Re: [PATCH v26 5/5] remoteproc: Add initial zynqmp R5 remoteproc driver

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Hi Mathieu

-----Original Message-----
From: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Date: Tuesday, March 9, 2021 at 8:53 AM
To: Ben Levinsky <BLEVINSK@xxxxxxxxxx>
Cc: "devicetree@xxxxxxxxxxxxxxx" <devicetree@xxxxxxxxxxxxxxx>, "linux-remoteproc@xxxxxxxxxxxxxxx" <linux-remoteproc@xxxxxxxxxxxxxxx>, "linux-kernel@xxxxxxxxxxxxxxx" <linux-kernel@xxxxxxxxxxxxxxx>, "linux-arm-kernel@xxxxxxxxxxxxxxxxxxx" <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>, Michal Simek <michals@xxxxxxxxxx>
Subject: Re: [PATCH v26 5/5] remoteproc: Add initial zynqmp R5 remoteproc driver

    [...]

    > +
    > +/**
    > + * zynqmp_r5_probe - Probes ZynqMP R5 processor device node
    > + *		       this is called for each individual R5 core to
    > + *		       set up mailbox, Xilinx platform manager unique ID,
    > + *		       add to rproc core
    > + *
    > + * @pdev: domain platform device for current R5 core
    > + * @node: pointer of the device node for current R5 core
    > + * @rpu_mode: mode to configure RPU, split or lockstep
    > + *
    > + * Return: 0 for success, negative value for failure.
    > + */
    > +static struct zynqmp_r5_rproc *zynqmp_r5_probe(struct platform_device *pdev,
    > +					       struct device_node *node,
    > +					       enum rpu_oper_mode rpu_mode)
    > +{
    > +	int ret, num_banks;
    > +	struct device *dev = &pdev->dev;
    > +	struct rproc *rproc_ptr;
    > +	struct zynqmp_r5_rproc *z_rproc;
    > +	struct device_node *r5_node;
    > +
    > +	/* Allocate remoteproc instance */
    > +	rproc_ptr = devm_rproc_alloc(dev, dev_name(dev), &zynqmp_r5_rproc_ops,
    > +				     NULL, sizeof(struct zynqmp_r5_rproc));
    > +	if (!rproc_ptr) {
    > +		ret = -ENOMEM;
    > +		goto error;
    > +	}
    > +
    > +	rproc_ptr->auto_boot = false;
    > +	z_rproc = rproc_ptr->priv;
    > +	z_rproc->rproc = rproc_ptr;
    > +	r5_node = z_rproc->rproc->dev.parent->of_node;
    > +
    > +	/* Set up DMA mask */
    > +	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
    > +	if (ret)
    > +		goto error;
    > +
    > +	/* Get R5 power domain node */
    > +	ret = of_property_read_u32(node, "power-domain", &z_rproc->pnode_id);
    > +	if (ret)
    > +		goto error;
    > +
    > +	ret = r5_set_mode(z_rproc, rpu_mode);
    > +	if (ret)
    > +		goto error;
    > +
    > +	if (of_property_read_bool(node, "mboxes")) {
    > +		ret = zynqmp_r5_setup_mbox(z_rproc, node);
    > +		if (ret)
    > +			goto error;
    > +	}
    > +
    > +	/* go through TCM banks for r5 node */
    > +	num_banks = of_count_phandle_with_args(r5_node, BANK_LIST_PROP, NULL);
    > +	if (num_banks <= 0) {
    > +		dev_err(dev, "need to specify TCM banks\n");
    > +		ret = -EINVAL;
    > +		goto error;
    > +	}
    > +
    > +	if (num_banks > NUM_SRAMS) {
    > +		dev_err(dev, "max number of srams is %d. given: %d \r\n",
    > +			NUM_SRAMS, num_banks);
    > +		ret = -EINVAL;
    > +		goto error;
    > +	}
    > +
    > +	/* construct collection of srams used by the current R5 core */
    > +	for (; num_banks; num_banks--) {
    > +		struct resource rsc;
    > +		struct device_node *dt_node;
    > +		resource_size_t size;
    > +		int i;
    > +
    > +		dt_node = of_parse_phandle(r5_node, BANK_LIST_PROP, i);

    Variable @i is not initialised but it is used as an index to retrieve a handle
    to the sram banks.  That code _should_ have failed frequently or at least have
    yielded abnormal results often enough to be noticed.  Why wasn't it the case?

