KIN-1492: drivers, misc: add U-Boot bootcount driver

This driver implements the Linux kernel half of the boot count feature -
the boot counter can only be reset after it is clear that the
application has been started and is running correctly, which usually
can only be determined by the application code itself. Thus the reset
of the boot counter must be done by application code, which thus needs
an appropriate driver.

Required feature by the Carrier Grade Linux Requirements Definition;
see for example document "Carrier Grade Linux Requirements Definition
Overview V3.0" at

http://www.linuxfoundation.org/collaborate/workgroups/cgl/requirements#SMM.6.0_Boot_Cycle_Detection

            Description: OSDL CGL specifies that carrier grade Linux
            shall provide support for detecting a repeating reboot cycle
	due to recurring failures. This detection should happen in
	user space before system services are started.

This driver provides read/write access to the U-Boot bootcounter
through sysfs file.

The bootcountregister gets configured via DTS.
for example on the enbw_cmc board:

bootcount@0x23060 {
                  compatible = "uboot,bootcount";
                  reg = <0x23060 0x1>;
                 };

original post from:
http://lkml.indiana.edu/hypermail/linux/kernel/1112.0/01142.html

Change-Id: Ie913096961043f918f515233470a9925981857bb
Signed-off-by: Avinash Tahakik <Avinash.Tahakik@imgtec.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/misc/uboot-bootcount.txt b/Documentation/devicetree/bindings/misc/uboot-bootcount.txt
new file mode 100644
index 00000000000..7ab1134c3f3
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/uboot-bootcount.txt
@@ -0,0 +1,34 @@
+U-Boot bootcount driver
+
+This driver implements the Linux kernel half of the boot count feature -
+the boot counter can only be reset after it is clear that the
+application has been started and is running correctly, which usually
+can only be determined by the application code itself. Thus the reset
+of the boot counter must be done by application code, which thus needs
+an appropriate driver.
+
+Required feature by the Carrier Grade Linux Requirements Definition;
+see for example document "Carrier Grade Linux Requirements Definition
+Overview V3.0" at
+
+http://www.linuxfoundation.org/collaborate/workgroups/cgl/requirements#SMM.6.0_Boot_Cycle_Detection
+
+        Description: OSDL CGL specifies that carrier grade Linux
+        shall provide support for detecting a repeating reboot cycle
+        due to recurring failures. This detection should happen in
+        user space before system services are started.
+
+This driver provides read/write access to the U-Boot bootcounter
+through sysfs file.
+
+Required properties:
+
+  - compatible : should be "uboot,bootcount"
+  - reg: the address of the bootcounter
+
+Example:
+
+bootcount@1c23000 {
+	compatible = "uboot,bootcount";
+	reg = <0x23060 0x1>;
+};