drivers/usb/host/ehci-sysfs.c

File Facts

System

Linux kernel

Corpus path

drivers/usb/host/ehci-sysfs.c

Extension

.c

Size

4292 bytes

Lines

169

Domain

Driver Families

Bucket

drivers/usb

Inferred role

Driver Families: implementation source

Status

source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• function Copyright
• function companion_store
• function uframe_periodic_max_show
• function uframe_periodic_max_store
• function create_sysfs_files
• function remove_sysfs_files

Annotated Snippet

if (allocated_max > uframe_periodic_max) {
			ehci_info(ehci,
				"cannot decrease uframe_periodic_max because "
				"periodic bandwidth is already allocated "
				"(%u > %u)\n",
				allocated_max, uframe_periodic_max);
			goto out_unlock;
		}
	}

	/* increasing is always ok */

	ehci_info(ehci, "setting max periodic bandwidth to %u%% "
			"(== %u usec/uframe)\n",
			100*uframe_periodic_max/125, uframe_periodic_max);

	if (uframe_periodic_max != 100)
		ehci_warn(ehci, "max periodic bandwidth set is non-standard\n");

	ehci->uframe_periodic_max = uframe_periodic_max;
	ret = count;

out_unlock:
	spin_unlock_irqrestore (&ehci->lock, flags);
	return ret;
}
static DEVICE_ATTR_RW(uframe_periodic_max);


static inline int create_sysfs_files(struct ehci_hcd *ehci)
{
	struct device	*controller = ehci_to_hcd(ehci)->self.controller;
	int	i = 0;

	/* with integrated TT there is no companion! */
	if (!ehci_is_TDI(ehci))
		i = device_create_file(controller, &dev_attr_companion);
	if (i)
		goto out;

	i = device_create_file(controller, &dev_attr_uframe_periodic_max);
out:
	return i;
}

static inline void remove_sysfs_files(struct ehci_hcd *ehci)
{
	struct device	*controller = ehci_to_hcd(ehci)->self.controller;

	/* with integrated TT there is no companion! */
	if (!ehci_is_TDI(ehci))
		device_remove_file(controller, &dev_attr_companion);

	device_remove_file(controller, &dev_attr_uframe_periodic_max);
}

Annotation

• Detected declarations: `function Copyright`, `function companion_store`, `function uframe_periodic_max_show`, `function uframe_periodic_max_store`, `function create_sysfs_files`, `function remove_sysfs_files`.
• Atlas domain: Driver Families / drivers/usb.
• Implementation status: source implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.