    I will stop here for the moment.

[Ben]
Yes this should be initialized. The reason this got through is that as i defaults to 0 and the 0th bank housed the required data. the case where SRAMS that can be written to, 0xFFE20000 in this case of split mode and on R5-0, was not caught.

Instead of i I will use 

                sram_node = of_parse_phandle(node, BANK_LIST_PROP,              
                                             num_banks - 1); 


sram_node is the var name given in the function called by probe to collect the SRAM information.



If there is other feedback please let me know

Thanks
Ben


    > +		if (!dt_node) {
    > +			ret = -EINVAL;
    > +			goto error;
    > +		}
    > +
    > +		ret = of_address_to_resource(dt_node, 0, &rsc);
    > +		if (ret < 0) {
    > +			of_node_put(dt_node);
    > +			goto error;
    > +		}
    > +
    > +		of_node_put(dt_node);
    > +		size = resource_size(&rsc);
    > +
    > +		/*
    > +		 * Find corresponding Xilinx platform management ID.
    > +		 * The bank information is used in prepare/unprepare and
    > +		 * parse_fw.
    > +		 */
    > +		for (i = 0; i < NUM_SRAMS; i++) {
    > +			if (rsc.start == zynqmp_banks[i].addr) {
    > +				z_rproc->srams[i].addr = rsc.start;
    > +				z_rproc->srams[i].size = size;
    > +				z_rproc->srams[i].id = zynqmp_banks[i].id;
    > +				break;
    > +			}
    > +		}
    > +
    > +		if (i == NUM_SRAMS) {
    > +			dev_err(dev, "sram %llx is not valid.\n", rsc.start);
    > +			ret = -EINVAL;
    > +			goto error;
    > +		}
    > +	}
    > +
    > +	/* Add R5 remoteproc */
    > +	ret = devm_rproc_add(dev, rproc_ptr);
    > +	if (ret) {
    > +		zynqmp_r5_cleanup_mbox(z_rproc);
    > +		goto error;
    > +	}
    > +
    > +	return z_rproc;
    > +error:
    > +	return ERR_PTR(ret);
    > +}
    > +
    > +/*
    > + * zynqmp_r5_remoteproc_probe
    > + *
    > + * @pdev: domain platform device for R5 cluster
    > + *
    > + * called when driver is probed, for each R5 core specified in DT,
    > + * setup as needed to do remoteproc-related operations
    > + *
    > + * Return: 0 for success, negative value for failure.
    > + */
    > +static int zynqmp_r5_remoteproc_probe(struct platform_device *pdev)
    > +{
    > +	int ret, core_count;
    > +	struct device *dev = &pdev->dev;
    > +	struct device_node *nc;
    > +	enum rpu_oper_mode rpu_mode = PM_RPU_MODE_LOCKSTEP;
    > +	struct list_head *cluster; /* list to track each core's rproc */
    > +	struct zynqmp_r5_rproc *z_rproc;
    > +	struct platform_device *child_pdev;
    > +	struct list_head *pos;
    > +
    > +	ret = of_property_read_u32(dev->of_node, "xlnx,cluster-mode", &rpu_mode);
    > +	if (ret < 0 || (rpu_mode != PM_RPU_MODE_LOCKSTEP &&
    > +			rpu_mode != PM_RPU_MODE_SPLIT)) {
    > +		dev_err(dev, "invalid cluster mode: ret %d mode %x\n",
    > +			ret, rpu_mode);
    > +		return ret;
    > +	}
    > +
    > +	dev_dbg(dev, "RPU configuration: %s\n",
    > +		rpu_mode == PM_RPU_MODE_LOCKSTEP ? "lockstep" : "split");
    > +
    > +	/*
    > +	 * if 2 RPUs provided but one is lockstep, then we have an
