drivers/of/fdt.c

Source file repositories/reference/linux-study-clean/drivers/of/fdt.c

File Facts

System
Linux kernel
Corpus path
drivers/of/fdt.c
Extension
.c
Size
33991 bytes
Lines
1350
Domain
Driver Families
Bucket
drivers/of
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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.

Dependency Surface

Detected Declarations

Annotated Snippet

if (len > limit*cell_size) {
			len = limit*cell_size;
			pr_debug("Limiting number of entries to %d\n", limit);
			fdt_setprop(initial_boot_params, memory, "reg", val,
					len);
		}
	}
}

bool of_fdt_device_is_available(const void *blob, unsigned long node)
{
	const char *status = fdt_stringlist_get(blob, node, "status", 0, NULL);

	if (!status)
		return true;

	if (!strcmp(status, "ok") || !strcmp(status, "okay"))
		return true;

	return false;
}

static void *unflatten_dt_alloc(void **mem, unsigned long size,
				       unsigned long align)
{
	void *res;

	*mem = PTR_ALIGN(*mem, align);
	res = *mem;
	*mem += size;

	return res;
}

static void populate_properties(const void *blob,
				int offset,
				void **mem,
				struct device_node *np,
				const char *nodename,
				bool dryrun)
{
	struct property *pp, **pprev = NULL;
	int cur;
	bool has_name = false;

	pprev = &np->properties;
	for (cur = fdt_first_property_offset(blob, offset);
	     cur >= 0;
	     cur = fdt_next_property_offset(blob, cur)) {
		const __be32 *val;
		const char *pname;
		u32 sz;

		val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
		if (!val) {
			pr_warn("Cannot locate property at 0x%x\n", cur);
			continue;
		}

		if (!pname) {
			pr_warn("Cannot find property name at 0x%x\n", cur);
			continue;
		}

		if (!strcmp(pname, "name"))
			has_name = true;

		pp = unflatten_dt_alloc(mem, sizeof(struct property),
					__alignof__(struct property));
		if (dryrun)
			continue;

		/* We accept flattened tree phandles either in
		 * ePAPR-style "phandle" properties, or the
		 * legacy "linux,phandle" properties.  If both
		 * appear and have different values, things
		 * will get weird. Don't do that.
		 */
		if (!strcmp(pname, "phandle") ||
		    !strcmp(pname, "linux,phandle")) {
			if (!np->phandle)
				np->phandle = be32_to_cpup(val);
		}

		/* And we process the "ibm,phandle" property
		 * used in pSeries dynamic device tree
		 * stuff
		 */
		if (IS_ENABLED(CONFIG_PPC_PSERIES) && !strcmp(pname, "ibm,phandle"))
			np->phandle = be32_to_cpup(val);

Annotation

Implementation Notes