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Date:   Mon, 11 Jan 2021 14:50:23 -0700
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     peng.fan@nxp.com
Cc:     ohad@wizery.com, bjorn.andersson@linaro.org,
        o.rempel@pengutronix.de, shawnguo@kernel.org,
        s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com,
        linux-imx@nxp.com, linux-remoteproc@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        paul@crapouillou.net, matthias.bgg@gmail.com, agross@kernel.org,
        patrice.chotard@st.com
Subject: Re: [PATCH V5 7/8] remoteproc: imx_rproc: ignore mapping vdev regions
Message-ID: <20210111215023.GJ144935@xps15>
References: <20201229033019.25899-1-peng.fan@nxp.com>
 <20201229033019.25899-8-peng.fan@nxp.com>
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On Tue, Dec 29, 2020 at 11:30:18AM +0800, peng.fan@nxp.com wrote:
> From: Peng Fan <peng.fan@nxp.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@nxp.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.  

So I am guessing that you have laid out the memory regions for the vrings
and the vdev0buffer in the DT "memory-region".

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.

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].

[1]. https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/remoteproc/remoteproc_core.c#L321
[2]. https://patchwork.kernel.org/project/linux-remoteproc/patch/20200722131543.7024-1-peng.fan@nxp.com/

>  		err = of_address_to_resource(node, 0, &res);
>  		if (err) {
>  			dev_err(dev, "unable to resolve memory region\n");
> -- 
> 2.28.0
>