drivers/sbus/char/flash.c

File Facts

System

Linux kernel

Corpus path

drivers/sbus/char/flash.c

Extension

.c

Size

4862 bytes

Lines

216

Domain

Driver Families

Bucket

drivers/sbus

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/types.h
• linux/errno.h
• linux/miscdevice.h
• linux/fcntl.h
• linux/poll.h
• linux/mutex.h
• linux/spinlock.h
• linux/mm.h
• linux/of.h
• linux/platform_device.h
• linux/uaccess.h
• asm/io.h
• asm/upa.h

Detected Declarations

• function flash_mmap
• function flash_llseek
• function flash_read
• function flash_open
• function flash_release
• function flash_probe
• function flash_remove

Annotated Snippet

static const struct file_operations flash_fops = {
	/* no write to the Flash, use mmap
	 * and play flash dependent tricks.
	 */
	.owner =	THIS_MODULE,
	.llseek =	flash_llseek,
	.read =		flash_read,
	.mmap =		flash_mmap,
	.open =		flash_open,
	.release =	flash_release,
};

static struct miscdevice flash_dev = { SBUS_FLASH_MINOR, "flash", &flash_fops };

static int flash_probe(struct platform_device *op)
{
	struct device_node *dp = op->dev.of_node;
	struct device_node *parent;

	parent = dp->parent;

	if (!of_node_name_eq(parent, "sbus") &&
	    !of_node_name_eq(parent, "sbi") &&
	    !of_node_name_eq(parent, "ebus"))
		return -ENODEV;

	flash.read_base = op->resource[0].start;
	flash.read_size = resource_size(&op->resource[0]);
	if (op->resource[1].flags) {
		flash.write_base = op->resource[1].start;
		flash.write_size = resource_size(&op->resource[1]);
	} else {
		flash.write_base = op->resource[0].start;
		flash.write_size = resource_size(&op->resource[0]);
	}
	flash.busy = 0;

	printk(KERN_INFO "%pOF: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
	       op->dev.of_node,
	       flash.read_base, flash.read_size,
	       flash.write_base, flash.write_size);

	return misc_register(&flash_dev);
}

static void flash_remove(struct platform_device *op)
{
	misc_deregister(&flash_dev);
}

static const struct of_device_id flash_match[] = {
	{
		.name = "flashprom",
	},
	{},
};
MODULE_DEVICE_TABLE(of, flash_match);

static struct platform_driver flash_driver = {
	.driver = {
		.name = "flash",
		.of_match_table = flash_match,
	},
	.probe		= flash_probe,
	.remove		= flash_remove,
};

module_platform_driver(flash_driver);

MODULE_DESCRIPTION("OBP Flash Device driver");
MODULE_LICENSE("GPL");

Annotation

• Immediate include surface: `linux/module.h`, `linux/types.h`, `linux/errno.h`, `linux/miscdevice.h`, `linux/fcntl.h`, `linux/poll.h`, `linux/mutex.h`, `linux/spinlock.h`.
• Detected declarations: `function flash_mmap`, `function flash_llseek`, `function flash_read`, `function flash_open`, `function flash_release`, `function flash_probe`, `function flash_remove`.
• Atlas domain: Driver Families / drivers/sbus.
• 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.