doc: dtbinding: Add file system firmware loader binding document

Add a document to describe file system firmware loader binding
information.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

2 files changed, 69 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/chosen.txt b/doc/device-tree-bindings/chosen.txt
index da7b4e6c45..86c533ad6d 100644
--- a/doc/device-tree-bindings/chosen.txt
+++ b/doc/device-tree-bindings/chosen.txt
@@ -83,3 +83,24 @@ of where said later stage was booted from.
 
 You should not define this property yourself in the device-tree, as it
 may be overwritten without warning.
+
+firmware-loader property
+------------------------
+Multiple file system firmware loader nodes could be defined in device trees for
+multiple storage type and their default partition, then a property
+"firmware-loader" can be used to pass default firmware loader
+node(default storage type) to the firmware loader driver.
+
+Example
+-------
+/ {
+        chosen {
+                firmware-loader = &fs_loader0;
+        };
+
+        fs_loader0: fs-loader@0 {
+                u-boot,dm-pre-reloc;
+                compatible = "u-boot,fs-loader";
+                phandlepart = <&mmc 1>;
+        };
+};
diff --git a/doc/device-tree-bindings/misc/fs_loader.txt b/doc/device-tree-bindings/misc/fs_loader.txt
new file mode 100644
index 0000000000..884fbf47c0
--- /dev/null
+++ b/doc/device-tree-bindings/misc/fs_loader.txt
@@ -0,0 +1,48 @@
+* File system firmware loader
+
+Required properties:
+--------------------
+
+- compatible: should contain "u-boot,fs-loader"
+- phandlepart: which block storage device and partition the image loading from,
+               this property is required for mmc, usb and sata. This is unsigned
+               32-bit array. For example phandlepart=<&mmc_0 1>, meaning use
+               that MMC0 node pointer, partition 1.
+- mdtpart: which partition of ubi the image loading from, this property is
+           required for ubi and mounting.
+- ubivol: which volume of ubi the image loading from, this property is required
+          for ubi and mounting.
+
+Example of storage device and partition search set for mmc, usb, sata and
+ubi in device tree source as shown in below:
+
+        Example of storage type and device partition search set for mmc, usb,
+        sata and ubi as shown in below:
+        Example for mmc:
+        fs_loader0: fs-loader@0 {
+                u-boot,dm-pre-reloc;
+                compatible = "u-boot,fs-loader";
+                phandlepart = <&mmc_0 1>;
+        };
+
+        Example for usb:
+        fs_loader1: fs-loader@1 {
+                u-boot,dm-pre-reloc;
+                compatible = "u-boot,fs-loader";
+                phandlepart = <&usb0 1>;
+        };
+
+        Example for sata:
+        fs_loader2: fs-loader@2 {
+                u-boot,dm-pre-reloc;
+                compatible = "u-boot,fs-loader";
+                phandlepart = <&sata0 1>;
+        };
+
+        Example for ubi:
+        fs_loader3: fs-loader@3 {
+                u-boot,dm-pre-reloc;
+                compatible = "u-boot,fs-loader";
+                mtdpart = "UBI",
+                ubivol = "ubi0";
+        };