Re: [PATCH 4/9] remoteproc: imx_rproc: surport early booted remote processor

[Mathieu Poirier]

On Wed, Feb 19, 2020 at 03:27:40PM +0800, peng.fan@xxxxxxx wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
> 
> When remote processor is booted by bootloader, Linux need to
> ignore firmware loading, and ignore remote processor start/stop
> related hardware operations. what should do is to need to handle
> memory-regions and resource table.
> 
> Add a src_started entry to check whether Cortex-M4 is started for i.MX7D
> and i.MX6SX.
> 
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
>  drivers/remoteproc/imx_rproc.c | 240 +++++++++++++++++++++++++++++++++++++----
>  1 file changed, 220 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 3e72b6f38d4b..b9fabe269fd2 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -74,6 +74,7 @@ struct imx_rproc_dcfg {
>  	u32				src_mask;
>  	u32				src_start;
>  	u32				src_stop;
> +	u32				src_started;
>  	const struct imx_rproc_att	*att;
>  	size_t				att_size;
>  };
> @@ -85,6 +86,7 @@ struct imx_rproc {
>  	const struct imx_rproc_dcfg	*dcfg;
>  	struct imx_rproc_mem		mem[IMX7D_RPROC_MEM_MAX];
>  	struct clk			*clk;
> +	bool				early_boot;
>  };
>  
>  static const struct imx_rproc_att imx_rproc_att_imx7d[] = {
> @@ -142,6 +144,7 @@ static const struct imx_rproc_dcfg imx_rproc_cfg_imx7d = {
>  	.src_mask	= IMX7D_M4_RST_MASK,
>  	.src_start	= IMX7D_M4_START,
>  	.src_stop	= IMX7D_M4_STOP,
> +	.src_started	= IMX7D_ENABLE_M4,
>  	.att		= imx_rproc_att_imx7d,
>  	.att_size	= ARRAY_SIZE(imx_rproc_att_imx7d),
>  };
> @@ -151,6 +154,7 @@ static const struct imx_rproc_dcfg imx_rproc_cfg_imx6sx = {
>  	.src_mask	= IMX6SX_M4_RST_MASK,
>  	.src_start	= IMX6SX_M4_START,
>  	.src_stop	= IMX6SX_M4_STOP,
> +	.src_started	= IMX6SX_ENABLE_M4,
>  	.att		= imx_rproc_att_imx6sx,
>  	.att_size	= ARRAY_SIZE(imx_rproc_att_imx6sx),
>  };
> @@ -162,6 +166,9 @@ static int imx_rproc_start(struct rproc *rproc)
>  	struct device *dev = priv->dev;
>  	int ret;
>  
> +	if (priv->early_boot)
> +		return 0;
> +
>  	ret = regmap_update_bits(priv->regmap, dcfg->src_reg,
>  				 dcfg->src_mask, dcfg->src_start);
>  	if (ret)
> @@ -177,6 +184,9 @@ static int imx_rproc_stop(struct rproc *rproc)
>  	struct device *dev = priv->dev;
>  	int ret;
>  
> +	if (priv->early_boot)
> +		return 0;
> +
>  	ret = regmap_update_bits(priv->regmap, dcfg->src_reg,
>  				 dcfg->src_mask, dcfg->src_stop);
>  	if (ret)
> @@ -240,10 +250,167 @@ static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>  	return va;
>  }
>  
> +static int imx_rproc_elf_load_segments(struct rproc *rproc,
> +				       const struct firmware *fw)
> +{
> +	struct imx_rproc *priv = rproc->priv;
> +
> +	if (!priv->early_boot)
> +		return rproc_elf_load_segments(rproc, fw);
> +
> +	return 0;
> +}
> +
> +static int imx_rproc_mem_alloc(struct rproc *rproc,
> +			       struct rproc_mem_entry *mem)
> +{
> +	struct device *dev = rproc->dev.parent;
> +	void *va;
> +
> +	dev_dbg(dev, "map memory: %p+%x\n", &mem->dma, mem->len);
> +	va = ioremap_wc(mem->dma, mem->len);
> +	if (IS_ERR_OR_NULL(va)) {
> +		dev_err(dev, "Unable to map memory region: %p+%x\n",
> +			&mem->dma, mem->len);
> +		return -ENOMEM;
> +	}
> +
> +	/* Update memory entry va */
> +	mem->va = va;
> +
> +	return 0;
> +}
> +
> +static int imx_rproc_mem_release(struct rproc *rproc,
> +				 struct rproc_mem_entry *mem)
> +{
> +	dev_dbg(rproc->dev.parent, "unmap memory: %pa\n", &mem->dma);
> +	iounmap(mem->va);
> +
> +	return 0;
> +}
> +
> +static int imx_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> +	struct imx_rproc *priv = rproc->priv;
> +	struct resource_table *resource_table;
> +	struct device_node *np = priv->dev->of_node;
> +	struct of_phandle_iterator it;
> +	struct rproc_mem_entry *mem;
> +	struct reserved_mem *rmem;
> +	int index = 0;
> +	int elems;
> +	int ret;
> +	u64 da;
> +
> +	if (!priv->early_boot)
> +		return rproc_elf_load_rsc_table(rproc, fw);

