linux-kernel - Re: [PATCH v2 11/11] memory: mtk-smi: mt8195: Add initial setting for smi-larb

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Message-ID: <CAATdQgCf2sNwZWBKOC=HJU7Ur+7J6+uc75UD6xjfMF71Dxr18Q@mail.gmail.com>
Date:   Tue, 3 Aug 2021 13:37:01 +0800
From:   Ikjoon Jang <ikjn@...omium.org>
To:     Yong Wu <yong.wu@...iatek.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Tomasz Figa <tfiga@...omium.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        srv_heupstream <srv_heupstream@...iatek.com>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        iommu@...ts.linux-foundation.org
Subject: Re: [PATCH v2 11/11] memory: mtk-smi: mt8195: Add initial setting for smi-larb

Hi,

On Thu, Jul 29, 2021 at 2:41 PM Yong Wu <yong.wu@...iatek.com> wrote:
>
> Hi Ikjoon,
>
> Just a ping.
>
> On Thu, 2021-07-22 at 14:38 +0800, Yong Wu wrote:
> > On Wed, 2021-07-21 at 21:40 +0800, Ikjoon Jang wrote:
> > > On Thu, Jul 15, 2021 at 8:23 PM Yong Wu <yong.wu@...iatek.com> wrote:
> > > >
> > > > To improve the performance, We add some initial setting for smi larbs.
> > > > there are two part:
> > > > 1), Each port has the special ostd(outstanding) value in each larb.
> > > > 2), Two general setting for each larb.

Honestly, I think nobody outside Mediatek will understand this.
Can you please update this to be more generic?
Like "Apply default bus settings for mt8195, without this, XXX
problems can happen.. "?

Or for example, adding brief descriptions on what
MTK_SMI_FLAG_LARB_THRT_EN, MTK_SMI_FLAG_LARB_SW_FLAG,
and MTK_SMI_FLAG_LARB_SW_FLAG[] are for would be better if it's available.

> > > >
> > > > In some SoC, this setting maybe changed dynamically for some special case
> > > > like 4K, and this initial setting is enough in mt8195.
> > > >
> > > > Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> > > > ---
> > [...]
> > > >  struct mtk_smi {
> > > > @@ -213,12 +228,22 @@ static void mtk_smi_larb_config_port_mt8173(struct device *dev)
> > > >  static void mtk_smi_larb_config_port_gen2_general(struct device *dev)
> > > >  {
> > > >         struct mtk_smi_larb *larb = dev_get_drvdata(dev);
> > > > -       u32 reg;
> > > > +       u32 reg, flags_general = larb->larb_gen->flags_general;
> > > > +       const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
> > > >         int i;
> > > >
> > > >         if (BIT(larb->larbid) & larb->larb_gen->larb_direct_to_common_mask)
> > > >                 return;
> > > >
> > > > +       if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_LARB_THRT_EN))
> > > > +               writel_relaxed(SMI_LARB_THRT_EN, larb->base + SMI_LARB_CMD_THRT_CON);
> > > > +
> > > > +       if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_LARB_SW_FLAG))
> > > > +               writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base + SMI_LARB_SW_FLAG);
> > > > +
> > > > +       for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++)
> > > > +               writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));
> > >
> > > All other mtk platform's larbs have the same format for SMI_LARB_OSTDL_PORTx()
> > > registers at the same offset? or is this unique feature for mt8195?
> >
> > All the other Platform's larbs have the same format at the same offset.
>
> In this case, Do you have some other further comment? If no, I will keep
> the current solution for this.

Sorry for the late response,
I have no further comments or any objections on here. Please go ahead for v3.
I just had no idea on the register definitions and wanted to be sure that
newly added register definitions are common to all MTK platforms.

Thanks!

>
> Thanks.
>
> >
> > >
> > > > +
> > > >         for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
> > > >                 reg = readl_relaxed(larb->base + SMI_LARB_NONSEC_CON(i));
> > > >                 reg |= F_MMU_EN;
> > > > @@ -227,6 +252,51 @@ static void mtk_smi_larb_config_port_gen2_general(struct device *dev)
> > > >         }
> > > >  }
> > > >
> >
> > [...]
> >
>