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

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Date:   Mon, 15 Aug 2022 08:42:14 +0000
From:   Peng Fan <peng.fan@....com>
To:     Abel Vesa <abel.vesa@...aro.org>,
        "Peng Fan (OSS)" <peng.fan@....nxp.com>
CC:     "abelvesa@...nel.org" <abelvesa@...nel.org>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "sboyd@...nel.org" <sboyd@...nel.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        dl-linux-imx <linux-imx@....com>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH 2/2] clk: imx: support fsl,protected-clocks

> 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?

Asymmetric Multi-Processing, I mean Cortex-M run together with A53.

Thanks,
Peng.

> 
> >
> > 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
> >