Once again I will concentrate on the scenario rather than making comments on the
code.

If I understand correctly if the AP is responsible for loading the firmware and
starting the MCU, the ELF image contains a resource table that describes all the
memory areas and vdev needed.

Otherwise the MCU firmware that is preloaded by the boot loader or the SCU
does _not_ have a resource table and as such specifics need to be coming from
the DT.  

Is my assesment correct?

> +
> +	/* Register associated reserved memory regions */
> +	of_phandle_iterator_init(&it, np, "memory-region", NULL, 0);
> +	while (of_phandle_iterator_next(&it) == 0) {
> +		rmem = of_reserved_mem_lookup(it.node);
> +		if (!rmem) {
> +			dev_err(priv->dev, "unable to acquire memory-region\n");
> +			return -EINVAL;
> +		}
> +
> +		/* No need to translate pa to da */
> +		da = rmem->base;
> +
> +		if (strcmp(it.node->name, "vdev0buffer")) {
> +			/* Register memory region */
> +			mem = rproc_mem_entry_init(priv->dev, NULL,
> +						   (dma_addr_t)rmem->base,
> +						   rmem->size, da,
> +						   imx_rproc_mem_alloc,
> +						   imx_rproc_mem_release,
> +						   it.node->name);
> +
> +			if (mem)
> +				rproc_coredump_add_segment(rproc, da,
> +							   rmem->size);
> +		} else {
> +			/* Register reserved memory for vdev buffer alloc */
> +			mem = rproc_of_resm_mem_entry_init(priv->dev, index,
> +							   rmem->size,
> +							   rmem->base,
> +							   it.node->name);
> +		}
> +
> +		if (!mem)
> +			return -ENOMEM;
> +
> +		rproc_add_carveout(rproc, mem);
> +		index++;
> +	}
> +
> +	/*Parse device tree to get resource table */
> +	elems = of_property_count_u32_elems(np, "rsrc-table");
> +	if (elems < 0) {
> +		dev_err(&rproc->dev, "no rsrc-table\n");
> +		return elems;
> +	}
> +
> +	resource_table = kzalloc(elems * sizeof(u32), GFP_KERNEL);
> +	if (!resource_table)
> +		return PTR_ERR(resource_table);
> +
> +	ret = of_property_read_u32_array(np, "rsrc-table",
> +					 (u32 *)resource_table, elems);
> +	if (ret)
> +		return ret;
> +
> +	rproc->cached_table = resource_table;
> +	rproc->table_ptr = resource_table;
> +	rproc->table_sz = elems * sizeof(u32);
> +
> +	return 0;
> +}
> +
> +static struct resource_table *
> +imx_rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
> +				    const struct firmware *fw)
> +{
> +	struct imx_rproc *priv = rproc->priv;
> +
> +	if (!priv->early_boot)
> +		return rproc_elf_find_loaded_rsc_table(rproc, fw);
> +
> +	return NULL;
> +}
> +
> +static int imx_rproc_elf_sanity_check(struct rproc *rproc,
> +				      const struct firmware *fw)
> +{
> +	struct imx_rproc *priv = rproc->priv;
> +
> +	if (!priv->early_boot)
> +		return rproc_elf_sanity_check(rproc, fw);
> +
> +	return 0;
> +}
> +
> +static u32 imx_rproc_elf_get_boot_addr(struct rproc *rproc,
> +				       const struct firmware *fw)
> +{
> +	struct imx_rproc *priv = rproc->priv;
> +
> +	if (!priv->early_boot)
> +		return rproc_elf_get_boot_addr(rproc, fw);
> +
> +	return 0;
> +}
> +
>  static const struct rproc_ops imx_rproc_ops = {
>  	.start		= imx_rproc_start,
>  	.stop		= imx_rproc_stop,
