summaryrefslogtreecommitdiff
path: root/drivers/of/fdt.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/of/fdt.c')
-rw-r--r--drivers/of/fdt.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 17be90f5445f..c4cddf0cd96d 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -21,6 +21,7 @@
#include <linux/slab.h>
#include <linux/libfdt.h>
#include <linux/debugfs.h>
+#include <linux/serial_core.h>
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#include <asm/page.h>
@@ -696,6 +697,61 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
}
#endif /* CONFIG_BLK_DEV_INITRD */
+#ifdef CONFIG_SERIAL_EARLYCON
+extern struct of_device_id __earlycon_of_table[];
+
+int __init early_init_dt_scan_chosen_serial(void)
+{
+ int offset;
+ const char *p;
+ int l;
+ const struct of_device_id *match = __earlycon_of_table;
+ const void *fdt = initial_boot_params;
+
+ offset = fdt_path_offset(fdt, "/chosen");
+ if (offset < 0)
+ offset = fdt_path_offset(fdt, "/chosen@0");
+ if (offset < 0)
+ return -ENOENT;
+
+ p = fdt_getprop(fdt, offset, "stdout-path", &l);
+ if (!p)
+ p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
+ if (!p || !l)
+ return -ENOENT;
+
+ /* Get the node specified by stdout-path */
+ offset = fdt_path_offset(fdt, p);
+ if (offset < 0)
+ return -ENODEV;
+
+ while (match->compatible) {
+ unsigned long addr;
+ if (fdt_node_check_compatible(fdt, offset, match->compatible)) {
+ match++;
+ continue;
+ }
+
+ addr = fdt_translate_address(fdt, offset);
+ if (!addr)
+ return -ENXIO;
+
+ of_setup_earlycon(addr, match->data);
+ return 0;
+ }
+ return -ENODEV;
+}
+
+static int __init setup_of_earlycon(char *buf)
+{
+ if (buf)
+ return 0;
+
+ return early_init_dt_scan_chosen_serial();
+}
+early_param("earlycon", setup_of_earlycon);
+#endif
+
/**
* early_init_dt_scan_root - fetch the top level address and size cells
*/