    > +	 * invalid configuration.
    > +	 */
    > +
    > +	core_count = of_get_available_child_count(dev->of_node);
    > +	if ((rpu_mode == PM_RPU_MODE_LOCKSTEP && core_count != 1) ||
    > +	    core_count > MAX_RPROCS)
    > +		return -EINVAL;
    > +
    > +	cluster = devm_kzalloc(dev, sizeof(*cluster), GFP_KERNEL);
    > +	if (!cluster)
    > +		return -ENOMEM;
    > +	INIT_LIST_HEAD(cluster);
    > +
    > +	ret = devm_of_platform_populate(dev);
    > +	if (ret) {
    > +		dev_err(dev, "devm_of_platform_populate failed, ret = %d\n", ret);
    > +		return ret;
    > +	}
    > +
    > +	/* probe each individual r5 core's remoteproc-related info */
    > +	for_each_available_child_of_node(dev->of_node, nc) {
    > +		child_pdev = of_find_device_by_node(nc);
    > +		if (!child_pdev) {
    > +			dev_err(dev, "could not get R5 core platform device\n");
    > +			ret = -ENODEV;
    > +			goto out;
    > +		}
    > +
    > +		z_rproc = zynqmp_r5_probe(child_pdev, nc, rpu_mode);
    > +		dev_dbg(dev, "%s to probe rpu %pOF\n",
    > +			ret ? "Failed" : "Able", nc);
    > +		if (IS_ERR(z_rproc)) {
    > +			ret = PTR_ERR(z_rproc);
    > +			goto out;
    > +		}
    > +		list_add_tail(&z_rproc->elem, cluster);
    > +	}
    > +	/* wire in so each core can be cleaned up at driver remove */
    > +	platform_set_drvdata(pdev, cluster);
    > +	return 0;
    > +out:
    > +	list_for_each(pos, cluster) {
    > +		z_rproc = list_entry(pos, struct zynqmp_r5_rproc, elem);
    > +		zynqmp_r5_cleanup_mbox(z_rproc);
    > +	}
    > +	return ret;
    > +}
    > +
    > +/*
    > + * zynqmp_r5_remoteproc_remove
    > + *
    > + * @pdev: domain platform device for R5 cluster
    > + *
    > + * When the driver is unloaded, clean up the mailboxes for each
    > + * remoteproc that was initially probed.
    > + */
    > +static int zynqmp_r5_remoteproc_remove(struct platform_device *pdev)
    > +{
    > +	struct list_head *pos, *temp, *cluster = (struct list_head *)
    > +						 platform_get_drvdata(pdev);
    > +	struct zynqmp_r5_rproc *z_rproc = NULL;
    > +
    > +	list_for_each_safe(pos, temp, cluster) {
    > +		z_rproc = list_entry(pos, struct zynqmp_r5_rproc, elem);
    > +		zynqmp_r5_cleanup_mbox(z_rproc);
    > +	}
    > +	return 0;
    > +}
    > +
    > +/* Match table for OF platform binding */
    > +static const struct of_device_id zynqmp_r5_remoteproc_match[] = {
    > +	{ .compatible = "xlnx,zynqmp-r5-remoteproc", },
    > +	{ /* end of list */ },
    > +};
    > +MODULE_DEVICE_TABLE(of, zynqmp_r5_remoteproc_match);
    > +
    > +static struct platform_driver zynqmp_r5_remoteproc_driver = {
    > +	.probe = zynqmp_r5_remoteproc_probe,
    > +	.remove = zynqmp_r5_remoteproc_remove,
    > +	.driver = {
    > +		.name = "zynqmp_r5_remoteproc",
    > +		.of_match_table = zynqmp_r5_remoteproc_match,
    > +	},
    > +};
    > +module_platform_driver(zynqmp_r5_remoteproc_driver);
    > +
    > +MODULE_AUTHOR("Ben Levinsky <ben.levinsky@xxxxxxxxxx>");
    > +MODULE_LICENSE("GPL v2");
    > -- 
    > 2.17.1
    > 





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