Hi,
I have a particular device tree node property which refuses to reach
the Linux kernel without corruption:
I am looking at the following call stack:
#0 of_platform_bus_create(...)
#1 of_platform_bus_create(...)
#2 of_platform_bus_create(...)
#3 of_platform_populate(...)
#4 sama5_dt_device_init(...)
#5 customize_machine(...)
#6 do_one_initcall(...)
#7 do_initcall_level(...)
#8 do_initcalls()
#9 do_basic_setup() at main.c:881
#10 kernel_init_freeable() at main.c:1004
#11 kernel_init(unused = <Value currently has no location>) at main.c:941
Once I reach the i2c node below, I can walk the properties linked list
in the debugger. Once I get to the lsm6ds3 child and the "interrupts"
property, the value is (second value corrupted as zero)
interrupts = <0xc 0x0>;
(I am investigating this because the second value which is used as the
interrupt trigger is always zero when the driver reads it).
I have done some additional tests using the dtc and fdtdump utility to
try and isolate the issue.
>From the extract below from the preprocessed file:
i2c1: i2c@f0018000 {
compatible = "atmel,at91sam9x5-i2c";
reg = <0xf0018000 0x4000>;
interrupts = <0x13 0x4 0x6>;
dmas = <0x2 0x2 0x9 0x2 0x2 0xa>;
dma-names = "tx", "rx";
pinctrl-names = "default";
pinctrl-0 = <0x12>;
#address-cells = <0x1>;
#size-cells = <0x0>;
clocks = <0x13>;
status = "okay";
clock-frequency = <0x61a80>;
atmel,recover-scl = <0x14 0x1b 0x0>;
atmel,recover-sda = <0x14 0x1a 0x0>;
lsm6ds3@6b {
compatible = "st,lsm6ds3";
reg = <0x6b>;
pinctrl-names = "default";
pinctrl-0 = <0x15>;
interrupt-parent = <0x16>;
interrupts = <0xc 0x1>;
interrupt-names = "lsm6ds_int1";
st,drdy-int-pin = <0x1>;
};
};
Version: DTC 1.4.0 (ubuntu package) for manual testing.
(1) fdtdump mix6000.dtb | grep interrupts
Thsi returns the interrupt line as:
interrupts = <0x0000000c 0x000001d0>;
(2) In the linux kernel the of_platform_populate() reads the same property as:
0x0000000c 0x00000000 with lenth=8
(3) If I take the DTS file and manually compile the DTB with the dtc
compiler, and convert it back to the DTS the correct values are shown
(4) If I change the interrupt value:
interrupts = <0xc 0x0>;
and I do:
cat <file-old.dtb> | od -t x1 > file1.txt
cat <file-mod.dtb> | od -t x1 > file2.txt
kdiff3 file1.txt file2.txt
I actually see a single hex byte change from 0x1 to 0x0.
If it was not for the faulty fdtdump output (in conjuection with the
Linux kernel zero at the same place) I would have said its definately
a kernel issue.
Any ideas?
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