@@ -36,6 +36,13 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE
backend for pstore by default. This setting can be overridden
using the efivars module's pstore_disable parameter.
+config UEFI_PARAMS_FROM_FDT
+ bool
+ help
+ Select this config option from the architecture Kconfig if
+ the EFI runtime support gets system table address, memory
+ map address, and other parameters from the device tree.
+
endmenu
config UEFI_CPER
@@ -20,6 +20,8 @@
#include <linux/init.h>
#include <linux/device.h>
#include <linux/efi.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
#include <linux/io.h>
struct efi __read_mostly efi = {
@@ -272,3 +274,80 @@ int __init efi_config_init(efi_config_table_type_t *arch_tables)
early_iounmap(config_tables, efi.systab->nr_tables * sz);
return 0;
}
+
+#ifdef CONFIG_UEFI_PARAMS_FROM_FDT
+
+#define UEFI_PARAM(name, prop, field) \
+ { \
+ { name }, \
+ { prop }, \
+ offsetof(struct efi_fdt_params, field), \
+ FIELD_SIZEOF(struct efi_fdt_params, field) \
+ }
+
+static __initdata struct {
+ const char name[32];
+ const char propname[32];
+ int offset;
+ int size;
+} dt_params[] = {
+ UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
+ UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
+ UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
+ UEFI_PARAM("MemMap Desc. Size", "linux,uefi-mmap-desc-size", desc_size),
+ UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", desc_ver)
+};
+
+struct param_info {
+ int verbose;
+ void *params;
+};
+
+static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
+ int depth, void *data)
+{
+ struct param_info *info = data;
+ void *prop, *dest;
+ unsigned long len;
+ u64 val;
+ int i;
+
+ if (depth != 1 ||
+ (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
+ return 0;
+
+ pr_info("Getting parameters from FDT:\n");
+
+ for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
+ prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
+ if (!prop) {
+ pr_err("Can't find %s in device tree!\n",
+ dt_params[i].name);
+ return 0;
+ }
+ dest = info->params + dt_params[i].offset;
+
+ val = of_read_number(prop, len / sizeof(u32));
+
+ if (dt_params[i].size == sizeof(u32))
+ *(u32 *)dest = val;
+ else
+ *(u64 *)dest = val;
+
+ if (info->verbose)
+ pr_info(" %s: 0x%0*llx\n", dt_params[i].name,
+ dt_params[i].size * 2, val);
+ }
+ return 1;
+}
+
+int __init efi_get_fdt_params(struct efi_fdt_params *params, int verbose)
+{
+ struct param_info info;
+
+ info.verbose = verbose;
+ info.params = params;
+
+ return of_scan_flat_dt(fdt_find_uefi_params, &info);
+}
+#endif /* CONFIG_UEFI_PARAMS_FROM_FDT */
@@ -483,6 +483,14 @@ struct efi_memory_map {
unsigned long desc_size;
};
+struct efi_fdt_params {
+ u64 system_table;
+ u64 mmap;
+ u32 mmap_size;
+ u32 desc_size;
+ u32 desc_ver;
+};
+
typedef struct {
u32 revision;
void *parent_handle;
@@ -616,6 +624,7 @@ extern void efi_initialize_iomem_resources(struct resource *code_resource,
extern void efi_get_time(struct timespec *now);
extern int efi_set_rtc_mmss(const struct timespec *now);
extern void efi_reserve_boot_services(void);
+extern int efi_get_fdt_params(struct efi_fdt_params *params, int verbose);
extern struct efi_memory_map memmap;
/* Iterate through an efi_memory_map */
ARM and ARM64 architectures use the device tree to pass UEFI parameters from stub to kernel. These parameters are things known to the stub but not discoverable by the kernel after the stub calls ExitBootSerives(). There is a helper function in: drivers/firmware/efi/fdt.c which the stub uses to add the UEFI parameters to the device tree. This patch adds a complimentary helper function which UEFI runtime support may use to retrieve the parameters from the device tree. If an architecture wants to use this helper, it should select CONFIG_UEFI_PARAMS_FROM_FDT. Signed-off-by: Mark Salter <msalter@redhat.com> --- drivers/firmware/efi/Kconfig | 7 ++++ drivers/firmware/efi/efi.c | 79 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/efi.h | 9 +++++ 3 files changed, 95 insertions(+)