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authorOliver Schinagl <oliver@schinagl.nl>2013-09-03 12:33:27 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 13:47:36 -0700
commit9fd379e929a2808208b1d2d4cd9697067e83a242 (patch)
treee3e7c5c4f7e2b0a3fb82d70f29b43287196cacac /Documentation/devicetree/bindings/misc
parent269ce62bbc00c4e80bf3ca2aa21823f20625bcf6 (diff)
downloadblackbird-op-linux-9fd379e929a2808208b1d2d4cd9697067e83a242.tar.gz
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ARM: sunxi: Initial support for Allwinner's Security ID fuses
Allwinner has electric fuses (efuse) on their line of chips. This driver reads those fuses, seeds the kernel entropy and exports them as a sysfs node. These fuses are most likely to be programmed at the factory, encoding things like Chip ID, some sort of serial number, etc. and appear to be reasonably unique. While in theory, these should be writeable by the user, it will probably be inconvenient to do so. Allwinner recommends that a certain input pin, labeled 'efuse_vddq', be connected to GND. To write these fuses however, a 2.5 V programming voltage needs to be applied to this pin. Even so, they can still be used to generate a board-unique mac from, board unique RSA key and seed the kernel RNG. On sun7i additional storage is available, this is initially used for an UEFI BOOT key, Secure JTAG key, HDMI-HDCP key and vendor specific keys. Currently supported are the following known chips: Allwinner sun4i (A10) Allwinner sun5i (A10s, A13) Allwinner sun7i (A20) Signed-off-by: Oliver Schinagl <oliver@schinagl.nl> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/devicetree/bindings/misc')
-rw-r--r--Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt17
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt b/Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt
new file mode 100644
index 000000000000..68ba37295565
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt
@@ -0,0 +1,17 @@
+Allwinner sunxi-sid
+
+Required properties:
+- compatible: "allwinner,sun4i-sid" or "allwinner,sun7i-a20-sid".
+- reg: Should contain registers location and length
+
+Example for sun4i:
+ sid@01c23800 {
+ compatible = "allwinner,sun4i-sid";
+ reg = <0x01c23800 0x10>
+ };
+
+Example for sun7i:
+ sid@01c23800 {
+ compatible = "allwinner,sun7i-a20-sid";
+ reg = <0x01c23800 0x200>
+ };
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