efi: add helper function to get UEFI params from FDT

[firefly-linux-kernel-4.4.55.git] / drivers / firmware / efi / efi.c

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 2e2fbdec0845414df2f32a8c0f862b4149ce3198..0c98165c1cd742f7726660e6a8038151abec02ad 100644 (file)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -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_EFI_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_EFI_PARAMS_FROM_FDT */