Messages in this thread | | | From | Ben Levinsky <> | Subject | [RFC PATCH 0/1] remoteproc: Enable getter for drivers that manage 2+ remotes | Date | Tue, 15 Nov 2022 07:37:52 -0800 |
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This RFC is to show the following (a) a use case for a new remoteproc API rproc_get_by_id() (b) patch for the new API rproc_get_by_id()
For context there exist multiple drivers in remoteproc that manage more than one remote processor. For these drivers, calls to rproc_get_by_phandle() are not sufficient as the check at https://github.com/torvalds/linux/blob/master/drivers/remoteproc/remoteproc_core.c#L2111 will not work. This is because for r->dev.parent, r->dev's parent is expected to be the platform device that corresponds to the platform-probe() call but instead is the child and this child does not have the driver field set.
An example to show this issue is as follows:
If a remoteproc driver has the following DTS binding:
/{ remoteproc_cluster { compatible = "soc,remoteproc-cluster";
core0: core0 { memory-region; sram; };
core1: core1 { memory-region; sram; } }; };
And in the corresponding driver the platform-probe() is as follows:
static int cluster_platform_probe(struct platform_device *pdev) { struct device_node *np = dev_of_node(dev); struct device *dev = &pdev->dev; struct platform_device *cpdev; struct device *child_dev; struct rproc *rp;
for_each_available_child_of_node(np, child) { cpdev = of_find_device_by_node(child); child_dev = &cpdev->dev;
rp = rproc_alloc(cdev, dev_name(cdev), dummy_ops, NULL, sizeof(struct dummy_ops)); }
return 0; }
After the rproc call is done and when another driver tries to access this rproc structure via a rproc_get_by_phandle(), the aforementioned check of r->dev.parent->driver will be NULL.
To account for a remoteproc driver that manages multiple remote processors, I have provided an API rproc_get_by_id() that enables getting rp given a phandle to the core in question with a DT binding and usage of the API.
Sample binding:
/{ platform_driver_sample { compatible = "custom_platform"; rproc = <&core1>; }; };
Sample usage:
static int custom_platform_probe(struct platform_device *pdev) { struct rproc *rp; struct device_node *node;
node = of_parse_phandle(pdev->dev.of_node, "rproc", 0);
/* Here get rproc 1, as its index should be 1 */ rp = rproc_get_by_id(node->phandle, 1);
return 0; } If we want further specification of getting the correct remoteproc ID, this can be inferred from the pdev->dev child's device child node and its dev->init_name field as this is set in rproc_alloc() as follows:
dev_set_name(&rproc->dev, "remoteproc%d", rproc->index);
We can then parse the pdev->dev child device as follows:
int index;
sscanf(dev_name(dev), "remoteproc%d", &index);
Additionally I have provided the implementation for the API in the subsequent patch.
Ben Levinsky (1): remoteproc: Introduce rproc_get_by_id API
drivers/remoteproc/remoteproc_core.c | 64 +++++++++++++++++++++++++++- include/linux/remoteproc.h | 1 + 2 files changed, 64 insertions(+), 1 deletion(-)
-- 2.25.1
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