1 The chosen node 2 --------------- 3 The chosen node does not represent a real device, but serves as a place 4 for passing data like which serial device to used to print the logs etc 5 6 7 stdout-path property 8 -------------------- 9 Device trees may specify the device to be used for boot console output 10 with a stdout-path property under /chosen. 11 12 Example 13 ------- 14 / { 15 chosen { 16 stdout-path = "/serial@f00:115200"; 17 }; 18 19 serial@f00 { 20 compatible = "vendor,some-uart"; 21 reg = <0xf00 0x10>; 22 }; 23 }; 24 25 tick-timer property 26 ------------------- 27 In a system there are multiple timers, specify which timer to be used 28 as the tick-timer. Earlier it was hardcoded in the timer driver now 29 since device tree has all the timer nodes. Specify which timer to be 30 used as tick timer. 31 32 Example 33 ------- 34 / { 35 chosen { 36 tick-timer = "/timer2@f00"; 37 }; 38 39 timer2@f00 { 40 compatible = "vendor,some-timer"; 41 reg = <0xf00 0x10>; 42 }; 43 }; 44 45 u-boot,spl-boot-order property 46 ------------------------------ 47 48 In a system using an SPL stage and having multiple boot sources 49 (e.g. SPI NOR flash, on-board eMMC and a removable SD-card), the boot 50 device may be probed by reading the image and verifying an image 51 signature. 52 53 If the SPL is configured through the device-tree, the boot-order can 54 be configured with the spl-boot-order property under the /chosen node. 55 Each list element of the property should specify a device to be probed 56 in the order they are listed: references (i.e. implicit paths), a full 57 path or an alias is expected for each entry. 58 59 A special specifier "same-as-spl" can be used at any position in the 60 boot-order to direct U-Boot to insert the device the SPL was booted 61 from there. Whether this is indeed inserted or silently ignored (if 62 it is not supported on any given SoC/board or if the boot-device is 63 not available to continue booting from) is implementation-defined. 64 Note that if "same-as-spl" expands to an actual node for a given 65 board, the corresponding node may appear multiple times in the 66 boot-order (as there currently exists no mechanism to suppress 67 duplicates from the list). 68 69 Example 70 ------- 71 / { 72 chosen { 73 u-boot,spl-boot-order = "same-as-spl", &sdmmc, "/sdhci@fe330000"; 74 }; 75 }; 76
