[PATCH v2 3/3] fdt: introduce fsapply command

[Andre Przywara]

Explicitly specifying the exact filenames of devicetree overlays files
on a U-Boot command line can be quite tedious for users, especially
when it should be made persistent for every boot.

To simplify the task of applying (custom) DT overlays, introduce a
"fdt fsapply" subcommand, that iterates a given directory in any
supported filesystem, and tries to apply every .dtbo file found it
there.

This allows users to simply drop a DT overlay file into a magic
directory, and it will be applied on the next boot automatically,
by the virtue of just a generic U-Boot command call.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 cmd/fdt.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/cmd/fdt.c b/cmd/fdt.c
index 1972490bdc2..00f92dbbb5d 100644
--- a/cmd/fdt.c
+++ b/cmd/fdt.c
@@ -12,12 +12,14 @@
 #include <env.h>
 #include <image.h>
 #include <linux/ctype.h>
+#include <linux/sizes.h>
 #include <linux/types.h>
 #include <asm/global_data.h>
 #include <linux/libfdt.h>
 #include <fdt_support.h>
 #include <mapmem.h>
 #include <asm/io.h>
+#include <fs.h>
 
 #define MAX_LEVEL	32		/* how deeply nested we will go */
 #define SCRATCHPAD	1024		/* bytes of scratchpad memory */
@@ -127,6 +129,81 @@ static int fdt_get_header_value(int argc, char *const argv[])
 	return CMD_RET_FAILURE;
 }
 
+#ifdef CONFIG_OF_LIBFDT_OVERLAY
+static int apply_all_overlays(const char *ifname, const char *dev_part_str,
+			      const char *dirname)
+{
+	unsigned long addr;
+	struct fdt_header *dtbo;
+	const char *addr_str;
+	struct fs_dir_stream *dirs;
+	struct fs_dirent *dent;
+	char fname[256], *name_beg;
+	int ret;
+
+	addr_str = env_get("fdtoverlay_addr_r");
+	if (!addr_str) {
+		printf("Invalid fdtoverlay_addr_r for loading overlays\n");
+		return CMD_RET_FAILURE;
+	}
+	addr = hextoul(addr_str, NULL);
+
+	ret = fs_set_blk_dev(ifname, dev_part_str, FS_TYPE_ANY);
+	if (ret)
+		return CMD_RET_FAILURE;
+
+	if (!dirname)
+		dirname = "/";
+	dirs = fs_opendir(dirname);
+	if (!dirs) {
+		printf("Cannot find directory \"%s\"\n", dirname);
+		return CMD_RET_FAILURE;
+	}
+
+	strcpy(fname, dirname);
+	name_beg = strchr(fname, 0);
+	if (name_beg[-1] != '/')
+		*name_beg++ = '/';
+
+	dtbo = map_sysmem(addr, 0);
+	while ((dent = fs_readdir(dirs))) {
+		loff_t size = 0;
+
+		if (dent->type == FS_DT_DIR)
+			continue;
+
+		if (strcmp(dent->name + strlen(dent->name) - 5, ".dtbo"))
+			continue;
+
+		printf("%s: ", dent->name);
+		strcpy(name_beg, dent->name);
+		fs_set_blk_dev(ifname, dev_part_str, FS_TYPE_ANY);
+		if (dent->size > SZ_2M)
+			size = SZ_2M;
+		else
+			size = dent->size;
+		ret = fs_read(fname, addr, 0, size, &size);
+		if (ret) {
+			printf("  errno: %d\n", ret);
+			continue;
+		}
+		if (!fdt_valid(&dtbo)) {
+			/* fdt_valid() clears the pointer upon failure */
+			dtbo = map_sysmem(addr, 0);
+			continue;
+		}
+
+		if (fdt_overlay_apply_verbose(working_fdt, dtbo) == 0)
+			printf("applied\n");
+	}
+	unmap_sysmem(dtbo);
+
+	fs_closedir(dirs);
+
+	return 0;
+}
+#endif
+
 /*
  * Flattened Device Tree command, see the help for parameter definitions.
  */
@@ -747,6 +824,15 @@ static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 		ret = fdt_overlay_apply_verbose(working_fdt, blob);
 		if (ret)
 			return CMD_RET_FAILURE;
+	/* apply all .dtbo files from a directory */
+	} else if (strncmp(argv[1], "fsap", 4) == 0) {
+		if (argc != 5)
+			return CMD_RET_USAGE;
+
+		if (!working_fdt)
+			return CMD_RET_FAILURE;
+
+		return apply_all_overlays(argv[2], argv[3], argv[4]);
 	}
 #endif
 	/* resize the fdt */
@@ -1104,6 +1190,7 @@ static char fdt_help_text[] =
 	"addr [-c] [-q] <addr> [<size>]  - Set the [control] fdt location to <addr>\n"
 #ifdef CONFIG_OF_LIBFDT_OVERLAY
 	"fdt apply <addr>                    - Apply overlay to the DT\n"
+	"fdt fsapply <ifname> <dev:part> <dir> - Apply all overlays in directory\n"
 #endif
 #ifdef CONFIG_OF_BOARD_SETUP
 	"fdt boardsetup                      - Do board-specific set up\n"
-- 
2.25.1