>  	.da_to_va       = imx_rproc_da_to_va,
> +	.load		= imx_rproc_elf_load_segments,
> +	.parse_fw	= imx_rproc_parse_fw,
> +	.find_loaded_rsc_table = imx_rproc_elf_find_loaded_rsc_table,
> +	.sanity_check	= imx_rproc_elf_sanity_check,
> +	.get_boot_addr	= imx_rproc_elf_get_boot_addr,
>  };
>  
>  static int imx_rproc_addr_init(struct imx_rproc *priv,
> @@ -309,6 +476,31 @@ static int imx_rproc_addr_init(struct imx_rproc *priv,
>  	return 0;
>  }
>  
> +static int imx_rproc_configure_mode(struct imx_rproc *priv)
> +{
> +	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
> +	struct device *dev = priv->dev;
> +	int ret;
> +	u32 val;
> +
> +	if (of_get_property(dev->of_node, "early-booted", NULL)) {
> +		priv->early_boot = true;
> +	} else {
> +		ret = regmap_read(priv->regmap, dcfg->src_reg, &val);
> +		if (ret) {
> +			dev_err(dev, "Failed to read src\n");
> +			return ret;
> +		}
> +
> +		priv->early_boot = !!(val & dcfg->src_started);
> +	}
> +
> +	if (priv->early_boot)
> +		priv->rproc->skip_fw_load = true;
> +
> +	return 0;
> +}
> +
>  static int imx_rproc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -347,27 +539,33 @@ static int imx_rproc_probe(struct platform_device *pdev)
>  
>  	dev_set_drvdata(dev, rproc);
>  
> -	ret = imx_rproc_addr_init(priv, pdev);
> -	if (ret) {
> -		dev_err(dev, "failed on imx_rproc_addr_init\n");
> +	ret = imx_rproc_configure_mode(priv);
> +	if (ret)
>  		goto err_put_rproc;
> -	}
>  
> -	priv->clk = devm_clk_get(dev, NULL);
> -	if (IS_ERR(priv->clk)) {
> -		dev_err(dev, "Failed to get clock\n");
> -		ret = PTR_ERR(priv->clk);
> -		goto err_put_rproc;
> -	}
> +	if (!priv->early_boot) {
> +		ret = imx_rproc_addr_init(priv, pdev);
> +		if (ret) {
> +			dev_err(dev, "failed on imx_rproc_addr_init\n");
> +			goto err_put_rproc;
> +		}
>  
> -	/*
> -	 * clk for M4 block including memory. Should be
> -	 * enabled before .start for FW transfer.
> -	 */
> -	ret = clk_prepare_enable(priv->clk);
> -	if (ret) {
> -		dev_err(&rproc->dev, "Failed to enable clock\n");
> -		goto err_put_rproc;
> +		priv->clk = devm_clk_get(dev, NULL);
> +		if (IS_ERR(priv->clk)) {
> +			dev_err(dev, "Failed to get clock\n");
> +			ret = PTR_ERR(priv->clk);
> +			goto err_put_rproc;
> +		}
> +
> +		/*
> +		 * clk for M4 block including memory. Should be
> +		 * enabled before .start for FW transfer.
> +		 */
> +		ret = clk_prepare_enable(priv->clk);
> +		if (ret) {
> +			dev_err(&rproc->dev, "Failed to enable clock\n");
> +			goto err_put_rproc;
> +		}
>  	}
>  
>  	ret = rproc_add(rproc);
> @@ -379,7 +577,8 @@ static int imx_rproc_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err_put_clk:
> -	clk_disable_unprepare(priv->clk);
> +	if (!priv->early_boot)
> +		clk_disable_unprepare(priv->clk);
>  err_put_rproc:
>  	rproc_free(rproc);
>  
> @@ -391,7 +590,8 @@ static int imx_rproc_remove(struct platform_device *pdev)
>  	struct rproc *rproc = platform_get_drvdata(pdev);
>  	struct imx_rproc *priv = rproc->priv;
>  
> -	clk_disable_unprepare(priv->clk);
> +	if (!priv->early_boot)
> +		clk_disable_unprepare(priv->clk);
>  	rproc_del(rproc);
>  	rproc_free(rproc);
>  
> -- 
> 2.16.4
>