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Date:   Thu, 25 Mar 2021 17:58:14 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     "Peng Fan (OSS)" <peng.fan@oss.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,
        Peng Fan <peng.fan@nxp.com>
Subject: Re: [PATCH 2/2] remoteproc: imx_rproc: support remote cores booted
 before Linux Kernel
Message-ID: <20210325235814.GD1982573@xps15>
References: <20210319104708.7754-1-peng.fan@oss.nxp.com>
 <20210319104708.7754-2-peng.fan@oss.nxp.com>
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In-Reply-To: <20210319104708.7754-2-peng.fan@oss.nxp.com>
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On Fri, Mar 19, 2021 at 06:47:08PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> Support remote cores booted before Linux Kernel booting.
> 
> Add rsc_table to hold the resource table published by remote cores
> Add attach hook

Missing a period "." and a new line between the paragraphs.

> Add imx_rproc_detect_mode to detect remote cores' working mode, and if
> remote cores are booted before booting Linux Kernel, parse the memory
> regions and initialize the table_ptr, table_sz, cached_table.
> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/remoteproc/imx_rproc.c | 64 ++++++++++++++++++++++++++++++++++
>  1 file changed, 64 insertions(+)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 24275429a7cc..fdaaf7599cc8 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -74,6 +74,16 @@ struct imx_rproc_att {
>  	int flags;
>  };
>  
> +enum imx_rproc_mode {
> +	/* Linux load/kick remote core */
> +	IMX_RPROC_NORMAL,
> +	/*
> +	 * remote core booted before kicking Linux, and remote core
> +	 * could be stopped & restarted by Linux
> +	 */
> +	IMX_RPROC_EARLY_BOOT,
> +};
> +
>  struct imx_rproc_dcfg {
>  	u32				src_reg;
>  	u32				src_mask;
> @@ -95,6 +105,8 @@ struct imx_rproc {
>  	struct mbox_chan		*rx_ch;
>  	struct work_struct		rproc_work;
>  	struct workqueue_struct		*workqueue;
> +	enum imx_rproc_mode		mode;
> +	void __iomem			*rsc_table;
>  };
>  
>  static const struct imx_rproc_att imx_rproc_att_imx8mq[] = {
> @@ -229,6 +241,9 @@ static int imx_rproc_stop(struct rproc *rproc)
>  	if (ret)
>  		dev_err(dev, "Failed to stop M4!\n");
>  
> +	if (priv->mode == IMX_RPROC_EARLY_BOOT)
> +		priv->mode = IMX_RPROC_NORMAL;
> +

Why is this needed?  What scenario are you trying to address?

>  	return ret;
>  }
>  
> @@ -398,9 +413,15 @@ static void imx_rproc_kick(struct rproc *rproc, int vqid)
>  			__func__, vqid, err);
>  }
>  
> +static int imx_rproc_attach(struct rproc *rproc)
> +{
> +	return 0;
> +}
> +
>  static const struct rproc_ops imx_rproc_ops = {
>  	.start		= imx_rproc_start,
>  	.stop		= imx_rproc_stop,
> +	.attach		= imx_rproc_attach,
>  	.kick		= imx_rproc_kick,
>  	.da_to_va       = imx_rproc_da_to_va,
>  	.load		= rproc_elf_load_segments,
> @@ -470,6 +491,8 @@ static int imx_rproc_addr_init(struct imx_rproc *priv,
>  		}
>  		priv->mem[b].sys_addr = res.start;
>  		priv->mem[b].size = resource_size(&res);
> +		if (!strcmp(node->name, "rsc_table"))
> +			priv->rsc_table = priv->mem[b].cpu_addr;
>  		b++;
>  	}
>  
> @@ -536,6 +559,43 @@ static void imx_rproc_free_mbox(struct rproc *rproc)
>  	mbox_free_channel(priv->rx_ch);
>  }
>  
> +static int imx_rproc_detect_mode(struct imx_rproc *priv)
> +{
> +	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
> +	struct rproc *rproc = priv->rproc;
> +	struct device *dev = priv->dev;
> +	int ret;
> +	u32 val;
> +
> +	ret = regmap_read(priv->regmap, dcfg->src_reg, &val);
> +	if (ret) {
> +		dev_err(dev, "Failed to read src\n");
> +		return ret;
> +	}
> +
> +	if (!(val & dcfg->src_stop))
> +		priv->mode = IMX_RPROC_EARLY_BOOT;
> +	else
> +		priv->mode = IMX_RPROC_NORMAL;
> +
> +	if (priv->mode == IMX_RPROC_EARLY_BOOT) {
> +		priv->rproc->state = RPROC_DETACHED;
> +
> +		ret = imx_rproc_parse_memory_regions(priv->rproc);

If you do this here it won't be possible to reattach to the remote processor
once it has been detached.  This kind of memory parsing should go in
rproc_ops::prepare().  I suggest you look at what has been done for STM32, the
example there is quite good and simple.

> +		if (ret)
> +			return ret;
> +
> +		if (!priv->rsc_table)
> +			return 0;
> +
> +		rproc->table_ptr = (struct resource_table *)priv->rsc_table;

The core is taking care of that, see rproc_set_rsc_table() for details.  

> +		rproc->table_sz = SZ_1K;
> +		rproc->cached_table = NULL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int imx_rproc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -590,6 +650,10 @@ static int imx_rproc_probe(struct platform_device *pdev)
>  		goto err_put_mbox;
>  	}
>  
> +	ret = imx_rproc_detect_mode(priv);
> +	if (ret)
> +		goto err_put_mbox;
> +

While reviewing this patch I noticed that of_node_put() is never called after
of_parse_phandle().  Please add a fix for that, in a patch on its own, in your
next revision.

Thanks,
Mathieu

>  	priv->clk = devm_clk_get(dev, NULL);
>  	if (IS_ERR(priv->clk)) {
>  		dev_err(dev, "Failed to get clock\n");
> -- 
> 2.30.0
>