linuxdebug/drivers/firmware/efi/fdtparams.c

130 lines
2.9 KiB
C

// 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 <asm/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];
const char params[PARAMCOUNT][26];
} dt_params[] = {
{
#ifdef CONFIG_XEN // <-------17------>
.path = "/hypervisor/uefi",
.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;
int size;
} target[] = {
[SYSTAB] = { &systab, sizeof(systab) },
[MMBASE] = { &mm->phys_map, sizeof(mm->phys_map) },
[MMSIZE] = { &mm->size, sizeof(mm->size) },
[DCSIZE] = { &mm->desc_size, sizeof(mm->desc_size) },
[DCVERS] = { &mm->desc_version, sizeof(mm->desc_version) },
};
BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name));
BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params));
if (!fdt)
return 0;
for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
node = fdt_path_offset(fdt, dt_params[i].path);
if (node < 0)
continue;
if (efi_enabled(EFI_DBG))
pr_info("Getting UEFI parameters from %s in DT:\n",
dt_params[i].path);
for (j = 0; j < ARRAY_SIZE(target); j++) {
const char *pname = dt_params[i].params[j];
if (!efi_get_fdt_prop(fdt, node, pname, name[j],
target[j].var, target[j].size))
continue;
if (!j)
goto notfound;
pr_err("Can't find property '%s' in DT!\n", pname);
return 0;
}
return systab;
}
notfound:
pr_info("UEFI not found.\n");
return 0;
}