1Allwinner SRAM for smp bringup: 2------------------------------------------------ 3 4Allwinner's A80 SoC uses part of the secure sram for hotplugging of the 5primary core (cpu0). Once the core gets powered up it checks if a magic 6value is set at a specific location. If it is then the BROM will jump 7to the software entry address, instead of executing a standard boot. 8 9Therefore a reserved section sub-node has to be added to the mmio-sram 10declaration. 11 12Note that this is separate from the Allwinner SRAM controller found in 13../../sram/sunxi-sram.txt. This SRAM is secure only and not mappable to 14any device. 15 16Also there are no "secure-only" properties. The implementation should 17check if this SRAM is usable first. 18 19Required sub-node properties: 20- compatible : depending on the SoC this should be one of: 21 "allwinner,sun9i-a80-smp-sram" 22 23The rest of the properties should follow the generic mmio-sram discription 24found in ../../misc/sram.txt 25 26Example: 27 28 sram_b: sram@20000 { 29 /* 256 KiB secure SRAM at 0x20000 */ 30 compatible = "mmio-sram"; 31 reg = <0x00020000 0x40000>; 32 #address-cells = <1>; 33 #size-cells = <1>; 34 ranges = <0 0x00020000 0x40000>; 35 36 smp-sram@1000 { 37 /* 38 * This is checked by BROM to determine if 39 * cpu0 should jump to SMP entry vector 40 */ 41 compatible = "allwinner,sun9i-a80-smp-sram"; 42 reg = <0x1000 0x8>; 43 }; 44 }; 45