linux-kernel - Re: [PATCH V5 7/8] remoteproc: imx_rproc: ignore mapping vdev regions

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Date:   Tue, 12 Jan 2021 11:46:29 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Peng Fan <peng.fan@....com>
Cc:     "ohad@...ery.com" <ohad@...ery.com>,
        "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "o.rempel@...gutronix.de" <o.rempel@...gutronix.de>,
        "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-remoteproc@...r.kernel.org" <linux-remoteproc@...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>,
        "paul@...pouillou.net" <paul@...pouillou.net>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "agross@...nel.org" <agross@...nel.org>,
        "patrice.chotard@...com" <patrice.chotard@...com>
Subject: Re: [PATCH V5 7/8] remoteproc: imx_rproc: ignore mapping vdev regions

On Tue, Jan 12, 2021 at 09:41:12AM +0000, Peng Fan wrote:
> > Subject: Re: [PATCH V5 7/8] remoteproc: imx_rproc: ignore mapping vdev
> > regions
> > 
> > On Tue, Dec 29, 2020 at 11:30:18AM +0800, peng.fan@....com wrote:
> > > From: Peng Fan <peng.fan@....com>
> > >
> > > vdev regions are vdev0vring0, vdev0vring1, vdevbuffer and similar.
> > > They are handled by remoteproc common code, no need to map in imx
> > > rproc driver.
> > >
> > > Signed-off-by: Peng Fan <peng.fan@....com>
> > > ---
> > >  drivers/remoteproc/imx_rproc.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/remoteproc/imx_rproc.c
> > > b/drivers/remoteproc/imx_rproc.c index f80428afb8a7..e62a53ee128e
> > > 100644
> > > --- a/drivers/remoteproc/imx_rproc.c
> > > +++ b/drivers/remoteproc/imx_rproc.c
> > > @@ -417,6 +417,9 @@ static int imx_rproc_addr_init(struct imx_rproc
> > *priv,
> > >  		struct resource res;
> > >
> > >  		node = of_parse_phandle(np, "memory-region", a);
> > > +		/* Not map vdev region */
> > > +		if (!strcmp(node->name, "vdev"))
> > > +			continue;
> > 
> > I am very confused and because I don't see an example for the DT in the
> > bindings document I have to guess what is going on.
> 
> V6 will include the DT yaml.
> 
> > 
> > So I am guessing that you have laid out the memory regions for the vrings and
> > the vdev0buffer in the DT "memory-region".
> 
> The dts part will be similar as following:
> 
> +    #include <dt-bindings/clock/imx8mm-clock.h>
> +    rsc_table: rsc_table@...ff000 {
> +      no-map;
> +      reg = <0x550ff000 0x1000>;
> +    };
> +
> +    vdev0vring0: vdev0vring0@...00000 {
> +      no-map;
> +      reg = <0x55000000 0x8000>;
> +    };
> +
> +    vdev0vring1: vdev0vring1@...08000 {
> +      reg = <0x55008000 0x8000>;
> +      no-map;
> +    };
> +
> +    vdevbuffer: vdevbuffer@...00000 {
> +      compatible = "shared-dma-pool";
> +      reg = <0x55400000 0x100000>;
> +      no-map;
> +    };
> +
> +    imx8mm-cm4 {
> +      compatible = "fsl,imx8mm-cm4";
> +      clocks = <&clk IMX8MM_CLK_M4_DIV>;
> +      mbox-names = "tx", "rx", "rxdb";
> +      mboxes = <&mu 0 1
> +                &mu 1 1
> +                &mu 3 1>;
> +      memory-region = <&vdevbuffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
> +      syscon = <&src>;
> +    };
> 
> > 
> > For the vrings I don't see the allocation of a carveout, which means that you
> > will take the memory out of the DMA pool and the reserve memory will be
> > wasted.
> 
> imx_rproc_parse_memory_regions will alloc carveout.

They _will_ but for now they don't and as such there a discrepancy between the
bindings and the code that was published in V6.  At this point you can either
drop the vrings in the DT or send another revision with the carveouts
allocated.  I would definitely prefer the latter because it wouldn't involve yet
another modification of the bindings.  

> 
> > 
> > For the vdev0buffer, what you have will work *only* if that entry is the first
> > one in the list of memory regions, as we agreed here [2].
> 
> Yes. I agree and follow this rule from then.
> 
> Thanks,
> Peng.
> 
> > 
> > [1].
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.b
> > ootlin.com%2Flinux%2Fv5.11-rc3%2Fsource%2Fdrivers%2Fremoteproc%2Fre
> > moteproc_core.c%23L321&amp;data=04%7C01%7Cpeng.fan%40nxp.com%7
> > C581784529b1646b9d34b08d8b67ae8c7%7C686ea1d3bc2b4c6fa92cd99c5c
> > 301635%7C0%7C0%7C637459986311799770%7CUnknown%7CTWFpbGZsb3
> > d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
> > %3D%7C1000&amp;sdata=Qur6YiTWlak0ZRnrUZRzawfoO38EBrAItqZm66b4
> > m20%3D&amp;reserved=0
> > [2].
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatch
> > work.kernel.org%2Fproject%2Flinux-remoteproc%2Fpatch%2F202007221315
> > 43.7024-1-peng.fan%40nxp.com%2F&amp;data=04%7C01%7Cpeng.fan%40n
> > xp.com%7C581784529b1646b9d34b08d8b67ae8c7%7C686ea1d3bc2b4c6fa9
> > 2cd99c5c301635%7C0%7C0%7C637459986311799770%7CUnknown%7CTW
> > FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX
> > VCI6Mn0%3D%7C1000&amp;sdata=b%2F8muWtb3yxKIsnXmKmRGYYV33%2
> > FHjwA6a8x58geY7eE%3D&amp;reserved=0
> > 
> > >  		err = of_address_to_resource(node, 0, &res);
> > >  		if (err) {
> > >  			dev_err(dev, "unable to resolve memory region\n");
> > > --
> > > 2.28.0
> > >