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Message-ID: <Yhy+qXnmo7gfGltn@abelvesa>
Date:   Mon, 28 Feb 2022 14:23:05 +0200
From:   Abel Vesa <abel.vesa@....com>
To:     Peng Fan <peng.fan@....com>
Cc:     "Peng Fan (OSS)" <peng.fan@....nxp.com>,
        "sboyd@...nel.org" <sboyd@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...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>,
        dl-linux-imx <linux-imx@....com>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...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>
Subject: Re: [PATCH 3/3] clk: imx8mp: remove SYS PLL 1/2 clock gates

On 22-02-28 02:39:45, Peng Fan wrote:
> Hi Abel,
> 
> > Subject: Re: [PATCH 3/3] clk: imx8mp: remove SYS PLL 1/2 clock gates
> > 
> > On 22-02-25 16:17:33, Peng Fan (OSS) wrote:
> > > From: Peng Fan <peng.fan@....com>
> > >
> > > Remove the PLL 1/2 gates as it make AMP clock management harder
> > > without obvious benifit.
> > >
> > > Signed-off-by: Peng Fan <peng.fan@....com>
> > > ---
> > >  drivers/clk/imx/clk-imx8mp.c | 48
> > > ++++++++++++------------------------
> > >  1 file changed, 16 insertions(+), 32 deletions(-)
> > >
> > > diff --git a/drivers/clk/imx/clk-imx8mp.c
> > > b/drivers/clk/imx/clk-imx8mp.c index f23b92906d3b..18f5b7c3ca9d
> > 100644
> > > --- a/drivers/clk/imx/clk-imx8mp.c
> > > +++ b/drivers/clk/imx/clk-imx8mp.c
> > > @@ -480,44 +480,28 @@ static int imx8mp_clocks_probe(struct
> > platform_device *pdev)
> > >  	hws[IMX8MP_ARM_PLL_OUT] = imx_clk_hw_gate("arm_pll_out",
> > "arm_pll_bypass", anatop_base + 0x84, 11);
> > >  	hws[IMX8MP_SYS_PLL3_OUT] = imx_clk_hw_gate("sys_pll3_out",
> > > "sys_pll3_bypass", anatop_base + 0x114, 11);
> > >
> > > -	hws[IMX8MP_SYS_PLL1_40M_CG] =
> > imx_clk_hw_gate("sys_pll1_40m_cg", "sys_pll1_bypass", anatop_base + 0x94,
> > 27);
> > 
> > Hmm, isn't there a chance that u-boot might gate these? Then, in kernel you
> > won't have a way to ungate them, leaving the consumers hanging.
> 
> Both NXP and Upstream U-Boot not touch these bits. With the CG managed
> by Linux, it is hard to support AMP. This is same to Lucas's patch to
> clk-imx8mq.c to drop the gate.
> 
> The other method to support AMP well, is to add the CGs clk in device tree node
> for Mcore. But we still need a method to support M core booted in U-Boot, and
> linux may gate off the clock.
> 

OK, thanks for clarifying that. Makes sense now.

> Thanks,
> Peng.
