drivers/firmware/efi/fdtparams.c

Source file repositories/reference/linux-study-clean/drivers/firmware/efi/fdtparams.c

File Facts

System
Linux kernel
Corpus path
drivers/firmware/efi/fdtparams.c
Extension
.c
Size
3061 bytes
Lines
134
Domain
Driver Families
Bucket
drivers/firmware
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.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only

#define pr_fmt(fmt) "efi: " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/efi.h>
#include <linux/libfdt.h>
#include <linux/of_fdt.h>

#include <linux/unaligned.h>

enum {
	SYSTAB,
	MMBASE,
	MMSIZE,
	DCSIZE,
	DCVERS,

	PARAMCOUNT
};

static __initconst const char name[][22] = {
	[SYSTAB] = "System Table         ",
	[MMBASE] = "MemMap Address       ",
	[MMSIZE] = "MemMap Size          ",
	[DCSIZE] = "MemMap Desc. Size    ",
	[DCVERS] = "MemMap Desc. Version ",
};

static __initconst const struct {
	const char	path[17];
	u8		paravirt;
	const char	params[PARAMCOUNT][26];
} dt_params[] = {
	{
#ifdef CONFIG_XEN    //  <-------17------>
		.path = "/hypervisor/uefi",
		.paravirt = 1,
		.params = {
			[SYSTAB] = "xen,uefi-system-table",
			[MMBASE] = "xen,uefi-mmap-start",
			[MMSIZE] = "xen,uefi-mmap-size",
			[DCSIZE] = "xen,uefi-mmap-desc-size",
			[DCVERS] = "xen,uefi-mmap-desc-ver",
		}
	}, {
#endif
		.path = "/chosen",
		.params = {	//  <-----------26----------->
			[SYSTAB] = "linux,uefi-system-table",
			[MMBASE] = "linux,uefi-mmap-start",
			[MMSIZE] = "linux,uefi-mmap-size",
			[DCSIZE] = "linux,uefi-mmap-desc-size",
			[DCVERS] = "linux,uefi-mmap-desc-ver",
		}
	}
};

static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname,
				   const char *rname, void *var, int size)
{
	const void *prop;
	int len;
	u64 val;

	prop = fdt_getprop(fdt, node, pname, &len);
	if (!prop)
		return 1;

	val = (len == 4) ? (u64)be32_to_cpup(prop) : get_unaligned_be64(prop);

	if (size == 8)
		*(u64 *)var = val;
	else
		*(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate

	if (efi_enabled(EFI_DBG))
		pr_info("  %s: 0x%0*llx\n", rname, size * 2, val);

	return 0;
}

u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm)
{
	const void *fdt = initial_boot_params;
	unsigned long systab;
	int i, j, node;
	struct {
		void	*var;

Annotation

Implementation Notes