linux-kernel - Re: [PATCH 2/2] clk: imx: support fsl,protected-clocks

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Message-ID: <YvoEtKd7GCL865C3@linaro.org>
Date:   Mon, 15 Aug 2022 11:32:52 +0300
From:   Abel Vesa <abel.vesa@...aro.org>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     abelvesa@...nel.org, mturquette@...libre.com, sboyd@...nel.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, linux-imx@....com,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Peng Fan <peng.fan@....com>
Subject: Re: [PATCH 2/2] clk: imx: support fsl,protected-clocks

On 22-08-15 11:36:32, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
> 
> For the clocks listed in fsl,protected-clocks, enable them to avoid
> Linux disable them. This will benifit root Linux and inmate cell run
> on top of Jailhouse hypervisor, and benifit AMP case.

Nitpick: s/benifit/benefit/

AMP?

> 
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/clk/imx/clk-imx8mm.c |  2 ++
>  drivers/clk/imx/clk-imx8mn.c |  2 ++
>  drivers/clk/imx/clk-imx8mp.c |  2 ++
>  drivers/clk/imx/clk-imx8mq.c |  2 ++
>  drivers/clk/imx/clk.c        | 21 +++++++++++++++++++++
>  drivers/clk/imx/clk.h        |  2 ++
>  6 files changed, 31 insertions(+)
> 
> diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
> index b6d275855b36..24ddb1620bce 100644
> --- a/drivers/clk/imx/clk-imx8mm.c
> +++ b/drivers/clk/imx/clk-imx8mm.c
> @@ -611,6 +611,8 @@ static int imx8mm_clocks_probe(struct platform_device *pdev)
>  
>  	imx_register_uart_clocks(4);
>  
> +	imx_clk_protect(dev, hws);
> +
>  	return 0;
>  
>  unregister_hws:
> diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
> index d37c45b676ab..57c486317d28 100644
> --- a/drivers/clk/imx/clk-imx8mn.c
> +++ b/drivers/clk/imx/clk-imx8mn.c
> @@ -604,6 +604,8 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
>  
>  	imx_register_uart_clocks(4);
>  
> +	imx_clk_protect(dev, hws);
> +
>  	return 0;
>  
>  unregister_hws:
> diff --git a/drivers/clk/imx/clk-imx8mp.c b/drivers/clk/imx/clk-imx8mp.c
> index 652ae58c2735..a95862cc04a4 100644
> --- a/drivers/clk/imx/clk-imx8mp.c
> +++ b/drivers/clk/imx/clk-imx8mp.c
> @@ -713,6 +713,8 @@ static int imx8mp_clocks_probe(struct platform_device *pdev)
>  
>  	imx_register_uart_clocks(4);
>  
> +	imx_clk_protect(dev, hws);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/clk/imx/clk-imx8mq.c b/drivers/clk/imx/clk-imx8mq.c
> index 882dcad4817d..2868e2390667 100644
> --- a/drivers/clk/imx/clk-imx8mq.c
> +++ b/drivers/clk/imx/clk-imx8mq.c
> @@ -603,6 +603,8 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
>  
>  	imx_register_uart_clocks(4);
>  
> +	imx_clk_protect(dev, hws);
> +
>  	return 0;
>  
>  unregister_hws:
> diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
> index 5582f18dd632..307da8bd5243 100644
> --- a/drivers/clk/imx/clk.c
> +++ b/drivers/clk/imx/clk.c
> @@ -2,6 +2,7 @@
>  #include <linux/bits.h>
>  #include <linux/clk.h>
>  #include <linux/clk-provider.h>
> +#include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
> @@ -214,4 +215,24 @@ static int __init imx_clk_disable_uart(void)
>  late_initcall_sync(imx_clk_disable_uart);
>  #endif
>  
> +int imx_clk_protect(struct device *dev, struct clk_hw * const clks[])
> +{
> +	struct device_node *np = dev->of_node;
> +	struct property *prop;
> +	const __be32 *p;
> +	u32 i;
> +	int ret;
> +
> +	of_property_for_each_u32(np, "fsl,protected-clocks", prop, p, i) {
> +		ret = clk_prepare_enable(clks[i]->clk);

I might be wrong here, but wouldn't CLK_IGNORE_UNUSED have the same effect?

I don't think we should circumvent that by adding vendor specific dts properties.

> +		if (ret) {
> +			dev_err(dev, "failed to enable %s\n", clk_hw_get_name(clks[i]));
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(imx_clk_protect);
> +
>  MODULE_LICENSE("GPL v2");
> diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
> index dd49f90110e8..3f8099190b99 100644
> --- a/drivers/clk/imx/clk.h
> +++ b/drivers/clk/imx/clk.h
> @@ -22,6 +22,8 @@ void imx_mmdc_mask_handshake(void __iomem *ccm_base, unsigned int chn);
>  void imx_unregister_clocks(struct clk *clks[], unsigned int count);
>  void imx_unregister_hw_clocks(struct clk_hw *hws[], unsigned int count);
>  
> +int imx_clk_protect(struct device *dev, struct clk_hw * const clks[]);
> +
>  extern void imx_cscmr1_fixup(u32 *val);
>  
>  enum imx_pllv1_type {
> -- 
> 2.37.1
>