> 
> > 
> > > -	hws[IMX8MP_SYS_PLL1_80M_CG] =
> > imx_clk_hw_gate("sys_pll1_80m_cg", "sys_pll1_bypass", anatop_base + 0x94,
> > 25);
> > > -	hws[IMX8MP_SYS_PLL1_100M_CG] =
> > imx_clk_hw_gate("sys_pll1_100m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 23);
> > > -	hws[IMX8MP_SYS_PLL1_133M_CG] =
> > imx_clk_hw_gate("sys_pll1_133m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 21);
> > > -	hws[IMX8MP_SYS_PLL1_160M_CG] =
> > imx_clk_hw_gate("sys_pll1_160m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 19);
> > > -	hws[IMX8MP_SYS_PLL1_200M_CG] =
> > imx_clk_hw_gate("sys_pll1_200m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 17);
> > > -	hws[IMX8MP_SYS_PLL1_266M_CG] =
> > imx_clk_hw_gate("sys_pll1_266m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 15);
> > > -	hws[IMX8MP_SYS_PLL1_400M_CG] =
> > imx_clk_hw_gate("sys_pll1_400m_cg", "sys_pll1_bypass", anatop_base +
> > 0x94, 13);
> > >  	hws[IMX8MP_SYS_PLL1_OUT] = imx_clk_hw_gate("sys_pll1_out",
> > > "sys_pll1_bypass", anatop_base + 0x94, 11);
> > >
> > > -	hws[IMX8MP_SYS_PLL1_40M] =
> > imx_clk_hw_fixed_factor("sys_pll1_40m", "sys_pll1_40m_cg", 1, 20);
> > > -	hws[IMX8MP_SYS_PLL1_80M] =
> > imx_clk_hw_fixed_factor("sys_pll1_80m", "sys_pll1_80m_cg", 1, 10);
> > > -	hws[IMX8MP_SYS_PLL1_100M] =
> > imx_clk_hw_fixed_factor("sys_pll1_100m", "sys_pll1_100m_cg", 1, 8);
> > > -	hws[IMX8MP_SYS_PLL1_133M] =
> > imx_clk_hw_fixed_factor("sys_pll1_133m", "sys_pll1_133m_cg", 1, 6);
> > > -	hws[IMX8MP_SYS_PLL1_160M] =
> > imx_clk_hw_fixed_factor("sys_pll1_160m", "sys_pll1_160m_cg", 1, 5);
> > > -	hws[IMX8MP_SYS_PLL1_200M] =
> > imx_clk_hw_fixed_factor("sys_pll1_200m", "sys_pll1_200m_cg", 1, 4);
> > > -	hws[IMX8MP_SYS_PLL1_266M] =
> > imx_clk_hw_fixed_factor("sys_pll1_266m", "sys_pll1_266m_cg", 1, 3);
> > > -	hws[IMX8MP_SYS_PLL1_400M] =
> > imx_clk_hw_fixed_factor("sys_pll1_400m", "sys_pll1_400m_cg", 1, 2);
> > > +	hws[IMX8MP_SYS_PLL1_40M] =
> > imx_clk_hw_fixed_factor("sys_pll1_40m", "sys_pll1_out", 1, 20);
> > > +	hws[IMX8MP_SYS_PLL1_80M] =
> > imx_clk_hw_fixed_factor("sys_pll1_80m", "sys_pll1_out", 1, 10);
> > > +	hws[IMX8MP_SYS_PLL1_100M] =
> > imx_clk_hw_fixed_factor("sys_pll1_100m", "sys_pll1_out", 1, 8);
> > > +	hws[IMX8MP_SYS_PLL1_133M] =
> > imx_clk_hw_fixed_factor("sys_pll1_133m", "sys_pll1_out", 1, 6);
> > > +	hws[IMX8MP_SYS_PLL1_160M] =
> > imx_clk_hw_fixed_factor("sys_pll1_160m", "sys_pll1_out", 1, 5);
> > > +	hws[IMX8MP_SYS_PLL1_200M] =
> > imx_clk_hw_fixed_factor("sys_pll1_200m", "sys_pll1_out", 1, 4);
> > > +	hws[IMX8MP_SYS_PLL1_266M] =
> > imx_clk_hw_fixed_factor("sys_pll1_266m", "sys_pll1_out", 1, 3);
> > > +	hws[IMX8MP_SYS_PLL1_400M] =
> > imx_clk_hw_fixed_factor("sys_pll1_400m",
> > > +"sys_pll1_out", 1, 2);
> > >  	hws[IMX8MP_SYS_PLL1_800M] =
> > imx_clk_hw_fixed_factor("sys_pll1_800m",
> > > "sys_pll1_out", 1, 1);
> > >
> > > -	hws[IMX8MP_SYS_PLL2_50M_CG] =
> > imx_clk_hw_gate("sys_pll2_50m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 27);
> > > -	hws[IMX8MP_SYS_PLL2_100M_CG] =
