drivers/char/dsp56k.c

File Facts

System

Linux kernel

Corpus path

drivers/char/dsp56k.c

Extension

.c

Size

12512 bytes

Lines

536

Domain

Driver Families

Bucket

drivers/char

Inferred role

Driver Families: operation-table or driver-model contract

Status

pattern 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.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• 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

• linux/module.h
• linux/major.h
• linux/types.h
• linux/errno.h
• linux/delay.h
• linux/fs.h
• linux/mm.h
• linux/init.h
• linux/device.h
• linux/mutex.h
• linux/firmware.h
• linux/platform_device.h
• linux/uaccess.h
• asm/atarihw.h
• asm/traps.h
• asm/dsp56k.h

Detected Declarations

• function dsp56k_reset
• function dsp56k_upload
• function dsp56k_read
• function dsp56k_write
• function dsp56k_ioctl
• function dsp56k_poll
• function dsp56k_open
• function dsp56k_release
• function dsp56k_init_driver
• function dsp56k_cleanup_driver
• module init dsp56k_init_driver

Annotated Snippet

static const struct file_operations dsp56k_fops = {
	.owner		= THIS_MODULE,
	.read		= dsp56k_read,
	.write		= dsp56k_write,
	.unlocked_ioctl	= dsp56k_ioctl,
	.open		= dsp56k_open,
	.release	= dsp56k_release,
	.llseek		= noop_llseek,
};


/****** Init and module functions ******/

static const char banner[] __initconst = KERN_INFO "DSP56k driver installed\n";

static int __init dsp56k_init_driver(void)
{
	int err;

	if(!MACH_IS_ATARI || !ATARIHW_PRESENT(DSP56K)) {
		printk("DSP56k driver: Hardware not present\n");
		return -ENODEV;
	}

	if(register_chrdev(DSP56K_MAJOR, "dsp56k", &dsp56k_fops)) {
		printk("DSP56k driver: Unable to register driver\n");
		return -ENODEV;
	}
	err = class_register(&dsp56k_class);
	if (err)
		goto out_chrdev;
	device_create(&dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
		      "dsp56k");

	printk(banner);
	goto out;

out_chrdev:
	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
out:
	return err;
}
module_init(dsp56k_init_driver);

static void __exit dsp56k_cleanup_driver(void)
{
	device_destroy(&dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
	class_unregister(&dsp56k_class);
	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
}
module_exit(dsp56k_cleanup_driver);

MODULE_DESCRIPTION("Atari DSP56001 Device Driver");
MODULE_LICENSE("GPL");
MODULE_FIRMWARE("dsp56k/bootstrap.bin");

Annotation

• Immediate include surface: `linux/module.h`, `linux/major.h`, `linux/types.h`, `linux/errno.h`, `linux/delay.h`, `linux/fs.h`, `linux/mm.h`, `linux/init.h`.
• Detected declarations: `function dsp56k_reset`, `function dsp56k_upload`, `function dsp56k_read`, `function dsp56k_write`, `function dsp56k_ioctl`, `function dsp56k_poll`, `function dsp56k_open`, `function dsp56k_release`, `function dsp56k_init_driver`, `function dsp56k_cleanup_driver`.
• Atlas domain: Driver Families / drivers/char.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• 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.