite_gate_disable(struct clk_hw *hw)
> +{
> +	/* composite clk requires the disable hook */
> +}
> +
> +static const struct clk_ops imx8m_clk_composite_gate_ops = {
> +	.enable = imx8m_clk_composite_gate_enable,
> +	.disable = imx8m_clk_composite_gate_disable,
> +	.is_enabled = clk_gate_is_enabled,
> +};
> +
>  struct clk_hw *__imx8m_clk_hw_composite(const char *name,
>  					const char * const *parent_names,
>  					int num_parents, void __iomem *reg,
> @@ -217,6 +245,7 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
>  	struct clk_mux *mux;
>  	const struct clk_ops *divider_ops;
>  	const struct clk_ops *mux_ops;
> +	const struct clk_ops *gate_ops;
>  
>  	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
>  	if (!mux)
> @@ -257,20 +286,22 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
>  	div->flags = CLK_DIVIDER_ROUND_CLOSEST;
>  
>  	/* skip registering the gate ops if M4 is enabled */

This comment doesn't seems to become inaccurate with this patch.

> -	if (!mcore_booted) {
> -		gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> -		if (!gate)
> -			goto free_div;
> -
> -		gate_hw = &gate->hw;
> -		gate->reg = reg;
> -		gate->bit_idx = PCG_CGC_SHIFT;
> -		gate->lock = &imx_ccm_lock;
> -	}
> +	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> +	if (!gate)
> +		goto free_div;
> +
> +	gate_hw = &gate->hw;
> +	gate->reg = reg;
> +	gate->bit_idx = PCG_CGC_SHIFT;
> +	gate->lock = &imx_ccm_lock;
> +	if (!mcore_booted)
> +		gate_ops = &clk_gate_ops;
> +	else
> +		gate_ops = &imx8m_clk_composite_gate_ops;

Please use positive logic. It's easier to read.

Sascha

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