> > imx_clk_hw_gate("sys_pll2_100m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 25);
> > > -	hws[IMX8MP_SYS_PLL2_125M_CG] =
> > imx_clk_hw_gate("sys_pll2_125m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 23);
> > > -	hws[IMX8MP_SYS_PLL2_166M_CG] =
> > imx_clk_hw_gate("sys_pll2_166m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 21);
> > > -	hws[IMX8MP_SYS_PLL2_200M_CG] =
> > imx_clk_hw_gate("sys_pll2_200m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 19);
> > > -	hws[IMX8MP_SYS_PLL2_250M_CG] =
> > imx_clk_hw_gate("sys_pll2_250m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 17);
> > > -	hws[IMX8MP_SYS_PLL2_333M_CG] =
> > imx_clk_hw_gate("sys_pll2_333m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 15);
> > > -	hws[IMX8MP_SYS_PLL2_500M_CG] =
> > imx_clk_hw_gate("sys_pll2_500m_cg", "sys_pll2_bypass", anatop_base +
> > 0x104, 13);
> > >  	hws[IMX8MP_SYS_PLL2_OUT] = imx_clk_hw_gate("sys_pll2_out",
> > > "sys_pll2_bypass", anatop_base + 0x104, 11);
> > >
> > > -	hws[IMX8MP_SYS_PLL2_50M] =
> > imx_clk_hw_fixed_factor("sys_pll2_50m", "sys_pll2_50m_cg", 1, 20);
> > > -	hws[IMX8MP_SYS_PLL2_100M] =
> > imx_clk_hw_fixed_factor("sys_pll2_100m", "sys_pll2_100m_cg", 1, 10);
> > > -	hws[IMX8MP_SYS_PLL2_125M] =
> > imx_clk_hw_fixed_factor("sys_pll2_125m", "sys_pll2_125m_cg", 1, 8);
> > > -	hws[IMX8MP_SYS_PLL2_166M] =
> > imx_clk_hw_fixed_factor("sys_pll2_166m", "sys_pll2_166m_cg", 1, 6);
> > > -	hws[IMX8MP_SYS_PLL2_200M] =
> > imx_clk_hw_fixed_factor("sys_pll2_200m", "sys_pll2_200m_cg", 1, 5);
> > > -	hws[IMX8MP_SYS_PLL2_250M] =
> > imx_clk_hw_fixed_factor("sys_pll2_250m", "sys_pll2_250m_cg", 1, 4);
> > > -	hws[IMX8MP_SYS_PLL2_333M] =
> > imx_clk_hw_fixed_factor("sys_pll2_333m", "sys_pll2_333m_cg", 1, 3);
> > > -	hws[IMX8MP_SYS_PLL2_500M] =
> > imx_clk_hw_fixed_factor("sys_pll2_500m", "sys_pll2_500m_cg", 1, 2);
> > > +	hws[IMX8MP_SYS_PLL2_50M] =
> > imx_clk_hw_fixed_factor("sys_pll2_50m", "sys_pll2_out", 1, 20);
> > > +	hws[IMX8MP_SYS_PLL2_100M] =
> > imx_clk_hw_fixed_factor("sys_pll2_100m", "sys_pll2_out", 1, 10);
> > > +	hws[IMX8MP_SYS_PLL2_125M] =
> > imx_clk_hw_fixed_factor("sys_pll2_125m", "sys_pll2_out", 1, 8);
> > > +	hws[IMX8MP_SYS_PLL2_166M] =
> > imx_clk_hw_fixed_factor("sys_pll2_166m", "sys_pll2_out", 1, 6);
> > > +	hws[IMX8MP_SYS_PLL2_200M] =
> > imx_clk_hw_fixed_factor("sys_pll2_200m", "sys_pll2_out", 1, 5);
> > > +	hws[IMX8MP_SYS_PLL2_250M] =
> > imx_clk_hw_fixed_factor("sys_pll2_250m", "sys_pll2_out", 1, 4);
> > > +	hws[IMX8MP_SYS_PLL2_333M] =
> > imx_clk_hw_fixed_factor("sys_pll2_333m", "sys_pll2_out", 1, 3);
> > > +	hws[IMX8MP_SYS_PLL2_500M] =
> > imx_clk_hw_fixed_factor("sys_pll2_500m",
> > > +"sys_pll2_out", 1, 2);
> > >  	hws[IMX8MP_SYS_PLL2_1000M] =
> > > imx_clk_hw_fixed_factor("sys_pll2_1000m", "sys_pll2_out", 1, 1);
> > >
> > >  	hws[IMX8MP_CLK_A53_DIV] =
> > imx8m_clk_hw_composite_core("arm_a53_div",
> > > imx8mp_a53_sels, ccm_base + 0x8000);
> > > --
> > > 2.25.1
> > >

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