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authorSascha Hauer <s.hauer@pengutronix.de>2018-05-08 08:14:56 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2018-05-08 08:14:56 +0200
commit6b85c20d46812bdbc062b863261c3e5100e30556 (patch)
treee067c9889eaf55d5e793b05a14000276f2669e9f /dts/Bindings/arm/sunxi/smp-sram.txt
parent9d8c00bdf7c1e8b614a797f0a15fa45bf6387224 (diff)
downloadbarebox-6b85c20d46812bdbc062b863261c3e5100e30556.tar.gz
barebox-6b85c20d46812bdbc062b863261c3e5100e30556.tar.xz
dts: update to v4.17-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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+Allwinner SRAM for smp bringup:
+------------------------------------------------
+
+Allwinner's A80 SoC uses part of the secure sram for hotplugging of the
+primary core (cpu0). Once the core gets powered up it checks if a magic
+value is set at a specific location. If it is then the BROM will jump
+to the software entry address, instead of executing a standard boot.
+
+Therefore a reserved section sub-node has to be added to the mmio-sram
+declaration.
+
+Note that this is separate from the Allwinner SRAM controller found in
+../../sram/sunxi-sram.txt. This SRAM is secure only and not mappable to
+any device.
+
+Also there are no "secure-only" properties. The implementation should
+check if this SRAM is usable first.
+
+Required sub-node properties:
+- compatible : depending on the SoC this should be one of:
+ "allwinner,sun9i-a80-smp-sram"
+
+The rest of the properties should follow the generic mmio-sram discription
+found in ../../misc/sram.txt
+
+Example:
+
+ sram_b: sram@20000 {
+ /* 256 KiB secure SRAM at 0x20000 */
+ compatible = "mmio-sram";
+ reg = <0x00020000 0x40000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0x00020000 0x40000>;
+
+ smp-sram@1000 {
+ /*
+ * This is checked by BROM to determine if
+ * cpu0 should jump to SMP entry vector
+ */
+ compatible = "allwinner,sun9i-a80-smp-sram";
+ reg = <0x1000 0x8>;
+ };
+ };